Effects of helium injection on thrust performance of a solid-gas hybrid rocket motor under two-phase non-equilibrium flow conditions

Release time:2026-03-10  Hits:

• Impact Factor:5.8
• DOI number:10.1016/j.ast.2026.111797
• Journal:AEROSPACE SCIENCE AND TECHNOLOGY
• Place of Publication:FRANCE
• Key Words:Solid-gas hybrid rocket motorHeliumTwo-phase flowSpecific impulseAluminum combustion
• Abstract:This study aims to elucidate the coupled mechanisms of helium injection and two-phase non-equilibrium flow in solid-gas hybrid rocket motors (SGHRM), and to systematically evaluate thrust performance. A multiphase EulerLagrange model was adopted, incorporating aluminum particle combustion to simulate gas-particle interactions and accurately capture the coupled flow-combustion behavior within the motor. The influence of helium injection mass flow rate and aluminum particles size distribution is systematically analyzed. Results indicate that, under two-phase non-equilibrium flow, the maximum specific impulse gain reaches 9.63 % at a helium mass flow rate of 1.5 kg/s, which is lower than the equilibrium-flow optimum of 2.0 kg/s due to small gas-phase mass under the non-equilibrium flow. Helium reduces the molecular weight of the gaseous combustion products, increases the gas-phase exit velocity, and in turn accelerates the particle-phase through aerodynamic drag, thus enhancing the motor specific impulse. Additionally, small aluminum particles with high specific surface area experience stronger aerodynamic drag and contribute more effectively to reducing velocity and temperature lag losses. Consequently, helium injection results in a higher specific impulse gain in cases with smaller aluminum particles. Although helium injection intensifies particle temperature lag as a result of inefficient interphase heat conduction, the associated particle heating locally enhances gas-phase velocity in high-helium regions near the axis. Specifically, at equal mixing ratio, the gas-phase velocity under non-equilibrium flow conditions exceeds that under equilibrium flow conditions. In conclusion, helium injection remains significantly increasing the motor thrust performance under two-phase flow conditions, particularly with finer aluminum particles, thereby advocating for the use of fine aluminum powder in propellant formulations of SGHRMs to achieve optimal performance.
• Indexed by:Journal paper
• Document Code:111797
• Discipline:Engineering
• Document Type:J
• Volume:173
• ISSN No.:1270-9638
• Translation or Not:no
• Date of Publication:2026
• Included Journals:SCI、EI