热障涂层活塞热应力分析的格点型有限体积法

为研究热障涂层(thermal barrier coating,TBC)活塞热应力问题,将二维格点型有限体积法(cell vertex FVM,CVFVM)推广用于三维复合材料热力性能研究.利用交错网格技术,通过将物性参数和待解变量分别定义在单元中心和节点上,将物性参数的空间变化引入离散过程,从而避免数值不连续问题.采用CV-FVM数值模拟普通活塞热应力场,计算结果与ANSYS计算结果吻合良好.数值模拟TBC活塞热应力场,分析活塞TBC区域的热力性能,结果表明:活塞的最大温度位于燃烧室与活塞顶面的交界区域;应力最大值位于粘结层与陶瓷层的分界面附近;周向应力对活塞的整体应力水平起主要影响.数值结果表明CV-FVM能够作为TBC活塞热力性能研究的数值预测工具.

Cell vertex FVM for thermoelastic analysis of the piston with thermal barrier coating

To analyze the performance of the piston with thermal barrier coating (TBC), two dimensional cell vertex FVM (CV-FVM) has been extended to the research of the thermoelastic performance of three-dimensional composite structures. The staggered grid technique was adopted to incorporate property variation into the course of solution so as to avoid numerical discontinuity. The unknown variable was defined at the cell vertex, while the material property was defined at the cell center. The developed CV-FVM was used to simulate the thermoelastic fields of the ordinary piston and the predicted results agreed with the ANSYS results. Then, the CV-FVM was used to simulate the thermoelastic fields of the TBC piston and the performance were analyzed. The maximum temperature is in the area between the combustion chamber and the top surface, and the maximum stress is around the interface between the ceramic layer and the cohesive layer. The circumferential stress contributes the main part of the thermoelastic stress in the TBC area. The successful application demonstrates that the CV-FVM can be used as a predictive tool for the thermoelastic analysis of the TBC piston.