A computational study on mixed convection with surface radiation in a channel in presence of discrete heat sources and vortex generator based on RSM

Numerical simulation of mixed convection and surface radiation in a horizontal rectangular channel with five discrete heat sources protruded from the bottom wall has been carried out. Air is considered as working fluid and flow to be laminar, steady, and incompressible. The parameters varied are Reynolds number (Re) = 100-750, the spanwise position of vortex generator (VG) x/H = 1.8, 2.8, 3.8 4.8 and 5.8, the pitchwise position of VG, y/H = 0.5, 0.6 and 0.7 and emissivity of the heat source, epsilon(c) = 0.1-0.9, while emissivity of the VG and channel walls is fixed as 0.9. The governing equations are solved based on SIMPLE algorithm using ANSYS 16.2. The results show that the Reynolds number, the position of vortex (spanwise and pitchwise), and emissivity of heat source have significant effects on heat transfer. It is also noticed that the maximum non-dimensional temperature (theta(max)) is 47.81% with VG at Re = 250 with change in emissivity of the heat sources from 0.1 to 0.9. Finally, a correlation has been developed for average non-dimensional temperature (theta(avg)) using response surface methodology.