Influence of Fuel Lewis Number on Flow Dynamics in Oblique Wall Quenching of V Shaped Premixed Flames in Turbulent Channels

The influence of fuel Lewis number LeF on the wall-normal variations of mean values of streamwise velocity component, temperature, and Reynolds stresses within turbulent boundary layers have been analysed using a Direct Numerical Simulation (DNS) database of oblique wall quenching of V-shaped premixed flames due to their interaction with inert isothermal walls in a turbulent channel flow configuration. The fuel Lewis numbers of LeF = 0.6, 1.0 and 1.4 have been considered for the current analysis. It has been found that the flame starts to interact with the wall further upstream for a smaller value of LeF due to an augmentation of the volume-integrated burning rate with a decrease in fuel Lewis number. The thermal expansion induced by heat release affects the variations of mean values of both streamwise velocity component and temperature in the wall-normal direction and they show significant deviations from the conventional log-law profiles. Recently proposed density-compensated modified wall functions for streamwise velocity and non-dimensional temperature, which were previously validated for head-on quenching configuration for unity Lewis number, are found to capture the corresponding behaviours extracted from DNS data for flame-wall interaction of V-shaped flames with non-unity LeF. The wall-normal distributions of Reynolds stresses also deviate significantly from the corresponding non-reacting fully developed channel flow profiles during flame-wall interaction and LeF affects the extent of this deviation. The anisotropy of Reynolds stresses has been found to increase with the progress of flame-wall interaction. The physical explanations for the observed mean velocity, mean temperature and Reynolds stress statistics have been provided and their implications for modelling of flame-wall interaction have been elaborated.