Natural convection heat transfer enhancement in new designs of plate-fin based heat sinks

Abstract

Experimental investigation was conducted to measure the convective heat transfer coefficient and thermal performance of plate fins and plate cubic pin-fins heat sinks, under natural convection regime. The investigation was conducted for Rayleigh number from 8 × 106 to 9.5 × 106 and input heat of 10 W to 120 W. The fin spacing and fin numbers are varied between 5–12 mm and 5–9, respectively. The results demonstrated that plate cubic pin-fins heat sinks have lower thermal resistance and higher heat transfer, compared to plate fins heat sinks. Heat transfer enhancement of new-designed heat sinks is about 10–41.6% higher, compared to normal pin-fins. Increasing fin spaces in all types of studied heat sinks cause lower thermal resistance. But, increasing fin numbers does not cause better heat transfer. The best heat sink design was a plate cubic pin–fin heat sink with 7 fins and 8.5 mm fin spacing. Finally, empirical equations have been developed to correlate the average Nusselt number as a function of number of fin plates, fin spacing to height ratio as well as Rayleigh (and consequently Grashof) number.