某型航空活塞发动机进排气系统优化分析

针对高空小型飞机的动力要求，对某型航空活塞发动机的进排气系统均匀性进行了分析，建立了某型航空活塞发动机的仿真模型，分析了进排气管路结构参数对发动机性能的影响.以进气质量流量不均匀度和进气压力波动效应为评价指标，对发动机的进排气系统结构参数进行了优化.通过改变进排气歧管和总管的长度，把不均匀度降低到5%以内，最大降幅为38%，并且提高了发动机的扭矩和功率，最大提高幅度为5%. 

Optimization analysis of a aircraft piston engine intake and exhaust system

To meet the power requirement of small high altitude aircraft, the intake and exhaust system flow uniform of a aircraft piston engine was analyzed. Simulation model of the aircraft piston engine was established, and the effects of intake and exhaust pipe structural parameters on engine performance were analyzed. The intake mass flow unevenness and pressure fluctuations were chosen as evaluating indicators to optimize the structural parameters of the engine's intake and exhaust system. By changing the length of intake manifold and duct, the unevenness is reduced to less than 5%, and the biggest decrease amplitude is 38%; the engine power and torque are improved by 5%.