Reynolds Number Effects on Scalar Dissipation Rate Transport and Its Modeling in Turbulent Premixed Combustion

Abstract

The effects of turbulent Reynolds number, Re t , on the transport of scalar dissipation rate of reaction progress variable in the context of Reynolds averaged Navier–Stokes simulations have been analyzed using three-dimensional simplified chemistry-based direct numerical simulation (DNS) data of freely propagating turbulent premixed flames with different values of Re t . Scaling arguments have been used to explain the effects of Re t on the turbulent transport, scalar–turbulence interaction, and the combined reaction and molecular dissipation terms. Suitable modifications to the models for these terms have been proposed to account for Re t effects, and the model parameters include explicit Re t dependence. These expressions approach expected asymptotic limits for large values of Re t . However, turbulent Reynolds number Re t does not seem to have any major effects on the modeling of the term arising from density variation.