Assessment of the thermo-hydraulic efficiency of an indoor-designed jet impingement solar thermal collector roughened with single discrete arc-shaped ribs

Abstract

This study illustrates the impact of single discrete arc-shaped ribs (SDASR)-type artificial roughness on the performance of a jet impingement solar thermal collector (JISTC). The impact of parametric variations of SDASR on the Nusselt number (Nu(sdr)), friction factor (f(sdr)), and thermohydraulic performance (eta(sdr)) is examined. The spacer length (S-sdr) of the SDASR was changed from 0 mm to 300 mm in stages of 100 mm during the experiment. The fixed parameters of the SDASR were a relative discrete distance (D-d/L-v) of 0.67, relative discrete width (g(w)/H-r) of 0.87, relative rib height (H-r/H) of 0.047, relative rib pitch (P-r/H) of 1.7, angle of an arc (alpha(sdr)) of 60 degrees, jet diameter ratio (D-j/D-hy) of 0.065, streamwise pitch ratio (X/D-hy) of 1.72, and spanwise pitch ratio (Y/D-hy) of 0.82. The Reynolds number (Re) was altered from 3000 to 19,000. The Nu(sdr) and f(sdr) of a JISTC with a roughened absorber plate was found to be enhanced by 5.25 and 5.98 times as compared to an STC without artificial roughness. The optimal findings of Nu(sdr), f(sdr), and eta(sdr) were achieved at S-sdr = 0 mm. The maximum value of the eta(sdr) obtained at S-sdr = 0 mm was 2.9.