Investigation of swirling impinging jet at low nozzle to plate distances

Flow field and heat transfer of an impinging swirling jet at low nozzle-to-plate distances have been investigated numerically for three different cases with six different turbulence models. The effects of Reynolds number (2100, 4100, 6100, 8100) and dimensionless nozzle-to-plate distance (H/D = 0.25, 0.5, 0.75, 1) on flow field and heat transfer of the swirling jet are studied parametrically. It is noted that the results of the cases employed exhibit sensitivity to the height of the computational domain defined on the impingement plate, particularly at low nozzle-to-plate distances. It is also seen that one of the cases used is in good agreement with the experimental results by employing Realizable k–ε turbulence model. Parametric analysis results show that the theoretical swirl number decreases with increasing Reynolds number at constant H/D and raises for H/D < 0.75. With the decrease in the Reynolds number from 8100 to 2100, although the H/D loses gradually effect on the heat transfer, H/D = 0.25 continues its effect. It is observed that the pressure peaks and the subatmospheric pressure on the impingement plate change with the nozzle-to-plate distance and Reynolds number. © 2023, Akadémiai Kiadó, Budapest, Hungary.