不同反压下椭圆形隔离段流场特征与气动性能

在反压条件下,对椭圆形等直隔离段进行了全三维数值仿真研究.结果表明:在对称的几何条件和边界条件以及均匀来流条件下,当来流马赫数较小时,流场与激波串结构基本对称;当来流马赫数较大(大于2)时,流场与激波串结构出现明显不对称现象,并且随着来流马赫数增大,这种不对称现象加剧.椭圆形隔离段抗反压能力随着长短半轴比减小逐渐增强,出口马赫数和温升比基本不受长短半轴比影响.不同来流马赫数下,当隔离段承受最大反压时,出口马赫数变化不大.

Flow characteristic and aerodynamic performance in elliptic shape isolator at different back pressures

Elliptic shape isolators under back pressure were studied with 3-D CFD(computational fluid dynamics) calculation.The results show that the shock train structure and the flow characteristic are symmetrical generally when the upstream Mach number is low under symmetrical free-stream and geometry,but the shock train structure and the flow characteristic become unsymmetrical obviously when the upstream Mach number is too high.As the ratio of major axis to minor axis decreases,the elliptic shape isolator's ability to support back pressure becomes better,but the Mach number and temperature of the isolator outlet are independent of the ratio of major axis to minor axis.As the upstream Mach number increases,the Mach number of outlet varies little once reaching maximum back pressure.