半刚性机械展开式再入飞行器气动特性研究

Study on Aerodynamic Characteristic of Semi-rigid Mechanical Deployable Reentry Vehicle

半刚性机械展开式再入飞行器具有受整流罩包络约束小、运载效率高、减速效果好等优点,具有广泛的应用前景。文章基于计算流体力学方法进行了不同马赫数及迎角下飞行器的流场数值计算,分析其流场特性及气动力、气动力矩,结果表明:由于粘性作用,飞行器背部有较明显的涡产生。随着马赫数的增大,气流压缩性效应更加显著,涡的范围变小,超声速情况下弓形激波离物面距离减小;迎角增大导致飞行器前端面驻点位置变化,为保证驻点位置位于刚性头锥上,飞行器再入时的迎角范围应在±20°范围内。迎角为0°和180°时,阻力系数大,迎角在90°附近时,阻力系数最小;飞行器质心在对称轴上时,在0°~180°范围内存在3个俯仰力矩系数为0的点,其中0°和180°为静稳定点,另一个为静不稳定点。文章的研究结果对半刚性机械展开式再入飞行器的设计及分析有一定参考意义。

Semi-rigid mechanical deployable reentry vehicle has broad application prospect for its advantages of less dimension restriction by rocket fairing envelope, higher efficiency in payload carrying, and better effect in aerodynamic deceleration. The flow field of different Mach numbers and attack angles are simulated and aerodynamic forces are analyzed by using computational fluid dynamics method in this paper. The results show that large vortexes can be found on the back of the main body of the vehicle due to viscosity. As Mach number grows, compressibility effect of airflow becomes more significant, which results in reduced vortexes range and decreased distance between bow shock and wall in supersonic situations. The stagnation point moves lower along the wall as the attack angle increases, so the attack angle of the vehicle should be limited within ±20° during its reentry to ensure that the stagnation point is in the range of rigid nose of the vehicle. The drag coefficient is maximum with 0° and 180° attack angle and minimum with around 90° attack angle. When the center of mass is on the axis of symmetry, there are three attack angles under which the moment coefficient equals to zero within the range of 0° to 180°. 0° and 180° situation are static stable and the other one is static unstable. The results of this paper have some reference value for design and analysis of semi-rigid mechanical deployable reentry vehicles.