掺氢天然气HCCI发动机燃烧特性数值模拟研究
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摘要
为了研究不同运转参数对掺氢天然气均质压燃(HCCI)发动机的燃烧特性影响,基于Chemkin模拟软件,结合GRI-Mech3.0化学反应动力学机理,建立了HCCI发动机的数值模型。数值模拟了掺氢天然气HCCI发动机在掺氢体积比为5%时不同运转参数下的燃烧特性,主要包括对发动机燃烧过程中缸内压力、温度、燃烧放热率和NO_x排放的影响。结果表明,在掺氢天然气HCCI发动机燃烧过程中,转速变化对缸内温度、压力和燃烧放热率的影响不大,但NO_x排放随转速增大而减小;缸内温度、压力、燃烧放热率及NO_x排放随过量空气系数增大而降低;缸内压力、燃烧放热率及NO_x排放随进气压力增大而提高,进气压力对缸内温度影响较小;缸内温度、压力、燃烧放热率及NO_x排放随进气温度增大而提高。为实际改善掺氢天然气HCCI发动机的燃烧动力性、经济性和减少排放提供了理论依据。
In order to study the influence of different operating parameters on combustion characteristics of the HCCI engine fueled with natural gas and hydrogen. Based on the Chemkin simulation software,combined with the GRI-Mech3.0 chemical reaction kinetics mechanism,a numerical model of the HCCI engine was established. The combustion characteristics of engine fueled with 5% hydrogen(volume percentage) were numerically simulated with different operating parameters. The main research includes the influence of different operating parameters on the pressure,temperature,the combustion heat release rate and NO_x emission in the engine combustion process. The results show that the temperature,pressure and the combustion heat release rate change little for different speeds. However,the amount of NO_x emission decreases with the increase of the rotational speed. The temperature,pressure,the combustion heat release rate and the formation of NO_x in the cylinder decrease with the increase of the excess air ratio and increase with the increase of the inlet temperature. The pressure in the cylinder,the combustion heat release rate and the formation of NO_x increase with the increase of the inlet pressure and the temperature of the engine cylinder,however,change with relatively small amounts. The paper provides a theoretical basis for improving the combustion power,economy and emission reduction of the HCCI engine fueled with natural gas and hydrogen.
In order to study the influence of different operating parameters on combustion characteristics of the HCCI engine fueled with natural gas and hydrogen. Based on the Chemkin simulation software,combined with the GRI-Mech3.0 chemical reaction kinetics mechanism,a numerical model of the HCCI engine was established. The combustion characteristics of engine fueled with 5% hydrogen(volume percentage) were numerically simulated with different operating parameters. The main research includes the influence of different operating parameters on the pressure,temperature,the combustion heat release rate and NO_x emission in the engine combustion process. The results show that the temperature,pressure and the combustion heat release rate change little for different speeds. However,the amount of NO_x emission decreases with the increase of the rotational speed. The temperature,pressure,the combustion heat release rate and the formation of NO_x in the cylinder decrease with the increase of the excess air ratio and increase with the increase of the inlet temperature. The pressure in the cylinder,the combustion heat release rate and the formation of NO_x increase with the increase of the inlet pressure and the temperature of the engine cylinder,however,change with relatively small amounts. The paper provides a theoretical basis for improving the combustion power,economy and emission reduction of the HCCI engine fueled with natural gas and hydrogen.
引文
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[11]SMITH G P,GOLDEN D M,FRENKLACH M,et a1.GRI-Mech 3.0[DB/OL].http://www.me.berkeley.edu/gri_mech/.
[2]LU Xingcai,HAN Dong,HUANG Zhen.Fuel Design and Manage-ment for the Control of Advanced CompressionIgnition Combustion Modes[J].Progress in Energy and Com-bustion Science,2011,37(6):741-783.
[3]LEE K,CHO S,KIM N,et al.A Study on Combustion Control and Operating Range Expansion of Gasoline HCCI[J].Energy,2015,91(C):1038-1048.
[4]KAKAEE A H,PAYKANI A,GHAJAR M.The Influence of Fuel Composition on the Combustion and Emission Characteristics of Natural Gas Fueled Engines[J].Renewable&Sustainable Energy Reviews,2014,38(2):64-78.
[5]牛仁旭,张岳韬,于秀敏,等.喷氢时刻对缸内直喷掺氢汽油机燃烧及排放的影响[J].内燃机学报,2017,35(1):32-37.NIU Renxu,ZHANG Yuetao,YU Xiumin,et al.Effect of Hydrogen Injection Timing on Combustion and Emission Characteristics in a Hydrogen-Blended Gasoline Engine[J].Transactions of CSICE,2017,35(1):32-37.(in Chinese)
[6]孙柏刚,田华宇,张冬生,等.氢内燃机汽车与传统内燃机汽车的经济性比较研究[J].汽车工程学报,2014,4(1):21-27.SUN Bogang,TIAN Huayu,ZHANG Dongsheng,etal.A Comparative Study of Differences Between Hydrogen Internal Combustion Engine Vehicles and Traditional Vehicles[J].Chinese Journal of Automotive Engineering,2014,4(1):21-27.(in Chinese)
[7]高宏达.掺氢天然HCCI发动机燃烧特性模拟研究[D].大连:大连理工大学,2013.GAO Hongda.Simulation Study on Combustion Characteristics of Hydrogen-Natural Gas HCCI Engine[D].Dalian:Dalian University of Technology,2013.(in Chinese)
[8]HORA T S,AGARWAL A K.Experimental Study of the Composition of Hydrogen Enriched Compressed Natural Gas on Engine Performance,Combustion and Emission Characteristics[J].Fuel,2015,160:470-478.
[9]PORPATHAM E,RAMESH A,NAGALINGAM B.Effect of Hydrogen Addition on the Performance of a Biogas Fuelled Spark Ignition Engine[J].International Journal of Hydrogen Energy,2007,32(12):2057-2065.
[10]汪硕峰,纪常伟,闫皓,等.混氢体积分数对汽油机性能影响的试验研究[J].内燃机工程,2011,32(1):43-48.WANG Shuofeng,JI Changwei,YAN Hao,et al.Experimental Study on Effect of Hydrogen Addition Fraction on Performance of SI Gasoline Engine[J].Chinese Internal Combustion Engine Engineering,2011,32(1):43-48.(in Chinese)
[11]SMITH G P,GOLDEN D M,FRENKLACH M,et a1.GRI-Mech 3.0[DB/OL].http://www.me.berkeley.edu/gri_mech/.