摘要
基于Amesim建立了两行程自由活塞发动机模型,针对直流扫气特点提出了单区三阶段扫气模型,根据CFD计算结果对扫气参数进行了标定,在准确预测扫气性能的基础上分析了耦合活塞动力学条件下的气体交换过程。研究结果表明,当气口的配气相位角不变时,自由活塞发动机的气口面积随时间的变化关系与曲柄发动机的气口面积随时间的变化关系存在显著差异。气口高度减小对提高充气效率有利,但是受到扫气效率过分下降的约束。排气流动控制明显改善了扫气性能,利用排气脉动效应可以显著提高充气效率。
Based on Amesim one-dimensional code was generated for two-stroke hydraulic free piston engine to predict the gas exchange process under direct coupling with piston dynamics.A single-zone three-phase scavenge model was first presented for uniflow scavenge simulation,and its parameters were calibrated by CFD results.It was meant to be a general gas dynamic program for accurate simulation of the gas flow.The simulation results show that the scavenge and exhaust time areas of free piston engine are significantly different from that of crank engine when the timing of the ports is fixed.Low port height is beneficial to charging efficiency,but is restricted by deterioration of scavenge efficiency.Exhaust flow control improves scavenge performance and increases charging efficiency significantly.
出处
《中国机械工程》
EI
CAS
CSCD
北大核心
2010年第18期2196-2201,共6页
China Mechanical Engineering
关键词
自由活塞
扫气
时-面值
充气效率
free piston
scavenge
time area
charging efficiency
