Heat transfer enhancement by grid-generated turbulence for a cylinder in crossflow

Abstract

The heat transfer coefficient is experimentally measured around a cylinder heated by ohmic effect. The heating technique approximates a uniform heat flux on the cylinder’s wall. Themodel is placed downstream of different perturbing grids in a wind tunnel. The Reynolds number based on the cylinder’s diameter varies between 10820 and 48830. At large distances from the grids, the heat transfer is significantly enhanced by using a fractal and a single square grid designed to increase turbulence intensity with a low blockage ratio. Significant differences exist between the heat transfer profiles measured in the production and in the decay region in positions where turbulence intensity is the same.