下游喉道对双喉道气动矢量喷管气动性能的影响

数值模拟研究了下游喉道高度H对二维双喉道气动矢量喷管(DTN)所能达到的最大矢量角的影响,并分析了不同H时喷管腔内流动的发展规律.结果表明:H对喷管推力矢量角影响较大,尤其是H大于1与H小于1的喷管腔内会出现不同的主流发展过程.当喷管腔内主流刚好发展为完全超声速,下游喉道处声速线消失时,可以获得它在所给工况下可能达到的最大矢量角;并且H大于1时可以在较少的二次流百分比下就可以达到最大矢量角,而H小于1时则需要在较高的二次流百分比下才能达到,但其最大矢量角明显大于H大于1的喷管所能达到的最大矢量角. 

Effects of downstream throat on aerodynamic performance of dual throat nozzle

Numerical simulation studies on 2-D dual throat nozzle (DTN) were performed on the downstream throat height H. The contents include: effects of H on the nozzle's maximum vector angle and the flow development in the nozzle's thrust cavity. The results show that: H has a significant influence on the nozzle's thrust vector angle; especially in two cases of H greater than 1 and H less than 1, the flow development in the nozzle's thrust cavity has a large difference. In all cases, it appears that the maximum vector angle could be achieved when the flow in the nozzle's thrust cavity has changed to the supersonic flow, meanwhile the sonic line at the downstream throat of the nozzle has vanished. The nozzle can achieve the maximum vector angle with a low ratio of secondary injection in the case of H greater than 1. The nozzle could be achieved maximum vector angle at larger ratio of secondary injection in the case of H less than 1, while the maximum vector angle is greater than that in the case of H greater than 1.