自由活塞式柴油机缸内流动过程研究

基于活塞运动规律对缸内流动过程的意义，采用等效转速变换法分析压燃式自由活塞内燃发电动力系统活塞运动特点，通过理论计算及三维数值仿真研究了活塞运动对缸内流动影响。CFD仿真的结果与理论计算结果基本一致。研究表明:与传统机型相比，自由活塞机型在上下止点附近的等效转速较高，中途位置相对较低。这导致其挤流与逆挤流峰值偏高，持续时间较短，二者平均湍动能曲线存在一定差异。 

Study on the In-Cylinder Flow Process of Diesel Free-Piston Linear Generator

As the piston movement is of great importance to the in-cylinder flow process, the piston movement characteristics of the diesel free-piston linear generator (FPLG) were analyzed with the equivalent speed transform method. Based on the analysis results, the influence of the piston movement on the in-cylinder flow was studied by using theoretical calculation and three-dimensional numerical simulation respectively. The results demonstrate that compared with the traditional engine, the equivalent speed of FPLA is higher both near TDC and BDC, but lower at the midterm of the stroke. It leads to a higher peak value of squish flow, shorter duration and different curves of mean turbulence kinetic energy.