Numerical investigation on orthogonal impingement of circular air jet on a heated flat plate at low jet plate spacing

Abstract

Jet impingement cooling has been studied extensively as this finds applications in the areas of reactor safety, electronic cooling etc. The convective heat transfer process between the circular air jet impingement on uniformly heated flat plate is studied numerically. In this numerical study, 3-D simulations are carried out in Fluent 14.5 to investigate the effect of Reynolds number, distance between nozzle exit and the plate on the heat transfer characteristics. Standard κ-ε, SST κ-ω, Standard κ-ω, V2F turbulence models have been studied for orthogonal jet impingement in this work. For Z/d ≥ 0.5, V2F model is best suited. Reynolds number of 12000, 20000, and 28000 has been studied. A typical feature of circular air jet impingement at low jet plate spacing is occurrence of secondary peak in Nusselt number variation along radial direction over the plate. V2F model correctly predicts the secondary peak in Nusselt number variation over the plate. Other models fail to predict the secondary peak which is of significant importance in air jet impingement at low jet-plate spacing. V2F model do not use wall functions. A fine grid at the surface of the wall is necessary to capture the flow behavior near the wall.