大曲率板壳综合冷却效率模化数值研究

Numerical Study on the Analogy Principle of the Overall Cooling Effectiveness for the Hot Components With Large Curvature

现阶段针对航空发动机热端部件复合冷却,提出的综合冷却效率来表征固体表面的无量纲温度分布。基于一维半无限大平板综合冷却效率模化公式为指导实验参数匹配与冷却结构设计提供了理论支持,然而在大曲率区域该模化公式预测误差较大。因此本文提出一种大曲率板壳综合冷却效率模化的公式,并建立不同曲率的冲击-气膜冷却板壳结构进行验证。结果显示,随着曲率增大,一维半无限大平板综合冷却效率模化公式得到的面平均综合冷却效率预测误差达到52%;在所研究的全部曲率半径模型中,大曲率板壳综合冷却效率模化公式的预测精度显著提高,误差值最大不超过26%。

The overall cooling effectiveness is proposed to represent the surface temperature field for the composite cooling of the aero-engine hot components.The analogy formula of the overall cooling effectiveness provides the theoretical reference for the experimental parameter matching and cooling structure design.However,the formula is ineffective in the region with large curvature.Hence an analogy method was proposed for the overall cooling in the large curvature components in this research.It is investigated by establishing conjugate heat transfer models of impingement-film cooling with different curvatures.And the prediction accuracy of different analogy formulas are compared.The results illustrate that the overall cooling effectiveness predicted by the conventional analogy method shows significant rising prediction error with the enlarging curvature.The maximum prediction error of area-averaged overall cooling effectiveness reaches 52%.While the prediction accuracy of the overall cooling analogy formula for large curvature plates significantly improves,with a maximum prediction error less than 26%.