Investigation of Circular and Shaped Effusion Cooling Arrays for Combustor Liner Application—Part 2: Numerical Analysis

Abstract

A numerical analysis of two different effusion cooled plates, with a feasible arrangement for combustor liner application, is presented in this paper. Though having the same porosity and very shallow injection angle (17°), the first configuration presents a “conventional” circular drilling, while the other has “shaped” holes with such an elliptical cross-section that leads to a circular imprint on the cooled surface. Either geometries were the object of an experimental survey in which both adiabatic and overall effectiveness were measured. In order to compensate for the lack of detailed aerodynamic measurements, 3D CFD computations were performed for the two geometries. Steady state RANS calculations were carried out using a k–ε Two Layer turbulence model, both in the standard isotropic and in an algebraically corrected non isotropic version specifically tuned to better predict the lateral spreading of jets in a cross flow. Flow characteristic reproduce typical effusion cooled combustor liner conditions with blowing ratio of 5 and coolant jet Reynolds number of 12500. Even though good agreement could not be obtained comparing thermal adiabatic effectiveness with experiments, the findings of the experiments regarding the rating of the cooling efficiency of the two configurations were confirmed. Additionally, conjugate simulations were performed for the circular hole geometry in order to quantify heat transfer effects and to directly compare them with raw experimental overall effectiveness data.