JET IMPINGEMENT ONTO A HOLE WITH CONSTANT WALL TEMPERATURE

Abstract

Jet impingement onto a hole finds application in process industries. In the present study, a jet impingement onto a hole with a constant wall temperature is examined. The governing flow and heat transfer equations are solved numerically using a control-volume approach. The Reynolds stress turbulence model (RSTM) is employed to account for the turbulence. In the simulations, four hole wall temperatures and two jet velocities are considered. The Nusselt number ratio (ratio of the Nusselt number predicted to the Nusselt number obtained for a fully developed turbulent flow based on the hole entrance Reynolds number) is computed and the mass flow ratio (ratio of mass flow rate through the hole to mass flow emanating from the nozzle) is determined. It is found that increasing hole wall temperature extends the stagnation region close to the top edge of the hole. This, in turn, results in hot gas opposing the impinging jet. Therefore, the mass flow ratio falls with increasing hole wall temperature. The Nusselt number ratio improves at the hole inlet and falls as the axial distance along the hole wall increases toward the hole exit. A Nusselt number ratio of greater than 1 resulted for all the situations employed in the present study.