Flow field prediction within liquid film cooled combustion chambers of storable bi-propellant rocket engines

Abstract

The ROCFLAM software, an inhouse development of Daimler-Benz Aerospace AG (Dasa) under ESTEC contract, is used to simulate the complex flow field within the liquid film cooled combustion chamber of a storable bi-propellant rocket engine. The paper briefly outlines the modeling which is applied to approximate the physics and combustion chemistry within such a thruster. Simulating Dasa's 400 N MMH/NTO apogee thruster, it is demonstrated that the code is capable to handle the three existing and interacting physical phases, namely the reactive gas mixture, the dispersed propellant droplets and the annular liquid cooling film. Especially the prescription of initial spray patterns instead of an accurate resolution of the liquid jet break-up is shown to be well-suited to reflect global thrust chamber characteristics. Available fullscale test data (chamber pressure, thrust and external wall temperature distribution) are used to evaluate the simulation results. Finally, the dependence and sensitivity of such threephase flow simulations on the estimated spray characteristics are illustrated. Good agreement of ROCFLAM simulation and measurement is obtained.