Application of Scalar Dissipation Rate Based Mean Reaction Rate Closure for Modelling of Premixed Flame-Wall Interaction within Turbulent Boundary Layers

A scalar dissipation rate-based mean reaction rate closure modified for premixed flame-wall interaction, which was previously proposed based on a priori Direct Numerical Simulation (DNS) analysis, is implemented for Reynolds Averaged Navier-Stokes (RANS) simulations in two configurations. The first configuration is the oblique wall quenching of a V-shaped premixed flame in a turbulent channel flow, and the second configuration is the head-on quenching of a statistically planar flame in a turbulent boundary layer. To avoid uncertainties associated with wall functions in reacting flows, a low Reynolds number $$k - \varepsilon $$ model that resolves the viscous sub-layer is used. Comparisons between RANS simulations using the modified closure and DNS data reveal satisfactory agreement for Favre mean streamwise velocity and Favre mean temperature. However, quantitative discrepancies are found in the predictions of the Favre-averaged reaction progress variable due to differences in mean reaction rate profiles between DNS and RANS results. This behaviour arises from differences in turbulence quantities (e.g. turbulent kinetic energy and dissipation rate) between RANS and DNS, leading to discrepancies in RANS predictions of the mean reaction rate and Favre-averaged scalar dissipation rate, despite these closures performing well in a priori analysis. Even with these discrepancies, the scalar dissipation-based mean reaction rate closure shows promise in predicting mean values of Favre-averaged streamwise velocity and non-dimensional temperature in premixed flame-wall interaction configurations.