Numerical study on convective mass transfer enhancement by lateral sweep vortex generators

Passive mass transfer enhancement from the surface of a liquefying substance using Lateral Sweep Vortex Generators (LSVG) placed in high-speed flow is presented. Numerical simulation of three-dimensional turbulent compressible flowfield involving species transport has been carried out using Advection Upstream Splitting Method (AUSM) scheme based Finite Volume solver. A temperature dependent mass efflux boundary condition has been developed and implemented in the computational procedure for updating the boundary mass flux. Computational procedure has been validated using the experimental wall pressure profile reported for a similar vortex generator placed in high speed flow and could capture the complex flow features resulted by the vortex-boundary layer interactions. Convective mass transfer of species is found to get improved in wake region of the LSVG by the horseshoe vortex and further get transported downstream by the counter-rotating vortex pair. Extensive numerical simulations have been carried out with several lateral sweep angles of LSVG to explore the role of vortices in promotion of the convective mass transfer. It has been observed that the mass efflux enhances with increase in sweep angle of the vortex generator due to the vorticity augmentation. Analysis of the vortex trajectories could figure out the influence of vortex interactions leading to the peak mass efflux. Further, an exponential-power law based correlation between relative Sherwood number and relative streamwise vorticity has been developed.