Heat Transfer Enhancement from a Heated Plate with Hemispherical Convex Dimples by Forced Convection Along with a Cross Flow Jet Impingement

Abstract

In the present study, heat transfer from a small three dimensional rectangular channel due to turbulent jet impinging from a nozzle normal to the main flow at the inlet has been investigated. Hemispherical convex dimples are attached to the bottom plate from where heat transfer calculations are to be performed. Numerical simulations were performed using the finite volume method with SST <i>k</i>– ω turbulence model. The duct and nozzle Reynolds number are varied in the range of <i>10000 ≤</i> Re<i>D ≤ 50000</i> and <i>6000 ≤</i> Re<i>d ≤ 12000</i>, respectively. Different nozzle positions (<i>X/D = 10.57</i>, <i>12.88</i>, <i>15.19</i>) along the axial direction of the rectangular duct have been considered. It has been found that higher heat transfer is observed at <i>X/D = 10.57</i> as compared to the other positions. The heat transfer enhancements with and without cross-flow effects have also been compared. It has been shown that the heat transfer rate with cross-flow is found to be much higher than that without cross-flow. Also, the effect of dimples on the heated surface on heat transfer was investigated. The heat transfer is found to be greater in the presence of a dimpled surface than a plane surface.