Heat transfer and flow characteristics of turbulent slot jet impingement on plane and ribbed surfaces

A computational study is carried out to assess the suitability of various RANS based turbulence models for slot jet impingement on flat and ribbed surfaces with various values of Reynolds number and jet to plate spacing. The com-puted results are compared with the reported experimental data. It was observed that none of the turbulence models considered predicted the heat transfer data accurately. However, some models predicted the experimental data with good trends, e.g., secondary peak and several spikes in Nusselt number for ribbed surface, with a precise computation of the stagnation point Nusselt number. Further, the effects of slot width, rib pitch and jet to ribbed surface spacing were investigated for jet impingement on a ribbed surface. It was observed that the local Nusselt number increased with slot width and rib to plate spacing. It was also observed that increasing Reynolds number had a positive effect on the local heat transfer. With increasing rib pitch the local Nusselt number increased near the stagnation zone but de-creased downstream. The observed flow pattern was different for jet impingement on a ribbed surface than that on a flat surface.