Mathematical modeling and analysis of cutoff impulse in a liquid-propellant rocket engine

Abstract

Thrust termination transient behavior of liquid-propellant rocket engines is important for launch vehicle to achieve the desired final velocity and, hence, fulfill the desired mission in placing a satellite in the intended orbit. A mathematical model has been developed for an open-cycle engine to predict the transient behavior of engine components, obtain the pressure changes of the combustion chamber, and to determine the cutoff impulse. By employing this model, the engine shutdown process has been simulated in four time intervals: (1) the duration from when cutoff command is issued to the time when the cutoff valves start to close, (2) closing of the cutoff valves, (3) discharge of combustion products from the chamber, and (4) the duration of the phase change and pressure fluctuations. The propellant flow has been modeled one-dimensionally in the cutoff valve and thermodynamically in the cooling channels and the combustion chamber. The results indicate that the time duration of the first two stages and the working pressure of the engine during the transmission of the cutoff command have considerable impacts on the increase or reduction of the thrust force. Also, with the improvement in modeling accuracy and the complete development of the engine processes, the results indicate a maximum error of 9% compared with the 15–41% error in the calculation of cutoff impulse achieved by previous works, which demonstrates the enhanced accuracy of the present modeling.

Numerical Simulation of Chemical Propulsion Systems: Survey and Fundamental Mathematical Modeling Approach

“…As small-size LPRE has become necessary recently [65], Inha University also developed a simulation program focusing on an electric-pump-fed cycle engine and verified it with a water flow test [66,67]. In addition to that, The Khajeh Nasir Toosi University of Technology (KNTU) in Iran also developed a simulation model of an open-cycle LPRE using Borland C to predict the effects of changes in the design of considered engine and apply it to other LPREs and a staged combustion cycle LPRE collaborated with BUAA in China [52,68,69].…”

Turbine inlet temperature effects on the start process of an expansion cycle liquid propellant rocket engine

“…The current study intends to use the sub-models that have been proposed and validated for simulating the transient regime of pressure-fed, closed, and open-cycle LPREs. 21,22,23,24,25 Studies show that Binder, 2,3,4 Durteste, 7 and Di Matteo 12,13,14 have undertaken three main activities to develop dynamic simulation tools for expansion cycle LPRE. The most important setback of the mentioned literatures was dependence on experimental data in simulating the dynamic behavior of LPRE, particularly in turbopump modeling, which all failed to simulate the starting process accurately.…”