入口流场不均匀性对固体火箭发动机大膨胀比喷管内流场的影响

During the high maneuver flight, the solid rocket motor(SRM)is subjected to a long-time small overload, which will change gas direction at the nozzle inlet.The spatially non-uniform combustion of the grain can lead to non-uniform distribution of the combustion gases density, which will affect the mass flux distribution at the nozzle inlet.Both of them will cause inlet gas flow non-uniformity, which is one of the main reasons for nozzle flow field non-uniformity and directly affects the SRM performance.In this paper, taking the SRM nozzle with expansion ratio 100 as the research object, the mass flux distribution and incident direction at the nozzle inlet were changed to investigate the effect of inhomogeneity at the nozzle inlet on flow field by using computational fluid dynamics software.The results show that when the nozzle inlet mass flux is distributed as paraboloid, the inhomogeneity of the inlet has little effect on flow field in the nozzle, and the inhomogeneity effect is basically eliminated in the nozzle throat;when the gas is non-vertically incident due to pitch overload, the circumferential unevenness of the flow field at the nozzle inlet is as high as 23%. With the full expansion of gas, the non-uniform effect weakens, when the nozzle expansion ratio reaches 92.8, the flow field is basically uniform, but under the condition of finite expansion ratio, the non-uniform effect caused by the incident angle cannot be completely eliminated.