基于CFD某增压柴油机不同海拔下的燃烧机理分析

在验证平原下某增压柴油机计算模型基础上，对某增压柴油机在海拔2900 m和海拔4250 m条件下缸内工作过程进行了三维数值计算．计算结果表明：与平原相比，随着海拔的升高，放热率峰值下降但放热率重心前移，缸内温度迅速升高，缸内最高温度分别上升309和357 K；缸内最高燃烧压力分别下降4.9和5.53 MPa；NOx 出现时间随海拔上升而稍微提前，NOx 排放量随海拔的上升而下降．研究结果为优化高原增压柴油机的性能提供了参考．

Study on combustion mechanism of turbocharged diesel engine in different altitude based on CFD

On the base of validating the calculation model of a turbocharged diesel on the plain ,three-dimension-al numerical simulation of in-cylinder working process at 2 900 and 4 250 meters above sea-level is carried out . The results show that ,compared with the situation on the plain ,the peak value of heat release rate lowers , but the crank angle of the center of heat release rate curve advances ,combustion temperature increases rapidly , the maxi-mum temperature rises 309 K and 357 K.The maximum combustion pressure is decreased by 4.9 MPa and 5.53 MPa,respectively;NOx appears earlier and NO x emission decreases with an increase in altitude .The research pro-vides reference for optimization of the turbocharged diesel′s performances at a high altitude .