Assessment of Multiphysics Computations of Flow over a Film-Cooled Plate

This paper summarizes findings from a collection of multiphysics analyses of a heated exhaust passing over a film-cooled plate obtained for the fifth AIAA Propulsion Aerodynamics Workshop. The experimental configuration examined was a subsonic convergent nozzle with a square exit blowing a heated exhaust over a plate with three film-cooling sections. Computational fluid dynamics solutions were obtained and compared to experimental measurements of flow velocities and temperatures, as well as plate surface temperatures. The heated nozzle operated with a Mach 0.3 exit flow at a static temperature ratio of 2.7. Cooling air blowing ratios of 0, 1, and 2 were considered. Computational meshes for the flow domain were provided for participants. Workshop participants from eight separate organizations represented government, industry, and academia. A variety of flow solutions were obtained: Most of the flow solutions employed a Reynolds-averaged Navier-Stokes (RANS) approach, but scale-resolving simulations were used in some cases, including wall-modeled large-eddy simulation (LES) and hybrid RANS-LES approaches. One lattice Boltzmann solver was employed. For heat transfer to the test article, several analyses used a conjugate heat transfer approach. Effects of mesh sensitivity, flow solution approach, and wall heat transfer approach are considered. In general, a fully coupled three-dimensional conjugate heat transfer approach enabled significantly better prediction of surface temperatures than simpler wall temperature boundary treatments. Also, the scale-resolving approaches more accurately calculated the hot flow/film interaction and, hence, static temperatures immediately above the plate where the hot jet exhaust boundary layer interacted with the cooling film. Comparisons of plate surface friction drag and heat transfer obtained from the computations are also presented.