Numerical simulation of local extinction effects in turbulent combustor flows of methane and air

Abstract

The finite-volume approach together with body-fitted curvilinear nonorthogonal coordinates and a non-staggered grid arrangement is used for investigating turbulent reacting flows inside gas-turbine combustion chambers. The high Reynolds number k-ε turbulence model was employed to model the turbulence. Two different combustion models, the eddy dissipation concept (EDC) and the laminar flamelet model have been employed to account for the turbulence chemistry interaction. An extinction model for the eddy dissipation concept is presented, and a new extinction model for the laminar flamelet model is set forth. First, the combusting flow in a sudden expansion axisymmetric can combustor is studied. The agreement between calculations and measurements is good only when the effects of local extinction are taken into account. Second, the effects of extinction on the combusting flow in an annular gas-turbine combustor with a complex 3D geometry are examined. Significant impact on the reaction rate in the primary and intermediate zones of the combustor due to local extinction effects is predicted.