Application of wall functions approaches in the contextof LRE combustion chambers simulations

A set of 3D and 2D wall-modeled numerical simulations is presented to address and discuss the use of wall functions in Liquid Rocket Engine (LRE) conditions. Two wall function approaches are implemented in an Unsteady Reynolds averaged Navier Stokes (URANS) framework employing a flamelet-based approach for the tabulation of flow thermochemical quantities. The tabulated approach is adapted to deal with both reactive mixtures and non-reacitve flows. Consequently, simulations of a gaseous oxygen/gaseous methane (GOx/GCH4) mixture in an experimental multi-injector combustion chamber and of cryogenic liquid hydrogen (LH2) flowing in a heated pipe flow resembling the regenerative cooling system of a LRE, are presented. Wall quantities such as wall heat flux and wall temperature obtained with the described wall function models are compared for validation purposes with experiments and discussed. Ultimately, the influence of the grid on the wall function models applied to the simulation of the cryogenic pipe flow is analyzed and discussed.