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Open Journal of Applied Sciences 2024年第2期14卷 545-560页

作者： Jean Fidele Nzihou Salou Hamidou Ousmane Zoundi Frederic Ouattara Bila Gerard Segda Formation and Research Unit in Sciences and Technologies University Norbert ZONGO Koudougou Burkina-Faso

The operation of biomass treatment devices such as gasifiers is based on the control of key parameters that play an important role in product formation. These include: temperature, excess oxygen, relative humidity and biomass composition. This work focuses on excess oxygen and temperature. Unfortunately, flue gas oxygen analyzers are expensive and not accessible to small industries. However, the equivalence ratio is linked to excess oxygen and has the advantage of not depending on biomass composition. This study therefore focuses on the design and development of a device for controlling this equivalence ratio by measuring oxygen concentration using a self-propelled Lambda probe, and a system for monitoring this equivalence ratio using an Arduino Uno 3 microcontroller. The temperature is recorded with an accuracy of ±1.5°C. For a heating time of 10 minutes, the response time to temperature change is around 3 seconds, which is sufficient for the device to function properly. This simple device is an efficient and cost-effective means of checking the equivalence ratio.

关键词： equivalence ratio Biomass Gasification Lambda Sensor Microcontroller C++

Effects of total pressures and equivalence ratios on kerosene/air rotating detonation engines using a paralleling CE/SE method

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Defence Technology（防务技术） 2021年第6期17卷 1805-1816页

作者： Fang Wang Chun-sheng Weng Yu-wen Wu Qiao-dong Bai Quan Zheng Han Xu National Key Laboratory of Transient Physics Nanjing University of Science and TechnologyNanjing210094China

In this paper,the kerosene/air rotating detonation engines(RDE)are numerically investigated,and the emphasis is laid on the effects of total pressures and equivalence ratios on the operation characteristics of RDE including the initiation,instabilities,and propulsive performance.A hybrid MPI t OpenMP parallel computing model is applied and it is proved to be able to obtain a more effective parallel performance on high performance computing(HPC)systems.A series of cases with the total pressure of 1 MPa,1.5 MPa,2 MPa,and the equivalence ratio of 0.9,1,1.4 are *** one hand,the total pressure shows a significant impact on the instabilities of rotating detonation *** instability phenomenon is observed in cases with low total pressure(1 MPa)and weakened with the increase of the total *** total pressure has a small impact on the detonation wave velocity and the specific *** the other hand,the equivalence ratio shows a negligible influence on the instabilities,while it affects the ignition process and accounts for the detonation velocity *** is more difficult to initiate rotating detonation waves directly in the lean fuel operation *** difference was observed in the thrust with different equivalence ratios of 0.9,1,and *** highest specific impulse was obtained in the lean fuel cases,which is around 2700 *** findings could provide insights into the understanding of the operation characteristics of kerosene/air RDE.

关键词： Kerosene/air rotating detonation waves Total pressure equivalence ratio Instabilities MPItOpenMP

Characterization of premixed swirling methane/air diffusion flame through filtered Rayleigh scattering

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Chinese Physics B 2022年第3期31卷 375-381页

作者：李猛闫博陈爽陈力母金河 State Key Laboratory of Aerodynamics China Aerodynamics Research and Development Center Mianyang 621000 China Science and Technology on Scramjet Laboratory National University of Defense Technology Changsha 410073China

Characteristics of a premixed, swirl methane/air diffusion flame at atmospheric pressure are measured by filtered Rayleigh scattering(FRS). Three operating conditions are investigated with the equivalence ratios of the methane/air flame covering a range of 0.67–0.83. Under each condition, single-shot and averaged FRS images over a region measured 39.3×65.6 mm^(2) at seven cross sections of the flame are collected to demonstrate the flame behavior. A gradient calculation algorithm is applied to identify reaction zone locations and structures in the instantaneous FRS *** analysis for the mean FRS measurements is performed by means of joint probability density functions. The experimental results indicate that thermochemical state of the swirl flame is strongly influenced by equivalence ratio, leading to varieties of flame structures and temperature distributions. The gradient of the instantaneous FRS images clearly illustrates the characteristics of the reaction zone. The results also demonstrate that FRS can provide detailed insights into the behavior of turbulent flames.

关键词： filtered Rayleigh scattering equivalence ratio swirl flame temperature measurement

乙炔-空气混合物中有限长楔面诱导斜爆轰波的起爆特性

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Acta Mechanica Sinica 2023年第2期39卷 138-146页

作者：张益晨项高翔涂启荣汪球魏浩天 School of Mechanics Civil Engineering&ArchitectureNorthwestern Polytechnical UniversityXi'an 710129China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518057China State Key Laboratory of High Temperature Gas Dynamics Institute of MechanicsChinese Academy of SciencesBejing 100190China School of Astronautics Northwestern Polytechnical UniversityXi'an 710129China

斜爆轰波在高超声速推进具有重要的应用潜力,受到了研究者们的广泛研究。以往的研究,大多基于氢气燃料,且楔面总是无限长的.本文基于详细的化学反应模型,通过求解二维考虑基元反应的多组分欧拉方程,对乙炔-空气混合物在有限长楔形面诱... 详细信息

斜爆轰波在高超声速推进具有重要的应用潜力,受到了研究者们的广泛研究。以往的研究,大多基于氢气燃料,且楔面总是无限长的.本文基于详细的化学反应模型,通过求解二维考虑基元反应的多组分欧拉方程,对乙炔-空气混合物在有限长楔形面诱导的斜爆轰进行了数值和理论研究.根据受限空间内的起爆判据,研究了膨胀波、来流马赫数和当量比对斜爆轰波起爆特性的影响.结果表明,乙炔诱导的斜爆轰波的起爆距离相对大于氢燃料诱导的。爆燃波的会聚位置和膨胀波的产生位置决定了斜爆轰波的起爆特性.当膨胀波的产生位置在爆燃波会聚位置的下游,斜爆轰波被点燃;否则,斜爆轰波不会起爆.诱导区特征长度在不同当量比下呈U型曲线分布,无论是富燃还是贫燃都会导致斜爆轰波不起爆.

关键词： Acetylene Finite wedge Oblique detonation Initiation characteristics equivalence ratio

Effects of dimethyl ether on soot formation in premixed laminar flame by laser induced incandescence method

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Journal of Traffic and Transportation Engineering(English Edition) 2020年第3期7卷 312-319页

作者： Zengqiang Zhu Zheyang Li Chao Liu Xiao Chen Shenghua Liu School of Energy and Power Engineering Xi'an Jiaotong UniversityXi'an 710049China Research Institute Weichai Holding Group Co.Ltd.Weifang 261001China

The control of PM emission is a rather complicated problem to be solved both for diesel engine and GDI *** are vast factors affecting PM emission,the fuel,A/F,combustion temperature and so *** undoubtedly,most efforts are paid to exhaust aftertreatment,rather than the control of *** paper is to investigate the effect of dimethyl ether(DME,CH3OCH3)on soot generation in ***,a laser induced incandescence(LII)measurement system for soot volume concentration measurements in flame is *** DME gaseous mixtures were prepared with equivalence ratios 1 and *** highlight its effect on soot formation,acetylene known as the precursor of soot,is added in different ***,CO2 is mixed to simulate exhaust gas recycling(EGR)effect in *** experimental results indicate that the fuel property and A/F ratio are the dominating factors for the generation of soot during *** combustion of DME doesn't emit soot obviously even under rich mixture *** burning the mixture of DME and acetylene(C2H2)in different proportion,there is barely soot emission at equivalence ratio of *** soot emission increases as the proportion of C2H2 increases at equivalence ratio 2,and the DME addition reduces the soot emission of C2H2 ***2 dilution doesn't lead to the increase of soot when burning DME at equivalence 1 and *** emission is lower when the mixture of DME and acetylene is diluted by CO2,though soot volume concentration increases slightly as the proportion of C2H2 *** kinetic analysis indicates that the combustion of DME does not produce the precursor of *** fuel-rich combustion conditions,C2H2 reacts with H radical to form C2H3,which leads to *** DME is added,it competes for H radical,which reduces the formation of C2H3 and thus reduces soot *** research carried out in this paper indicates that DME fuel has obviously power to reduce soot formation during combustion,no matter whether

关键词： Energy and power engineering DME Acetylene Soot Laser induced incandescence equivalence ratio

Development and testing of a detailed kinetic mechanism of natural gas combustion in internal combustion engine

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Journal of Natural Gas Chemistry 2010年第2期19卷 97-106页

作者： M.Mansha A.R.Saleemi Badar M.Ghauri Naveed Ramzan Department of Chemical Engineering University of Engineering & TechnologyLahore 5457Pakistan Institute of Space Technology Islamabad 44000Pakistan

A detailed chemical mechanism to describe the combustion of natural gas in internal combustion （IC） engine has been developed,which is consisting of 233 reversible reactions and 79 *** mechanism accounts for the oxidation of methane,ethane,propane and *** has been tested using IC engine model of CHEMKIN 4.1.1 and experimental *** performance of the proposed mechanism was evaluated at various equivalence ratios （φ=0.6 to φ=1.3）,initial reactor conditions （Tini=500 to 3500 ℃; Pini=1.0 to 10 atm） and engine speed （2000-7000 rpm）.The proposed kinetic mechanism shows good concordances with GRI3.0 mechanism especially in the prediction of temperature,pressure and major product species （H2O,CO2） profiles at stoichiometric conditions （φ=1.0）.The experimental results of measured cylinder pressure,species fractions were also in agreement with simulation results derived from the proposed kinetic *** proposed mechanism successfully predicts the formation of gaseous pollutants （CO,NO,NO2,NH3） in the engine *** there are some discrepancies among each simulation profile,the proposed detailed mechanism is good to represent the combustion of natural gas in IC engine.

关键词： natural gas detailed mechanism equivalence ratio pollutants emission combustion

Thrust measurement method verification and analytical studies on a liquid-fueled pulse detonation engine

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Chinese Journal of Aeronautics 2014年第3期27卷 497-504页

作者： Lu Jie Zheng Longxi Wang Zhiwu Peng Changxin Chen Xinggu School of Power and Energy Northwestern Polytechnical University

In order to test the feasibility of a new thrust stand system based on impulse thrust mea- surement method, a liquid-fueled pulse detonation engine （PDE） is designed and built. Thrust per- formance of the engine is obtained by direct thrust measurement with a force transducer and indirect thrust measurement with an eddy current displacement sensor （ECDS）. These two sets of thrust data are compared with each other to verify the accuracy of the thrust performance. Then thrust data measured by the new thrust stand system are compared with the verified thrust data to test its feasibility. The results indicate that thrust data from the force transducer and ECDS system are consistent with each other within the range of measurement error. Though the thrust data from the impulse thrust measurement system is a litter lower than that from the force transducer due to the axial momentum losses of the detonation jet, the impulse thrust measurement method is valid when applied to measure the averaged thrust of PDE. Analytical models of PDE are also discussed in this paper. The analytical thrust performance is higher than the experimental data due to ignoring the losses during the deflagration to detonation transition process. Effect of equivalence ratio on the engine thrust performance is investigated by utilizing the modified analytical model. Thrust reaches maximum at the equivalence ratio of about 1.1.

关键词： Analytical model equivalence ratio Impulse method Liquid fuel Pulse detonation engine Thrust measurements

Flow Characteristics in Compact Thermal Spray Coating Systems with Minimum Length Nozzle

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Plasma Science and Technology 2009年第5期11卷 550-554页

作者： Seung-Hyun KIM Youn-Jea KIM School of Mechanical Engineering Sungkyunkwan University

In this study, numerical analysis is performed to adopt the equivalence ratio on the high velocity oxygen fuel （HVOF） thermal spray coating systems equipped with a minimum length nozzle. The analysis is applied to investigate the axisymmetric, steady-state, turbulent, and chemically combusting flow both within the torch and in a free jet region between the torch and the substrate to be coated. The combustion is modeled using a single-step and eddy-dissipation model which assumes that the reaction rate is limited by the turbulent mixing rate of the fuel and oxidant. As the diameter of the nozzle throat is increased, the location of the Mach shock disc moves backward from the nozzle exit. As the throat diameter and the divergent portion are 6 mm and 8 mm, respectively, the pressure in the HVOF system is the lowest at the chamber and the expanding gas is steadily maintained with both high velocity and high temperature for different equivalence ratios. Thus, relatively minor amendments of the equivalence ratio and the geometry of HVOF can lead to improved control over coating characteristics.

关键词： minimum length nozzle HVOF equivalence ratio

Three-Dimensional Models for Analyzing the Cyclic Variations in a Lean Burn CNG Engine

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Journal of Beijing Institute of Technology 2007年第3期16卷 274-278页

作者：李国岫虞育松刘建英 School of Mechanical Electronic and Control EngineeringBeijing Jiaotong University

Three-dimensional models, consisting of the flame kernel formation model, flame kernel development model and natural gas single step reaction model, are used to analyze the contribution of cyclic equivalence ratio variations to cyclic variations in the compressed natural gas （CNG） lean burn spark ignition engine. Computational results including the contributions of equivalence ratio cyclic variations to each combustion stage and effects of engine speed to the extent of combustion variations are discussed. It is concluded that the equivalence ratio variations affect mostly the main stage of combustion and hardly influence initial kernel development stage.

关键词： three-dimensional model lean burn CNG engine equivalence ratio combustion cyclic variations

Experimental evaluation of a 35 kVA downdraft gasifier

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Frontiers in Energy 2013年第3期7卷 300-306页

作者： Ashok Jayawant Rao KECHE Gaddale AMBA PRASAD RAO Department ol Mechanical Englneenng National Institute of lecnnology Warangal 506004 (AP) India

Energy conversion systems based on biomass are particularly interesting because biomass utilization effectively closes the carbon cycle besides achieving selfsustainability. Biomass is particularly useful for highly populated and agriculture dependent economic nations like China and India. A compact and cost effective downdrafl gasifcation system was developed. The present paper describes an experimental investigation on a biomass based gasifier engine system with a capacity of 35 kVA for power generation application. The problem of cooling and cleaning the hot and dirty gas from the gasifier has been satisfactorily solved by the effective cooling and filtration system. The gasifier developed is observed to be operation friendly. The quality of gas was evaluated in terms of its composition, conversion efficiency and total particulate matter. The maximum output of the power plant was obtained at the combustion zone temperature of 850~C. The experimental investigations showed that the percen- tage reduction in total particulate matter is 89.32%. The conversion efficiency of the biomass gasifier is found to be dependent on the operation conditions and fuel properties of the gasifier. The optimum value of equivalence ratio was observed to be 0.3134 for achieving the maximum gas conversion efficiency of the present gasifier configuration.

关键词： biomass gasification producer gas equivalence ratio total particulate matter conversion efficiency of gasifier