Liquid Rocket Engine Feed System Dynamics by the Method of Characteristics

Abstract

A new approach was developed to predict pressure and flow transients in rocket engine feed systems. The one-dimensional equations of momentum and continuity were reduced by the method of characteristics from partial derivatives to a set of total derivatives describing state properties along specified paths. System components, e.g., valves and tanks, are represented by pseudo-steady state relations at discrete junctions in the system. Experiments were run on a typical attitude control feed system employing monomethylhydrazine (MMH) and nitrogen telroxide (NTO) as the propellant combination. The essential aspects of the analytical model mere verified by the excellent correlation achieved between the predicted and observed transjents.