Convective Heat Transfer Performance of Water and FC-72 in an One Side Heated Rectangular Channel Having Pin-Fins

This study investigates the convective heat transfer performance of two fluids (water and FC-72) in a one side heated rectangular channel of 20mm in width and 2mm in height. The heated side has either a smooth surface or a pin-finned surface. The inlet fluid temperature was maintained at 30°C. The total length of the test channel was 113 mm, with a heated length of 25mm. The flow rate varied between 80 and 960 ml/min, and the heat flux was between 18 and 98 W/cm². Single phase convection was the dominant heat transfer mechanism in the present water tests, and the performance was mainly controlled by flow rate. Contrarily, the heat flux was the major factor for the heat transfer performance in FC-72 as a result of the dominant boiling effect. At a fixed flow rate, the pin-finned surface yielded up to 30% higher heat transfer coefficient and greater critical heat flux than those of a smooth surface. The convective heat transfer coefficient of FC-72 was greater than water at low flow rates (80∼160 ml/min) and heat fluxes between 18 and 35 W/cm². However, the heat transfer performance of water was superior to FC-72 at high flow rates.