Study on the design criteria of the coaxial injector for a LOX/hydrogen rocket engine -evaluation of design for injectors of the LE-5 engine and its derivatives

Abstract

Based on the author's recent study on detailed modeling of the atomization characteristics of a liquid/gas phase coaxial injector, an improved computation model for predicting the combustion performance of a LOX/hydrogen engine is proposed. The features of this model are that it allows calculation of the local rate of atomization of the LOX jet and deals with droplet size distribution of the LOX spray. Additionally the model applies the burning rate constant of LOX/hydrogen combustion derived by the author's former experiment. Using this model, evaluations of the design criteria for the LE-5 engine, which was equipped on the H-2 launcher, and its derivative engines, which have been used with the H-2A launcher, were conducted. Furthermore, optimization of the derivative engine's injector design to improve combustion stability and combustion performance was discussed. © 2007 The Japan Society for Aeronautical and Space Sciences.