Thrust Control by Fluidic Injection in Solid Rocket Motors

TLDR

The study investigates how the effective throat‑area ratio, thrust‑adjustment ratio, and the influence of gas or liquid medium affect thrust‑vector‑control characteristics of a fluidic nozzle throat combined with shock vector control. Cold‑flow, thermal, and numerical simulations were conducted to examine the thrust‑adjustment and thrust‑vector‑control behavior of a fluidic nozzle throat integrated with shock vector control, aiming to enhance thrust‑control effectiveness. The experiments confirm that a fluidic nozzle throat is feasible for solid rocket motors, and demonstrate that the effective throat‑area ratio, thrust‑adjustment ratio, and thrust‑vector angle increase with the modified mass‑flow‑rate ratio and can be tuned by injection angle, injector placement, and secondary‑flow distribution, thereby reducing flow‑interface loss and maintaining acceptable thrust‑vector‑control performance.

Abstract

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.