高海拔条件下压气机结构优化及其对柴油机性能的影响
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摘要
基于二级可调增压柴油机高海拔性能试验,采用计算流体力学(CFD)和柴油机工作过程计算方法,开展高海拔条件下压气机叶轮结构优化及其对柴油机性能影响的研究.研究结果表明:海拔5 500 m,压气机叶轮主叶片及分流叶片前缘前掠6.27°、分流叶片向主叶片压力面偏折12.09°,压气机叶轮流道内流动损失明显降低,出口处流动稳定性提高,压比、效率及流量范围分别提高4.16%、2.63%及6.58%;压气机叶轮优化后,二级可调增压柴油机中低转速燃烧过程得到明显改善,滞燃期和燃烧持续期缩短;柴油机1 200 r/min全负荷工况最高燃烧压力升高9.53%,累计放热量提高8.78%,转矩提高5.82%,燃油消耗率降低4.42%.
On the basis of the performance test of a two-stage adjustable turbocharged diesel engine at high altitude,the structural optimization of its centrifugal compressor impeller and the corresponding effect on its performance were investigated using computational fluid dynamics and the calculation method for the working process.Results showed that at an altitude of 5 500 m,the angle between the main blade and the splitter blade leading edge sweep was 6.27°,and the angle between the splitter blade and the suction surface of main blade angle was12.09°.The overall loss in flow passage obviously decreased,and the flow stability at the outlet improved.The impeller's pressure ratio,efficiency and flow range improved by 4.16%,2.63%,and 6.58%,respectively.After optimization,the combustion process of the two-stage adjustable turbocharger diesel engine at medium-and lowspeeds clearly improved,and the ignition delay period and combustion duration were shortened.Under the working condition of 1 200 r/min and full-load,the maximum combustion pressure,cumulative heat,and torque were improved by 9.53%,8.78%,and 5.82%,respectively,whereas the fuel consumption rate was reduced by4.42%.
On the basis of the performance test of a two-stage adjustable turbocharged diesel engine at high altitude,the structural optimization of its centrifugal compressor impeller and the corresponding effect on its performance were investigated using computational fluid dynamics and the calculation method for the working process.Results showed that at an altitude of 5 500 m,the angle between the main blade and the splitter blade leading edge sweep was 6.27°,and the angle between the splitter blade and the suction surface of main blade angle was12.09°.The overall loss in flow passage obviously decreased,and the flow stability at the outlet improved.The impeller's pressure ratio,efficiency and flow range improved by 4.16%,2.63%,and 6.58%,respectively.After optimization,the combustion process of the two-stage adjustable turbocharger diesel engine at medium-and lowspeeds clearly improved,and the ignition delay period and combustion duration were shortened.Under the working condition of 1 200 r/min and full-load,the maximum combustion pressure,cumulative heat,and torque were improved by 9.53%,8.78%,and 5.82%,respectively,whereas the fuel consumption rate was reduced by4.42%.
引文
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[2]Li Hualei.Research on the power recovery of diesel engines with regulated two-stage turbocharging system at different altitudes[J].International Journal of Rotating Machinery,2014,2014:209084-01-10.
[3]董素荣,刘卓学,熊春友,等.二级可调增压共轨柴油机的高海拔燃烧特性[J].燃烧科学与技术,2017,23(1):36-40.Dong Surong,Liu Zhuoxue,Xiong Chunyou,et al.High altitude combustion characteristics of common rail diesel engine with two-stage regulated turbocharging system[J].Journal of Combustion Science and Technology,2017,23(1):36-40(in Chinese).
[4]刘瑞林,林春城,董素荣,等.柴油机二级可调增压系统高海拔标定试验[J].内燃机学报,2016,34(6):543-548.Liu Ruilin,Lin Chuncheng,Dong Surong,et al.High-altitude calibration for the regulated two-stage turbocharging system of diesel engine[J].Transactions of CSICE,2016,34(6):543-548(in Chinese).
[5]王如根,周敏,赵英武,等.跨声速压气机低雷诺数下流动失稳机制研究[J].航空动力学报,2009,24(2):414-419.Wang Rugen,Zhou Min,Zhao Yingwu,et al.Research on flow instability mechanism of transonic compressor at low Reynolds number[J].Journal of Aerospace Power,2009,24(2):414-419(in Chinese).
[6]Gülich J F.Effect of Reynolds number and surface roughness on the efficiency of centrifugal pumps[J].Journal of Fluids Engineering,2003,125(4):670-679.
[7]霍磊,刘火星.低雷诺数下离心压气机性能及流动影响的数值研究[J].航空动力学报,2013,28(4):911-920.Huo Lei,Liu Huoxing.Numerical analysis of centrifugal compressor performance and flow at low Reynolds number[J].Journal of Aerospace Power,2013,28(4):911-920(in Chinese).
[8]刘卓学,董素荣,张众杰,等.高原环境对离心压气机性能及流动特性的影响[J].军事交通学院学报,2017,19(8):47-52.Liu Zhuoxue,Dong Surong,Zhang Zhongjie,et al.Influence of plateau environment on performance and flow characteristic of centrifugal compressor[J].Journal of Military Transportation University,2017,19(8):47-52(in Chinese).