This paper presents a method of large eddy simulation on unstructured grids designed to predict the wall heat transfer in typical aeronautical applications featuring turbulent flows and complex geometries. Two types of wall treatment are considered: a wall-function model using a full tetrahedral grid and a wall-resolved method computed on a hybrid tetrahedral-prismatic grid. These two approaches are tested against the square cylinder case at moderate Reynolds number (Re = 22 050) where many reference data are available for flow dynamics and heat transfer. Both predict accurately the unsteady flow around the cylinder and in its near-wake but only the wall-resolved approach reproduces the Nusselt number global value and its spatial distribution around the cylinder wall. This latter method is used to investigate the coupling between periodic vortex shedding and wall heat transfer using a phase-averaged analysis. Nomenclature CD = drag coefficient C f = algebraic friction coefficient Cp = pressure coefficient
Lean Premixed Prevaporized (LPP) combustion is a widely used concept for reducing pollutant emissions in gas turbines. In LPP systems, a mixing tube is added between the injector and the combustion chamber to promote mixing and combustion efficiency. These devices are efficient to reduce pollutant emissions but can be sensitive to complex transient phenomena such as blow-off or flashback which are still beyond the prediction capabilities of most numerical tools. The present study describes a joint experimental and numerical study to evaluate the capacities of Large Eddy Simulation (LES) for the prediction of flame dynamics in a swirl-stabilized LPP burner operated with propane. Combustion regimes are first identified experimentally: compact flames (the normal regime for LPP) but also flashback regimes (where the flame is stabilized in the mixing tube) as well as lean
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