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1
Noël, Florian, Claire Trocquet, Christophe A. Serra, and Stéphane Le Calvé. "Experimental Validation of a Novel Generator of Gas Mixtures Based on Axial Gas Pulses Coupled to a Micromixer." Micromachines 12, no. 6 (June 18, 2021): 715. http://dx.doi.org/10.3390/mi12060715.
Повний текст джерелаАнотація:
In this work, a novel generator of gas mixtures previously numerically investigated and based on axial gas pulses coupled to a micromixer has been conceived, manufactured, and validated. Standard gaseous pollutant mixtures and pure nitrogen or pure air were introduced in a microdevice designed to generate alternating axial gas pulses which were downstream homogenized by means of a multi-stage modular micromixer. The dilution, and therefore the final pollutant concentration, was controlled by two parameters: the ratio between the times of each of the two gas pulses and the partial pressure of the pollutant(s) mixture added to the device. The gas mixture generator was coupled to an analyzer to monitor the concentration of aromatic pollutants. The response time was optimized to be lower than 2 min in accordance with the analytical instrument. The quantity of pollutants measured at the micromixer’s outlet increased linearly with the expected gas concentration of 3.7–100 ppb generated by this novel microfluidic generator and fitted perfectly with those obtained by a reference gas dilution bench. At 5 ppb, the precision on the concentration generated is close to that obtained with the conventional gas mixing bench, i.e., around 10%.
2
Venkata Ramesh Mamilla, Dr, K. Sri Rama Murthy, M. M.Vamsi Krishna, T. S.S.S ManikanthaSwamy, A. S.S.S ManikanthaSwamy4, A.Ramesh, and M. Uday Krishna. "Production of Brown’s Gas using Hydroxy Generator." International Journal of Engineering & Technology 7, no. 4.5 (September 22, 2018): 428. http://dx.doi.org/10.14419/ijet.v7i4.5.20198.
Повний текст джерелаАнотація:
This paper deals with the designing of hydroxyl (HHO) generator and thus use the Brown’s Gas liberated from it as a supplement to increase fuel efficiency in IC engines. The combustion process in IC engines is very primitive and hence unburnt fuel remains after the combustion process. This is a very challenging problem being faced by today’s automobile industry as this unburnt mixture is a serious air pollutant. The proposed approach is based on an ordinary HHO generator. Although people use HHO generators in practice a very little research has been carried out in implementing an efficient system. This project is mainly focused on finding an efficient configuration of an ordinary HHO generator that is efficient than an ordinary system. Here the generator was tested under several conditions in order to determine a convenient design for an efficient HHO generator.
3
Frolov, S. M., V. I. Zvegintsev, V. S. Aksenov, I. V. Bilera, M. V. Kazachenko, I. O. Shamshin, P. A. Gusev, and M. S. Belotserkovskaya. "Deflagration-to-detonation transition in air mixtures of polypropylene pyrolysis products." Доклады Академии наук 488, no. 2 (September 24, 2019): 162–66. http://dx.doi.org/10.31857/s0869-56524882162-166.
Повний текст джерелаАнотація:
A new method for determining the detonability of fuel is proposed based on the measured values of the detonation run-up distance and time in the standard pulsed detonation tube (PDT). Granulated polypropylene (GP) was used as a fuel. A test bench with the PDT and a gas generator was designed and manufactured for the preparation of the GP pyrolysis products at a decomposition temperature of up to 800 °C. Experiments on deflagration-to-detonation transition in air mixtures of pyrolysis products of the GP showed that such mixtures exhibit detonability close to that of liquefied hydrocarbon gas (LPG) of the propane-butane automobile brand in a stoichiometric mixture with air under normal conditions.
4
Tykhomyrov, Anatolii, Sergey Zaitsev, Vadim Chichеnin, and Victor Kуshnevsky. "IMPROVEMENT OF GAS MONITORING METHODS IN WATER OF THE HYDROGEN-WATER COOLING SYSTEM OF NPP’S TURBINE GENERATOR." WATER AND WATER PURIFICATION TECHNOLOGIES. SCIENTIFIC AND TECHNICAL NEWS 29, no. 1 (July 30, 2021): 49–58. http://dx.doi.org/10.20535/2218-930012021233705.
Повний текст джерелаАнотація:
The relevance of research is to ensure and improve the reliability of turbine generators (TG) with a hydrogen-water cooling system by monitoring the content of dissolved gases in the water of a hydrogen-water cooling system with monoethanolamine (MEA) – C2H7NO and water vapor in the cooling hydrogen of the turbine. In this work, the influence of ultrasonic vibrations on the decomposition of a mixture of water and turbine oil, organic acids (acetic acid - С2Н4О2, formic acid - СН2О2, oxalic acid - С2Н2О4) or monoethanolamine was determined. The distribution coefficients values were definedd for the following dissolved gases Н2, О2, N2, СО, СН4, С2Н2, С2Н4, С2Н6, С3Н6, С3Н8, which are of degradation products of water mix components when exposed to ultrasonic oscillation in the following system: «dissolved gas – mixture «water + monoethanolamine» – extractant argon (Ar)». The obtained values of the Кі distribution coefficients for dissolved gases in systems «dissolved gas – mixture «water + С2Н7NО» – extractant argon (Ar)» at a temperature of 293 K and a concentration of С2Н7NО at the level of 1 g/dm3 are close to similar values for dissolved gases in deionized water. The principle flow chart of multichannel gas chromatograph for detecting dissolved gases in water and steam of water in hydrogen was developed. Developed flow chart of 4-chennel gas chromatographer for defining dissolved gases in water includes the one gas chromatographer with conductivity detector, methanator, flame ionization detector, argon gas-bearing and supplementary gases of hydrogen and air.
5
Song, Eunhye, and Juhun Song. "Modeling of kerosene combustion under fuel-rich conditions." Advances in Mechanical Engineering 9, no. 7 (July 2017): 168781401771138. http://dx.doi.org/10.1177/1687814017711388.
Повний текст джерелаАнотація:
The turbo-pump and turbine are driven by liquid fuel fed into a gas generator, where the fuel is oxidized with a liquid oxidizing agent. For stable operation of the turbine, the combustion temperature of the gas generator must be maintained below 1000 K. The thermodynamic characteristics of kerosene oxidation in the gas generator must be understood to optimize the design and operation conditions of the liquid-fueled rocket engine system. Herein, the 3-species surrogate mixture model for kerosene was selected, and the detailed Dagaut’s kerosene oxidation mechanism consisting of 225 chemical species and 1800 reversible chemical reactions was utilized. The exit gas temperature and product gas composition in the gas generator under fuel-rich conditions were simulated by applying the perfectly stirred reactor model. The perfectly stirred reactor model was used in combination with the liquid spray model for evaporation of the droplets and the two-temperature model for evaluation of the flame temperature separately from the locally averaged reactor temperature. The theoretical prediction of the gas species fraction and soot yield could be improved by applying the tar cracking mechanism, where the reaction characteristics under high temperature were taken into account.
6
Dudinin, Aleksey, Vladimir Tuponogovov, Igor Karasev, and Anastasia Bagutdinova. "Preparation of syngas from the semi-coke of Borodino coal for solid oxide fuel cells." MATEC Web of Conferences 245 (2018): 04012. http://dx.doi.org/10.1051/matecconf/201824504012.
Повний текст джерелаАнотація:
Syngas for the battery of solid oxide fuel cells is produced in a gas generator with a fluidized layer consisting of a mixture of electrocorundum and semi-coke of the Borodino coal at the temperature of 850 °C, fluidizable by steam in a retort heated from the outside. The concentration of semi-coke is 627 kg per 1m3 of mixture of electrocorundum and semi-coke. The heat of combustion of the obtained syngas is 13359 kJ/kg. Syngas is purified in a cyclone – dust collector and gas purification from SO2 and H2O.
7
Fiala, Jozef, Marcel Kuracina, Ivan Hrušovský, and Maros Soldan. "Study of Basic Characteristics of Hydrogen Generator." Applied Mechanics and Materials 448-453 (October 2013): 3078–81. http://dx.doi.org/10.4028/www.scientific.net/amm.448-453.3078.
Повний текст джерелаАнотація:
HHO technology appeared in USA in 1950s but only in last years it became more interesting due to rising of fossil fuels price. In a device called HHO generator, hydrogen and oxygen are produced onboard on vehicle by electrolysis of water solution of NaOH or KOH. This mixture of gases is known as a HHO gas and it is used as an additive to gasoline in conventional internal combustion engines. Construction of a HHO generator is relatively simply process with small money requirements. All measurements were realized with 10% KOH solution because this electrolyte at this concentration is considered as the best available one. KOH solution excels in chemical stability and efficiency of HHO gas production. For comparison, the 10% NaOH solution was prepared because of low price and good availability of NaOH and all measurements were repeated and results were compared.
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Wang, He Tang, De Ming Wang, and Wan Xing Ren. "Computer Simulation on Key Structure Parameters of Foam Generator for Dust Control in Underground Coal Mines." Advanced Materials Research 466-467 (February 2012): 421–24. http://dx.doi.org/10.4028/www.scientific.net/amr.466-467.421.
Повний текст джерелаАнотація:
Foam is a high efficient technology for controlling dust in underground coal mine,and foam generator is one of the core components of the technology. Aiming at designing the key structural parameters of foam generator scientifically, the velocity and pressure distribution of foam generator under different parameters were simulated and displayed by CFD (Computational Fluid Dynamics) software. The results show that the intensity of gas-liquid mixture in foam generator reaches the maximum when the vortex generator is 24mm away from the throat and the baffle with a 45° angle. Under the circumstances, the pressure is well-distributed around the vortex generator and the outlet of foam generator, and the foaming effect best.
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Becker, Anaïs, Nathaly Lohmann, Christophe A. Serra, and Stéphane Le Calvé. "Development of a Portable and Modular Gas Generator: Application to Formaldehyde Analysis." Chemosensors 10, no. 4 (March 31, 2022): 131. http://dx.doi.org/10.3390/chemosensors10040131.
Повний текст джерелаАнотація:
This work aims at developing and validating under laboratory-controlled conditions a gas mixture generation device designed for easy on-site or laboratory calibration of analytical instruments dedicated to air monitoring, such as analysers or sensors. This portable device, which has been validated for formaldehyde, is compact and is based on the diffusion of liquid formaldehyde through a short microporous interface with an air stream to reach non-Henry equilibrium gas–liquid dynamics. The geometry of the temperature-controlled assembly has been optimised to allow easy change of the aqueous solution, keeping the microporous tube straight. The formaldehyde generator has been coupled to an on-line formaldehyde analyser to monitor the gas concentration generated as a function of the liquid formaldehyde concentration, the temperature, the air gas flow rate, and the microporous tube length. Our experimental results show that the generated gaseous formaldehyde concentration increase linearly between 10 and 1740 µg m−3 with that of the aqueous solution ranging between 0 and 200 mg L−1 for all the gas flow rates studied, namely 25, 50 and 100 mL min−1. The generated gas phase concentration also increases with increasing temperature according to Henry’s law and with increasing the gas–liquid contact time either by reducing the gas flow rate from 100 to 25 mL min−1 or increasing the microporous tube length from 3.5 to 14 cm. Finally, the performances of this modular formaldehyde generator are compared and discussed with those reported in the scientific literature or commercialised by manufacturers. The technique developed here is the only one allowing to operate with a low flow rate such as 25 to 100 mL min−1 while generating a wide range of concentrations (10–1000 µg m−3) with very good accuracy.
10
Yagi, H., T. Ide, H. Toyota, and Y. Mori. "Generation of microwave plasma under high pressure and fabrication of ultrafine carbon particles." Journal of Materials Research 13, no. 6 (June 1998): 1724–27. http://dx.doi.org/10.1557/jmr.1998.0239.
Повний текст джерелаАнотація:
A microwave plasma generator, which functions under high pressure, has been developed and used in the fabrication of fine carbon particles. The plasma generator is a two-stage-type resonator, which consists of rectangular and semi-cylindrical-type resonators which are coupled in series for torching plasma and keeping it stable under high pressure. The plasma can be torched in helium gas at 3 × 106 Pa by tuning the dimensions of apparatus elements. Fine carbon particles of ~50 nm are obtained using a mixture of helium and methane gas. The particles are found to be crystalline from the results of transparent electron microscopy and diffraction analysis.
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KOROTIN, Semyon Y., and Anatoliy I. SHCHELOKOV. "RESEARCH OF MULTI-COMPONENT HEAT CARRIERS AND DEVELOPMENT OF TECHNICAL MEANS OF THEIR RECEIVING." Urban construction and architecture 8, no. 4 (December 15, 2018): 133–36. http://dx.doi.org/10.17673/vestnik.2018.04.22.
Повний текст джерелаАнотація:
The possibility and expediency of using multicomponent coolants in thermal technological processes, obtained by injection and subsequent evaporation of small water droplets by direct contact with the products of complete combustion of hydrocarbon fuel, is considered. The results of studies of the formation of gas-vapor mixture in the heat generator with the injection of superheated water into the stream of products of complete combustion of gas fuel are given.
12
Yuan, Chenheng, Cuijie Han, Mian Yang, and Yan Zhang. "Numerical investigation into the fuel evaporation and mixture formation characteristics of a free-piston diesel engine." International Journal of Engine Research 21, no. 7 (August 19, 2019): 1180–92. http://dx.doi.org/10.1177/1468087419870361.
Повний текст джерелаАнотація:
The free-piston engine generator becomes a new-type potential substitute for the conventional crankshaft combustion engine. This article presents a simulation to study the fuel spray and mixing characteristics of a diesel free-piston engine generator by comparing a corresponding crankshaft combustion engine. A full-cycle model which couples with piston dynamics, combustion, and gas exchange is developed to simulate the fuel spray, atomization, and mixing in the free-piston engine generator. The result indicates that compared with the crankshaft combustion engine, the free-piston engine generator provides a higher temperature and pressure for fuel spray and mixing during the ignition delay, but its ignition delay lasts shorter. The free-piston engine generator shows a shorter spray penetration and more fuel impingement due to its smaller combustion chamber volume during the injection process. The free-piston engine generator exhibits a lower level of air utilization and worse uniformity of fuel–air mixture in combustion chamber. In addition, the shorter ignition delay of free-piston engine generator makes the time of atomization, evaporation, and mixing of fuel shorter, and the mixing effect of free-piston engine generator is worse, resulting in less combustible mixture formed during the ignition delay. In addition, some guiding suggestions have been proposed to improve the fuel spray and fuel–air mixing characteristics of free-piston engine generator.
13
Yuan, Chenheng, Jiahui Li, Liange He, and Yituan He. "Effect of injection position on fuel spray and mixture preparation of a free-piston linear engine generator." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 234, no. 8 (January 13, 2020): 1161–74. http://dx.doi.org/10.1177/0957650919900101.
Повний текст джерелаАнотація:
Fuel spray and mixing in linear engines is coupled by dynamics, combustion, and gas exchange, which differs from that in conventional engines. This work presents a system simulation to reveal the multi-process coupling effect of injection position on the fuel spray and mixing of a free piston linear diesel engine (FPLE). A full-cycle fuel spray model which couples with dynamic, combustion, and gas exchange is established to predict the coupled effect on mixture formation. The results indicate that the variable injection position changes the FPLE motion through multi-process coupling effect, resulting in different boundary conditions for fuel spray and mixing. Relatively large injection advance position leads to more residual gas, fast speed, intense turbulence, low gas pressure, and temperature at the moment of injection for mixture formation. The earlier fuel injection generally makes the longer spray penetration, smaller Sauter mean diameter of droplets, less fuel impingement, faster fuel evaporation rate, and more evaporated fuel mass. However, too early injection does not support the above results. Suggesting that in order to achieve homogeneous combustion mode, the large injection advance position injection schedule operation is a good choice for the FPLE due to its long ignition delay duration for fuel atomization, evaporation, and mixing.
14
Saik, Pavlo, Roman Dychkovskyi, Vasyl Lozynskyi, Volodymyr Falshtynskyi, Edgar Cabana, and Leonid Hrytsenko. "Studying the features of the implementation of underground coal gasification technology in terms of Lvivvuhillia SE." E3S Web of Conferences 168 (2020): 00036. http://dx.doi.org/10.1051/e3sconf/202016800036.
Повний текст джерелаАнотація:
Topical issues of the possibilities for changes in the coal extraction technology in terms of Stepova mine of Lvivvuhillia SE have been highlighted. Analysis of the current state of mining operations has been carried out. Design solutions as for introduction of the coal gasification technology in the life cycle of the mining enterprise has been proposed on the basis of the analytical, experimental, and industrial studies; the technology has been described. Percentage ratio of the output of combustion generator gases (Н2, СО, СН4) has been identified; gas combustion value and efficiency of the process depending on certain changes in the blowing mixture composition supplied into the underground gas generator have been determined. Heat balance of the process of underground coal gasification has been studied making it possible to evaluate its energy balance. The algorithm to determine coal reserves in a mine pillar to be gasified has been proposed. Indices of the output of combustion generator gases from the gasification column have been defined. The relevant issues have been studied of ensuring the possibility of underground coal gasification technology when uncovering the mining extracted area for the underground gas generator operation.
15
Baumgärtner, Max H., and Thomas Sattelmayer. "Improvement of the turn-down ratio of gas turbines by autothermal on board syngas generation." Journal of the Global Power and Propulsion Society 1 (June 30, 2017): D0HPA5. http://dx.doi.org/10.22261/d0hpa5.
Повний текст джерелаАнотація:
Abstract The low reactivity of natural gas leads to a sudden increase of carbon monoxide (CO) and unburned hydrocarbons (UHC) emissions below a certain load level, which limits the part load operation range of current utility gas turbines in combined cycle power plants (CCPP). The feasibility of catalytic autothermal syngas generation directly upstream of gas turbine burners to improve burn-out at low flame temperatures is studied in this paper. The adiabatic reformer is supplied with a mixture of natural gas, air and water and generates syngas with high reactivity, which results in better low-temperature combustion performance. Substitution of part of the natural gas by syngas provides the opportunity of lowering overall equivalence ratio in the combustion chamber and of extending the operation range towards lower minimum power output without violating emission limits. A generic gas turbine with a syngas generator is modelled by analytic equations to identify the possible operating window of a fuel processor constrained by pressure loss, low and high temperature limits and carbon formation. A kinetic study shows good conversion of methane to syngas with a high hydrogen share. A calculation of the one-dimensional laminar burning velocity of mixtures of syngas and methane and the assessment of the corresponding Damköhler number show the potential for lowering the minimum equivalence ratio with full burn-out by fuel processing. The study shows that such a fuel processor has a possible operating range despite the before mentioned constraints and it has potential to reduce the lowest possible load of gas turbines in terms of thermal power by 20%.
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Lezsovits, Ferenc, Sándor Könczöl, and Krisztián Sztankó. "CO emission reduction of a HRSG duct burner." Thermal Science 14, no. 3 (2010): 845–54. http://dx.doi.org/10.2298/tsci1003845l.
Повний текст джерелаАнотація:
A heat-recovery steam generator was erected after a gas-turbine with a duct burner into the district heat centre. After commissioning, the CO emissions were found to be above the acceptable level specified in the initial contract. The Department of Energy Engineering of the BME was asked for their expert contribution in solving the problem of reducing these CO emissions. This team investigated the factors that cause incomplete combustion: the flue-gas outlet of the gas-turbine has significant swirl and rotation, the diffuser in between the gas-turbine and heat-recovery steam generator is too short and has a large cone angle, the velocity of flue-gas entering the duct burner is greater than expected, and the outlet direction of the flammable mixture from the injector of the duct burner was not optimal. After reducing the flow swirl of flue-gas and modifying the nozzle of the duct burner as suggested by the Department of Energy Engineering of the BME, CO emissions have been reduced to an acceptable level. The method involves the application of CFD modeling and studying images of the flames which proved to be very informative.
17
Sharif, Yousef A., Saad S. Jasim, Rafeq A. Khalefa, and Shivan J. Taher. "Experimental Investigation of the Hydroxy Gas Generation as a Clean Energy Source for Spark Ignition Engine Operation Using Different Electrolytes." Polytechnic Journal 11, no. 1 (August 26, 2021): 16–21. http://dx.doi.org/10.25156/ptj.v11n1y2021.pp16-21.
Повний текст джерелаАнотація:
The main objective of this research is to generate the hydrogen gas as a fuel and part of hydroxy gas (HHO) from the drinking water (H2O) using electrolyzing method with a different electrolytes such as sodium hydroxide (NaOH), sodium carbonate (Na2CO3), and Vinegar in HHO generator for best results, the practical examinations were done by a generator that designed and built for this purpose using plate electrodes, with a rechargeable 12-volt battery and the produced gas was measured at each case and used as a fuel for operating a small single-cylinder spark-ignition engine (Honda G 200) with taking into account the safety precautions. The results show that increasing the ratio of (NaOH) grams/liter of H2O increases the gas production, while the other two electrolytes (Na2CO3 and vinegar) are not effecting too much, and using the mixing procedure (%) of the electrolytes (NaOH with Na2CO3) and (Na2CO3 with Vinegar), it is observed that the HHO generation noticeable increases with increasing the mixing ratio of the first mixture and not too much with the second.
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Elbarghthi, Anas F. A., Mohammad Yousef Hdaib, and Václav Dvořák. "A Novel Generator Design Utilised for Conventional Ejector Refrigeration Systems." Energies 14, no. 22 (November 17, 2021): 7705. http://dx.doi.org/10.3390/en14227705.
Повний текст джерелаАнотація:
Ejector refrigeration systems are rapidly evolving and are poised to become one of the most preferred cooling systems in the near future. CO2 transcritical refrigeration systems have inherently high working pressures and discharge temperatures, providing a large volumetric heating capacity. In the current research, the heat ejected from the CO2 gas cooler was proposed as a driving heating source for the compression ejector system, representing the energy supply for the generator in a combined cycle. The local design approach was investigated for the combined plate-type heat exchanger (PHE) via Matlab code integrated with the NIST real gas database. HFO refrigerants (1234ze(E) and 1234yf) were selected to serve as the cold fluid on the generator flowing through three different phases: subcooled liquid, a two-phase mixture, and superheated vapour. The study examines the following: the effectiveness, the heat transfer coefficients, and the pressure drop of the PHE working fluids under variable hot stream pressures, cold stream flow fluxes, and superheated temperatures. The integration revealed that the cold fluid mixture phase dominates the heat transfer coefficients and the pressure drop of the heat exchanger. By increasing the hot stream inlet pressure from 9 MPa to 12 MPa, the cold stream two-phase convection coefficient can be enhanced by 50% and 200% for R1234yf and R1234ze(E), respectively. Conversely, the cold stream two-phase convection coefficient dropped by 17% and 37% for R1234yf and R1234ze(E), respectively. The overall result supports utilising the ejected heat from the CO2 transcritical system, especially at high CO2 inlet pressures and low cold channel flow fluxes. Moreover, R1234ze(E) could be a more suitable working fluid because it possesses a lower pressure drop and bond number.
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Планковский, Сергей Игоревич, Ольга Владимировна Шипуль, Олег Валерьевич Трифонов та Сергей Александрович Заклинский. "АЛГОРИТМ УПРАВЛЕНИЯ СИСТЕМОЙ ГЕНЕРАЦИИ СМЕСИ ДЛЯ ПРЕЦИЗИ-ОННОЙ ТЕРМОИМПУЛЬСНОЙ ОБРАБОТКИ". Aerospace technic and technology, № 5 (8 листопада 2018): 58–66. http://dx.doi.org/10.32620/aktt.2018.5.09.
Повний текст джерелаАнотація:
The subjects of the study are methods and devices of generating gas mixtures with a specified accuracy and a high repeatability of the component dosing. The purpose of the article is to develop an algorithm for controlling the fuel mixture generation system for precision thermal pulse treatment. In that behalf, the research tasks are the improvement of the critical hole method with reference to the thermal pulse treatment and the methodology development of parameters assigning for mixture generation system ensuring high accuracy and repeatability of the dosing of its components and heat flows in thermal pulse treatment. The following results are obtained. The method of dynamic mixture formation based on the method of critical holes is proposed. Its special advantage is that during the filling of the chamber, the components of the fuel mixture expire from the pre-filled intermediate pressure vessels with the controlled volume without the application of any regulating devices. The technique for choosing the diameters of critical apertures, the volumes of intermediate tanks and the initial pressure in them, providing accuracy of components dosing at the level 0,01 % is developed. The technical solutions that allow to stabilize the value of heat flow during thermal pulse treatment, considering the operation dynamics of the valves in the mixture generation system and the variable temperature of the chamber walls are proposed. The following conclusions are formulated. The method of generating fuel mixtures for precision thermal pulse treatment based on the method of critical holes is proposed. It is characterized by the fact that during the mixture formation, the free exhaust of gases from pre-filled intermediate tanks is applied. The developed procedure for calculating the parameters of the mixture generator on the basis of the proposed method makes it possible to determine the ratio of the areas of the critical holes, the volumes of the tanks, the initial pressure in them and the time of filling the chamber according to the given composition and pressure of the mixture at normal temperature. The algorithm for controlling the generation of a mixture for precision thermal pulse processing is developed. The necessity of controlling the opening and closing speed of the gas supply valves is shown taking into account the required ratio of the areas of critical holes. To ensure a stable value of heat fluxes during cyclic thermal pulse treatment, it is shown that it is necessary to simultaneously monitor the charge mass and the pressure in the chamber when the fuel mixture is supplied, followed by correcting the treatment time according to the calculated initial temperature of the fuel mixture
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Parise, John B., Xianyin Chen, Anna M. Plonka, William R. Woerner, Debasis Banerjee, David Connors, and Nancy Goroff. "XRD-DSC: a screening tool for identifying effective MOFs for selective gas sorption from humid gas streams." Powder Diffraction 34, no. 1 (February 7, 2019): 3–12. http://dx.doi.org/10.1017/s088571561900006x.
Повний текст джерелаАнотація:
A commercially available combined X-ray diffraction – differential scanning calorimetry (XRD-DSC) stage was adapted for studies of gas loading in microporous materials, including metal organic frameworks (MOFs). Insertion of a custom-built humid atmosphere swing chamber (HASC) between a humidity generator and the XRD-DSC stage facilitates both humid atmosphere and vacuum swing gas loading. The HASC is necessary to buffer between the humidity generator and the XRD-DSC stage, allowing the gas mixture to homogenize prior to sample exposure, so that both humid atmosphere and vacuum swings could be performed. The changes in XRD can be used to follow structural changes, including collapse, which is indicative of a lack of microporosity upon activation, and the flexibity of frameworks upon gas sorption–desorption cycles. Measurements of the area under the DSC curve allows for calculation of the isosteric heat of adsorption (Qst; kJ molGAS−1). Vacuum-atmosphere swing experiments performed at different pressure steps allow for the reconstruction of the enthalpy of gas adsorption before and after a phase transition. These modes of operation are illustrated in three case studies from a program of exploratory MOF synthesis used to discover novel materials for selective gas sorption from humid gas streams: (1) gas binding in Stony Brook metal organic framework-1, (2) zeolitic imidazolate framework-7 response to variable pressure vacuum-atmosphere swing, and (3) high throughput evaluation of the selectivity of novel MOFs synthesized from customized linkers.
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Zaichenko, S., S. Korol, V. Opryshko, D. Derevyanko, and N. Zhukova. "MODELING OF THE PROCESS OF ELECTROMECHANICAL CONTROL OF GAS DISTRIBUTION OF AN ELECTRIC ENERGY GENERATOR WITH AN INTERNAL COMBUSTION ENGINE." POWER ENGINEERING: economics, technique, ecology, no. 1 (October 11, 2021): 51–58. http://dx.doi.org/10.20535/1813-5420.1.2021.242160.
Повний текст джерелаАнотація:
The use of generators at different load levels allows you to use part of the rated power of the engines, by reducing the speed of the internal combustion engine, thus reducing fuel consumption and increase the overall efficiency of the system as a whole. However, it should be noted that the optimal operation of the internal combustion engine at fixed gas distribution parameters is possible only at a certain engine speed. Reducing the engine speed leads to a deterioration of the filling of the fuel-air mixture and the release of exhaust gases from the engine, accompanied by the intake of exhaust gases into the intake manifold and the emission of part of the fuel
mixture into the exhaust pipe. The paper presents the results of the study of generator parameters and the general concept of creating an autonomous power supply control system based on an internal combustion engine in order to reduce the specific indicators of electricity generation. The expediency of regulating the power level of an internal combustion engine has been experimentally proved. To achieve this goal, it is proposed to adjust the opening and closing angles of the internal combustion engine with a solenoid valve. The use of this system allows to reduce the specific costs by more than 4 times when generating electricity with low generator load. Based on the phase distribution diagram of the internal combustion engine, the dependence of the change of the opening and closing angles of the inlet and outlet valves on the power of the autonomous energy source is proposed.
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Chiu, Hsiu Mei, Po Chuang Chen, Yau Pin Chyou, and Ting Wang. "Efficiency Analysis of Gas Turbine Combined-Cycle Fed with Synthetic Natural Gas (SNG) and Mixture of Syngas and SNG." Key Engineering Materials 656-657 (July 2015): 113–18. http://dx.doi.org/10.4028/www.scientific.net/kem.656-657.113.
Повний текст джерелаАнотація:
The effect of synthetic natural gas (SNG) and mixture of syngas and SNG fed to Natural Gas Combined-Cycle (NGCC) plants is presented in this study via a system-level simulation model. The commercial chemical process simulator, Pro/II®V8.1.1, was used in the study to build the analysis model. The NGCC plant consists of gas turbine (GT), heat recovery steam generator (HRSG) and steam turbine (ST). The study envisages two analyses as the basic and feasibility cases. The former is the benchmark case which is verified by the reference data with the GE 7FB gas turbine. According to vendor’s specification, the typical net plant efficiency of GE 7FB NGCC with two gas turbines to one steam turbine is 57.5% (LHV), and the efficiency is the benchmark in the simulation model built in the study. The latter introduces a feasibility study with actual parameters in Taiwan. The SNG-fed GE 7FB based combined-cycle is evaluated, and the mixture of SNG and syngas is also evaluated to compare the difference of overall performance between the two cases. The maximum ratio of syngas to SNG is 0.14 due to the constraint for keeping the composition of methane at a value of 80 mol%, to meet the minimum requirement of NG in Taiwan. The results show that the efficiency in either case of SNG or mixture of SNG and syngas is slightly lower than the counterpart in the benchmark one. Because the price of natural gas is much higher than that of coal, it results in higher idle capacity of NGCC. The advantage of adopting SNG in Taiwan is that it could increase the capacity factor of combined-cycles in Taiwan. The study shows a possible way to use coal and reduce the CO2emission, since coal provides nearly half of the electricity generation in Taiwan in recent years.
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Podlesniy, D. N., A. Yu Zaichenko, E. A. Salgansky, and M. V. Salganskaya. "Stability of the Front of Filtration Combustion of Bidisperse Fuel Mixture in an Inclined Rotating Gas Generator." Russian Journal of Applied Chemistry 90, no. 11 (November 2017): 1783–88. http://dx.doi.org/10.1134/s107042721711009x.
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Saik, Pavlo, Roman Dychkovskyi, Vasyl Lozynskyi, Volodymyr Falshtynskyi, Edgar Caseres Cabana, and Leonid Hrytsenko. "Chemistry of the Gasification of Carbonaceous Raw Material." Materials Science Forum 1045 (September 6, 2021): 67–78. http://dx.doi.org/10.4028/www.scientific.net/msf.1045.67.
Повний текст джерелаАнотація:
The paper represents the studies of the process of carbonaceous raw material gasification. The initial material is represented by bituminous coal of grade H with the carbon (C) content of 79.2-85.3 %. Experimental studies have been used to substantiate the parameters of combustible generator gases (СО, Н2, СН4) output depending on the temperature of a reduction zone of the reaction channel and gas flow velocity along its length. It has been identified that the volume of the raw material input to be used for gasification process changes in direct proportion depending on the amount of burnt-out carbon and blow velocity. The gasification is intensified in terms of equal concentration of oxygen and carbon in the reaction channel of an underground gas generator. The gasification rate is stipulated by the intensity of chemical reactions, which depend immediately on the modes of blow mixture supply. Moreover, they depend directly on the intensity of oxygen supply to the coal mass and removal of the gasification products.
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Avramenko, Andrii. "Numerical Simulation of the Process of Combustion of a Stoichiometric Hydrogen-Oxygen Mixture in a Steam Generator." French-Ukrainian Journal of Chemistry 9, no. 2 (2021): 34–51. http://dx.doi.org/10.17721/fujcv9i2p34-51.
Повний текст джерелаАнотація:
Numerical methods are used to study the process of combustion of a stoichiometric hydrogen-oxygen mixture. The mathematical models were validated using experimental data. The combustion process is modelled in the three-dimensional unsteady formulation. With account of the recommendations of other authors, the turbulent flows are described in the paper using the standard k-ε turbulence model. The Eddy Dissipation Model (EDM) is used to describe the process of combustion of the hydrogen-oxygen mixture. The description of the complex heat transfer between the gas, flame and walls in the paper accounts for radiant heat transfer by using the P1 model. The paper deals with combustion processes in a burner and a model steam generator. Numerical methods were used to evaluate the effect of inlet flow turbulisation, and the flow rate and the method of feeding extra water to the combustion chamber on the process of combustion of the stoichiometric hydrogen-oxygen mixture. The influence of the design and operating mode factors on the alteration of the flame-steam interface and on the flame extinguishing conditions were studied. The results obtained can be used in future in designing equipment that uses hydrogen as a fuel to increase nuclear power plant (NPP) manoeuvrability.
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Zhang, Bo, Huai Wei Zhang, Jia Jun Mao, Jie Guo, Zeng Li Liao, Qiu Ju Li, and Xin Hong. "Mathematical Modeling for Developing Iron Bath Reactor with H2-C Mixture Reduction." Advanced Materials Research 268-270 (July 2011): 269–74. http://dx.doi.org/10.4028/www.scientific.net/amr.268-270.269.
Повний текст джерелаАнотація:
The basic idea of H2-C mixture reduction reflexes using hydrogen as main reductor and carbon as main heat generator in iron bath smelt reduction reactors on purpose to cut down total energy consumption and CO2 emission. The author applied the methods of modeling for separating regions and [1]complex integration to research the kinetics behavior of the reactor. Changes of temperature and concentration field in each region were calculated after modeling from theories for solid-liquid, solid-gas and gas-liquid reactions combining theories of shrinking core, combustion and deoxidization etc. Besides some boundary- and initial conditions were got from inlet variables, other conditions included substance and energy exchanges on boundaries between different reaction regions were determined from the translation of all boundary coordination. After dispersion treatment with Control-Volume-Method, the whole model was programmed into special software for digital simulation. Corresponding author: HONG Xin, Shanghai University, Phone/Fax: 021-56331176, E-mail: xhong@online.sh.cn
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Yaroschuk, A. M. "EGYPT, DASHUR: AN ANCIENT CO/CO2 GAS GENERATOR DISCOVERED ON THE LOWER LEVEL OF THE BENT PYRAMID OF SNEFERU." Bulletin of Kemerovo State University, no. 2 (June 29, 2017): 104–10. http://dx.doi.org/10.21603/2078-8975-2017-2-104-110.
Повний текст джерелаАнотація:
The article researches the design and the purpose of the lower tier chamber in the Bent Pyramid of Sneferu in Dashure. The review of the earlier archeological research materials has shown that the purpose of the chamber has not been determined. In the process of the current research a technological link between the lower and the upper tiers of the pyramid has been found. It has been proven that the lower tier elements (the chamber itself, the shaft, and the chimney) all together comprised an ancient furnace – a CO/CO2 gas generator. Its purpose was to produce a mixture of carbon monoxide and carbon dioxide gas to fill the space of the upper tier of the pyramid. The goal of the architect or was to make the pyramid chambers deadly for burglars. Constructive similarities between the furnace in the lower tier of the Sneferu Pyramid and the modern CO/CO2 gas generator have been established. A theory about the presence of the secret chambers in the pyramid, including the chamber containing the Sarcophagus of the Pharaoh has been substantiated. A theory explaining the purpose of changing the shape and the construction of the Bent Pyramid specifically has been proposed.
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Cipitì, F., V. Recupero, L. Pino, A. Vita, and M. Laganà. "5 kWe LPG Hydrogen Generator for Polymer Electrolyte Fuel Cells: Momentum-Based Modeling of an Autothermal Reformer." Journal of Fuel Cell Science and Technology 4, no. 2 (April 13, 2006): 210–18. http://dx.doi.org/10.1115/1.2393319.
Повний текст джерелаАнотація:
This paper presents a two-dimensional model to describe the gas flow in an integrated reactor, developed at the CNR-ITAE Institute, and aimed to design a βeta5kWe hydrogen generator, named HYGen II, to integrate with polymer electrolyte fuel cells (PEFCs) for residential applications. The model is able to simulate velocity profiles in order to investigate the reactor geometrical key parameters. The unit can convert light hydrocarbons (methane, propane, LPG, butane) into a hydrogen rich mixture. The processing unit consists of an innovative integrated dual bed reactor, filled with pellet catalysts: a proprietary Pt∕CeO2 autothermal reforming (ATR) and a commercial intermediate temperature water gas shift (ITWS). For the last clean-up step, a single-stage preferential oxidation (PROX) process has been adopted. Moreover, an automation system to monitor operating conditions and control plant equipment has been designed.
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Geiling, Thomas, Tilo Welker, and Jens Müller. "Design, Fabrication, and Operation of a Nitrogen Measurement Device Based on LTCC." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2012, CICMT (September 1, 2012): 000167–74. http://dx.doi.org/10.4071/cicmt-2012-tp42.
Повний текст джерелаАнотація:
We present a so called micro total analytical system (μTAS) for the measurement of low nitrogen monoxide (NO) concentrations in gas flows. The measurement principle is based on the chemiluminescent reaction of NO with ozone (O3). The presented system scales down this measurement principle into the realm of micro fluidics and micro sensors. Low temperature co-fired ceramics (LTCC) have proven to be the ideal technology for the realization of a μTAS, as they offer high chemical and thermal stability as well as high degree of freedom of design. The system consists of 4 components: an ozone generator, an ozone concentration measurement via UV transmission, a chemiluminescent detection (CLD) chamber, and an exhaust gas treatment. The ozone generator is a micro plasma device in which ozone is produced by a dielectric barrier discharge (DBD) mechanism. From the generator the ozone is fed into a chamber with an optical port, where the concentration is determined by UV transmission measurements. Then it is brought into contact with the NO-containing analyte gas inside the reaction chamber, where the chemiluminescent reaction occurs. The reaction chamber is outfitted with an optical port as well, so that the emitted radiation can be detected and analyzed with a photo diode. The gas mixture leaving the reaction chamber is fed through a platinum catalyst, in order to decompose leftover ozone and prevent buildup of hazardous concentrations in the surroundings of the device. The contribution presents the design of each component as wells as the integrated system and gives detailed measurements of its operation.
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Geiling, Thomas, Tilo Welker, Christiane Ehrling, and Jens Müller. "Design, Fabrication, and Operation of a Nitrogen Monoxide Measurement Device Based on LTCC." Journal of Microelectronics and Electronic Packaging 9, no. 4 (October 1, 2012): 171–77. http://dx.doi.org/10.4071/imaps.343.
Повний текст джерелаАнотація:
We present a so-called micro total analytical system (μTAS) for the measurement of low nitrogen monoxide (NO) concentrations in gas flows. The measurement principle is based on the chemiluminescent reaction of NO with ozone (O3). The presented system scales down this measurement principle into the realm of microfluidics and microsensors. Low temperature cofired ceramics (LTCC) have proven to be the ideal technology for the realization of a μTAS, as they offer high chemical and thermal stability as well as high degree of freedom of design. The system consists of four components: an ozone generator, an ozone concentration measurement via UV transmission, a chemiluminescent detection (CLD) chamber, and an exhaust gas treatment. The ozone generator is a microplasma device in which ozone is produced by a dielectric barrier discharge (DBD) mechanism. From the generator, the ozone is fed into a chamber with an optical port, where the concentration is determined by UV transmission measurements. Then it is brought into contact with the NO-containing analyte gas inside the reaction chamber, where the chemiluminescent reaction occurs. The reaction chamber is outfitted with an optical port as well, so that the emitted radiation can be detected and analyzed with a photodiode. The gas mixture leaving the reaction chamber is fed through a platinum catalyst, in order to decompose leftover ozone and prevent buildup of hazardous concentrations in the surroundings of the device. This paper presents the design of each component as well as the integrated system and gives detailed measurements of its operation.
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Yang, Pengnian, Zhixun Xia, Likun Ma, BinBin Chen, Yunchao Feng, Chaolong Li, and Libei Zhao. "Influence of the Multicavity Shape on the Solid Scramjet." International Journal of Aerospace Engineering 2021 (October 26, 2021): 1–14. http://dx.doi.org/10.1155/2021/9718537.
Повний текст джерелаАнотація:
In this paper, a modular solid scramjet combustor with multicavity was proposed. The influence of multicavity shape on the performance of solid scramjet was investigated by the direct-connected tests. The experiments simulated a flight Mach 5.5 at 25 km. The boron-based fuel-rich propellant was used. The microstructure of combustion products was analyzed by SEM. The experimental results show that the fuel-rich mixture produced by the gas generator would ignite rapidly in the solid scramjet combustor. The combustion process showed a typical characteristic of establishment-development-maintenance-attenuation. Compared to the flame-holding cavity, the other shapes of cavities, e.g., narrow and lobe, can improve mixing and combustion. In our experiment, the combustion efficiency increased from 0.41 to 0.48, and the total pressure recovery was 0.36. In summary, the proposed solid scramjet combustor can effectively solve the ignition delay problem of the fuel-rich mixture, and the narrow/lobe cavity shows the ability to improve the mixing and combustion of the fuel-rich mixture.
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Alekseev, N. N., A. N. Balabaev, A. A. Vasilyev, Yu A. Satov, S. M. Savin, B. Yu Sharkov, A. V. Shumshurov, and V. C. Roerich. "Development of laser-plasma generator for injector of C4+ ions." Laser and Particle Beams 30, no. 1 (January 19, 2012): 65–73. http://dx.doi.org/10.1017/s0263034611000693.
Повний текст джерелаАнотація:
AbstractThe results of the development of the ITEP accelerator carbon ion injector based on a repetition-rate CO2 laser ion source are described. The improvement includes a modified pulsed HV-feeding generator for the discharge formation in the laser gas mixture. The advanced discharge module ensures essential increase of the laser active volume and specific electrical deposition energy. The comparative computer simulations of the discharge characteristics for the improved and the prototype lasers are applied. The design and the output spatial-temporal parameters of the free-running laser “Malish-M” are shown, so the significant increase of the laser power is reached. The spatial characteristics of the laser beam obtained with diffraction calculations are compared to measured radial distribution of the energy density. The target laser intensity and the different channels of the energy loss of the laser beam in the optical scheme are estimated. Finally, the output C4+ current trace of heavy ion injector as well as the injector scheme are shown.
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Vane, R., and G. Strossman. "Evactron™ Cleaning of SEM Specimens using an In-Situ RF Plasma on the SEM Chamber." Microscopy and Microanalysis 7, S2 (August 2001): 888–89. http://dx.doi.org/10.1017/s1431927600030518.
Повний текст джерелаАнотація:
The EVACTRON is a new device (US Patent 6,105,589) designed to remove hydrocarbons from SEM specimens and SEM chambers to prevent contamination artifacts. The device uses a lowpowered RF plasma to make oxygen radicals from air. These radicals oxidize hydrocarbons to make CO, H2O, and CO2 that can be removed by the vacuum pump. The use of air as an oxygen source is convenient to the SEM operator but limits the cleaning effectiveness of the system to easily oxidized carbon species. The system does remove high percentages of the usual contamination problems of vacuum pump oil and skin oil hydrocarbons from surfaces in a relatively short time.The EVACTRON SEM-CLEAN™ system provides a safe method for plasma cleaning inside the SEM. Air as a diluted oxygen gas mixture is chosen as the plasma reactant gas. Air is passed through a low-power RF glow-discharge to create oxygen radicals inside a generator mounted on a specimen chamber port. The generator chamber is subject to the same vacuum as the specimen chamber, and the vacuum pressure and gas flow are controlled by the EVACTRON SEM-CLEAN controller. The radicals are carried out of the plasma into the whole of the specimen chamber by convection. in the chamber they react with all exposed surfaces including the specimen if present. The plasma itself is confined to the generator chamber, which prevents ion and electron bombardment damage to the instrument or specimen.
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Osintsev, Konstantin, Sergei Aliukov, and Sulpan Kuskarbekova. "Development of Methodological Bases of the Processes of Steam Formation in Coil Type Boilers Using Solar Concentrators." Energies 14, no. 8 (April 20, 2021): 2333. http://dx.doi.org/10.3390/en14082333.
Повний текст джерелаАнотація:
A mathematical model of the vaporization process in the coil is developed, taking into account the experimental data. To investigate and visualize the evaporation procedure in the coil, a mathematical pattern of the vapor-liquid mixture motion is compiled and reproduced. In the methodology of the study of the movement of the steam-water mixture, correction coefficients are proposed for calculating the velocities of the coolant in non-standard coaxial coils. The parameters were calculated using data sensitivity analysis and data validation was performed by repeated tests; uncertainty was detected when using the instruments, as well as the total extended uncertainty, the upper and lower limit of uncertainty for each measured parameter. In addition, as part of the steam generator set, solar collectors operate in the summer mode. Using the example of the studied steam generator operating in the conditions of an oil and gas field in the subarctic climate, it is shown that it is possible to use air-type solar collectors for the ventilation system of the production room, as well as water-heating solar collectors for technical systems of hot water supply and chemical water treatment.
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Stoyanovskaya, Olga P., Vitaliy V. Grigoryev, Anastasiya N. Suslenkova, Maxim N. Davydov, and Nikolay V. Snytnikov. "Two-Phase Gas and Dust Free Expansion: Three-Dimensional Benchmark Problem for CFD Codes." Fluids 7, no. 2 (January 24, 2022): 51. http://dx.doi.org/10.3390/fluids7020051.
Повний текст джерелаАнотація:
In the computational mechanics of multiphase dispersed flows, there is an issue of computing the interaction between phases in a mixture of a carrier fluid and dispersed inclusions. The problem is that an accurate dynamics simulation of a mixture of gas and finely dispersed solids with intense interphase interaction requires much more computational power compared to pure gas or a mixture with moderate interaction between phases. To tackle this problem, effective numerical methods are being searched for to ensure adequate computational cost, accuracy, and stability of the results at an arbitrary intensity of momentum and energy exchange between phases. Thus, to assess the approximation, dispersive, dissipative, and asymptotic properties of numerical methods, benchmark solutions of relevant test problems are required. Such solutions are known for one-dimensional problems with linear plane waves. We introduce a novel analytical solution for the nonlinear problem of spherically symmetric expansion of a gas and dust ball into a vacuum. Therein, the dynamics of carrier and dispersed phases are modeled using equations for a compressible inviscid gas. Solid particles do not have intrinsic pressure and are assumed to be monodisperse. The carrier and dispersed phases exchange momentum. In the derived solution, the velocities of gas and dust clouds depend linearly on the radii. The results were reproduced at high, moderate, and low momentum exchange between phases using the SPH-IDIC (Smoothed Particle Hydrodynamics with Implicit Drag in Cell) method implemented based on the open-source OpenFPM library. We reported an example of using the solution as a benchmark for CFD (computational fluid dynamics) models verification and for the evaluation of numerical methods. Our benchmark solution generator developed in the free Scilab environment is publicly available.
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Filatov, I. E., D. L. Kuznetsov, and V. V. Uvarin. "Study of steam methane reforming in plasma generated by nanosecond surface gas discharge." Journal of Physics: Conference Series 2064, no. 1 (November 1, 2021): 012093. http://dx.doi.org/10.1088/1742-6596/2064/1/012093.
Повний текст джерелаАнотація:
Abstract The paper represents the results of the experimental study of steam methane reforming under the action of spark discharge on water surface. Values of conversion rate and output of reaction products at methane pressures of 1 to 5 atm were obtained, and specific energy consumption of reforming process was determined. Pulse generator with a voltage amplitude up to 200 kV and a pulse duration of 15 ns was used to power the discharge. Although an increase in pressure decreases both the methane conversion rate and the energy deposition into the gas mixture, the conversion efficiency and specific energy consumption remain the same. The obtained minimum value of specific energy consumption for steam methane reforming amounted to 10 eV/molecule.
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Quan, Rui, Tao Li, Yousheng Yue, Yufang Chang, and Baohua Tan. "Experimental Study on a Thermoelectric Generator for Industrial Waste Heat Recovery Based on a Hexagonal Heat Exchanger." Energies 13, no. 12 (June 17, 2020): 3137. http://dx.doi.org/10.3390/en13123137.
Повний текст джерелаАнотація:
To study on the thermoelectric power generation for industrial waste heat recovery applied in a hot-air blower, an experimental thermoelectric generator (TEG) bench with the hexagonal heat exchanger and commercially available Bi2Te3 thermoelectric modules (TEMs) was established, and its performance was analyzed. The influences of several important influencing factors such as heat exchanger material, inlet gas temperature, backpressure, coolant temperature, clamping pressure and external load current on the output power and voltage of the TEG were comparatively tested. Experimental results show that the heat exchanger material, inlet gas temperature, clamping pressure and hot gas backpressure significantly affect the temperature distribution of the hexagonal heat exchanger, the brass hexagonal heat exchanger with lower backpressure and coolant temperature using ice water mixture enhance the temperature difference of TEMs and the overall output performance of TEG. Furthermore, compared with the flat-plate heat exchanger, the designed hexagonal heat exchanger has obvious advantages in temperature uniformity and low backpressure. When the maximum inlet gas temperature is 360 °C, the maximum hot side temperature of TEMs is 269.2 °C, the maximum clamping pressure of TEMs is 360 kg/m2, the generated maximum output power of TEG is approximately 11.5 W and the corresponding system efficiency is close to 1.0%. The meaningful results provide a good guide for the system optimization of low backpressure and temperature-uniform TEG, and especially demonstrate the promising potential of using brass hexagonal heat exchanger in the automotive exhaust heat recovery without degrading the original performance of internal combustion engine.
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Belyaev, E. N., V. K. Chvanov, and V. V. Chervakov. "The Outflow of a Two-Phase Gas-Liquid Mixture from the Mixing Head of a Gas Generator when Starting a Liquid-Propellant Rocket Engine." High Temperature 43, no. 3 (May 2005): 446–51. http://dx.doi.org/10.1007/s10740-005-0083-7.
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Tran, Thanh Phong, Quang Minh Nguyen, and Quoc Cuong Tran. "Feasibility of Studying Fuel Mixer Design for High Power Engines Using Completely Biogas." Applied Mechanics and Materials 889 (March 2019): 231–43. http://dx.doi.org/10.4028/www.scientific.net/amm.889.231.
Повний текст джерелаАнотація:
Nowadays, the original source of mineral fuel for engines was depleting increasingly while combustion products make the environment to be polluted, CO2emission which caused many greenhouse gases; this also makes crude oil prices fluctuate and rise. They tend to use biogas as a fuel for internal combustion engines which have been interested in the powerful countries. Supply of biogas from the waste of farms, flour production, fish processing, landfills, etc., with hundreds or thousands of cube meter of biomass daily leads demand on high-power generators using biogas in order to make good use of produced gas. This article introduces a technology solution for fuel engines using purely large-capacity biogas and operating under compression type fire. Accordingly, the tubular biogas Venturi mixer with electronic controller has been used to supply the mixture of fuel to engine. The CDI-DC ignition circuit provides a high voltage of 28kV for forced combustion of the mixture. Experimental results show that the mixer operates stably, well controlled and allows adjusting the ratio of air/fuel, as well as easily changing its speed when it is used as a hybrid engine for the generator. Some results of performance evaluation of biogas mixer will be presented in this article.
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Banaszkiewicz, Tomasz. "The Possible Coupling of LNG Regasification Process with the TSA Method of Oxygen Separation from Atmospheric Air." Entropy 23, no. 3 (March 15, 2021): 350. http://dx.doi.org/10.3390/e23030350.
Повний текст джерелаАнотація:
Liquefied Natural Gas (LNG) must be vaporized before it is used in the combustion process. In most regasification terminals, energy that was previously expended to liquefy natural gas is dissipated in the environment. The paper proposes the use of the thermal effect of LNG regasification for the atmospheric air separation as a possible solution to the LNG exergy recovery problem. The presented idea is based on the coupling of the LNG regasification unit with an oxygen generator based on the Temperature Swing Adsorption (TSA) process. Theoretical analysis has revealed that it is thermodynamically justified to use the LNG enthalpy of vaporization for cooling of the TSA adsorption bed for increasing its adsorptive capacity. It has been shown that 1 kg of LNG carries enough exergy for separating up to approximately 100 g of oxygen using the TSA method. Although the paper suggests using the enthalpy of LNG vaporization for atmospheric air separation, similar processes for other gas mixture separations using the TSA method can be applied.
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Ma, Qing Fen. "Location Selection of Extra Nuclei Injecting for Inner - Core SGS Device with Droplet Enlargement Measure." Advanced Materials Research 516-517 (May 2012): 931–34. http://dx.doi.org/10.4028/www.scientific.net/amr.516-517.931.
Повний текст джерелаАнотація:
Supersonic gas separation (SGS) is a novel gas separation technology proposed in recent years. The Inner-core SGS device with droplet enlargement measure has been proved to perform effectively for processing low-pressure gas mixture with one condensable component. The effectiveness of the droplet enlargement measure depends largely on the adding location of extra nuclei. A two-phase flow model was established in which the droplet movement was simulated by dispersed phase model. Using the model, movements of nuclei from three potential locations of Inner-core SGS device, inlet of swirl generator (Ⅰ), throat of supersonic nozzle (Ⅱ) and inner-taper core (Ⅲ), were simulated and the possibility of vapor condensation on nuclei was predicted. The simulation results showed that the droplets injected from location Ⅲ had smaller size (0.0183mm~ 0.0953mm), longer residence time (0.43 ms) and longer axial running distance (58.9 mm). The gas flow near that region had bigger supersaturation (larger than 1). Thus, the best location of Inner-core SGS device for nuclei injection was determined at the throat of the inner-taper core (Ⅲ).
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Dimitrov, Radostin, Zdravko Ivanov, Penka Zlateva, and Veselin Mihaylov. "Optimization of biogas composition in experimental studies." E3S Web of Conferences 112 (2019): 02007. http://dx.doi.org/10.1051/e3sconf/201911202007.
Повний текст джерелаАнотація:
The article is focused on the potential and application of biogas, as an alternative fuel from Renewable Energy Sources, for use mainly in gas-generator stations. Biogas fuel is basically a mixture of methane and carbon dioxide. Its composition depends on the type of raw material used for its production. Methane concentration in biogas is between 50÷80%. To be possible engine to work with maximum efficiency with different biogas fuels, it is necessary to modify specific adjustment parameters depending on the concentration of methane in the mixture. This requires the creation of a biogas simulation system for different concentrations of the main components. The aim is to investigate and determine the optimum and permissible biofuel blend concentrations and their impact on engine performance and fuel consumption. Biogas can be used as a fuel to produce electricity, heat or steam or as fuel for internal combustion engine, and its use will help to reduce harmful emissions into the atmosphere.
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Papurello, Davide, Marta Gandiglio, and Andrea Lanzini. "Experimental Analysis and Model Validation on the Performance of Impregnated Activated Carbons for the Removal of Hydrogen Sulfide (H2S) from Sewage Biogas." Processes 7, no. 9 (August 21, 2019): 548. http://dx.doi.org/10.3390/pr7090548.
Повний текст джерелаАнотація:
Organic waste exploitation is crucial for waste emissions restraint in air, soil and water. This type of waste can be exploited to produce biogas, a valuable fuel exploitable for energy purposes. A circular approach for energy production is much cleaner and more sustainable than the traditional linear approach. In this work, organic waste was used for biogas production to feed a highly efficient solid oxide fuel cell power generator, which requires an ultra-purified fuel. Commercial sorbents were experimentally studied in conjunction with a dynamic adsorption model to predict the breakthrough time and organize the material change-over. In the presence of 0.1% oxygen in the gas mixture, AirDep® CKC showed a marked increase in the adsorption capacity (from 3.91 to 84.87 mg/g), overcoming SulfaTrap® R8G (49.91 mg/g). The effect of several operating parameters on adsorption capacity was evaluated: inlet H2S concentration, filter geometry and gas mixture velocity. Experimental data revealed that adsorption capacity increases with initial H2S concentration, following the typical trend of the Langmuir isotherm. Model simulations were in good agreement compared to experimental results, with an average relative error lower than 7%. A sensitivity analysis on the adsorption capacity was accomplished considering parameters from operational and empirical correlations.
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Eremin, S. A., N. O. Kudryashova, I. A. Leontiev, and Y. M. Yashnov. "Hybrid carbon-hydrocarbon structure." Perspektivnye Materialy 9 (2021): 79–84. http://dx.doi.org/10.30791/1028-978x-2021-9-79-84.
Повний текст джерелаАнотація:
A new hybrid carbon-hydrocarbon structure was discovered after pumping a gas mixture of methane and hydrogen through 314 – 400 µm synthetic diamond powder. The experiment was carried out on the microwave plasmachemical installation designed for deposition of polycrystalline diamond films. The main parameters during the experiment were the following: the power of the microwave generator 3,5 kW, the flow rate of hydrogen 400 ml/min, methane 20 ml/min, the pressure in the reactor chamber 63 torr. The gas mixture was pumped at pressure drop of 13 torr. The diamond powders were placed in molybdenum cups inserted into a copper pedestal. In the gaps between the diamond particles of the surface layer unidirectional thread-like structures (length 100 – 500 μm, diameter 2 μm) were found, some of which ended in spherical formations (average diameter 18 μm). Such a composition of thread-like structures and spherical formations was called “dandelion” one. Raman spectroscopy was performed to examine the nature of these formations. The thread-like structure was determined as monocrystalline graphite. The surface of the spherical formation was represented by spindle-shaped structures of nanocrystalline graphite (length 2 μm, thickness 200 nm) and nanodiamond grains with trans-polyacetylene chains [C2H2]n.
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Notaristefano, Andrea, and Paolo Gaetani. "Design and Commissioning of a Combustor Simulator Combining Swirl and Entropy Wave Generation." International Journal of Turbomachinery, Propulsion and Power 5, no. 4 (October 19, 2020): 27. http://dx.doi.org/10.3390/ijtpp5040027.
Повний текст джерелаАнотація:
Modern aero-engine combustion chambers burn a lean and premixed mixture, generating a turbulent flame which involves large heat-release fluctuations, thus producing unsteady temperature phenomena commonly referred to as entropy waves (EWs). Furthermore, to enhance the fuel air mixing, combustion air is swirled, leading to vorticity disturbances. These instabilities represent one of the biggest challenges in gas turbine design. In this paper, the design and testing of a novel entropy wave generator (EWG) equipped with a swirler generator (SG) are described. The novel EWG will be used in future works on the high-speed test rig at Politecnico di Milano to study the combustor–turbine interaction. The paper shows the process of the EWG geometry and layout. The EWG is able to produce an engine-representative EW, the extreme condition is at the maximum frequency of 110 Hz, a peak-to-valley temperature value of 20 °C and swirling angles of ±25° are measured. By virtue of these results, the proposed system outperforms other EWG devices documented in the literature. Furthermore, the addition of a swirling generator makes this device one of a kind.
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Martinez-Frias, Joel, Salvador M. Aceves, J. Ray Smith, and Harry Brandt. "Thermodynamic Analysis of Zero-Atmospheric Emissions Power Plant." Journal of Engineering for Gas Turbines and Power 126, no. 1 (January 1, 2004): 2–8. http://dx.doi.org/10.1115/1.1635399.
Повний текст джерелаАнотація:
This paper presents a theoretical thermodynamic analysis of a zero-atmospheric emissions power plant. In this power plant, methane is combusted with oxygen in a gas generator to produce the working fluid for the turbines. The combustion produces a gas mixture composed of steam and carbon dioxide. These gases drive multiple turbines to produce electricity. The turbine discharge gases pass to a condenser where water is captured. A stream of pure carbon dioxide then results that can be used for enhanced oil recovery or for sequestration. The analysis considers a complete power plant layout, including an air separation unit, compressors and intercoolers for oxygen and methane compression, a gas generator, three steam turbines, a reheater, two preheaters, a condenser, and a pumping system to pump the carbon dioxide to the pressure required for sequestration. This analysis is based on a 400 MW electric power generating plant that uses turbines that are currently under development by a U.S. turbine manufacturer. The high-pressure turbine operates at a temperature of 1089 K (1500°F) with uncooled blades, the intermediate-pressure turbine operates at 1478 K (2200°F) with cooled blades and the low-pressure turbine operates at 998 K (1336°F). The power plant has a net thermal efficiency of 46.5%. This efficiency is based on the lower heating value of methane, and includes the energy necessary for air separation and for carbon dioxide separation and sequestration.
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Tahara, Hirokazu, Yasutaka Ando, and Takao Yoshikawa. "Plasma Characteristics of Supersonic Nitrogen/Hydrogen-Mixture and Ammonia Plasma Jets and Nitrided Material Properties." Materials Science Forum 449-452 (March 2004): 373–76. http://dx.doi.org/10.4028/www.scientific.net/msf.449-452.373.
Повний текст джерелаАнотація:
Spectroscopic and electrostatic probe measurements were made to examine plasma characteristics under nitriding for a 10-kW-class direct-current arc plasma jet generator with a supersonic expansion nozzle in a low pressure environment. Heat fluxes into the plate from the plasma were also evaluated. Ammonia and mixtures of nitrogen and hydrogen were used as the working gas. The H-atom electronic excitation temperature and the N2 molecule-rotational excitation temperature intensively decreased downstream in the nozzle although the NH molecule-rotational excitation temperature did not show an axial decrease. As approaching the titanium plate, the thermodynamical nonequilibrium plasma came to be a temperature-equilibrium one. Both the electron number density near the plate and the heat flux increased with H2 mole fraction for mixtures gases. In cases with mixtures of N2 and H2, a radical of NH with a radially wide distribution is considered to contribute to the better nitriding as a chemically active and non heating process.
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Rokhman, B. B., N. I. Dunayevska, V. G. Vyfatnuik, and I. V. Beztsennyi. "Numerical studies on thermochemical processing of peat in a fixed layer." Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, no. 1 (February 28, 2022): 38–45. http://dx.doi.org/10.33271/nvngu/2022-1/038.
Повний текст джерелаАнотація:
Purpose. To investigate the gasification process of peat in gas generators with a fixed bed at a pressure of 1.5 MPa and create the initial conditions at the entrance to the waste burners required for combustion of the binary mixture. Methodology. The objects of research were peat granules of Volyn peat. To calculate the process of gasification of peat gas, the constructed model of thermochemical processing of solid fuel, described in the first part of the work by the authors was used. Findings. It is shown that in the area close to the upper boundary of the fixed bed, where the process of gasification of peat is stationary, there is a jump in the temperature of peat particles from 300 to 772C, in which the tar is practically not released, and thus the obtained pyrolysis gas contains CO2, H2O, H2 and CO. The structural and physicochemical characteristics of gas generators are obtained and the initial conditions at the entrance to the discharge burners of the chamber furnace of the steam generator TPP-210A are formed. Originality. It is shown that when the velocity of peat particles decreases, a slag bed is formed between the zone of maximum heat release and the grate, which consists of cooled ash particles, which protect the grate from overheating. With such an organization of the process it is possible to achieve the stationary process of gasification with mechanical incompletely burned material equal to zero. Practical value. It is shown that with the help of the model of thermochemical processing of solid fuels it is possible to adjust the height of the dry distillation zone by changing the velocity of the dispersed phase and the rate of heterogeneous and homogeneous chemical reactions by changing the proportion of O2 or H2O air enrichment.
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Kim, Gu, Young Duk Lee, and Chae Hoon Sohn. "A Numerical Study on Mixing of Fuel/Air Mixture and NOx Emission in a Gas Turbine Burner with a Vortex Generator." Journal of the Korean Society of Combustion 18, no. 3 (September 30, 2013): 68–74. http://dx.doi.org/10.15231/jksc.2013.18.3.068.
Повний текст джерела
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Gürbüz, Habib, and Hüsameddin Akçay. "Experimental investigation of an improved exhaust recovery system for liquid petroleum gas fueled spark ignition engine." Thermal Science 19, no. 6 (2015): 2049–64. http://dx.doi.org/10.2298/tsci150417181g.
Повний текст джерелаАнотація:
In this study, we have investigated the recovery of energy lost as waste heat from exhaust gas and engine coolant, using an improved thermoelectric generator (TEG) in a LPG fueled SI engine. For this purpose, we have designed and manufactured a 5-layer heat exchanger from aluminum sheet. Electrical energy generated by the TEG was then used to produce hydrogen in a PEM water electrolyzer. The experiment was conducted at a stoichiometric mixture ratio, 1/2 throttle position and six different engine speeds at 1800-4000 rpm. The results of this study show that the configuration of 5-layer counterflow produce a higher TEG output power than 5-layer parallel flow and 3-layer counterflow. The TEG produced a maximum power of 63.18 W when used in a 5-layer counter flow configuration. This resulted in an improved engine performance, reduced exhaust emission as well as an increased engine speed when LPG fueled SI engine is enriched with hydrogen produced by the PEM electrolyser supported by TEG. Also, the need to use an extra evaporator for the LPG fueled SI engine is eliminated as LPG heat exchangers are added to the fuel line. It can be concluded that an improved exhaust recovery system for automobiles can be developed by incorporating a PEM electrolyser, however at the expense of increasing costs.