Experimental study on flow control system of an electric pump-fed cycle for thrust control.

An electric pump-fed cycle can enable the electrical control of pump revolutions and rapidly vary the propellant flow rate. This paper proposes the pump control method as a flow control system of an electric pump-fed cycle. In order to evaluate the applicability of the designed flow control system, the test equipment that simulates an electric pump-fed cycle was constructed, including the Li-ion battery power system and communication instruments. The designed PID controller demonstrated rapid flow stabilization and robustness compared to the system without a controller. Meanwhile, under the initial pressurized condition in the run tank that simulated an engine start-up sequence, the controller response delay occurred was more than 500 ms. In addition, the dynamic loads, such as the water hammer effects and overshoot, were identified. The start-up sequence of an EP cycle was adjusted to alleviate those issues. Consequently, the supply stabilizing time and overshoot were adjusted to 400 ms and 1.7 %, respectively. This study can be the first step in utilizing an electric pump-fed cycle for the thrust control technology in the upper stage of a mission. • An electric pump-fed cycle has a simple system with an electric motor and battery system replacing a gas generator and turbine of a gas-generator cycle. • An electric pump-fed cycle can be used as a throttleable and restartable rocket engine technology, providing a rapid response enabled by the quick propellant feeding through an electrical signal control. • The pump control system with PID controller shortened the flow stabilizing in the experiments compared to the flow control system without the PID controller. • By adjusting the electric pump-fed cycle start-up sequence, it can effectively mitigate the water hammer and shorten the stabilizing time. [ABSTRACT FROM AUTHOR]