Comparison of combustion characteristics for GO₂/CH₄ and GH₂/GO₂ injectors

In order to obtain the differences and connections of the GO₂/CH₄ and GH₂/GO₂ combustion characteristics, to provide experience of the GH₂/GO₂ injector for guiding GO₂/CH₄ injector design, comparison of GO₂/CH₄ and GH₂/GO₂ combustion characteristics for shear-coaxial injectors was conducted in the same combustion chamber by numerical simulation and experiment. The results show that under the similar design parameters, the size of GO₂/CH₄ injector is almost equal to that of GH₂/GO₂ injector. On condition that the pressure at design point and dimensions are the same, in order to produce the same thrust, the mass flow rate of GO₂/CH₄ (mixture ratio 3.5) is about 1.27 times as GH₂/GO₂ (mixture ratio 6.0). Furthermore, combustion characteristic length of GO₂/CH₄ is approximately 1.48 times as much as GH₂/GO₂ combustion chamber, and the thermal load of the GO₂/CH₄ combustion chamber is about half of the GH₂/GO₂ combustion chamber.