Simulation and measurement of flow and heat transfer in two planar impinging jets

摘要

The flow and heat transfer in two planar impinging jets are investigated using Large-Eddy simulation and experiments. The jet Reynolds number based on nozzle width and centerline velocity is 500. Predictions are obtained of unforced jets in addition to forced cases in which periodic injection and suction is applied at the nozzle exit of each jet. The goal of the current effort is to characterize the predictions of the flow from the numerical simulations prior to future efforts aimed at applying techniques to control the heat transfer on the impinging wall. Forcing results in significant changes to the flow structure with a rapid development of large-scale vortices in the shear layers emerging from the nozzle, which does not occur in the unforced jets. For both the forced and unforced flows, spanwise vorticity is apparent in the structure of the wall jet that forms as the flow develops near and along the impingement surface. The influence of the forcing raises the local Nusselt number in the vicinity of the stagnation line by about 10% compared to the unforced case.