Study on Piston Slap -induced Liner Cavitation

内燃机有时会遇到由活塞拍打引起的空化侵蚀。活塞与缸套之间的冲击振动使缸套冷却液侧产生压力波动，在动压低于其蒸汽压的情况下产生空化现象。建立了活塞拍打引起衬套振动的分析方法，分析了实际柴油机在真空条件下水冷液通道的声学特性，并与实测结果进行了比较。在此基础上，提出了确定结构与水声场耦合振动特性的理论方法。该方法采用有限元法和模态分析技术。将矩形水箱的振动声特性计算结果与实测结果进行了比较，并阐明了重流体载荷对矩形水箱振动声特性的影响。

The internal combustion engine sometimes encounters the cavitation erosion induced by piston slap. The impact vibration between the piston and cylinder liner generates the pressure fluctuation on the coolant side of the liner and leads to occur the cavitation in the case that dynamic pressure falls below its vapor pressure. Authors developed the analytical method to predict the liner vibration caused by the piston slap and the acoustic characteristic of the water coolant passage of the actual diesel engine in vacuum condition was analyzed and compared with the measured result. Moreover, theoretical method to determine the coupled vibratory characteristics of structure and water acoustic field was developed. This method employs Finite Element Method and modal analysis technique. Calculated results of vibro-acoustic characteristics of the rectangular tank were compared with the measured ones and the effect of the heavy fluid loading was elucidated.