ABILITY OF A POPULAR TURBULENCE MODEL TO CAPTURE CURVATURE EFFECTS: A FILM COOLING TEST CASE

ABSTRACT Computations are performed in conjunction with code validation quality experiments found in the open literature to specifically address the usage of popular two-equation eddy viscosity models in day-to-day gas turbine applications. In such simulations many features such as pressure gradients, curvature effects are present. The present work is focused on testing a popular turbulence model to resolve film cooling on curved surfaces. A systematic computational methodology has been employed in order to minimize numerical errors and evaluate the performance of a popular turbulence model. The test cases were examined for a single row of holes, blowing rates ranging from 1 to 2.5, isolated effects of convex and concave curvature on film cooling, density ratio close to 2, and an injection angle of 35°. Key aspects of the study include: (1) extremely dense, high quality, multi-block, multi-topology grid involving over 3 million finite volumes; (2) higher order discretization; (3) turbulence model with two-layer near-wall treatment; (4) strict convergence criteria; and (5) grid independence. A fully-implicit, pressurecorrection Navier-Stokes solver is used to obtain all the solutions. Results for adiabatic cooling effectiveness are compared with measurements in order to document the: (1) Range of applicability of the present modeling capability; and (2) Possible reasons for discrepancies. The data shows that the computations predicted the effects of curvature on mean flow, however effect on turbulence field is not captured. A clear set of recommendations is provided for future treatments of this class of problems