Miao Shujing, Liu Haiyang, Cen Haitang, Liu Jiang, Li Huaqiang, Xu Gang
School of Mechanical Engineering, Inner Mongolia University of Technology, Hohhot 010051, China.
Micromachines (Basel). 2022 Aug 14;13(8):1314. doi: 10.3390/mi13081314.
The two-stroke micro free piston swing engine (MFPSE) is a portable power device. Its seal performance plays an important role in the dynamic properties and efficiency of microengines. The present work established the leakage model of the two-stroke micro free piston swing engine by utilizing the compressible flow Reynolds Navier-Stokes equation. The obtained nondimensional mass leakage was related to the seal gap height, seal inlet pressure, size factor and compression ratio. Simulation investigated how the different seal gap heights and size factors affected the pressure, temperature and mass leakage of micro engines. The results showed that when the seal gap height of the combustion chamber increased, the maximum pressure and cycle power declined, obviously. However, the maximum temperature was scarcely affected. The mass leakage was not greatly impacted when the compression ratio was less than 5. However, the mass leakage dramatically increased when the seal gap was more than 10 μm or the size factor was less than 0.4. The investigation revealed these mass leakage effect factors and provided a guide for the seal and structure design of the two-stroke micro free piston swing engine.
二冲程微型自由活塞摆动发动机（MFPSE）是一种便携式动力装置。其密封性能对微型发动机的动力学特性和效率起着重要作用。本研究利用可压缩流动的雷诺-纳维-斯托克斯方程建立了二冲程微型自由活塞摆动发动机的泄漏模型。得到的无量纲质量泄漏与密封间隙高度、密封进口压力、尺寸因子和压缩比有关。通过模拟研究了不同的密封间隙高度和尺寸因子如何影响微型发动机的压力、温度和质量泄漏。结果表明，当燃烧室的密封间隙高度增加时，最大压力和循环功率明显下降。然而，最高温度几乎不受影响。当压缩比小于5时，质量泄漏影响不大。然而，当密封间隙大于10μm或尺寸因子小于0.4时，质量泄漏急剧增加。该研究揭示了这些质量泄漏影响因素，为二冲程微型自由活塞摆动发动机的密封和结构设计提供了指导。
