EFFECTS OF ASYMMETRICAL VORTEX INTERACTION BY VARIABLE SWEPT VORTEX GENERATOR (VSVG) ON MASS TRANSFER ENHANCEMENT
Large Eddy Simulation (LES) of a three-dimensional compressible turbulent flow field generated by the placement of a Variable Sweep Vortex Generator (VSVG) in a high-speed flow and the resulting asymmetrical vortex interaction on a mass transferring surface are discussed. Passive mass transfer enhancement methods are inevitable in applications with limited residence time for convective transport. Present VSVG has a wedge shape with different sweep angles on its lateral sides and a slant top surface. These novel geometrical features induce large-scale asymmetrical transverse vortices in its wake region as the compressible freestream spills and expand over it. Thus, VSVG realizes larger gradients on associated boundaries that promote transfer effects. The present numerical study focuses on the unsteady flow dynamics and associated mass transfer enhancement. A special boundary condition is implemented on the flat mass transfer surface, which can simulate mass evolution as a function of temperature in the adjoining flow field. The present computational procedure is validated using the heat transfer data reported for a similar vortex generator. Extensive computations have been performed to study the effect of various geometrical aspects of VSVG in the promotion of convective mass transfer enhancement. Oscillatory nature of the transverse counter rotating vortex pair interaction enables the evolved mass to convect further into the free stream. Mass transport profile in the entire flow field is found to strongly depend on the vortical fluid motion.