Experimental Investigation of Dual-Thrust Rocket Motor with Intermediate Nozzle

Abstract

Dual-thrust solid propellant rocket motors are used in applications where the vehicle is boosted with a high thrust to reach very quickly a high speed that is then sustained by a low thrust. Dual-thrust rocket motors have a variety of designs; however, the one with intermediate nozzle yields high thrust ratio as well as a stable operation. Motivated by the shortage in related studies, the present paper is intended to shed more light on the topic of dual-thrust rocket motors with intermediate nozzle. The paper discusses the results of a set of static firing tests on a developed test motor covering all modes of motor operation. It is found that the thrust ratio can be maximized if the pressure difference across the intermediate nozzle is minimized. If the flow through the intermediate nozzle is initially reversed, a risk of motor damage should be taken into account.