Experimental investigation on jet impingement heat transfer analysis in a channel flow embedded with V-shaped patterned surface

Abstract

ABSTRACT Heating and cooling systems benefit from jet impingement as it increases efficiency while reducing operating costs. The combined methodology, integrating jet impingement and passive heat transfer through the use of roughened surfaces, offers significant potential for improving heat transfer. This research presents the results of an experimental study on a channel flow commonly used for air heating, known as a solar air heater (SAH), with impinging air on the heated surface. The surface is embedded with V-shaped ribs as turbulence promoters, and it receives a continuous heat flow of 1,000 W/m2. Various design combinations were tested experimentally, including streamwise pitch ratio X/Dh = 0.866, spanwise pitch ratio Y/Dh = 0.866, jet diameter to hydraulic diameter ratio Dj/Dh = 0.065, and an angle of attack (α) ranging from 45° to 90°. During these experiments, the Re varied from 3,500 to 18,000. The optimal improvement was observed at values of X/Dh = Y/Dh = 0.866, Dj/Dh = 0.065, and α = 60°. This paper presents novel findings demonstrating that incorporating V-shaped rib patterns in SAHs can yield Nusselt numbers up to 5.2 times higher than those in smooth duct SAHs, offering substantial potential for enhanced energy efficiency. When the entering jet impacts and flows along the ribs of the absorber, the findings suggest that the V-shaped ribs accelerate the flow, resulting in enhanced heat transfer. All datasets were also analyzed for their thermo-hydraulic performance, with the maximum value recorded as 3.301 within the constraint range used in this analysis.