热障涂层在涡轮叶片应用中的热防护有效性

建立了含热障涂层的涡轮叶片简化传热模型,通过理论推导建立了热障涂层的有效性判据,并基于此进行了热防护有效性分析。理论分析与数值实验表明:由热障涂层带来的复合传热表面传热系数的变化会显著影响热障涂层的热防护效果；在发动机典型工况下,对于处于高温区的高压涡轮叶片前缘处,热障涂层引起的复合传热表面传热系数变化率最大值的范围为1.25%~10.83%以满足热防护有效性要求。在工程中应特别注意由于热障涂层的应用带来的复合传热表面传热系数的变化,否则会导致热防护失效,甚至产生反效果。 

Thermal protection effectiveness of thermal barrier coatings in turbine blade applications

A validity criterion of thermal barrier coating was developed by theoretical derivation based on a simplified heat transfer model of turbine blades with thermal barrier coating. Besides, the effectiveness of thermal protection was analyzed based on the validity criterion and engineering practice. Theoretical analysis and numerical experiments showed that the change of composite heat transfer coefficient caused by thermal barrier coating could greatly affect the thermal protection effect. For the front edge of the high pressure turbine blade in the high temperature zone, the maximum rate of change of the composite heat transfer coefficient caused by the thermal barrier coating should be range from 1.25% to 10.83% to meet the thermal protection effectiveness. In practice, special attention should be paid to the change of the composite heat transfer coefficient due to the application of the thermal barrier coating, otherwise it will cause thermal protection failure or even counter effect.