Large-Eddy Simulation for Turbulent Heat Transfer

The paper gives an overview of different components of conducting large-eddy simulations (LES) for convective heat transfer in practical applications. Subgrid stress models, wall models, and the generation of inlet turbulent boundary conditions are highlighted. For application to complex high Reynolds number flows, a two-layer LES wall model is used together with a synthetic eddy method (SEM) for generating turbulent inlet conditions for developing flows. Representative results highlighting LES predictions are given in a dimpled fin arrangement relevant to compact heat exchangers, in a simulated leading edge film cooling geometry, and in a developing ribbed duct and 180 deg turn relevant to turbine blade cooling. The use of LES wall modeling with the SEM is shown in an experimental can combustor with swirl, and finally a simulation which combines Reynolds-averaged Navier-Stokes (RANS) with wall modeled LES and SEM to predict combustor linear heat transfer is highlighted. It is shown that the combined use of these techniques can reduce computational time by at least an order of magnitude for developing flows. In all cases, predictions of mean turbulent quantities and heat transfer coefficients compare favorably with experiments.