COMPARISON OF COOLING FILM DEVELOPMENT CALCULATIONS FOR TRANSPIRATION COOLED FLAT PLATES WITH DIFFERENT TURBULENCE MODELS

摘要

A transpiration cooled flat plate configuration is investigated numerically by application of a 3-D conjugate fluid flow and heat transfer solver, CHT-Flow. The geometrical setup and the fluid flow conditions are derived from modem gas turbine combustion chambers. The plate is composed of three layers, a substrate layer (CMSX-4) with a thickness of 2 ram, a bond-coat (MCrAlY) with thickness 0.15 ram, and a thermal barrier coating (EB-PVD, Yttrium stabilized ZrO{sub}2) with thickness 0.25 ram, respectively. The numerical grid contains the coolant supply (plenum), the solid body, and the main flow area upon the plate. The transpiration cooling is realized by freest drilled holes with a diameter of 0.2 mm that are shaped in the region of the thermal barrier coating. The holes are inclined with an angle of 30°. Two different configurations are investigated that differ in the shaping of the holes in their outlet region. The numerical investigation focus on the influence of different turbulence models on the results. Regarding the secondary flow, the cooling film development and complex jet mixing vortex systems are analyzed. Additionally, the impact on the temperature distribution both on the plate surface and in the plate is investigated. It is shown that the choice of the turbulence model has a significant influence on the prediction of the flow structure, and, consequently, on the calculation of the thermal load of the solid body.