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Journal of Central South University 2022年第7期29卷 2213-2224页

作者： JIN Shou-ying LI Jin-ze ZI Zhen-yuan LIU Ya-long WU Bin-yang State Key Laboratory of Engines Tianjin UniversityTianjin 300072China

Research on dual-fuel(DF)engines has become increasingly important as engine manufacturers seek to reduce carbon dioxide *** are significant advantages of using diesel pilot-ignited natural gas engines as DF ***,different combustion modes exist due to variations in the formation of the *** research used a simulation model and numerical simulations to explore the combustion characteristics of high-pressure direct injection(HPDI),partially premixed compression ignition(PPCI),and double pilot injection premixed compression ignition(DPPCI)combustion modes under a low-medium *** results revealed that the DPPCI combustion mode provides higher gross indicated thermal efficiency and more acceptable total hydrocarbon(THC)emission levels than the other *** to its relatively good performance,an experimental study was conducted on the DPPCI mode engine to evaluate the impact of the diesel dual-injection strategy on the combustion *** the DPPCI mode,a delay in the second pilot ignition injection time increased THC emissions(a maximum value of 4.27g/(kW·h)),decreased the emission of nitrogen oxides(a maximum value of 7.64 g/(kW·h)),increased and then subsequently decreased the gross indicated thermal efficiency values,which reached 50.4%under low-medium loads.

关键词： diesel pilot-ignited natural gas engine direct injection of natural gas combustion mode thermal efficiency emissions

Experimental study on combustion characteristics of supersonic combustor based on alternating-wedge strut

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Chinese Journal of Aeronautics 2024年第5期37卷 214-227页

作者： Jie LI Wenyan SONG Yuhang WANG School of Power Energy Northwestern Polytechnical UniversityXi’an 710129China

Acetone Planar Lase-Induced Fluorescence(PLIF)and OH-PLIF were employed to capture the fuel distribution and OH distribution downstream for the supersonic combustor based on the alternating-wedge *** combustion establishment process and combustion mode in the combustor under different fuel injection methods and different equivalence ratios were *** with the kerosene-PLIF and OH-PLIF results in the cavity combustor,a comparative analysis was conducted to understand the combustion characteristics and combustion modes between the alternating-wedge strut-based combustor and the cavity-based *** results show that the combustor is in weak combustion mode in the case of low equivalence ratio,and the combustor is in intensive combustion mode in the case of high equivalence *** lower limit of the equivalence ratio of the combustor to maintain the intensive combustion mode varies based on different fuel injection *** OH distribution under reacting condition has a strong correlation with the fuel distribution under non-reacting *** OH fluorescence signal near the injector is weaker when the fuel distribution is more *** injector position located at the base of the strut rear has better mixing performance,enabling the combustor to be in intensive combustion mode at a lower equivalence *** combustion reaction in the alternating-wedge strut-based combustor is not necessarily dominated by mass transfer due to the mixing enhancement and premixed zone downstream of strut,while the combustion reaction process in the cavity-based combustor is mainly influenced by mass transfer.

关键词： Supersonic combustor Alternating-wedge strut Cavity PLIF Fuel injection Fuel distribution combustion characteristics combustion mode

Thermal behavior of an isolator with mode transition inducing back-pressure of a dual-mode scramjet

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Chinese Journal of Aeronautics 2017年第2期30卷 595-601页

作者： Yang Qingchun Bao Wen Chetehouna Khaled Zhang Silong Gascoin Nicolas School of Astronautics Beihang University 100083 China School of Energy Science and Engineering Harbin Institute of Technology 150001 Harbin China INSA Centre Val de Loir 88 Boulevard Lahitolle 18000 Bourges France

combustion mode transition is a valuable and challenging research area in dual-mode scramjet *** thermal behavior of an isolator with mode transition inducing backpressure is investigated by direct-connect dual-mode scramjet experiments and theoretical *** experiments are conducted under the incoming airflow conditions of total temperature1270 K and Mach 2.A small increment of the fuel equivalence ratio is scheduled to trigger mode ***,the variation of the coolant flow rate is very *** on the measured wall pressures,the heat-transfer model can quantify the thermal state variation of the engine with active *** with the combustor,mode transition has a greater effect on the isolator thermal behavior,and it significantly changes the isolator heat-flux and wall *** further study the isolator thermal behavior from flight Mach 4 to Mach 7,a theoretical analysis is carried *** the critical point of combustion mode transition,sudden changes of the isolator flowfield and thermal state are discussed.

关键词： combustion mode Dual-mode scramjet Isolator mode transition Thermal behavior

Anisotropic combustion of Aluminum Nanoparticles in Carbon Dioxide and Water Flows

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Journal of Thermal Science 2022年第3期31卷 867-881页

作者： CHANG Xiaoya CHEN Dongping CHU Qingzhao State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China Explosion Protection and Emergency Disposal Technology Engineering Research Center of the Ministry of Education Beijing100081China

Shock-induced combustion of aluminum nanoparticles was examined in the CO_(2)and H_(2)O flows up to 8 km/s using reactive molecular *** morphological evolutions and heat/mass transfer of ANPs were discussed to reveal the nature of anisotropic *** breakage of triatomic gas molecule and the formation of key intermediates were identified to illustrate the reaction mechanisms at the atomic *** was found that surface reactions prevail for cases in lower flow velocity(≤6 km/s),and gas-phase reactions govern the oxidation process under the intense impact(8 km/s).In particular,we converted the flow velocity to the initial kinetic energy of flow molecules to highlight the impact of oxidizing ability on the shock-induced *** the regime of low initial kinetic energy(458.1 k J/mol),the overall oxidation is governed by the microexplosion mechanism,and different oxidizers share almost the same ignition delay.

关键词： anisotropic reaction surface reaction ignition combustion mode molecular dynamics simulation

Ignition Characteristics of Lean Coal Used a Novel Alternating-Current Plasma Arc Approach

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Journal of Thermal Science 2022年第2期31卷 571-581页

作者： YAN Gaocheng School of Electric Power Civil Engineering and ArchitectureShanxi UniversityTaiyuan 030013China

In order to achieve the target of reducing oil consumption to zero for pulverized coal(PC)boiler in power plant,the paper developed a novel coal pulverized ignition approach,called as Alternating-Current plasma(AC plasma)ignition,with the advantages of excellent PC combustion behavior and longer electrode *** scientific principle of how to generate the AC plasma arc was elaborated in ***,the experiments on life-span of electrodes inside AC plasma generator had been conducted,finding a workable way to extend its life-span beyond 530 ***,a new AC plasma burner specifically designed for lean coal according to the principle of PC staged combustion had been illustrated with diagrams and then used to ignite the PC-air stream under four kinds of conditions with a varying AC plasma power from 150 kW to 300 kW,focusing on analyses of the influence of AC plasma power on combustion behaver,such as combustion temperature,carbon burnout rate as well as PC combustion *** following results showed that in the case of the power of the AC plasma was P=300 kW,a satisfied PC combustion process could achieved,with the average PC combustion temperature of about 940°C,combustion flame length of 6.3 m,and the total carbon burnout rate of up to 52.2%.In addition,about 80%of the nozzle outlet section was filled with bright flame,while 81%of the PC was in zone of the cylindrical flame *** PC combustion modes were changed repeatedly during the process of combustion,which went from homogeneous combustion mode at initial ignition stage to combined combustion mode and heterogeneous combustion mode at middle stage,finally to combined combustion mode at later *** research conclusion in this paper has proved that the AC plasma ignition approach is feasible and effective to ignite low-rank coal without the present of fuel oil.

关键词： pulverized coal combustion alternating-current plasma ignition oil-free ignition utility boiler start-up combustion mode

Numerical study on the combustion process in a gas turbine combustor with different reference velocities

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Advances in Aerodynamics 2023年第1期5卷 497-517页

作者： Cheng Gong Shufan Zhao Weiqiang Chen Wenyu Li Yu Zhou Ming Qiu Aerospace Technology Institute China Aerodynamics Research and Development CenterMianyang 621000China

The mixing and combustion processes under different reference velocities in a gas turbine combustor were numerically investigated using the Flamelet Generated Manifold(FGM)model based on the Reynolds Averaged Navier-Stokes(RANS)*** flow and combustion fields show strong self-similarity except on the slow auto-ignition in the mixing layer between fuel-rich product and fresh air upstream of the flame stabilization *** time-scale analysis was carried out to understand the combustion modes inside the *** general,the residence time of the fuel-mixture is much longer than both the chemical time scale and the mixing time ***,the combustion properties in each sub-zone were dominated by the mean flow ***,the combustion process exhibits a mixing-controlled feature in ***,partially premixed combustion still appears on the flame *** of the fuel was found to be oxidized in the primary zone and the intermediate zone;however,the slow oxidization reactions also play a non-negligible role on the whole combustion ***,a sketch map on the space of mixture fraction and combustion efficiency was proposed to understand the mixing and oxidization experiences of the fuel mixture.

关键词： Gas turbine combustor Swirling flame FGM combustion mode Time-scale analysis