The effect of pipeline length on the transient process of an electric pump during start-up of a hybrid rocket motor

The electric pump in the propellant supply system, with a wide range of fast thrust adjustment capabilities, can significantly enhance rocket motor performance. Previous research has focused on the performance and feasibility of hydrogen peroxide electric pumps for hybrid rocket motors; however, their dynamic characteristics remain unclear. This study numerically and experimentally investigated the transition stages in the flow field and head for an electric pump during the start-up of a hybrid rocket motor, as well as analyzed the effect of pipeline length between the pneumatic valve and the adjustable Venturi on the flow field and head. The simulation and experimental results indicate that during the start-up of the hybrid rocket motor, six transient stages are recorded when the pipeline length between the pneumatic valve and adjustable Venturi is 3 m. The head and internal flow field of the electric pump during the transient process were determined by the throttling position as well as by the filling status of the pipeline. The simulation results suggest that the shorter the pipeline length, the steadier and safer is the supply system. Our investigation provides a practical optimization strategy for electric pump supply systems in rocket motors.