Thèse de DOCTORAT D’ÉTAT, Spécialité : Energétique
Numerical film cooling investigations applied on gas turbine blades
Présenté et soutenue publiquement par : Azzi Abbès
Keywords : Film cooling - Volume finite method - Turbulence modelling - EASM models - Two-layer model - Multi-bloc method - Bounded convective schemes.
Abstract Typical film-cooling configurations are numerically investigated using a three-dimensional finite volume method. The computational method uses arbitrary curvilinear, body-fitted, multi-block, structured, non-staggered grids for implicitly solving the incompressible averaged Navier-Stokes equations. An appropriate momentum-interpolation technique is used to prevent pressure-field oscillations. The pressure-velocity coupling is achieved using the SIMPLEC algorithm. The accuracy of the code is improved by using a second order-bounded scheme for convection terms for all equations including the k and ? turbulence model equations. The code is calibrated through applications to a wide range of flows such a 2D channel flow, a lid driven cavity and a back step flow and the results are compared to DNS data (Direct Numerical Simulation). The first aim of the thesis is to use a standard model with wall function in order to investigate the physics of the flow. The second aim is to investigate the capability of some new trends in modelling jets-in-cross flow with relevance to film cooling of turbine blades. The aim is to compare two classes of recently developed turbulence models with respect to their predictive performance in reproducing flow physics. The study focuses on anisotropic eddy-viscosity/diffusivity models and explicit algebraic stress models up to cubic fragments of strain and vorticity tensors.
