Journal articles on the topic 'Rocket engines – Combustion – Mathematical models'
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1
Sidlerov, D. A., and S. A. Fedorov. "Numerical Investigation of Work Cycle Characteristics in the Combustion Chamber of a Lox/Methane Liquid-Propellant Rocket Engine Featuring Reductant Power Gas Combustion." Herald of the Bauman Moscow State Technical University. Series Mechanical Engineering, no. 2 (141) (June 2022): 43–53. http://dx.doi.org/10.18698/0236-3941-2022-2-43-53.
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We performed a numerical investigation of cumulative efficiency and the structure in detail concerning the working process in the combustion chamber of a lox/methane liquid-propellant rocket engine operating in steady-state, boosted and throttled modes. In order to do it, we used tools developed by JSC SSC "Center Keldysh", that is, physical and mathematical models, numerical methods and software packages for numerical simulation of two-phase turbulent flows with combustion in liquid-propellant engine combustion chambers. The paper presents numerical simulation and investigation results concerning the specifics of fuel component flows, their mixing and combustion in the combustion chamber of a lox/methane liquid-propellant rocket engine using staged combustion cycle with reductant gas in steady-state, boosted (117 % by thrust) and throttled (30 % by thrust) operation modes. We performed a comparative analysis of work cycle parameters in combustion chambers at different fuel component consumption rates and pressure levels. The paper shows that the boosted mode increases the interaction of fuel jets, which intensifies mixing and burnout processes, while the deep throttling mode decreases the mixing and fuel burnout amplitudes as compared to the steady-state mode. The numerical simulation results may be used to investigate fuel combustion processes in combustion chambers of promising liquid-propellant rocket engines at the stages of development, design and refinement
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Chernova, A. A. "Validation of RANS Turbulence Models for the Conjugate Heat Exchange Problem." Nelineinaya Dinamika 18, no. 1 (2022): 61–82. http://dx.doi.org/10.20537/nd220105.
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This paper addresses problems of mathematical modeling of heat exchange processes in the pre-nozzle volume of a solid propellant rocket engine with a charge with starlike cross-section and a recessed hinged nozzle. Methods of mathematical modeling are used to solve the quasi-stationary spatial conjugate problem of heat exchange. An analysis is made of the influence of RANS turbulence models on the flow structure in the flow channels of the engine and on the computed heat flow distributions over the surface of the recessed nozzle. Methods of mathematical modeling are used to solve the quasi-stationary spatial conjugate problem of heat exchange. Results of validation of RANS turbulence models are presented using well-known experimental data. A comparison of numerical and experimental distributions of the heat-transfer coefficient over the inlet surface of the recessed nozzle for the engine with a cylindrical channel charge is made for a primary choice of turbulence models providing a qualitative agreement between calculated and experimental data. By analyzing the results of numerical modeling of the conjugate problem of heat exchange in the combustion chamber of the solid propellant engine with a starlike channel, it is shown that the SST $k-\omega$ turbulence model provides local heat-transfer coefficient distributions that are particularly close to the experimental data.
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Gorskiy, V. V., M. G. Kovalsky, and V. G. Resh. "Method of Calculating Carbon Ablation in the Jet of Liquid Rocket Engine Combustion Products." Herald of the Bauman Moscow State Technical University. Series Mechanical Engineering, no. 5 (128) (October 2019): 4–21. http://dx.doi.org/10.18698/0236-3941-2019-5-4-21.
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Nowadays carbon materials are widely used as ablating thermal protection for high-temperature structural elements in aerospace technology. Prediction of changes in the shape of the external surfaces of these elements, due to the burning of thermal protection, is closely related to the use of computational-theoretical methods describing the flow of various physicochemical and mechanical processes associated with the occurrence of the phenomenon under consideration. At the same time, it is crucial to test such methods on the results of experimental studies conducted under conditions which are implemented during the process of testing thermal protection in jets of aerodynamic units. The main elements of ablation of carbon materials include their erosion, i.e., mechanical ablation of mass, observed in high-pressure gas flows. In the process of experimental development, it is necessary to carry out research on large-scale models, which has led to widespread use of underexpanded jets of combustion products of liquid rocket engine combustion products for modeling the erosion process of thermal protection. The theoretical model of ablation of thermal protection in such jets requires taking into account the complex chemical composition of the gas mixture flowing into the model; physical and chemical interaction of this gas with thermal protection, which causes gasification of the latter; use of mathematical models describing the process of material erosion due to mechanical impact of high-pressure gas flow. The paper describes the development of the carbon material ablation calculating and theoretical methodology which could be used to determine the material erosion characteristics on the basis of solving a complex problem of circumfluence, heating, heat penetration and ablation of thermal protection.
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Ramesh, Davood, Hasan Karimi M., and Massoud Shahheidari. "Cycle optimization of the staged combustion rocket engines." Aircraft Engineering and Aerospace Technology 89, no. 2 (March 6, 2017): 304–13. http://dx.doi.org/10.1108/aeat-12-2013-0229.
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Purpose The purpose of this paper is to introduce new and modified “staged combustion” cycles in the form of engineering algorithm as a possible propulsion contender for future aerospace vehicle to achieve the highest possible “total impulse” to “mass” of propulsion system. Design/methodology/approach In this regard, the mathematical cycle model is formed to calculate the engine’s parameters. In addition, flow conditions (pressure, temperature, flow rate, etc). in the chamber, nozzle and turbopump are assessed based on the results of turbo machinery power balance and initial data such as thrust, propellant mixture ratio and specifications. The developed code has been written in the modern, object-oriented C++ programming language. Findings The results of the developed code are compared with the Russian RD180 engine which demonstrates the superiority and capability of new “thermodynamic diagrams”. Research limitations/implications This algorithm is under constraint to control the critical variation of combustion pressure, turbine rpm, pump cavitation and turbine temperature. It is imperative to emphasize that this paper is limited to “oxidizer-rich staged combustion” engines with “single pre-burner”. Originality/value This study sheds light on using fuel booster turbopump and the second-stage fuel pump to moderate the effect of cavitation on pumps which reduces tank pressure and, as a consequence, decreases the propulsion system weight.
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Betelin, V. B., R. M. Shagaliev, S. V. Aksenov, I. M. Belyakov, Yu N. Deryuguin, D. A. Korchazhkin, A. S. Kozelkov, V. F. Nikitin, A. V. Sarazov, and D. K. Zelenskiy. "Mathematical simulation of hydrogen–oxygen combustion in rocket engines using LOGOS code." Acta Astronautica 96 (March 2014): 53–64. http://dx.doi.org/10.1016/j.actaastro.2013.11.008.
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ONEL, Alexandru-Iulian, Oana-Iuliana POPESCU, Ana-Maria NECULAESCU, Tudorel-Petronel AFILIPOAE, and Teodor-Viorel CHELARU. "Liquid rocket engine performance assessment in the context of small launcher optimisation." INCAS BULLETIN 11, no. 3 (September 9, 2019): 135–45. http://dx.doi.org/10.13111/2066-8201.2019.11.3.12.
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The paper presents a fast mathematical model that can be used to quickly asses the propulsive characteristics of liquid propelled rocket engines. The main propulsive parameters are computed using combustion surfaces obtained after a nonlinear data fitting analysis. This approach is much more time efficient than using standard codes which rely on frequent calls of the Fuel Combustion Charts and interpolating their data. The tool developed based on the proposed mathematical model can be used separately or it can be integrated in a multidisciplinary optimisation algorithm for a preliminary microlauncher design.
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Vasiliev, Igor, Boris Kiforenko, and Yaroslav Tkachenko. "COMPARATIVE ANALYSIS OF THE EFFICIENCY OF CONSTANT POWER THROTTLED ROCKET ENGINES FOR INTERORBITAL FLIGHTS TO GEOSTATIONAR." Journal of Automation and Information sciences 6 (November 1, 2021): 66–77. http://dx.doi.org/10.34229/1028-0979-2021-6-7.
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Carrying out low-thrust transfers of spacecrafts in the near-earth space from intermediate elliptic to the geostationary orbit using electric rocket engines seems to be one of the most important tasks of modern cosmonautics. Electric rocket engines, whose specific impulse of the reactive jet is an order of magnitude more than in chemical RD, are preferable for interorbit flights with a maximum payload in the case when a significant increase in the duration of the maneuver is permissible. Ability to throttling the rocket engine thrust is traditionally considered as one of the ways to reduce both the engine mass and the required fuel assumptions for performing the specified maneuver. Using the concept of an ideal-rocket engine provides the upper estimates of the payload mass of interborbital flights for the given power level. Accounting for the properties of real engines leads to the need of considering the mathematical models with more strict limits on control functions. A study of the efficiency of three modes of thrust control of an electric propulsion rocket engine was carried out when performing practically interesting spacecraft flights from highly elliptical intermediate near-earth orbits to geostationary orbits. A mathematical model of constant power relay rocket engine has been built. The formulation of the variational problem of the Maer type is given about the execution of a given dynamic maneuver for the throttled and unregulated electric rocket engines of constant power. Using the Pontryagin maximum principle, an analysis of the optimal control functions was carried out, for which the final relations were written out, which allowed to write down the system of differential equations of the optimal movement of the spacecraft, equipped with relay electric rocket engine. The obtained numerical and quality results of the study of the effectiveness of various modes of thrust control of an electric propulsion engine to increase the payload of a given orbital maneuver confirmed the correctness of mathematical models of throttled and relay engines and, in general, the efficiency of using solutions of the averaged equations of optimal motion of a spacecraft for numerical solution of the corresponding boundary value problems in an exact formulation.
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Strelnikov, G. A., A. D. Yhnatev, N. S. Pryadko, and S. S. Vasyliv. "Gas flow control in rocket engines." Technical mechanics 2021, no. 2 (June 29, 2021): 60–77. http://dx.doi.org/10.15407/itm2021.02.060.
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In the new conditions of application of launch vehicle boosters, space tugs, etc., modern rocket engines often do not satisfy the current stringent requirements. This calls for fundamental research into processes in rocket engines for improving their efficiency. In this regard, for the past 5 years, the Department of Thermogas Dynamics of Power Plants of the Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine has conducted research on gas flow control in rocket engines to improve their efficiency and functionality. Mechanisms of flow perturbation in the nozzle of a rocket engine by liquid injection and a solid obstacle were investigated. A mathematical model of supersonic flow perturbation by local liquid injection was refined, and new solutions for increasing the energy release rate of the liquid were developed. A numerical simulation of a gas flow perturbed by a solid obstacle in the nozzle of a rocket engine made it possible to verify the known (mostly experimental) results and to reveal new perturbation features. In particular, a significant increase in the efficiency of flow perturbation by an obstacle in the transonic region was shown up, and some dependences involving the distribution of the perturbed pressure on the nozzle wall, which had been considered universal, were refined. The possibility of increasing the efficiency of use of the generator gas picked downstream of the turbine of a liquid-propellant rocket engine was investigated, and the advantages of a new scheme of gas injection into the supersonic part of the nozzle, which provides both nozzle wall cooling by the generator gas and the production of lateral control forces, were substantiated. A new concept of rocket engine thrust vector control was developed: a combination of a mechanical and a gas-dynamic system. It was shown that such a thrust vector control system allows one to increase the efficiency and reliability of the space rocket stage flight control system. A new liquid-propellant rocket engine scheme was developed to control both the thrust amount and the thrust vector direction in all planes of rocket stage flight stabilization. New approaches to the process organization in auxiliary elements of rocket engines on the basis of detonation propellant combustion were developed to increase the rocket engine performance.
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Vaulin, S. D., and K. I. Khazhiakhmetov. "The State-of-the-Art and Prospects of Aerospike Engines." Proceedings of Higher Educational Institutions. Маchine Building, no. 10 (739) (October 2021): 74–83. http://dx.doi.org/10.18698/0536-1044-2021-10-74-83.
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Currently, there is a worldwide trend of growing interest in projects aimed at reducing the cost of spacecraft launches. The search for solutions to this topical issue reveals new requirements for the rocket engines. However, existing rocket engines are incapable of fully meeting modern requirements. Consideration of new technical solutions indicates the prospects of using aerospike engines, which have the property of self-regulation and can operate with optimal flow expansion throughout the entire operation. This property allows this type of engine to be used as a propulsion system for single-stage return launcher. However, aerospike engines have not been sufficiently studied at the moment and haven’t found widespread use. Therefore it is necessary to summarize the existing knowledge about aerospike and the aerospike research has been performed. As a result mathematical models of the workflows were created, methods of designing and optimization of the contour were determined, and a number of design and technological solutions were found. However, the mathematical models verified by experimental data were not found.
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Pylypenko, O. V., O. O. Prokopchuk, S. I. Dolgopolov, O. D. Nikolayev, N. V. Khoriak, V. Yu Pysarenko, I. D. Bashliy, and S. V. Polskykh. "Mathematical modelling of start-up transients at clustered propulsion system with POGO-suppressors for CYCLON-4M launch vehicle." Kosmìčna nauka ì tehnologìâ 27, no. 6 (2021): 3–15. http://dx.doi.org/10.15407/knit2021.06.003.
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Liquid-propellant rocket propulsion systems of the first stages of launch vehicles of medium, heavy, and super-heavy class usually include POGO-suppressors, which are one of the most widely used methods to eliminate launch vehicle longitudinal structural vibrations (POGO phenomena). However, until now, the theoretical studies and analysis of the effect of the POGO-suppressors’ installation in the feedlines of main liquid rocket engines on transient processes in systems during rocket engine starting have not been carried out due to the complexity of such analysis and the lack, first of all, reliable nonlinear models of cavitation phenomena in rocket engine pumps. A mathematical model for the start-up of a clustered rocket propulsion of the Cyclone-4M launch vehicle has been developed that takes into account the low-frequency dynamics of the POGO-suppressors and the asynchronous start-up timeline sequences of the rocket engines. The first stage of the launch vehicle propulsion system includes four RD-870 rocket engines. A nonlinear mathematical model of low-frequency dynamic processes of the POGO-suppressor with bellows separation of liquid and gaseous media is presented. A significant effect of cavitation in the pumps of engines and the POGO-suppressor installation to the LOX feedline on the propulsion system dynamic gains is shown. Based on the developed mathematical model of the clustered rocket propulsion start-up, the studies of the Cyclone-4M main engines’ start-up transients were carried out. The asynchronous start-up timeline sequences of the rocket engine and the places of installation of the POGO-suppressors in the LOX feedline branches to the RD-870 rocket engine – near the general feedline collector as standard placement or directly at the entrance to the engines – were investigated. The analysis of start-up transients in the oxidizer feed system of the considered propulsion (the time dependences of the flowrate and pressure at the engine inlet) showed the following. Firstly, while the synchronous start-up of the engines, the installation of the POGO-suppressors near the feedline collector makes it possible to eliminate all engine inlet overpressures that exist in the rocket propulsion system in case of the absence of the POGO-suppressors. Secondly, the RD-870 engine asynchronous start-up operation affects negatively the time dependences of the propellant flowrate and pressure at the engine inlet if the POGO-suppressors are located near the feedline collector. So, in the propulsion system’s start-up timeline interval 0.95 s - 1.35 s, for some computational variants of the initial moments of the engine operation start, an abnormally large drop in the LOX flow rate and the overpressures at the engine inlet is observed. The asynchronous start-up of the RD-870 engines with the installation of the POGO-suppressors at the engine inlet does not significantly change the start-up transients compared to the synchronous starting of the engines. Thirdly, thus, it is shown that the installation of the POGO-suppressors both at the engine inlet and at the RD-870 branches near the collector has a significant positive effect on the quality of start-up transient processes for the main engines of the 1st stage of the Cyclone-4M launch vehicle. Placing the POGO-suppressors at the engine inlets is not standard and is considered without reference to the propulsion system layout. Nevertheless, the POGO-suppressors installed at the inlet to the engines are an effective means of preventing overshoots and dips in the parameters of the liquid-propellant rocket engine, including the conditions of asynchronous starting of the liquid rocket engines in the clustered propulsion system. The results obtained can be used in mathematical modeling of the start-up of the first stage propulsion system either for multistage sustainer rockets used in parallel with booster rockets or for the clustered multi-engine rocket propulsion system containing POGO-suppressors.
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Nikolayev, O. D., and I. D. Bashliy. "Assessment of thrust chamber stability margins to high-frequency oscillations based on mathematical modeling of coupled ‘injector – rocket combustion chamber’ dynamic system." Technical mechanics 2022, no. 1 (April 26, 2022): 3–15. http://dx.doi.org/10.15407/itm2022.01.003.
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High-frequency instability of a liquid-propellant rocket engine (LRE) during static firing tests is often accompanied by a significant increase in dynamic loads on the combustion chamber structure, often leading to a chamber destruction. This dynamic phenomenon can also be extremely dangerous for the dynamic strength of a liquid-propellant rocket engine. The calculation of acoustic combustion product oscillation parameters is important in the design and static firing tests of such rocket engines. The determination of the oscillation parameters (natural frequencies and stability margins such as oscillation decrement) is one of the problems solved in the LRE design period as part of the development of measures to ensure the engine stability. The main aim of the paper is to develop a numerical approach to determining the parameters of acoustic oscillations of combustion products in liquid-propellant rocket engines combustion chambers taking into account the features of combustion space configuration and the variability of gaseous medium physical properties depending on the axial length of the chamber, acoustic impedance in critical throat and dissipation effects (damping experimental values) in the shell structure and the gas media in the chamber. The approach is based on mathematical modeling of the coupled ‘chamber shell structure – gas’ dynamic system by using the finite element method and the CAE (Computer Aided Engineering) system. The developed approach testing and further analysis of the results for the RD 253 engine using nitrogen tetroxide and unsymmetrical dimethylhydrazine as a propellant pair were carried out. The dynamic system shapes and frequencies of longitudinal, tangential and radial modes are determined. The results of mathematical modeling of the dynamic system indicate a satisfactory agreement of the calculated decrements of the first longitudinal oscillation mode and third tangential oscillation mode with the experimental decrements obtained by hot-fire tests data. From system harmonic analysis of the thrust chamber, it follows that the dynamic pressure gain factor of the gas media in the chamber at the first longitudinal mode frequency is 1.6 times greater than the system dynamic gain in the tangential mode. At the same time, the oscillation decrement for the system tangential mode is 2 times smaller than that of the first longitudinal mode. This means that the thrust chamber tangential mode is more dangerous and can lead to rocket engine combustion instability. The effect of the injector on the high-frequency stability of the combustion chamber and the possibility of partial suppression of combustion chamber thermoacoustic oscillations by adjusting the high-frequency dynamics of the injector are shown theoretically.
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Kravchenko, Serhii, Oleg Linkov, Maxim Shelestov, Alexander Bekaryuk, and Eduard Bozhko. "Mathematical Modeling of the Working Process of a Two-Stroke Engine with Countermoving Pistons." NTU "KhPI" Bulletin: Power and heat engineering processes and equipment, no. 4 (December 30, 2021): 22–28. http://dx.doi.org/10.20998/2078-774x.2021.04.03.
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Simulation of the working process of an internal combustion engine is the basis for all further calculations and studies of the engine. Of particular relevance is the availability of an adequate mathematical model of the engine process due to the fact that due to the trend of continuous improvement of engine performance, it is necessary to take into account many influencing factors to obtain a satisfactory result. The most complex and dependent on many physicochemical parameters is the process of combustion of fuel in the engine. Models of combustion in diesel engines can be divided into three groups: detailed models; empirical and semipemirical models. The analysis of world experience in research and mathematical modeling of combustion process in internal combustion engines is performed in the work. The advantages and disadvantages of different mathematical models are indicated. It is proposed to use a semi-empirical mathematical model of combustion which describes the differential characteristic of the combustion rate by two curves corresponding to the periods of the first flash and diffusion combustion. Use of such model simplifies performance of calculations and at the same time allows to receive qualitative results considering many factors of influence.
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D’Alessandro, Simone, Marco Pizzarelli, and Francesco Nasuti. "A Hybrid Real/Ideal Gas Mixture Computational Framework to Capture Wave Propagation in Liquid Rocket Combustion Chamber Conditions." Aerospace 8, no. 9 (September 4, 2021): 250. http://dx.doi.org/10.3390/aerospace8090250.
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The present work focuses on the development of new mathematical and numerical tools to deal with wave propagation problems in a realistic liquid rocket chamber environment. A simplified real fluid equation of state is here derived, starting from the literature. An approximate Riemann solver is then specifically derived for the selected conservation laws and primitive variables. Both the new equation of state and the new Riemann solver are embedded into an in-house one-dimensional CFD solver. The verification and validation of the new code against wave propagation problems are then performed, showing good behavior. Although such problems might be of interest for different applications, the present study is specifically oriented to the low order modeling of high-frequency combustion instability in liquid-propellant rocket engines.
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Ryzhkov, V. V., and I. I. Morozov. "Technology of computational analysis of the working process parameters of low-thrust rocket engines running on gaseous oxygen-hydrogen fuel with the use of ANSYS CFD." VESTNIK of Samara University. Aerospace and Mechanical Engineering 18, no. 2 (July 2, 2019): 62–74. http://dx.doi.org/10.18287/2541-7533-2019-18-2-62-74.
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The paper presents the description of a mathematical model of the working process of a low-thrust rocket engine operating on gaseous oxygen-hydrogen fuel and some fragments of the technology of computational analysis of distribution of gas-dynamic parameters in the engine duct. We present the results of calculating the stream line distribution, the distribution of total temperature profile along the flow path of the engine chamber and at its characteristic cross sections, the axial component of (total) speed of combustion products in the Laval nozzle output section. The results of calculating the temperature in the area of the rocket engine’s inner wall are presented. It is shown that the distribution of the combustion products’ stagnation temperature has a significant impact on the efficiency of fuel conversion in the engine chamber, its thermal state and makes it possible to identify the ways of improving the workflow of the low-thrust rocket engine.
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Sotskov, Ivan. "Developing mathematical model of the 3D turbulent flow of combustion products in solid propellant rocket engines." Vestnik Moskovskogo aviatsionnogo instituta 28, no. 1 (2021): 107–14. http://dx.doi.org/10.34759/vst-2021-1-107-114.
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Nikolayev, O. D., I. D. Bashliy, N. V. Khoriak, and S. I. Dolgopolov. "Evaluation of the high-frequency oscillation parameters of a liquid-propellant rocket engine with an annular combustion chamber." Technical mechanics 2021, no. 1 (April 30, 2021): 16–28. http://dx.doi.org/10.15407/itm2021.01.016.
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The high-frequency instability (HF instability) of a liquid-propellant rocket engine (LPRE) during static firing tests is often accompanied by a significant increase in dynamic loads on the combustion chamber structure, often leading to the chamber destruction. This dynamic phenomenon can also be extremely dangerous for the dynamic strength of a liquid-propellant rocket engine with an annular combustion chamber. Computation of the parameters of acoustic combustion product oscillations is important in the design and static firing tests of such rocket engines. The main aim of this paper is to develop a numerical approach to determining the parameters of acoustic oscillations of combustion products in annular combustion chambers of liquid-propellant rocket engines taking into account the features of the configuration of the combustion space and the variability of the physical properties of the gaseous medium depending on the axial length of the chamber. A numerical approach is proposed. The approach is based on mathematical modeling of natural oscillations of a “shell structure of an annular chamber – gas” coupled dynamic system by using the finite element method. Based on the developed finite-element model of coupled spatial vibrations of the structure of the annular combustion chamber and the combustion product oscillations, the oscillation parameters of the system under consideration (frequencies, modes, and effective masses) for its dominant acoustic modes, the vibration amplitudes of the combustion chamber casing, and the amplitudes of its vibration accelerations can be determined. The operating parameters of the liquid-propellant rocket engine potentially dangerous for the development of thermoacoustic instability of the working process in the annular combustion chamber can be identified. For the numerical computation of the dynamic gains (in pressure) of the combustion chamber, a source of harmonic pressure excitation is introduced to the finite element model of the dynamic system “shell structure of an annular configuration – gas” (to the elements at the start of the chamber fire space). The developed approach testing and further analysis of the results were carried out for an engine with an annular combustion chamber (with a ratio of the outer and inner diameters of 1.5) using liquid oxygen – methane as a propellant pair. The system shapes and frequencies of longitudinal, tangential and radial modes are determined. It is shown that the frequency of the first acoustic mode in the case of a relatively low stiffness of the combustion chamber casing walls can be reduced by 40 percent in comparison with the frequency determined for a casing with rigid walls.
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Timoshenko, V. I., V. P. Halynskyi, and Yu V. Knyshenko. "Theoretical studies on rocket/space hardware aerogas dynamics." Technical mechanics 2021, no. 2 (June 29, 2021): 46–59. http://dx.doi.org/10.15407/itm2021.02.046.
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This paper presents the results of theoretical studies on rocket/space hardware aerogas dynamics obtained from 2016 to 2020 at the Department of Aerogas Dynamics and Technical Systems Dynamics of the Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine along the following lines: rocket aerodynamics, mathematical simulation of the aerogas thermodynamics of a supersonic ramjet vehicle, jet flows, and the hydraulic gas dynamics of low-thrust control jet engines. As to rocket aerodynamics, computational methods and programs (CMPs) were developed to calculate supersonic flow past finned rockets. The chief advantage of the CMPs developed is computational promptness and ease of adding wings and control and stabilization elements to rocket configurations. A mathematical simulation of the aerogas thermodynamics of a supersonic ramjet vehicle yielded new results, which made it possible to develop a prompt technique for a comprehensive calculation of ramjet duct flows and generalize it to 3D flow past a ramjet vehicle. Based on marching methods, CMPs were developed to simulate ramjet duct flows with account for flow past the airframe upstream of the air inlet, the effect of the combustion product jet on the airframe tail part, and its interaction with a disturbed incident flow. The CMPs developed were recommended for use at the preliminary stage of ramjet component shape selection. For jet flows, CMPs were developed for the marching calculation of turbulent jets of rocket engine combustion products with water injection into the jet body. This made it possible to elucidate the basic mechanisms of the effect of water injection, jet–air mixing, and high-temperature rocket engine jet afterburning in atmospheric oxygen on the flow pattern and the thermogas dynamic and thermalphysic jet parameters. CMPs were developed to simulate the operation of liquid-propellant low-thrust engine systems. They were used in supporting the development and ground firing tryout of Yuzhnoye State Design Office’s radically new system of control jet engines fed from the sustainer engine pipelines of the Cyclone-4M launch vehicle upper stage. The computed results made it possible to increase the informativity of firing test data in flight simulation. The CMPs developed were transferred to Yuzhnoye State Design Office for use in design calculations.
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Borysiuk, Dmytro, Viacheslav Zelinskyi, Igor Tverdokhlib, and Yurii Polievoda. "MATHEMATICAL MODEL OF AUTOMATION OF THE DIAGNOSIS OF INTERNAL COMBUSTION ENGINES OF THE YAMZ-238 FAMILY." ENGINEERING, ENERGY, TRANSPORT AIC, no. 4(115) (December 24, 2021): 12–23. http://dx.doi.org/10.37128/2520-6168-2021-4-2.
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Constructive improvement of mobile energy means, in particular their main unit - the internal combustion engine, is directed on: maintenance of differentiation of size of parameters of functioning of mechanisms of systems depending on variability of conditions and modes of operation of cars; increase of technical resource at use of cars on purpose in the set operating conditions. The existing methods and tools for diagnosing vehicle engines do not fully determine their current technical condition, which requires the development of mathematical models to automate the process of diagnosing their components and parts was found іn the analysis of literature sources. The object of diagnosis is a diesel internal combustion engine of the YaMZ-238 family, which is part of the power unit of most vehicles. Mathematical model of automation of the process of diagnosing internal combustion engines of the YaMZ-238 family is presents in the article. Replacing real technical devices with their idealized models allows the widespread use of various mathematical methods. In this case, the internal combustion engine of the YaMZ-238 family, as the object of diagnosis, is presented in the form of a «black box», the input and output parameters of which have a finite set of values. In general, the mathematical model is a system of functional relationships between each diagnostic signal and structural parameters. For internal combustion engines of the YaMZ-238 family, a diagnostic matrix has been compiled, which includes a list of faults and signs of faults. It is determined that the process of diagnosis based on the model of the diagnostic object is possible if the inverse transformation of the number of signs of malfunctions into the number of structural parameters (malfunctions) of the object was unambiguous. The proposed mathematical model of automation of the process of diagnosing internal combustion engines of the family YaMZ-238 will detect faults of components and parts depending on their characteristics.
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Junevičius, Raimundas, Marijonas Bogdevičius, and Ádám Török. "MODELLING OF INTERNAL COMBUSTION ENGINES’ EMISSION THROUGH THE USE OF TRAFFIC FLOW MATHEMATICAL MODELS." TRANSPORT 26, no. 3 (October 5, 2011): 271–78. http://dx.doi.org/10.3846/16484142.2011.621978.
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Road traffic flows on a straight road segment are modelled in this article. The mathematical model of traffic flows has been constructed by using the method of lumped parameters. CO2, CO, CH, NOx, PM regression equations of internal combustion engines’ (ICE) emission has been developed. The accuracy of regression equations is 0.98÷0.99. The article presents assumptions for constructing the mathematical model, description of the mathematical model and gives simulation results. Traffic flow parameters, such as traffic flow concentration and traffic flow speed are presented as modelling results. ICE emission depending on the concentration and traffic flow speed are presented as well.
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Ryzhkov, V. V., and I. I. Morozov. "Сalculated analysis of the influence of operation and design factors on the parameters of oxygen-hydrogen low-thrust rocket engines." VESTNIK of Samara University. Aerospace and Mechanical Engineering 18, no. 3 (October 31, 2019): 131–42. http://dx.doi.org/10.18287/2541-7533-2019-18-3-131-142.
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The paper presents the results of calculating thermodynamic and thermophysical properties of the combustion products of gaseous oxygen-hydrogen fuel according to the ideal LRE model taking into account the phase state of the components, as well as the parameters of a low-thrust engine according to the model of computational gas dynamics to ensure the selection of operation and design factors that define the design of a thruster for advanced aerospace objects. It is shown that ideal models can be used for the selection of some parameters, such as: the excess oxidant ratio, the pressure in the combustion chamber, the geometric degree of area expansion ratio. High-level computational gas dynamics models need to be used for the selection of some of the parameters of the engine to be designed, such as: design parameters of the propellant injection pattern, reduced length of the combustion chamber and some others. Air specific impulse was used as the selection criterion. The obtained calculation data allow one to choose the main parameters of the engine being designed with account for real processes in the combustion chamber and the nozzle of the engine.
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KULCZYCKI, Andrzej. "Theoretical approach to modeling the combustion process in turbine engines fuelled by alternative aviation fuels containing various components/biocomponents." Combustion Engines 171, no. 4 (November 1, 2017): 245–49. http://dx.doi.org/10.19206/ce-2017-441.
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The aim of this paper is presentation of the possibility of combustion processes modelling so that to better describe the influence of fuels chemistry on fuels combustion. This is important for prediction the behaviour of different alternative fuels in processes in combustion chamber. Currently used mathematical models do not sufficiently take into account the influence of fuels chemical composition on combustion process. The idea of new mathematical model is proposed in this paper. The paper presents the main assumptions of this model and the results of its preliminary verification using MiniJetRig.
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Horeniuk, Vadym. "Integration of kinematic and dynamic mathematical models of a two-axle electric car in the problem of estimating its stability on turns." ScienceRise, no. 5 (October 29, 2021): 23–29. http://dx.doi.org/10.21303/2313-8416.2021.002145.
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Object of research: the process of movement of cars with internal combustion engines or the electric drive on a road curve.
Investigation problem: assessment of the stability of cars with internal combustion engines or electric drive on a road curve and determination of conditions of its ensuring.
The main scientific result. The article evaluated the stability of cars with internal combustion engines or electric drive on a road curve and determines the conditions of its ensuring using an algorithm that combines mathematical models of car movement on a road curve, synthesized based on balance equations of both kinematics and dynamics. The proposed models consider the change in speed of cars while driving on a road curve, and therefore belong to the class of differential equations. The analysis of these models allows calculating changes in time of values of limiting and critical speeds of movement of the car on a road curve. The article identifies the prospects of integration into this set of mathematical models another one, synthesized in the space of linguistic variables that characterize the uncertainty of the road surface and the degree of tire wear on different wheels of the car.
The area of practical application of the research results: Automotive enterprises specializing in equipping cars with traffic control systems.
Innovative technological product: A method of determining the limiting parameters of movement of the car on road curves, at which the car does not overturn while passing turns, and an algorithm for its implementation, which combines kinematic and dynamic mathematical models of car movement on the road curve.
Scope of application of the innovative technological product: Equipping cars with additional control systems that assess the critical values of the traffic parameters on turns to ensure the conditions of non-overturning when the car passes these turns
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Bolotov, M. A., V. A. Pechenin, N. V. Ruzanov, and D. M. Balyakin. "Neural network model in digital prediction of geometric parameters for relative position of the aircraft engine parts." Information Technology and Nanotechnology, no. 2416 (2019): 87–94. http://dx.doi.org/10.18287/1613-0073-2019-2416-87-94.
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The quality of aircraft and rocket engines depends primarily on the geometric accuracy of assembly units and parts. Mathematical models implemented in the form of computer models are used to predict quality indicators (in particular, assembly parameters). Direct modeling of the conjugation process using numerical conjugation and finite-element models of assemblies requires significant computational resources and is often accompanied by problems convergence of solutions. In order to solve the above problems, it is possible to use neural network models describing the main regularities of the pairing process based on the accumulated results. The work presents a neural network model for predicting assembly parameters of the parts based on the use of actual surfaces of the parts obtained as a result of mathematical modeling. Assembly on conical surfaces is considered. A convolutional neural network was used to predict assembly parameters.
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Cuper Przybylska, Dominika. "Overview of combustion process models in a cylinder of piston engine." AUTOBUSY – Technika, Eksploatacja, Systemy Transportowe 19, no. 4 (April 30, 2018): 48–52. http://dx.doi.org/10.24136/atest.2018.020.
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The article presents an overview of models used to calculate combustion process parameters in piston engines. One of the applied techniques is modelling based on the mathematical description of physical phenomena. The level of complexity of such a description depends, however, on the purpose of the model, the efficiency of calculations and the possibility of obtaining reliable measurement data. The paper presents various methods of modelling phenomena occurring in the cylinder of a Diesel engine. Presented are assumptions and effects of modelling using models from 0-dimensional and single-zone to complex 3-dimensional models, describing the phenomena of turbulent mass movements using computer fluid mechanics.
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Mednikov, Aleksandr, Alexey Maksimov, and Elina Tyurina. "Mathematical modeling of mini-CHP based on biomass." E3S Web of Conferences 69 (2018): 02005. http://dx.doi.org/10.1051/e3sconf/20186902005.
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One of the promising directions of small-scale distributed power generation for Russia is the use of biomass. The present work is devoted to studies of an mini-CHP based on multi-stage biomass gasification. Mathematical models of elements and mini-CHP in general based on technological schemes were constructed. The mathematical models were constructed with the software developed at Melentiev Energy Systems Institute of Siberian Branch of the Russian Academy of Sciences. The calculations were made for two sizes of internal combustion engines. Thus, we obtained the values of flow rates, temperatures of heat carriers at various points of flow charts of the plants.
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DUMITRACHE, Mihail Lucian, and Catalin FAITAR. "POSSIBILITIES TO REDUCE POLLUTANT EMISSIONS IN NAVAL DIESEL ENGINES." Mechanical Testing and Diagnosis 10, no. 3 (October 15, 2020): 5–9. http://dx.doi.org/10.35219/mtd.2020.3.01.
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The combustion process is, by far, the most important and complex process that takes place in engines. Its importance is given by the fact that it provides the flow of energy used in the engine and is the source of all pollutant emissions, the efficiency of the engine being directly influenced by it. The mechanisms of combustion are particularly complex and are not fully known even today, the most difficult problem being the mechanisms of mixture formation and the chemistry of the combustion process. Over time, depending on the evolution of knowledge in the field and computer technology, various mathematical models have been developed, which have. Emission estimation and theoretical verification, in the first phase, of the solutions applicable to in-service enginescould greatly reduce research and production costs, given that there are a variety of engines onboard ships and measurements in operation are very difficult.
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ASTAKHOV, Sergey A., and Vasilii I. BIRIUKOV. "Problems of ensuring the acceleration dynamics of aircraft during track tests at a speed of 1600 m/s." INCAS BULLETIN 12, S (July 28, 2020): 33–42. http://dx.doi.org/10.13111/2066-8201.2020.12.s.3.
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The article discusses the problems that arise when creating new models of supersonic and hypersonic aircraft, which can be solved by model high-speed ground track tests. Mathematical modelling of the aerodynamic characteristics of an aircraft (test object) placed on a rail carriage and accelerated by the solid fuel rocket engines is performed. The numerical method solves the problem of the motion of a body of variable mass along a rail track. To determine the required length of the rail track, a mathematical model of the ballistic characteristics of the upper stage of the rocket carriage was compiled, calculations were made, and the influence of various factors on achieving the maximum speed of the test object was analysed. An analysis is made of the influence of the total mass of the carriage with the load and engine thrust on the possibility of accelerating the test object to the Mach speed (4-5).
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Palej, Patryk, and Tomasz Palacz. "Preliminary Design Analysis of Regenerative Cooling for N2O/Alcohol Small Scale Liquid Rocket Engine." Transactions on Aerospace Research 2018, no. 3 (September 1, 2018): 87–102. http://dx.doi.org/10.2478/tar-2018-0024.
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Abstract This paper presents a concept of a small scale liquid-propellant rocket engine designed in AGH Space Systems for sounding rocket. During preliminary design of thermal aspects various ways of cooling were evaluated and described. Possible issues and design approaches for ablative, radiation and regenerative cooling are raised. The authors describe available solutions. Regenerative cooling is especially concerned as it is most popular solution in bi-liquid engines, in which alcohol fuel acts as coolant and is preheated before it reaches combustion chamber. To estimate a possible temperature distribution - and thus an applicability of such a system in the engine - a mathematical model of heat transfer was developed. Unique element of said engine is its oxidizer - nitrous oxide, which have been rarely used to date. Comparison between typical LOX bi-liquids is given and major differences that affect cooling arrangement are discussed. The authors compared different combinations of coolants, fuel/oxidizer ratios etc. to optimize the temperature distribution which is a key factor for the engine performance.
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Anisimov, Victor, and Vasyl Muzychuk. "DETERMINATION OF RESIDUAL FUEL RESOURCE AUTOTRACTOR DIESEL EQUIPMENT BY MATHEMATICAL MODELING WITH METHOD APPLICATION SMALL DEVELOPMENTS." ENGINEERING, ENERGY, TRANSPORT AIC, no. 3(110) (October 30, 2020): 4–15. http://dx.doi.org/10.37128/2520-6168-2020-3-1.
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The reliability of automotive internal combustion engines is a function of the reliability of their mechanisms and systems. For many years, domestic and foreign engineers have tested many auto-tractor internal combustion engines and it has been proven that if mathematical models reliably describe physical phenomena, cycles or processes that take place in engines, then the theory of small deviations for theoretical research is much better than any experiment on control characteristics and many second parameters The theory of small deviations for fuel equipment of autotractor diesel engines is considered in the article. The method of transition from the ordinary differential equations describing the quality of diesel fuel spraying to the equations in small deviations. Equation of kinematics and hydrodynamics of precision pairs of fuel equipment in small deviations. Consumption characteristics of fuel in the process of injection in small deviations. Methods of similarity, dimension theory, mathematical statistics, and probability theory, which are used in determining the resource and predicting the operation of tractor engines. It is shown that the most practically accepted method for determining the residual life of autotractor engines is the method of mathematical statistics and probability theory. The role of mathematical modeling in determining the residual life of fuel equipment of autotractor diesel engines is established. It is also noted that it is advisable to use the small deviation method to accurately describe the processes in the fuel equipment of autotractor diesel engines. The mathematical model is based on the known physical laws that describe the interdependencies of the two groups of parameters, control and operational, both within and between groups. The transition of the classical differential equations describing the processes of fuel supply and injection, taking into account fuel leaks in precision pairs, into equations with small deviations of parameters, is shown. The relationship between injection, fuel supply and fuel leakage is analyzed and the most influential parameters found. Impact coefficients are found and their dependencies are plotted on their corresponding parameters. Using the obtained dependencies, the influence of the technical condition of precision pairs on the effective performance of the engine is characterized. Dependences of change of injection characteristics on small deviations of parameters characterizing the technical condition of precision pairs of fuel equipment are also established.
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Mikulski, Maciej, Sławomir Wierzbicki, and Andrzej Piętak. "Verification of a 2–Phase, Zero-Dimensional Model of a Multifuel Compression-Ignition Engine in Single Fuel Operation." Applied Mechanics and Materials 817 (January 2016): 47–56. http://dx.doi.org/10.4028/www.scientific.net/amm.817.47.
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Improving the efficiency or work and reducing the emissions of toxic substances into the atmosphere are the two key directions of development of modern combustion engines. Improvement of engine efficiency is feasible only by increasing the precision of control thereof, which necessitates long-term operating tests. Regrettably, due to complexity of processes taking place during the combustion of fuel, these phenomena can only be tested on simulation models, based on a mathematical description of the phenomena.This paper presents the results of verification tests of the developed fuel combustion model in a multifuel compression-ignition engine for an engine running only on diesel fuel.
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SICZEK, Krystian, and Krzysztof SICZEK. "Studies on the dynamics the valve train with machined valve springs." Combustion Engines 168, no. 1 (February 1, 2017): 100–109. http://dx.doi.org/10.19206/ce-2017-116.
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An analysis of the literature for currently used solutions of valve trains in internal combustion engines and analytical studies on the dynamics the valve train of the internal combustion engine provided with machined valve springs were carried out. The aim of the study was to compare the dynamic parameters of the two valve trains for the established internal combustion engine: the first one equipped with machined springs and the second one with coil springs. The numerical models for investigated valve trains, using the Finite Element Method and additional mathematical relationships were developed and presented in the article. The article describes the results of the researches and formulated conclusions.
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Alazeezi, Mohammed, Nikola Popovic, and Predrag Elek. "Two-component propellant grain for rocket motor: Combustion analysis and geometric optimization." Thermal Science 26, no. 2 Part B (2022): 1567–78. http://dx.doi.org/10.2298/tsci210604290a.
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The paper considers utilization of rocket motor propellant grains that consist of two propellants. The idea is to achieve approximately neutral burning using an outer surface inhibited cylindrical shape and complex contact surface between propellants. An existing propellant grain with complex geometry has been analytically modeled in terms of determination of evolution of corresponding burning surface areas. The analytical and experimental results? diagrams of this grain have been found to have a saw-tooth shape because of the segments that separate the two propellants, causing potential problems in the burning process during the relatively short active phase, showing an obvious need for further optimization. This has created an opportunity for development of improved propellant grain geometry and corresponding mathematical model for determination of main interior ballistic parameters. Comparison between calculation results based on both models and experimentally determined chamber pressure data shows very good agreement. Therefore, two-component propellant grains have significant application possibilities using the suggested modeling approaches.
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Bhanji, Sassan. "How Can Ablative Cooling in A Solid Propellant Rocket Engine Be Accurately Modelled in Order to Optimise Performance?" International Journal for Research in Applied Science and Engineering Technology 10, no. 8 (August 31, 2022): 881–92. http://dx.doi.org/10.22214/ijraset.2022.46180.
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Abstract: This essay investigates the use of ablative cooling in solid propellant rocket engines. It begins by exploring the mechanisms by which ablation occurs. It then demonstrates how heat transfer to an ablator can be modelled, and how this can be used to find ablator recession rate and hence the necessary ablator thickness for a rocket engine. It does so by considering simplified mathematical models. These are then compared to the more complex models that have recently been developed. The different variables involved and how they might be used or calculated are discussed. The next section of the essay ties this theoretical knowledge and modelling into practical engineering use by considering the impact ablation has on performance. MATLAB is used to demonstrate how an expanding throat diameter of the nozzle can decrease thrust and specific impulse, and that this can greatly decrease payload capacities. Other variables involved in creating a thrust profile for a solid propellant rocket engine are considered. Finally, the essay will look at how to choose an optimal ablator. It goes through the universally desirable characteristics and uses the Space Shuttle SRMs as an example of disadvantages that may not initially be considered when selecting an ablator
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OSIPOV, K. N. "DESIGN AND ANALYSIS OF PREDICTIVE MODELS OF DANGEROUS TECHNICAL STATE OF MACHINE-BUILDING PRODUCTS." Fundamental and Applied Problems of Engineering and Technology, no. 1 (2021): 138–45. http://dx.doi.org/10.33979/2073-7408-2021-345-1-138-145.
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An approach to the design of adaptive empirical multidimensional mathematical predictive models based on the results of measurements used to assess the risk of transition of technically complex products to a dangerous technical condition during production (acceptance and control) tests is proposed. The issues of verification and evaluation of the speed of adaptation of the proposed models to changing conditions and test goals are considered. As an example, we consider the process of modeling and forecasting changes in the technical conditions of high-speed internal combustion engines with forced spark ignition.
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Peshkov, R. A., and D. R. Ismagilov. "Numerical simulation of the interaction between combustion products of a cartridge pressure accumulator and oxygen in the launch container." Journal of «Almaz – Antey» Air and Space Defence Corporation, no. 1 (March 30, 2019): 68–73. http://dx.doi.org/10.38013/2542-0542-2019-1-68-73.
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The paper introduces a mathematical model for calculating the gas-dynamic parameters in the launch container. The model takes into account chemical interactions between the main components of the combustion products, i.e. carbon monoxide and hydrogen, and oxygen. The resulting energy can be used to increase the initiating pulse of the rocket. Within the research, we described the basic requirements for the grid model, and analyzed the accuracy of the results obtained. Furthermore, we compared calculation data of pressure in the launch container with the results of the known method. Findings of research show that the use of two-dimensional and three-dimensional models makes it possible to obtain not only medium-volume gas-dynamic parameters, such as pressure, temperature, density, but also the distribution of these parameters over the computational domain. The developed method of numerical simulation will allow us to estimate the effect of changes in the configuration of the sub-rocket volume and other parameters on the dynamics of the rocket movement without conducting an expensive experiment
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Pylypenko, O. V. "Solving current problems in engineering system dynamics." Technical mechanics 2021, no. 2 (June 29, 2021): 3–19. http://dx.doi.org/10.15407/itm2021.02.003.
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This paper overviews the main results obtained over the past few years at the Department of Hydromechanical Systems Dynamics and Vibration Protection Systems, Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine, in the solution of current problems in the dynamics of liquid-propellant rocket engines (LPREs), liquid-propellant launch vehicle pogo stability, vibration protection system dynamics, the gas dynamics of aircraft gas turbine engine components, and the dynamics of hydraulic systems with cavitating elements. These results are as follows. A mathematical model of LPRE pump dynamics was developed. The model complements a hydrodynamic model of LPRE cavitating pumps by allowing a mathematical simulation of choking regimes. An approach was developed to the construction of a nonlinear mathematical model of LPRE hydraulic line filling. The approach allows one to automatically change, if necessary, the finite element partitioning scheme of a hydraulic line in the process of its filling during LPRE startup calculations. An investigation was conducted into the startup dynamics of a multiengine liquid-propellant propulsion system that consists of four staged-combustion oxidizer-rich LPRDs with account for the possibility of their nonsimultaneous startup. The maximum values of oxidizer and fuel pressure surges and undershoots at the liquid-propellant jet system (LPJS) inlet at an engine spartup and shutdown were determined and used in determining the LPJS operability at the startup and shutdown of the RD861K sustainer engine. The pogo stability of the Cyclone-4M launch vehicle was analyzed analytically using Nyquist’s criterion. A numerical approach was developed to characterizing acoustic oscillations of the combustion products in annular rocket combustion chambers with account for the configuration features of the fire space and the variation of the physical properties of the gaseous medium with the axial length of the chamber. A prototype vibration protection system was developed and made, and its dynamic tests confirmed its high efficiency in damping impact and harmonic disturbances. Approaches were developed to the aerodynamic improvement of aircraft gas turbine engine components. Topical problems in solids grinding in a liquid medium with the use a cavitation pulse technology were solved.
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Hernandez Nuñez, Mario, Angelica E. Bonilla-Blancas1, and Angelica E. Bonilla-Blancas. "Inferential statistics models to relate the rejections of an engine cold testing and the machining defects in camshaft assembly bores." INGENIERÍA Y COMPETITIVIDAD 24, no. 02 (May 26, 2022): 1–13. http://dx.doi.org/10.25100/iyc.v0i00.11607.
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In the manufacturing industry it is of great importance to reduce machining deviations as soon as possible to avoid cost associated with reworks. The definition of mathematical models that predict future errors in the machining of components of combustion engines, it is a way that helps to save time and money in a process.
This paper proposes the analysis and establishment of correlations between the deviations of the machining in cylinder heads and the rejections of an engine cold testing in an automotive manufacturing company. To determine the relationships, a sample of heads and engines were measured in a period of two months and using inferential statistics, statistical models were established. The above was in order to ensure product quality and implement a methodology in the company for manufacturing problem solving.
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Ahmed, Heersh, and Boris Osipov. "MULTI-MODE IDENTIFICATION OF OBTAINING THE ADEQUATE MODEL OF TURBOJET ENGINE TJ-100A-Z FOR DIAGNOSTICS BY THERMALGASDYNAMIC PARAMETERS." Perm National Research Polytechnic University Aerospace Engineering Bulletin, no. 60 (2020): 5–14. http://dx.doi.org/10.15593/2224-9982/2020.60.01.
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When monitoring and diagnosing the state of gas turbine engines by thermodynamic parameters, adequate mathematical models of these engines are used. This name means diagnostic methods based on special processing and analysis of the values of thermogasdynamic and other parameters measured on a working turbojet engine [1] using its mathematical model. The most important in the system of technical diagnostics is the mathematical model of the engine. Its creation is a problem since, as a rule, the specifications of engine components are not given in the technical documentation. In this regard, obtaining complete mathematical models of engines for diagnostic purposes is an urgent task. There are various approaches to obtaining the characteristics of nodes and one of them is the use of generalized characteristics, for example, developed at the N.E. Zhukovsky Air Force Engineering Academy at the Department 201 "Theory of Air-Jet Engines" under the direction of Professor Nechayev Yu.N. Experience using such characteristics has shown that such characteristics can be used, but in a fairly narrow range of throttle modes. As a rule, this range was limited to no more than 40 % of the calculated (nominal) mode, which significantly limits the capabilities of the mathematical model of turbojet engines when implementing diagnostics using thermodynamic and dynamic parameters. This article proposes an algorithm developed by the authors a lot of mode identification, implemented as a computer program. As an object of study used turbojet engine TJ-100A-Z manufactured in the Czech Republic. For this, the turbojet engine obtained the characteristics of the main components (compressor, combustion chamber, turbine and nozzle) using the throttle characteristics given in the technical conditions. The calculation results are presented in the form of tables and graphs with error analysis in the calculation before and after identification. The comparison of the errors of the parameters of the throttle characteristics with the errors of the sensors for measuring these parameters is given.
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Ferreira, Jessimon, Bianca Marin, Giane G. Lenzi, Calequela J. T. Manuel, José M. Balthazar, Wagner B. Lenz, Adriano Kossoski, and Angelo M. Tusset. "Neural Network Modeling and Dynamic Analysis of Different Types of Engine Mounts for Internal Combustion Engines." Sensors 22, no. 5 (February 25, 2022): 1821. http://dx.doi.org/10.3390/s22051821.
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This paper presents the results of studies on reducing the amount of vibrations in different frequency ranges generated by a combustion engine through the use of different types of engine mounts. Three different types of engine supports are experimentally and numerically analyzed, namely an elastomeric engine mount, an elastomeric engine mount with a hydraulic component and standard decoupling, and an elastomeric engine mount with a hydraulic component and a modified decoupler—with this engineering design being a novelty in the literature. Experimental tests that considered different excitation frequencies were performed for the three types of engine mounts. Experimental data for stiffness and damping were used to obtain nonlinear mathematical models of the two systems with hydraulic components through the use of an Artificial Neural Network (ANN). For the results, all of the mathematical models presented coefficients of determination, R2, greater than 0.985 for both stiffness and damping, showing an excellent fit for the nonlinear experimental data. Numerical results using a quarter-car suspension model showed a large reduction in vibration amplitudes for the first vibration model when using the hydraulic systems, with values ranging between 48.58% and 66.47%, depending on the tests. The modified system presented smaller amplitudes and smoother behavior when compared to the standard hydraulic model.
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Sharapov, A. I., A. A. Chernykh, and A. V. Peshkova. "Supersonic flow of two-phase gas- droplet flows in nozzles." Power engineering: research, equipment, technology 21, no. 3 (November 29, 2019): 86–98. http://dx.doi.org/10.30724/1998-9903-2019-21-3-86-96.
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For practical applications, the description of processes occurring during the flow of two-phase gas-liquid mixtures requires a simple physical and mathematical model that describes the behavior of a two-phase medium in the entire range of phase concentrations changes and in a wide range of pressure changes. Problems of this kind arise in various branches of industry and technology. In the space industry, one often has to deal with the movement of various gases in rocket nozzles, consider the combustion, condensation of various vapors on the nozzle walls and their further impact on the velocity sublayer at the nozzle wall. The large acoustic effect arising from the engines affects the gas-liquid mixture in the nozzles of rocket engines. In the metal industry, metal cooling occurs with the help of nozzles in which the emulsion mixture is supplied under high overpressure. But this is only a short list of applied issues in which one has to deal with a problem of this type. The paper presents the results and directions of study of the problems of two-phase dispersed gas-droplet flows in the nozzles. The main methods of investigation of two- phase heterogeneous flows are described. The main characteristics of heterogeneous two-phase flows in the nozzles, which were confirmed by experimental results, are presented. The calculation of the air-droplet flow in the Laval nozzle is given. The technique, which is based on integral energy equations for two-phase dispersed flows, is described. The main problems and questions concerning the further description and studying of two-component flows are stated.
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Vasyliv, S. S., V. S. Zhdanov, and M. V. Yevseyenko. "Determination of receiver consumption characteristics using computer simulation." Computer Modeling: Analysis, Control, Optimization 8, no. 2 (December 2020): 10–14. http://dx.doi.org/10.32434/2521-6406-2020-8-2-10-14.
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The problem of implementing the detonation mode of fuel combustion in thermal propulsion systems has been widely studied last decade. There are many works on fundamental and applied research on pulsating detonation. Solid propellant detonation engines can develop significant forces for a short time at low structural masses, and therefore they are ideal for auxiliary systems for the removal of separated rocket parts. In addition, detonation processes can be used to create control forces for correcting the trajectory of aircraft. All these facts determine the relevance of the area of work. For studying detonation installations, it is necessary to create test stands, but the design of test installations is an urgent and complex optimization problem. It is advisable to solve this problem with the help of computer simulation. In the existing experimental methods, for designing, it is necessary to determine in advance the geometric parameters of receivers and pipelines that provide the necessary gas consumption for firing tests of detonation rocket engines. The work is devoted to the development of a method for determining the flow characteristics of a receiver with a pipeline of complex configuration based on the constructed model of the stand. Based on the initial data, a computer simulation of the air leakage process from the receiver was carried out, for which the Solid Works software package was used. The places of pressure drop, maximum flow rate, and air mass flow are determined. The low value of the flow rate factor is due to the complex configuration of the pipeline with numerous bends and two bellows. Comparison of calculation results with experimental data was held. The difference between the experimental and calculated values does not exceed 3.6%. The obtained information is used to select the required value of the oxidizer excess coefficient during firing tests of detonation rocket engine models. Keywords: flow rate, gas leakage, receiver, model.
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Козел, Дмитрий Викторович. "Выбор геометрических характеристик фронтового устройства и длины камеры сгорания прямоточного типа." Aerospace technic and technology, no. 4sup2 (August 27, 2021): 19–28. http://dx.doi.org/10.32620/aktt.2021.4sup2.03.
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A method has been developed for selecting the geometric characteristics of the front and the length of the direct-flow combustion chamber. Afterburner combustion chambers are of the ramjet type and are used for a short-term increase in the thrust of a gas turbine engine during takeoff, for overcoming the sound barrier by an aircraft and for flying at supersonic speed, and for making maneuvers. As part of ramjet engines, ramjet combustion chambers are used as the main combustion chambers in which the process of fuel combustion and heat supply to the working fluid is ensured. The developed method for selecting the geometric characteristics consists in optimizing the main operating characteristics of the combustion chamber. Mathematical models are proposed for describing the dependence of the total pressure loss, the combustion efficiency and the range of stable operation of the combustion chamber against the parameters of the flow at the inlet to the combustion chamber and the geometric characteristics of the front device and the length of the combustion chamber. The analysis of the dependences of the combustion chamber working characteristics on the geometric characteristics of the front-line device and its length is carried out. As a result of the analysis of mathematical models, a list of the main geometric characteristics of the front device was determined, on which the total pressure loss, the combustion efficiency and the range of stable operation of the combustion chamber depend. Optimization parameters, optimization criterion and limits for solving the optimization problem are determined. As an implementation of the optimization method, it is proposed to use a diagram of the combustion chamber performance in the coordinates of the optimization parameters. The developed method makes it possible to ensure the optimal basic operating characteristics of the combustion chamber - total pressure loss, combustion efficiency and combustion stability limits.
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Barbosa, J. P. W., W. Balmant, C. H. Matiolo, A. B. Mariano, and J. V. C. Vargas. "MODELING AND SIMULATION OF COMPRESSION-IGNITION INTERNAL COMBUSTION ENGINES’ EMISSIONS PRODUCED BY DIESEL AND BIODIESEL MIXTURES." Revista de Engenharia Térmica 20, no. 4 (February 9, 2022): 10. http://dx.doi.org/10.5380/reterm.v20i4.84640.
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Biofuels have been identified as possible solutions to the problems caused by the usage of fossil fuels in energy production. Although they generally produce fewer emissions, there are indications that engines powered with biodiesel mixtures emit pollutants such as nitrogen oxides in greater quantities than when powered by fossil diesel. So, further investigation on the emissions produced by these two fuels is needed, with the goal of best knowing what kind of harm to the environment each one of those is causing. One of the best tools available for expanding any subject’s comprehension, without spending lots of resources, are mathematical models. In order to better understand the relations between the fuel used to power a compression-ignition internal combustion engine (ICO) and the emissions produced as subproducts of the thermodynamic process, this paper aims at developing a mathematical model of the production of emissions according to the fuel mixture used. The main goal is to develop a simple model, from the point of view of chemical kinetics, but with the support of well-collected experimental data, and methods of mathematical model adjustments and validations, to make the model describe the reality of the phenomena with satisfactory precision. This Mathematical Model is completely implemented using FORTRAN® Language. There are 2 sorts of data: one used to calibrate and adjust the model’s constants so the model can properly describe the reality of the events, and the other as the basis of comparison for the validation of the model after adjustments and calibrations. With this work, it is expected that the knowledge about how the use of these fuels impact global emissions, and how it is possible to optimize our energy production by using the best mixture of fuels at the optimal point between net power outtake and net emissions produced.
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Barbosa, J. P. W., W. Balmant, C. H. Matiolo, A. B. Mariano, and J. V. C. Vargas. "MODELING AND SIMULATION OF COMPRESSION-IGNITION INTERNAL COMBUSTION ENGINES’ EMISSIONS PRODUCED BY DIESEL AND BIODIESEL MIXTURES." Revista de Engenharia Térmica 20, no. 4 (February 9, 2022): 10. http://dx.doi.org/10.5380/reterm.v20i4.84640.
Full textAbstract:
Biofuels have been identified as possible solutions to the problems caused by the usage of fossil fuels in energy production. Although they generally produce fewer emissions, there are indications that engines powered with biodiesel mixtures emit pollutants such as nitrogen oxides in greater quantities than when powered by fossil diesel. So, further investigation on the emissions produced by these two fuels is needed, with the goal of best knowing what kind of harm to the environment each one of those is causing. One of the best tools available for expanding any subject’s comprehension, without spending lots of resources, are mathematical models. In order to better understand the relations between the fuel used to power a compression-ignition internal combustion engine (ICO) and the emissions produced as subproducts of the thermodynamic process, this paper aims at developing a mathematical model of the production of emissions according to the fuel mixture used. The main goal is to develop a simple model, from the point of view of chemical kinetics, but with the support of well-collected experimental data, and methods of mathematical model adjustments and validations, to make the model describe the reality of the phenomena with satisfactory precision. This Mathematical Model is completely implemented using FORTRAN® Language. There are 2 sorts of data: one used to calibrate and adjust the model’s constants so the model can properly describe the reality of the events, and the other as the basis of comparison for the validation of the model after adjustments and calibrations. With this work, it is expected that the knowledge about how the use of these fuels impact global emissions, and how it is possible to optimize our energy production by using the best mixture of fuels at the optimal point between net power outtake and net emissions produced.
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Witwit, Azher Razzaq Hadi, Azman Yasin, Horizon Gitano, and Tarun Kumar Yadav. "New Model for Knock Factors Optimization in Internal Combustion Engine (SI)." Advanced Materials Research 980 (June 2014): 219–24. http://dx.doi.org/10.4028/www.scientific.net/amr.980.219.
Full textAbstract:
The main goal of this paper is to construct a new mathematical model and study the behavior of the factors affecting the problem of knocking in internal combustion engines. Curve fitting technique was used in construction of the model, and also Akaike Information Criterion (AIC) was used as a test in choosing the best model. Factors affecting the problem of knocking have been identified through the use of test engine had promised to do so. The mathematical model was built through real data under certain conditions. Three influential factors (Temp., TPS and RPM) have been taken into consideration. Curve fitting models were used in achieving the goal and then studied the effect of one of the factors in the problem of knocking was investigated. Results obtained through the application of the new model is a low level knocking with increasing temperature (Temp) at the same points in Throttle (TPS), the Revolution Per Minute (RPM), which shows the effectiveness of the new model with non-linear behavior of the factors affecting the knock.
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Lebedevas, Sergejus, Saugirdas Pukalskas, and Vygintas Daukšys. "MATHEMATICAL MODELLING OF INDICATIVE PROCESS PARAMETERS OF DUAL-FUEL ENGINES WITH CONVENTIONAL FUEL INJECTION SYSTEM." Transport 35, no. 1 (March 16, 2020): 57–67. http://dx.doi.org/10.3846/transport.2020.12212.
Full textAbstract:
Modern engine research uses multi-dimensional Mathematical Models (MMs) that are applicable to multi-fuel engines. However, their use involves the availability of detailed technical data on the design and characteristics of the engine, which is not always possible. The use of a one-dimensional MM is more expedient for the prediction of engine parameters, but their application for this purpose has not yet been sufficiently investigated. This publication presents the results of numerical studies evaluating the application of a one-dimensional MM with bi-phase Vibe combustion laws for dual-fuel (DF) Diesel (D) and Natural Gas (NG) engine power parameters. The motor test results of a high-speed 4ČN79.5/95.5 Diesel Engine (DE) with a conventional fuel injection system were used as adequacy criteria. The engines were operated with D100 and DF D20/NG80, in high- (HLM), medium- (MLM), and low- (LLM) load modes, and the angle of Diesel-fuel Injection Timing (DIT) was changed from −1 to −13 °CA in the Before Top Dead Center (BTDC) range. Modelling of the single-phase Vibe combustion law has limited applicability for efficient use only in HLM (with an error of 7%). In the MLM and LLM regimes, owing to non-compliance with real bi-phasic combustion with a strongly extended NG diffusive second phase, the modelling error is 50%. Individual MM matching in MLM and LLM in a DF D20/NG80 experiment detected a burn time increase from between 45 and 50 °CA, to 110 and 200 °CA, respectively. Limited use of the one-dimensional MM in the evaluation of DF engine performance has been identified. When comparing a one-dimensional MM with experimental data, a bi-phase law of heat release characteristic should be considered for better coincidence. In addition, individual MM matching with an experiment on each engine load mode ensured acceptable accuracy in testing and optimising the parameters of the indicator process, including DIT.
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Monieta, Jan. "The use of thermography in the diagnosis of ship piston internal combustion engines." MATEC Web of Conferences 182 (2018): 01027. http://dx.doi.org/10.1051/matecconf/201818201027.
Full textAbstract:
The intensity of infrared radiation emitted by objects depends mainly on their temperature. One of the diagnostic signals may be the temperature field. In infrared thermography, this quantity is used as an indicator of the technical condition of marine objects. The article presents an overview of the use of infrared thermography for the diagnosis mainly of marine piston floating objects and various types of reciprocating internal combustion engines as well as examples of own research results. A general introduction to infrared thermography and common procedures for temperature measurement and non-destructive testing are presented. Experimental research was carried out both in laboratory conditions and in the operating conditions of sea-going vessels. Experimental studies consisted of the presentation of photographs of the same objects made in visible light and the use of infrared thermography. The same objects were also compared, but for different cylinders of the tested internal combustion engines as well as for the up state and fault state. The characteristics of the temperature values at selected points were taken depending on the engine load along with the approximation mathematical models of these dependencies.
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Руднев, Б. И., and О. В. Повалихина. "Control measured complex for the investigation of parameters of operation process and radiative convection heat transfer in the combustion chamber of a marine high speed diesel engine." MORSKIE INTELLEKTUAL`NYE TEHNOLOGII)</msg>, no. 2(56) (June 9, 2022): 73–78. http://dx.doi.org/10.37220/mit.2022.56.2.009.
Full textAbstract:
Сокращение сроков доводки новых моделей судовых дизелей по-прежнему остается актуальной проблемой. Основная причина увеличения указанных сроков – это весьма существенное отличие расчетных и экспериментальных данных, полученных на испытательных стендах. В частности, по локальным тепловым потокам, передаваемым от рабочего тела к деталям камеры сгорания, упомянутое отличие составляет 25 – 50%. Это не позволяет на стадии проектирования с достаточной точностью задать граничные условия при расчетном анализе теплового и напряженно-деформированного состояния деталей, образующих камеру сгорания (крышки цилиндров, поршня и втулки) и влечет за собой значительное увеличение сроков экспериментальной доводки новых моделей судовых дизелей. Показано, что даже при использовании современных программных комплексов, в которых реализуются весьма сложные с физической точки зрения математические модели, требуется задавать некоторые параметры априори или пользоваться существующими экспериментальными данными. Целью данной статьи является представление 12 канального контрольно-измерительного комплекса, реализующего современные экспериментальные методики по определению параметров рабочего процесса и радиационно-конвективного теплообмена и позволяющего получить достоверные экспериментальные данные. Отмечено, что полученные с помощью этого комплекса экспериментальные данные могут составить надежную базу данных для проверки адекватности математических моделей, используемых конструкторами на стадии проектирования судовых дизелей. Reduction of terms of drive new models of marine diesel engines is actual problem as before. The mean reason of increasing this terms in based on difference of calculation and experimental data reseeded in experimental stands. As for local heat fluxes transferred from gases to details of combustion chamber which is 25 – 50 per cent. This desnot determine boundary conditions in calculative analysis thermal and power deformable condition of details formed the combustion chamber (heat of cylinder, piston, liner of cylinder) and involves great terms of experimental drive in new models of marine diesel engines. It is shown that even in using modern programmers complexes in which mathematical models physical complex some parameters need to use experimental data or a priori. The purpose of this paper is presentation of 12 canal control measured complex that realized modern experimental methods in definition of parameters gases and radiative convective heat transfer and given reliable experimental data. Experimental data received with this complex may present base of data for control of equivalent mathematical models used by designers dinning designing of marine diesel engines.
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Magalhães, Leandro, Francisco Carvalho, André Silva, and Jorge Barata. "Turbulence Modeling Insights into Supercritical Nitrogen Mixing Layers." Energies 13, no. 7 (April 1, 2020): 1586. http://dx.doi.org/10.3390/en13071586.
Full textAbstract:
In Liquid Rocket Engines, higher combustion efficiencies come at the cost of the propellants exceeding their critical point conditions and entering the supercritical domain. The term fluid is used because, under these conditions, there is no longer a clear distinction between a liquid and a gas phase. The non-conventional behavior of thermophysical properties makes the modeling of supercritical fluid flows a most challenging task. In the present work, a Reynolds Averaged Navier Stokes (RANS) computational method following an incompressible but variable density approach is devised on which the performance of several turbulence models is compared in conjunction with a high accuracy multi-parameter equation of state. In addition, a suitable methodology to describe transport properties accounting for dense fluid corrections is applied. The results are validated against experimental data, making it clear that there is no trend between turbulence model complexity and the quality of the produced results. For several instances, one- and two-equation turbulence models produce similar results. Finally, considerations about the applicability of the tested turbulence models in supercritical simulations are given based on the results and the structural nature of each model.
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Dolgopolov, S. I. "Determination of the effect of internal and external factors on the thrust spread of a cluster propulsion system." Technical mechanics 2022, no. 2 (June 30, 2022): 47–58. http://dx.doi.org/10.15407/itm2022.02.047.
Full textAbstract:
The thrust spread of a stand-alone rocket engine caused by external (the pressure and temperature of the propellant components at the engine inlet) and internal (spread in the geometry and operating conditions of the engine units and assemblies) factors is known from experimental tests or can be computed by a known procedure. As a rule, liquid-propellant propulsion systems (LPPSs) of launch vehicle lower stages include a cluster of several engines, whose thrust spread cannot often be determined from firing tests due to limited capabilities of bench equipment. The aim of this work is to develop an approach to determining the thrust spread of an LPPS comprising a cluster of two and more engines. For a multiengine propulsion system, this methodological approach also includes the development of a mathematical model of engine interaction in an LPPS and calculations of an LPPS startup at different combinations of spread in the external and internal factors in cases where the parameter spreads of all engines are both identical and different. For an LPPS with two engines and a common oxidizer feed pipeline, the paper gives an example of calculating the effect of external and internal factors on the thrust spread of each engine and the LPPS as a whole during an LPPS startup. . It is shown that the calculated spread of the 90 percent thrust (combustion chamber pressure) time lies in the range – 0.0917 s to +0.0792 s (engine 1) and –0.0941 s to +0.0618 s (engine 2). The calculated variations of the combustion chamber pressure (engine thrust) from its nominal value lie in the range –6.2 percent to +7.0 percent (engine 1) and -6.8 percent to +6.3 percent (engine 2). The calculated spreads of the 90 percent thrust time and the thrust for the LPPS as a whole are far smaller (about by 40 percent) and lie in the range – 0.0733 s to +0.0457 s for the time and – 4.8 percent to +4.8 percent for the thrust (about the nominal thrust). Using Pearson’s chi-squared test, an estimate is obtained for the goodness of fit of the anticipated theoretical distributions of the 90 percent thrust time spread and the steady thrust spread to the obtained statistical ones both for the two engines and for the LPPS as a whole.