Experimental investigation of the thermal-hydraulic characteristics of liquid cooling heat sinks with novel pin fins

Pin-fin heat sinks (PFHSs) in single-phase liquid cooling systems possess significant potential for extracting higher levels of heat from avionics. However, there is a scarcity of investigations on PFHSs with innovative pin fin shapes. Here, petaloid I and II, pinwheel-like, and honeycombed shapes were designed, and their thermal-hydraulic characteristics were examined under inlet temperatures of 10 and 20 degrees C, flow rates of 400-2000 mL/min, and heat fluxes of 60-150 kW/m2. Among these PFHSs, the honeycombed shape exhibited the highest heat transfer coefficient, followed by the pinwheel-like shape; they also displayed the lowest wall temperature. However, their Nusselt numbers were lower than those of petaloid heat sink I. The Nusselt number of each heat sink exhibited a downward trend with the increasing inlet temperature and heat flux, while the friction factor remained largely unaffected. The performances were evaluated by a comprehensive factor, and the honeycombed PFHS ranked first. New correlations for the Nusselt number and friction factor of these PFHSs were developed. The mean absolute deviations were all less than 5%, with most predicted values falling within the +/- 5% range compared to experimental values. These novel heat sinks are crucial for enhancing the performance of airborne liquid cooling systems.