Computational Investigation of Combustion Efficiency in LOX-HTPB Hybrid Rocket Motors

Hybrid rocket engines that use hydroxyl-terminated polybutadiene (HTPB) fuel and liquid oxygen (LOX) oxidiser are appealing because they are safe, work well, and are good for the environment. Nevertheless, combustion efficiency is still low because the oxidiser and fuel are not mixed well enough. This study offers a computational and experimental analysis of the internal ballistics of LOX–HTPB hybrid motors, focusing on injector design and chamber flow dynamics. CFD simulations validated with experimental data were used to compare swirl and pintle injectors to baseline injectors. The results show that pintle and tangential swirl injectors make combustion more efficient by improving the distribution of oxygen, turbulence, and pressure uniformity. The results show how to make the design of injectors and chambers better in hybrid propulsion systems.