CFD Simulation of LOx/H2 Single Coaxial Element Rocket Combustor

Abstract

The accurate prediction of heat loads is one of the key problems of rocket engine design. The design of rocket combustion chambers requires an extensive trial-and-error testing while CFD (computational fluid dynamics) modelling not only helps to reduce the amount of expensive hot tests but also makes possible the transfer of the results of sub-scale tests to full scale engines. The scope of the present work is the accurate predictions of wall heat fluxes in a rocket combustion chamber. The goal of the work is to validate a CFD model on the particular test case [1]. The test case allows to confirm the ability of the numerical model to predict the wall heat fluxes and the pressure in hydrogen rocket combustion chambers. The test case was used for validation also by other researchers. This gave us an opportunity to asses correctly the performance of our own numerical model in the terms of accuracy and required computational resources. The present work has been carried out using the commercial CFD code ANSYS CFX. The simulation has been performed in 2D axisymmetric numerical domains. The turbulent flow has been modelled with the help of the SST turbulence model. The turbulent combustion has been modelled with the use of a modified EDM model. The modified EDM model is an in-house development, which has an aim to adapt the EDM model for the modelling of the turbulent combustion of cryogenic oxygen and hydrogen at high pressures. The numerical simulations are in good agreement with the experimental data on the wall heat fluxes. The important benefit of the developed combustion model is that it is very efficient in terms of required computational resources. In spite of the prominent characteristics the potential for development of the modified EDM model is at the end. The further improvement of the accuracy of numerical simulations is possible only with the use of more sophisticated turbulence and combustion models. [1] Suslov, D., Hardi, J., Knapp, B., and Oschwald, M., “Hot-fire testing of LOx/H2 single coaxial injector at high pressure conditions with optical diagnostics,” Progress in Propulsion Physics, edited by M. Calabro, L. DeLuca, S. Frolov, L. Galfetti, and O. Haidn, 2015.