CAJ | 학술논문

高空高马赫数条件下，化学非平衡效应将对飞行器气动特性产生影响，影响飞行器气动布局优化和飞行弹道设计。文章通过三维化学非平衡流动求解程序，针对再入返回器开展数值研究与机理分析，通过对比完全气体模型和化学非平衡气体模型获得的气动力参数，揭示化学非平衡效应对流场结构和气动力特性的影响和规律。结果表明，对Apollo的气动力计算结果验证了模型和计算方法；化学非平衡效应影响下，激波层内化学反应消耗大量能量，致使激波脱体距离减小，气体压缩性增强；典型状态高度为70 km，Ma=30条件下，化学非平衡效应导致返回器升力系数增大约6%、阻力系数增大约1.3%～3.3%、升阻比增大3%左右、俯仰力矩系数增大，从而使配平攻角减小约2.5°；通过机理分析，发现化学非平衡效应影响下表面压力系数发生变化的原因是飞行器周围激波形状及驻点压力改变，表现为气体沿流线经激波层、压缩区和膨胀区的历程变化；对于钝体形状的返回器，迎风面前体压力系数增加和后体压力系数降低，造成轴向力和法向力系数增大。
고공고마혁수조건하，화학비평형효응장대비행기기동특성산생영향，영향비행기기동포국우화화비행탄도설계。문장통과삼유화학비평형류동구해정서，침대재입반회기개전수치연구여궤리분석，통과대비완전기체모형화화학비평형기체모형획득적기동력삼수，게시화학비평형효응대류장결구화기동력특성적영향화규률。결과표명，대Apollo적기동력계산결과험증료모형화계산방법；화학비평형효응영향하，격파층내화학반응소모대량능량，치사격파탈체거리감소，기체압축성증강；전형상태고도위70 km，Ma=30조건하，화학비평형효응도치반회기승력계수증대약6%、조력계수증대약1.3%～3.3%、승조비증대3%좌우、부앙력구계수증대，종이사배평공각감소약2.5°；통과궤리분석，발현화학비평형효응영향하표면압력계수발생변화적원인시비행기주위격파형상급주점압력개변，표현위기체연류선경격파층、압축구화팽창구적역정변화；대우둔체형상적반회기，영풍면전체압력계수증가화후체압력계수강저，조성축향력화법향력계수증대。
Chemical non-equilibrium effect has a strong impact on aerodynamic characteristics of vehi-cles flying at high altitude and highMa number, which will affect aerodynamic shape optimization and flight trajectory design. The numerical investigation and mechanism analysis are carried out on reentry vehicles using a three dimensional chemical non-equilibrium flow solver, to understand the impact and regularity of chemical non-equilibrium effect on the flow field structures and aerodynamic forces, in comparison with a perfect gas model. The good agreement between current result and reference data for AS-202 flight test validates the model and numerical methods. The stand-off distance of the forebody shockwave is reduced, and the compressibility of the gas is enhanced, because of large energy consumption of the chemical reactions; In typical status, at alti-tude 70 km,Ma=30, chemical non-equilibrium causes the lift coefficient increased by 6%, the drag coefficient grown up by 1.3%~3.3%, the ratio of lift to drag raised by 3% and the trim angle decreased by 2.5 degrees for the pitching moment coefficient rises up in chosen typical flight conditions; through the mechanism analysis, it has been found that the reason why the surface pressure contribution changes under the influence of chemical non-equilibrium effect is that the shape of the shock around the vehicle varies and the stagnation pressure in-creases; in that case the journey of the gas flowing past the shock, the compression and the expansion zone would be different; for blunt reentry vehicles, because the pressure coefficient in windward increases on fore-body and decrease on afterbody, the axial and normal force coefficients get bigger.