Accelerated unwinding of the rotor booster pump of liquid rocket engines under start-up conditions

In this article there is the assessment of possibility and effectiveness of accelerated unwinding of the rotor booster pump of liquid rocket engine under start-up conditions. A method for reducing the error of rate in the unwinding of the booster pump and turbopump units is based on the organization in the process of starting the engine with supplying additional working liquid to the turbine of boost directly from the output of the pump of the oxidizer. There is a rocket engine, working on the components of the liquid oxygen - kerosene, made according to the scheme of oxidizer generator gas with afterburning. During rocket engine start-up and turbopump rotor unwinding, the maximum pressure in the engine is realized at the outlet of the pumps. When starting the engine using additional liquid driving, which starts earlier than the gas driving, the boost pump acceleration occurs much earlier. To analyze this problem, a dynamic mathematical model of the rocket engine is using. The goal of the calculation is to study start-up process of rocket engine to select the static parameters of liquid driving line, providing engine start under the lowest possible components on the pressure in the engine inlet. Among the parameters, that affect the operation of the liquid driving, the inertial pressure losses selected in the line supplying the additional working liquid to the turbine of boost pump. Mathematical modeling of engine start-up in the absence of liquid driving, and at present, but with different characteristics of the driving line was conducted. The efficiency of the use of preliminary unwind of oxidizer boost pump by additional liquid component, coming directly from the output of the pump the oxidizer is shown. The influence of the value of the area of the nozzle section of the liquid driving and inertial losses of pressure of additional oxidizer line on the effectiveness of unwinding of the rotor booster pump of liquid rocket engine when engine start was conducted.