Performance Evaluation of a Micro-Thruster Based on a Porous Medium Combustor

Investigating the influence of a porous medium combustor on the performance of micro-thrusters is of great significance. In this work, a hydrogen-oxygen micro-thruster based on a porous medium combustor (P-HOP) is designed, and the numerical model is validated against experimental data from both a porous medium combustor and a micro-thruster. The effects of combustor length, porosity, and material type on steady-state performance (temperature, velocity, pressure, thrust, and specific impulse) are systematically studied. Results show that over the combustor length range of 45–5 mm, the porous medium increases thrust by up to 15.97% and specific impulse by up to 15.87%. Decreasing porosity reduces combustion uniformity, yet even at ε = 0.3, thrust and specific impulse remain 2.03% and 2.07% higher than those without the porous medium. A high-thermal-conductivity material (SiC) yields the most uniform temperature distribution and the best steady-state performance. Furthermore, transient startup analysis reveals that the porous medium significantly improves hot-start response time (by 70.6%) and settling time (by 19.7%) due to its thermal storage effect, which is critical for pulse-mode operation in microsatellite attitude control. This study verifies the feasibility of integrating porous media with micro-thrusters and provides a reference for their application in micro-propulsion systems.