组合发动机蒙皮壁温计算方法研究

Calculation Method of Engine Skin Temperature for Combined-Cycle Engine

关键词:  组合发动机  蒙皮壁温  气动加热  辐射传热  发射率  攻角

Key words:  Combined-cycle engine  Skin temperature  Aerodynamic heating  Radiative heat transfer  Emissivity  Angles of attack

摘要:

为满足组合发动机总体热防护的需要，分别采用参考温度法和大气透过率计算软件MODTRAN4计算了组合发动机蒙皮所受的气动加热和环境热辐射。利用本文建立的稳态热平衡方程，迭代求解得到组合发动机蒙皮在典型飞行工况下的一维稳态温度分布。将本文计算的结果与美国航空航天局(NASA)的实验结果进行对比，误差不大于6%。对典型飞行工况下不同蒙皮壁面发射率、不同飞行攻角进行了系列研究。结果表明:随着发射率的提高，蒙皮壁温逐渐降低，随着攻角的增加，蒙皮壁温逐渐增高。在某标准工况下，发射率为1.0的蒙皮温度比发射率为0.1的蒙皮温度低98.01K，降幅为12.76%。攻角为45°的蒙皮温度比攻角为0°的蒙皮温度高95.45K，增幅为13.14%。

Abstract:

In order to meet the demand of the thermal protection for a combined-cycle engine，the aerodynamic heating and radiative heat transfer of the combined-cycle engine were calculated by reference temperature approach and atmospheric transmittance calculation soft MODTRAN4，respectively. The one dimensional steady state temperature distribution of the combined-cycle engine skin under some typical flight operation conditions was obtained by iterative computating the equation of steady state heat balance. Comparison between the calculated results and the experiment results conducted by NASA shows that the error was less than 6%. A series of studies with different skin emissivities，different angles of attack under some typical flight operation conditions were carried out. The results show that，the skin temperature decreases with the growing emissivity and increases with the growing angle of attack. Under a typical flight operation condition，the skin temperature decreases by 98.01K，a decline of 12.76% ，when the skin emissivity varies from 0.1 to 1.0，and the skin temperature increases by 95.45K，a rise of 13.14% ，when the angle of attack varies from 0° to 45°.