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Статті в журналах з теми "RECTANGULAR MULTI BAFFLED CHAMBER"
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Liu, Haijun, Zhanbin Guo, Lixin Zhao, Xinyu Wang, and Shan Lan. "Numerical simulation and experimental verification of stability on multi-cavity spiral cascade heat transfer system." Thermal Science, no. 00 (2020): 319. http://dx.doi.org/10.2298/tsci200625319l.
Повний текст джерелаАнотація:
In order to improve the insufficient effect of heat transfer in pyrolysis carbonization system and reveal the effects of velocity and temperature field of hot flue gas on heat transfer and stability in the biomass, the structure with rectangular groove combined with a spiral baffle is designed to form a multi-cavity spiral cascade heat transfer system. Numerical simulation and experimental verification of stability are carried on multi-cavity spiral cascade heat transfer system. The results show that the hot flue gas with high temperature flows fast at the inlet and outlet, while the flow speed is slow and stable in the cavity of heat transfer. The temperature of hot flue gas reaches the highest at the entrance, and decreases in the heat exchange chamber in a cascade. The spiral inclination angle of 35? and the pitch of 1.2m. The combustion of gas produced by pyrolysis of raw materials can meet the requirement of continuous and stable operation, when the temperature of monitor point 1, 3, 6 and 8 reaches 800 ?, 530 ?, 250 ?and 200 ? respectively. The temperature of hot flue gas changes fluctuate in the range of 15 ?. The combustion of pyrolysis gas generated during the pyrolysis process of raw materials can ensure the continuous and stable operation of the equipment.
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Chang, Y. C., and M. C. Chiu. "Optimization of Rectangular Multi-Chamber Plenums Equipped with Multiple Extended Tubes Using the BEM, Neural Networks, and the Genetic Algorithm." Journal of Mechanics 30, no. 6 (October 21, 2014): 571–84. http://dx.doi.org/10.1017/jmech.2014.66.
Повний текст джерелаАнотація:
AbstractThe focal point of this paper is to uncover, by analyzing the higher order wave effect, an improved mechanism for space-constrained rectangular plenums using a simplified objective function in conjunction with a genetic (GA). Three kinds of rectangular mufflers hybridized with extended tubes will be assessed: Plenum A: A two-chamber plenum equipped with an extended tube; plenum B: A three-chamber plenum with two extended tubes; and plenum C: A two-chamber plenum equipped with three extended tubes. In order to shorten the numerical assessment, a simplified objective function (OBJ) is established using a boundary element model (BEM) in conjunction with the neural network model (NNM). To expediently approach an optimal plenum, the best OBJ will be numerically searched using a genetic algorithm (GA). However, before the GA operation is performed, the accuracy of the BEM is verified using analytical data. And, because the simplified objective function (OBJ) is seen to be in agreement with the BEM, the numerical cases of sound elimination relative to the various parameter sets and pure tones (300, 750, and 1300Hz) can be carried out.Results reveal that the maximum value of the sound transmission loss (STL) can be accurately obtained at the desired frequencies. Additionally, the acoustical performance of the lower frequencies will be improved if the number of chambers and rectangular tubes are increased. However, the acoustical performance of the higher frequencies will decrease when the number of chambers and rectangular tubes are decreased. Consequently, the algorithms proposed in this study will efficiently develop optimal rectangular plenums with multiple rectangular extended tubes.
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Philo, John J., Rohan M. Gejji, and Carson D. Slabaugh. "Injector-coupled transverse instabilities in a multi-element premixed combustor." International Journal of Spray and Combustion Dynamics 12 (January 2020): 175682772093283. http://dx.doi.org/10.1177/1756827720932832.
Повний текст джерелаАнотація:
Combustion instabilities in a high-pressure, multi-element combustor are studied in order to understand the relationship between the chamber and injector dynamics. A linear array of seven injectors supplies premixed natural gas and air into a rectangular combustion chamber designed to promote high-frequency, transverse thermoacoustic instabilities. The effect of equivalence ratio on the combustion dynamics was investigated for two injector lengths, 62.5 and 125 mm. For all operating conditions, the 125 mm injectors promote high-amplitude instabilities of the fundamental transverse (1T) mode, which has a frequency of 1750–1850 Hz. Reducing the injector length significantly lowers the instability amplitudes for all operating conditions and, for lower equivalence ratio cases, excites an additional mode near 1550 Hz. The delineating feature controlling the growth of the instabilities in each injector configuration is the coupling with axial pressure fluctuations in the injectors that occur in response to the transverse modes in the chamber.
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Krupińska, Andżelika, Marek Ochowiak, Sylwia Włodarczak, Magdalena Matuszak, and Julia Kaźmierczak. "Analysis of the dedusting process in a rectangular chamber filter." Polish Journal of Chemical Technology 24, no. 4 (December 1, 2022): 72–77. http://dx.doi.org/10.2478/pjct-2022-0031.
Повний текст джерелаАнотація:
Abstract Purifying air from dust is a very important, current topic. There are many methods to minimize the amount of dust, one of them being chamber filters. This paper presents the research results of a newly designed rectangular chamber filter. The efficiency of the dedusting process is influenced by contamination properties, but also by the construction of the apparatus, inlet, and outlet location, the ratio of certain dimensions, and the gas flow rate. The airflow containing solid particles is a multi-phase, difficult-to-describe issue, therefore an attempt to determine the trajectory of particle movement in the apparatus was carried out using the PIV method. A decrease in the dedusting efficiency was observed with the increase of the gas flow rate, as well as for smaller diameters of the solid particles. The obtained values of the efficiency of the apparatus are comparable with the values obtained for the constructions discussed in other papers.
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Zhang, Wanqing, Xin Gao, and Angui Li. "Effects of multi-orifice plate with different geometric parameters on flow distribution of plenum chamber for ventilation duct systems." E3S Web of Conferences 356 (2022): 02044. http://dx.doi.org/10.1051/e3sconf/202235602044.
Повний текст джерелаАнотація:
Plenum chambers are common devices used for flow and pressure equalization in ventilation and air conditioning systems. Aiming for reducing energy consumption and improving ventilation performance, the optimal cross-sectional aspect ratio (W/H) and length (L) of the single-path unlined rectangular plenum chamber is obtained through the authors’ preliminary research. In this study, based on the analysis of interior flow characteristics of single-path plenum chamber, it is shown that the traditional chamber configuration commonly used in engineering is not an ideal structure that can achieve uniform flow distribution. The multi-orifice plate is proposed to add inside chamber to improve flow uniformity. Under the two typical design schemes of W/H=1/1 and 5/1, the effect of multi-orifice plate with different geometric parameters on flow distribution of plenum chamber is investigated, and the optimal installation position and aperture rate of orifice plate is proposed. The optimized aperture ratio is designed to be 30% for both the two typical chamber configurations. When W/H=1/1, it is recommended to install the multi-orifice plate at the position of y/L=0.1, as for W/H=5/1, the y/L=0.3 is preferred. Besides, the fluid equalizing effect of the plenum chamber with multi-orifice plate is verified under four commonly used air ducts specifications in engineering.
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Kim, Hongsuck, Byunggoon Kim, Jiyeon Kim, and Jaecheul Yu. "Effect of organic loading rates and influent sources on energy production in multi-baffled single chamber microbial fuel cell." Desalination and Water Treatment 56, no. 5 (August 18, 2014): 1217–22. http://dx.doi.org/10.1080/19443994.2014.950986.
Повний текст джерела
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Chiu, Min-Chie, Ying-Chun Chang, Ho-Chih Cheng, and Wei-Ting Tai. "Shape Optimization of Mufflers Composed of Multiple Rectangular Fin-Shaped Chambers Using Differential Evolution Method." Archives of Acoustics 40, no. 3 (September 1, 2015): 311–19. http://dx.doi.org/10.1515/aoa-2015-0034.
Повний текст джерелаАнотація:
Abstract There has been considerable research done on multi-chamber mufflers used in the elimination of industrial venting noise. However, most research has been restricted to lower frequencies using the plane wave theory. This has led to underestimating acoustical performances at higher frequencies. Additionally, because of the space-constrained problem in most plants, the need for optimization of a compact muffler seems obvious. Therefore, a muffler composed of multiple rectangular fin-shaped chambers is proposed. Based on the eigenfunction theory, a four-pole matrix used to evaluate the acoustic performance of mufflers will be deduced. A numerical case for eliminating pure tones using a three-fin-chamber muffler will also be examined. To delineate the best acoustical performance of a space-constrained muffler, a numerical assessment using the Differential Evolution (DE) method is adopted. Before the DE operation for pure tone elimination can be carried out, the accuracy of the mathematical model must be checked using experimental data. The results reveal that the broadband noise has been efficiently reduced using the three-fin-chamber muffler. Consequently, a successful approach in eliminating a pure tone using optimally shaped three-fin-chamber mufflers and a differential evolution method within a constrained space has been demonstrated.
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Guo, Kangkang, Yongjie Ren, Yiheng Tong, Wei Lin, and Wansheng Nie. "Analysis of self-excited transverse combustion instability in a rectangular model rocket combustor." Physics of Fluids 34, no. 4 (April 2022): 047104. http://dx.doi.org/10.1063/5.0086226.
Повний текст джерелаАнотація:
A methane/oxygen mixture is considered to be an appropriate propellant for many future rocket engines due to its practicality and low cost. To better understand the combustion instability in methane/oxygen-fed rocket engines, the spontaneous transverse combustion instability in a rectangular multi-element combustor (RMC) was analyzed both experimentally and numerically. Severe combustion instabilities occurred in the RMC during repeatable hot-fire tests. The physical mechanisms were systematically investigated through numerical simulations based on the stress-blended eddy simulation and flamelet-generated manifolds method with detailed chemical mechanisms (GRI Mech 3.0). The numerical results for the frequency spectrum and spatial modes agree well with the theoretical analysis and experimental data. The driven regions of the combustion instability were identified on both sides of the combustion chamber through a Rayleigh index analysis. The longitudinal pressure oscillations in the oxidizer post were found to be coupled with the transverse pressure waves in the combustion chamber and led to periodic oscillations of the mass flow rate of propellant. Moreover, the mixing was highly enhanced when the pressure wave interacted with walls of the combustion chamber. Therefore, a sudden release of heat occurred. The pressure oscillations were enhanced by pulsated heat release. A closed-loop system with positive feedback associated with periodic oscillations mass flow rate of the propellant, and sudden heat release, was believed to account for the present combustion instability.
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Yang, Shiliang, Hua Wang, Yonggang Wei, Jianhang Hu, and Jia Wei Chew. "Particle-scale characteristics of the three distinct regions in the multi-chamber slot-rectangular spouted bed." Powder Technology 360 (January 2020): 658–72. http://dx.doi.org/10.1016/j.powtec.2019.10.038.
Повний текст джерела
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Yi, Tae-Hyeong, Jing Lou, Cary Kenny Turangan, and Piotr Wolanski. "Numerical Study of Detonation Processes in Rotating Detonation Engine and its Propulsive Performance." Transactions on Aerospace Research 2020, no. 3 (September 1, 2020): 30–48. http://dx.doi.org/10.2478/tar-2020-0015.
Повний текст джерелаАнотація:
AbstractNumerical studies on detonation wave propagation in rotating detonation engine and its propulsive performance with one- and multi-step chemistries of a hydrogen-based mixture are presented. The computational codes were developed based on the three-dimensional Euler equations coupled with source terms that incorporate high-temperature chemical reactions. The governing equations were discretized using Roe scheme-based finite volume method for spatial terms and second-order Runge-Kutta method for temporal terms. One-dimensional detonation simulations with one- and multi-step chemistries of a hydrogen-air mixture were performed to verify the computational codes and chemical mechanisms. In two-dimensional simulations, detonation waves rotating in a rectangular chamber were investigated to understand its flowfield characteristics, where the detailed flowfield structure observed in the experiments was successfully captured. Three-dimensional simulations of two-waved rotating detonation engine with an annular chamber were performed to evaluate its propulsive performance in the form of thrust and specific impulse. It was shown that rotating detonation engine produced constant thrust after the flowfield in the chamber was stabilized, which is a major difference from pulse detonation engine that generates repetitive and intermittent thrust.
Дисертації з теми "RECTANGULAR MULTI BAFFLED CHAMBER"
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YADAV, MOHIT. "COMPUTATIONAL FLUID DYNAMICS (CFD) ANALYSIS OF RECTANGULAR MULTI BAFFLED CHAMBER USING ANSYS FLUENT." Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14663.
Повний текст джерелаАнотація:
ABSTRACT
In this Dissertation, using ANSYS Fluent software (R14.5) computational fluid
dynamics (CFD) analysis of 3D Rectangular Baffled Chamber is done. The
Model consists of combination of vertical standing as well as hanging angled
baffles. Flow patterns are taken into consideration. The dead zones and stream
lines together with velocity vectors are analyzed of chamber by changing number
of baffles in terms of spacing and the discharge coming into the chamber. In a
finite volume, the numbers of chambers form 4 to 6 are increased by reducing the
spacing in terms of width between them and discharge from 10 liters per hour to
50 liters per hour is varied to value of less, equals and more than the capacity of
chamber. The combination of stream lines and Velocity vectors covering
maximum area of chamber is presented which will increase the (baffling
performance) efficiency as well as the effective volume utilized. In results, the
velocity graph at locations i.e. near bottom, mid depth and near surface of models
containing different number of chambers is shown. The Results obtained can be
used in further improvement of ABR design.
Тези доповідей конференцій з теми "RECTANGULAR MULTI BAFFLED CHAMBER"
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Marshall, William, Sibtosh Pal, Roger Woodward, and Robert Santoro. "Experimental Study of Transverse Combustion Instabilities in a Multi-Element, Rectangular Rocket Chamber." In 43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2007. http://dx.doi.org/10.2514/6.2007-5588.
Повний текст джерела
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Lammel, Oliver, Tim Rödiger, Michael Stöhr, Holger Ax, Peter Kutne, Michael Severin, Peter Griebel, and Manfred Aigner. "Investigation of Flame Stabilization in a High-Pressure Multi-Jet Combustor by Laser Measurement Techniques." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-26376.
Повний текст джерелаАнотація:
In this contribution, comprehensive optical and laser based measurements in a generic multi-jet combustor at gas turbine relevant conditions are presented. The flame position and shape, flow field, temperatures and species concentrations of turbulent premixed natural gas and hydrogen flames were investigated in a high-pressure test rig with optical access. The needs of modern highly efficient gas turbine combustion systems, i.e., fuel flexibility, load flexibility with increased part load capability, and high turbine inlet temperatures, have to be addressed by novel or improved burner concepts. One promising design is the enhanced FLOX® burner, which can achieve low pollutant emissions in a very wide range of operating conditions. In principle, this kind of gas turbine combustor consists of several nozzles without swirl, which discharge axial high momentum jets through orifices arranged on a circle. The geometry provides a pronounced inner recirculation zone in the combustion chamber. Flame stabilization takes place in a shear layer around the jet flow, where fresh gas is mixed with hot exhaust gas. Flashback resistance is obtained through the absence of low velocity zones, which favors this concept for multi-fuel applications, e.g. fuels with medium to high hydrogen content. The understanding of flame stabilization mechanisms of jet flames for different fuels is the key to identify and control the main parameters in the design process of combustors based on an enhanced FLOX® burner concept. Both experimental analysis and numerical simulations can contribute and complement each other in this task. They need a detailed and relevant data base, with well-known boundary conditions. For this purpose, a high-pressure burner assembly was designed with a generic 3-nozzle combustor in a rectangular combustion chamber with optical access. The nozzles are linearly arranged in z direction to allow for jet-jet interaction of the middle jet. This line is off-centered in y direction to develop a distinct recirculation zone. This arrangement approximates a sector of a full FLOX® gas turbine burner. The experiments were conducted at a pressure of 8 bar with preheated and premixed natural gas/air and hydrogen/air flows and jet velocities of 120 m/s. For the visualization of the flame, OH* chemiluminescence imaging was performed. 1D laser Raman scattering was applied and evaluated on an average and single shot basis in order to simultaneously and quantitatively determine the major species concentrations, the mixture fraction and the temperature. Flow velocities were measured using particle image velocimetry at different section planes through the combustion chamber.
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Akyuzlu, K. M., K. Albayrak, and C. Karaeren. "A Numerical Study of Thermoacoustic Oscillations in a Rectangular Channel Using CMSIP Method." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-13109.
Повний текст джерелаАнотація:
This paper presents a mathematical model that was developed to study instabilities (primarily thermoacoustic oscillations) experienced inside a channel (with a rectangular cross section) heated symmetrically (from its top and bottom.) The heated channel is configured to simulate a combustion chamber of a rocket hybrid rocket motor and is connected to a converging–diverging nozzle in the downstream and to a plenum with a flow straightener in the upstream side. The working fluid is supplied from a pressurized storage tank to the upstream plenum through a throttle valve. A multi-component approach is used to model this test apparatus. In this integrated component model, the unsteady flow through the throttle valve and the nozzle is assumed to be one-dimensional and isentropic where as the flow in the forward plenum and the heated channel is assumed to be a two-dimensional, unsteady, compressible, turbulent, and subsonic. The physics based mathematical model of the flow in the channel consists of conservation of mass, momentum (two-dimensional Navier-Stokes) and energy equations subject to appropriate boundary conditions as defined by the physical problem stated above. The working fluid is assumed to be compressible where the density of the fluid is related to the pressure and temperature of the fluid through a simple ideal gas relation. The governing equations are discretized using second order accurate central differencing for spatial derivatives and second order accurate (based on Taylor expansion) finite difference approximations for temporal derivatives. The resulting nonlinear equations are then linearized using Newton’s linearization method. The set of algebraic equations that result from this process are then put into a matrix form and solved using a Coupled Modified Strongly Implicit Procedure (CMSIP) for the unknowns (primitive variables, i.e., pressure, temperature, and the velocity field) of the problem. The turbulence model equations and the unsteady flow equation for the throttle valve are solved using a second order accurate explicit finite difference technique. Convergence and grid independence studies were done to determine the optimum mesh size and computational time increment. Furthermore, two benchmark cases (unsteady driven cavity and laminar channel flows) were simulated using the developed numerical model to verify the accuracy of the proposed solution procedure. Numerical experiments were then carried out to simulate the thermoacoustic oscillations inside rectangular channels with various aspect ratios ranging from 5 to 20 for various operating conditions (i.e., for Re numbers between 102 and 106) and to determine the flow regions where these oscillations are sustained. The numerical simulation results indicate that the mathematical model for the gas flow in the heated channel predicts the expected unsteady temperature and pressure distributions, and the velocity field, successfully. Furthermore, it is concluded that the proposed integrated component model is successful in generating the characteristics of the instabilities associated with thermal, hydrodynamic, and thermoacoustic oscillations in heated channels.
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Vasilyev, A., V. Zakharov, V. Lyashenko, R. Medvedev, O. Chelebyan, and A. Maiorova. "Experience of Low-Emission Combustion of Aviation and Bio Fuels in Individual Flames After Front Mini-Modules of a Combustion Chamber." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-75419.
Повний текст джерелаАнотація:
In the world economy more and more attention is paid to the environment protection. This has brought a requirement for reduction of harmful substances emission from the gas turbine engine combustors to the foreground scene. Several concepts of low-emission combustion of liquid fuels have been suggested to solve the problem of nitric oxide emission reduction. The authors consider combustion of lean homogenized (quick-mixed) fuel-air mixtures to be the most promising concept for a multi-mode combustion chamber. Based on the accumulated experience, the authors have formed some notion with respect to design peculiarities of low-emission combustors. Based on such general notions, an attempt has been made to create a model combustion chamber for decreasing harmful substances emission. A design for compact mixing modules has been worked out, as well as for a perforated flame tube. 3D computations have been carried out for the flow in the combustor compartment with 3 mini-modules, so to compare design and experimental data. In calculations the air entered the flame tube through a channel with a rectangular cross-section and, further, through swirlers of three burners (60% of air flow). Besides, the air came into the gap between the flame tube and casing through two side channels and, further, it got inside the flame tube through cooling system holes (40% of air flow). In parallel, tests have been carried out in similar combustor compartment, using standard fuels, measuring harmful substances emission at gas temperature (T4) up to 1700 K. Data obtained testifies to essential reduction of nitric oxides in the experimental combustor being considered. Emission index NOx does not exceed value of 1 g/kg f in all the conditions investigated. Fuel efficiency is ≥ 99% for all the measurement regimes, except one, where it is 98%. Additionally, tests have been conducted, using bio fuel obtained from plant raw material. Research results have revealed problems of changeover to such type of fuel mixtures. Comparing test data with 3D simulation results, it can be noted that there, where computed value of the fuel combustion efficiency coincides with the measured one, NOx value also coincides. However, the emission index value is higher there, where the fuel combustion efficiency value obtained in computation is higher, i.e. where there are zones with higher temperature. The experimental results obtained have confirmed possibility of organizing low-emission combustion, as well as possibility of achieving the nitric oxide emission index level equal to 1 g/kg f at the combustor inlet temperature of 682K. It is evident that more detailed design study is required for transfer of the experimental technology to the working compartment of the combustion chamber. The achieved level of harmful substances emission, after improvement and implementation of technology, may allow meeting the strictest ICAO requirements and reducing the airport fees significantly.
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Asmatulu, R., S. Gokathoti, H. Liao, and C. Yip. "Temperature and Humidity Effects on the Mechanical Properties of Polymeric Nanocomposites." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-12337.
Повний текст джерелаАнотація:
An environmental testing was conducted on polymeric nanocomposites fabricated by dispersing the carbon nanotubes (CNTs) into polymeric epoxy resins in order to determine their shelf life, reliability, stability, as well as other property changes as a function of temperature and humidity. In this study, various multi wall CNTs (∼140 nm diameter and ∼7 μm length) ranging from 0.5% to 2.0% were initially dispersed in ethanol using a magnetic stirrer, and then an epoxy resin was added to the mixtures under continuous stirring. When the solvent completely evaporated after 18 hours of stirring, a hardener was added to the dispersion. The mixtures were then poured into rectangular shape molds and cured for 48 hours at the room temperature and pressure. Furthermore, a few samples of plain epoxy without nanotubes were also cast for comparison purposes. Dog-bone specimens were tested on a tensile testing machine after different hours of degradation in an environmental chamber. The experimental results showed that the yield stress, ultimate tensile strength and modulus of elasticity gradually reduced over time, indicating that nanocomposites were highly dependent on the humidity and temperature conditions. The results provide a useful guideline for a variety of applications of the nanocomposites in the future.