低超声速飞行器瞬态热状况解耦算法

Decoupling Method for Transient Thermal Status of Low Supersonic Aircrafts

针对低超声速飞行器非稳态飞行条件下内外流固耦合一体化计算的复杂性,将飞行器外部流场的实时气动热转化为浮动的第三类边界条件进行解耦.以加速俯冲的超声速三维头锥体为例,分别采用浮动温差法和辐射平衡法提取表面对流换热系数进行解耦计算,并与直接耦合计算结果进行比较,验证两种解耦算法的可靠性.结果表明,将非稳态飞行过程离散为不同飞行状态点,通过提取对流换热系数解耦计算得到的不同状态点的锥体表面温度分布与直接耦合计算得到的结果吻合较好.两种解耦算法在计算效率方面均要优于耦合计算方法;在外界气动环境发生剧烈变化的过程中,最大相对误差均不超过2%.

Considering complexity of coupled fluid-solid calculation of low supersonic aircraft under unsteady flight condition, real time aerodynamic heat by outer fluid field is converted into floated third type boundary conditions for decoupled calculation. Take three-dimensional head cone experiencing accelerating diving as example, floated temperature and radiation equilibrium methods are adopted to extract surface heat transfer coefficients for decoupling calculation. Results are compared with coupled results to validate reliability of decoupling methods. It shows that with dispersed state points representing unsteady process, temperature distributions of cone surface at different state points by decoupling methods agree well with coupling ones. Calculating efficiency of decoupling methods is superior to coupling ones. Maximum relative errors of decoupling methods are both within 2%, even as external aerodynamic environment changes dramatically.