Preliminary design of a liquid bipropellant microfabricated rocket engine

Abstract

This thesis discusses the design of a microfabricated rocket engine. Micro-rockets feature a thrust to weight ratio up to two orders of magnitude greater than conventional rocket motors at small thrust levels and hence are very attractive for satellite propulsion applications and micro-satellite development. All major rocket components have been characterized and evaluated for micro-scale opera­tion. These include a 300 atm pumping system, a 3000 K and 125 atm combustion chamber and a Mach 3.5 thrusting nozzle. Studies indicate that a turbopump system is feasible while further investigations on bearings are required to fully validate the concept. The viability of the combustion chamber is believed to be dependent on the mixing performance of an innovative injection scheme which features inter-digitated fuel/oxidizer jets impinging at a 180° angle. The nozzle is projected to perform satisfactorily, incurring a mere 2% loss in thrust according to 2D CFD calculations. Modeling of the system transients has indicated an acceleration time on the order of 0.1 sec. as well as notable sensitivities to the injector diameter and turbine blade turning angles. The analysis suggests that the micro-rocket engine concept is feasible and identifies the engineering challenges ahead.