Investigation on an Impinging Square Jet

ABSTRACT: This paper focuses on an impinging laminar square jet, experimental and numerical investigated, under several Richardson number conditions. The experimental measurements have been performed by means of a PIV (Particle Image Velocimetry) technique in order to infer the structure of a square single jet impinging on a heated flat plate, maintained at a constant temperature. The experiments have been carried out for jet Reynolds number between 250 and 400 and Richardson number between 0 (isothermal condition) and 0.8. The investigated jet-to-plate spacing was 0.3 L and 0.1 L, where L is the jet width. Numerical simulations using CFD software have been then performed, investigating numerically through the solution of the three-dimensional Navier-Stokes and energy equations in steady state. The obtained results show that: in the case of jet-to-plate distances H/L=0.1 the jet is substantially diverted in the transverse direction and the wall jet fills substantially the whole gap between the plate and the plenum in all the investigated Richardson number. In the case of H/L=0.3 the results are substantially different. In fact the buoyancy generated by the warm gas adjacent the warm plate are able to deviate the wall jet with the formation of coherent vortex depended of the adopted Reynolds number.