Numerical investigation of turbulent heat transfer enhancement by generation of longitudinal vortices in sublayer

Heat transfer enhancement by generation of longitudinal vortices in the viscous sublayer of turbulent channel flows has been numerically investigated. Longitudinal vortices have been generated by rectangular winglets of the size of roughness elements. Flow fields have been calculated by solving three-dimensional Reynolds averaged Navier-Stokes equations and thermal energy equation. Turbulence has ben modeled by low Reynolds number {kappa}-{epsilon} model. Results show that depending on the angle of attack of winglets the average Nusselt number Nu in the channel with vortex generators can increase by a factor of 400% over the plain channel.