民用飞机机体外部对流换热系数计算方法研究

Research on calculation method of external convective heat transfer coefficient of civil aircraft

飞行条件下,飞机外部对流换热系数的计算需考虑气体压缩性和热交换的影响。目前工程上通常采用的参考温度法忽略了飞机结构的影响,将飞机各部位的外部对流换热系数视为一个数值,势必会严重影响计算结果的准确性。通过对民用飞机外部对流换热系数计算原理的研究,提出一种可用于求解飞行条件下飞机机体各区域外部对流换热系数的仿真计算方法——极限温差法。以STAR-CCM+软件为计算平台,基于某民用飞机,从仿真计算角度对其可行性进行分析,采用理论的参考温度法和传热公式法对极限温差法计算结果的准确性进行验证。结果表明,传热公式法和极限温差法得到的模拟值基本相同,且不同模拟值与参考温度法的理论值之间的差值均约为理论值的8%,极限温差法计算结果与理论值基本吻合。

In flight condition,the calculation of convective heat transfer coefficient should consider the influence of gas compressibility and heat exchange.Under flight conditions,the gas compressibility and heat exchange should be considered in the calculation of external convective heat transfer coefficient of aircraft.At present,the reference temperature method commonly used in engineering that ignores the influence of aircraft structure,and regards the external convective heat transfer coefficient of each part of the aircraft as a numerical value,which is bound to seriously affect the accuracy of calculation results.Based on the study of calculation principle of external convective heat transfer coefficient of civil aircraft,this paper proposes a simulation calculation method,that is limit temperature difference method,which can be used to solve the external convective heat transfer coefficient of each part of aircraft under flight conditions.STAR-CCM+software is used as the calculation platform to analyze the feasibility of a civil aircraft from the perspective of simulation calculation.Theoretical reference temperature method and heat transfer formula method are used to verify the accuracy of the calculation results of limit temperature difference method.The results show that the simulated values obtained by heat transfer formula method and limit temperature difference method are basically the same,and the difference between the different simulated values and the theoretical value of reference temperature method is about 8%of the theoretical values,so the results calculated by limit temperature difference method are in good agreement with the theoretical values.