RANS simulations of plane impinging jets: On the influence of plate velocity in the Nusselt number secondary peak

Abstract

In the present work, heat transfer characteristics of a turbulent confined slot jet impinging on a heated moving plate are studied by means of time-averaged Navier-Stokes simulations. Three different plate conditions are considered: zero plate velocity (stationary plate), plate moving with a constant velocity, and plate moving with a constant acceleration. The jet nozzle-to-plate ratio and the jet inlet Reynolds number are equal to 4 and 2 ? 104, respectively. The objective of the present research is to investigate the role of the plate velocity condition on the development of the second peak in the Nusselt number profile along the impingement plate. The k-kl-? transition RANS model was validated against direct numerical simulation and experimental data and was able to correctly predict both the size and location of the Nusselt number secondary peak. A third re-circulation zone appears as the plate velocity increases and the Nusselt number secondary peaks location shifts slightly downstream. The development of the third re-circulation zone induces an accentuated decrease in the local and average Nusselt numbers. Furthermore, the plate acceleration delays the movement of the transition in the wall jets and the appearance of the third re-circulation zone. Consequently, the average Nusselt number increases with time, and the heat transfer from the plate is enhanced up to 8%.