Thrust Control by Fluidic Injection in Solid Rocket Motors

Cold-flow tests, thermal tests, and numerical simulation were performed to study the thrust-adjustment characteristics, and the thrust-vector-control characteristics, of a fluidic nozzle throat combined with the method of shock vector control. The effective throat-area ratio, thrust-adjustment ratio of the fluidic nozzle throat, and the effect of gas and liquid medium on thrust-vector-control characteristics were investigated. The feasibility of a fluidic nozzle throat being applied to solid rocket motor was verified. Finally, the relationship between the effective throat-area ratio, the thrust-adjustment ratio, and the modified mass-flow-rate ratio has been obtained to provide accessibility for fluidic-nozzle-throat design. The combination of fluidic nozzle throat and shock vector control has been studied with a view to increasing the thrust-control effect. Results show that the effective throat-area ratio, thrust-vector angle, and adjustment ratio are associated with the injection angle, injector placement, and distribution of secondary flow, and increase with the modified mass-flow-rate ratio. By proper placement of secondary-flow injectors, the flow-interface loss can be effectively decreased to retain acceptable thrust-vector-control performance by the combination of fluidic nozzle throat and shock vector control.