Liquid Rocket Engine Combustion Simulations with Radiation Heat Transfer

In this study, we look at the effect of radiation heat transfer on combustion dynamics in unstable and stable liquid rocket engine simulations. Radiation heat transfer is not typically included in these types of analysis due to the significant additional cost and complexity of incorporating full non-gray radiative properties and radiative transfer equation solvers into the CFD simulations. A novel dual-mesh approach is used where the reacting flowfield and radiation heat transfer are solved on different overset grids. This approach allows a coarser grid to be used for the radiation heat transfer thereby reducing the overall computational cost. Two radiation heat transfer models are examined, an optically thin model, and the more accurate, and spherical harmonics P1 model with Full-spectrum k-distributions for nongray combustion gases. For the particular unstable combustor examined in this work, we find that the overall impact of radiation heat transfer on the combustion dynamics was not significant. As expected, the optically thin model over-predicts the effect of the radiation but even that does not result in altering the combustion dynamics.