Performance Characteristics of Hydrogen Peroxide/Kerosene Staged-Bipropellant Engine with Axial Fuel Injector

Abstract

A 1200 N vacuum-thrust-class staged-bipropellant engine that uses decomposed hydrogen peroxide as an oxidizer and kerosene as a fuel was developed and tested with the aim of investigating an axial fuel injector integrated with a distributor. This fuel injector geometry, where fuel is injected into the turbulent flow of decomposed hydrogen peroxide, was tested to evaluate the influence of the designed injector on engine performance with respect to the equivalence ratio, the pattern of fuel injection orifices, and the characteristic length L*. For characteristics such as autoignition and stable combustion, firing tests over a wide range of equivalence ratios from 0.26 to 1.86 were carried out. Autoignition was successfully achieved under all experimental conditions. The pressure rising time from monopropellant to bipropellant mode and the pressure fluctuation in the combustion chamber were approximately 100 ms and less than +/- 1.1%, respectively. In the parametric study, the characteristic velocity c* and its efficiency were influenced by the pattern of fuel injection, whereas varying the orifice diameter had no effect. The effect of L* was also estimated, and the c* efficiency was measured to be over 95% for all equivalence ratios at an L* of 1.20 m.