MODELING OF TURBULENT REACTING FLOWS PAST A BLUFF-BODY - ASSESSMENT OF ACCURACY AND EFFICIENCY

The accuracy and efficiency of numerical calculations of turbulent rea cting flows past bluff bodies have been studied. The Reynolds-averaged Navier-Stokes equations, together with a two-equation k-epsilon model and a premixed flame model, are solved using finite differences on a system of global and locally refined grids. To improve the calculation efficiency, a multgrid (MG) method is employed. The influence of the grid resolution on the solution accuracy and the effects of the model parameters, boundary conditions and different reaction mechanisms are studied numerically. Comparisons are made between predictions and meas urements of propane-air reacting flow past a bluff body placed in a wi nd tunnel. The results show that the computational time can be reduced considerably using an MG method, and the numerical accuracy can be ma intained economically by using a local grid refinement technique. With proper model parameters, the solution of the simplified mathematical models is in good agreement with the experimental data.