空间再入充气结构的流固及热固单向耦合研究

One way fluid-structure and thermo-structure interaction on an inflatable space re-entry aeroshell

为描述空间再入充气结构的非线性结构动力学行为,基于二维坐标系计算了再入返回过程中的弹道方程,利用CFD数值模拟研究了不同再入高度处的流场及表面热流分布。同时基于有限元理论建立了空间再入充气结构的有限元模型,研究了充气压力、薄膜厚度等材料非线性因素对静力学特性和模态特征的影响,并利用流固及热固单向耦合的方法,分析了考虑高超声速流场气动压力和气动热作用下空间再入充气结构的特性变化。研究表明:驻点最大热流密度随半锥角的增大而减小,随初始再入角的增大而增大;当飞行高度大于40km时需着重考虑气动加热效应对结构热应力及热模态的影响,而飞行高度小于40km时气动压力对结构静应力及模态特征影响更大。

As an emerging space technology, inflatable return technology has become a hot spot of space power research because of its large payload ratio, small launch volume, and flexible return. However, the theoretical research on reentrant structures at home and abroad is not mature enough, and the analysis of structural characteristics is not comprehensive. For the description of the nonlinear structural dynamic behavior of a burgeoning inflatable re-entry vehicle （IRVE）, the modeling of two dimensional coordinate system for the IRVE system was presented to calculate the trajectory equation during the reentry process. Half taper angle and initial re entry angle were optimized by genetic algorithm, and the trajectory was exerted as the boundary condition of CFD simulation to obtain the heat flux distribution. A structural dynamic model of IRVE system was established based on the finite element theory, and the effects of different inflation pressures and film thickness on the static and naodal characteristics were investigated. Based on the unidirectional couplings of fluid-solid and thermal solid, the effects of aerodynamic and aeroheating on static and modal characteristics of IRVE system were studied. The results show that the maxinaum heat flux decreases with the increase of the half taper angle while rises with the increase of the initial reentry angle. When half taper angle is chosen 57.65° and initial reentry angle is chosen 1.35°, the overload can reach a minimum value of 1.96g. The static characteristic is most affected by aerodynamic pressure when flight height is below 40 km while most affected by aeroheating when flight height is above 40 km.