建立了活塞激光热负荷数值模拟模型,研究了不同冷却介质对活塞热负荷的影响。结果表明,激光卸载过程活塞顶和通油孔通气冷却,温度波动发生在活塞顶薄层区域,与活塞在实际稳定工况下的温度响应一致;激光卸载过程活塞内腔和通油孔通气或通油孔通水冷却,温度波动区域都不能反应在实际稳定工况下的状态。低周热疲劳采用激光卸载过程配合活塞顶通气、活塞内腔和通油孔通水能缩短试验周期、加速活塞的热疲劳损伤。数值模拟与试验结果基本吻合,验证了模型的有效性。

Numerical simulation model of thermal loading on piston by laser is established. By virtue of the model,the influence of different cooling matters on thermal loading of piston is investigated. The results show that temperature fluctuations occur at thin-layer regional of piston top surface when cooling air is applied to piston top surface and tunnel with cessation laser heating,which is in accordance with actual stable conditions. Temperature fluctuations is not consistent with actual stable conditions of air cooling of piston inner chamber and tunnel or water cooling of tunnel. Low-cycle fatigue with air cooling of piston top surface,water cooling of inner chamber and tunnel can accelerate damage to piston. Meanwhile,these regions of concave,tunnel and inner chamber are most vulnerable to form crack due to the cool medium contacting with them. The numerical results are in agreement with the experimental results,which indicates that the established numerical mode is correct and reliable.