飞行器热防护结构的相似准则问题研究

高速飞行带来的气动热与热防护问题是制约高速飞行器系统提高技术水平和能力的一个主要技术瓶颈。在飞行器结构设计过程中,对飞行器结构进行考核试验必不可少。受风洞设备试验能力限制,试验模型尺寸、来流条件等与实际飞行通常存在较大差异,要在试验中完全模拟实际飞行环境、温度和应力状况无法做到。对飞行器进行缩放处理后进行模型的风洞热结构考核,并通过相似准则获得真实结构的温度/应力分布特性,为飞行器热防护设计提供支撑有着迫切需求。本文通过热传导方程和热弹性动力学方程组,对其中的模型相似参数进行讨论,并根据模型试验边界情况进行了讨论研究。提出了飞行器热防护结构地面考核试验的相似准则,并建立了不同试验类型情况下需要遵循的相似准则条件。该相似准则体系具有较大的灵活度,同时具有很高的实用价值。

Study on the similarity criteria of aircraft thermal protection structures

The performance parameters of thermal protection system (TPS)are essential for the design and optimization of high-speed aircraft.Most of these performance parameters are ob-tained from wind tunnel assessment test.Due to the limitation of the equipment capacity of wind tunnel ,the size of the test model and the flow conditions are very different from the actual flight. The experimental data are not practicable directly and need to be converted to those under actual flight conditions based on the flight-ground conversion method.In this paper,the similarity pa-rameters in the heat conduction equation and thermoelasticity equations are discussed.The wind tunnel environment is also studied.The similarity criterion equations and boundary condition e-quations are obtained.Finally,parts of the similarity parameters in this paper are calculated and analyzed.Based on the results,the wind tunnel test can be adjusted according to this similarity criterion to improve the precision and efficiency of experiments.