节流方式对隔离段流场结构影响的数值仿真

Numerical simulation of the impacts of block modes on the flow field of isolator

在隔离段尾部设计节流装置是试验上模拟反压对隔离段流场影响的常用方法。针对不同节流方式对隔离段流场结构的影响,采用数值模拟方法进行了比较研究。比较三种节流方式,包括在斜坡面尾部设置节流直板、在头罩面尾部设置节流直板和流场中间布置对称斜楔等。结果表明,由于隔离段斜坡面和头罩面边界层发展的非对称性,三种方式所产生的激波串结构均靠近头罩一侧的壁面。第二种方式产生的激波串强度较大,边界层分离较为严重,容易造成流场堵塞,在实际中不利于激波串的试验研究。另外两种方式所产生的流场结构类似,但是第一种方式在设计加工上相对容易实现。

The design of a blockage adjustor at the exit is commonly used in simulating the impacts of backward pressure on the isolator flow field. Numerical simulation was adopted to study the effects of different block modes. Three modes were compared,including installing a flat on the ramp side wall,a flat on the cowl side wall and a wedge in the middle of the flow field. The results show that due to the asymmetric boundary layer on the ramp wall and cowl wall,the shock trains formed by them are all next to the cowl side. The intensity of the shock train generated by the second mode is stronger and the boundary layer separates more evidently,which chocks the isolator more easily and poses difficulty for the study of shock train in experiment. The other two modes can generate similar flow field,but the first one can be realized more easily.