Simulation of flow and combustion in H2/O2 rocket thrust chambers using a 2D spray combustion method

Abstract

A new parameter setting to simulate H2/O2 rocket thrust chambers is found for the currently used two-dimensional, axisymmetric CFD-code Rocflam-II at Astrium GmbH in Ottobrunn, Germany. The generation program used for creating the necessary equilibrium lookup tables to the simulation is validated against an older version to make the generation for different fuel mixtures more consistent. Calculation of the isothermal compressibility of a multiple phase mixture is implemented together with unsuccessful measures to significantly decrease computational power. The program is also successfully modified to generalize the number of reaction products treated. The influence of the table resolution to Rocflam-II simulations is studied using the Vinci subscale thrust chamber. The study shows upon a possibility to slightly increase precision of the simulated rocket performance values by adjusting the mixture fraction resolution. The resolutions of the other parameters are found to be acceptable in their default settings. A formulation change is implemented in the Rocflam-II source to increase consistency between injected liquid droplets of different propellants. New correction functions for the droplet distribution for “warm” and “cold” injection of H2 are found using the CALO test case. The new correction functions and the Rocflam-II formulation change are applied to full-scale simulations of the Vulcain 2 rocket engine with good agreement to previous simulation results.