A Wall-Function Based Model for Multi-Perforated Walls Available to Purchase

Effusion cooling is one of the most effective techniques to prevent combustor liner from being damaged. As effusion-cooled liners are comprised of a large number of sub-millimeters closely-spaced holes, full 3D numerical simulations of the combustion chamber are still unaffordable. Thus, aero-thermal models are needed to describe the main flow-liner interaction. The aim of this paper is to provide a homogeneous wall model for gas turbine combustor liners based on wall-function similarities. In order to develop such a model, a numerical database was built up covering a wide range of interest for gas turbine applications. The model proposed here consists of two modified wall-functions for both sides of a liner and an analytical model to take into account the heat exchange within the holes. As holes are not reproduced and coarse near-wall grids are sufficient, the computational cost of this methodology is very low. The performance and limitations of the model are discussed. The model has proved satisfactory in assessing the effect of a liner on the surrounding and vice-versa. Although discrepancies were observed for the first rows, momentum and heat fluxes between the flow and the impinged wall are reproduced with a good level of agreement. Overall effectiveness is predicted with a mean relative error of less than 5%.