Experimental study on heat transfer enhancement of a helically baffled heat exchanger combined with three-dimensional finned tubes

Heat transfer and pressure drop of helically baffled heat exchanger combined with petal-shaped finned tubes for oil (ISO VG-32) cooling with water as coolant was experimentally studied. The tube side heat transfer coefficient was obtained by a modified Wilson plot technique. Results were presented as plots of the shell side heat transfer coefficient based on the actual outside surface area of tube bundle and pressure drop against volumetric flow rate of oil. Under experimental conditions, the maximum shell side heat transfer coefficient is 2265 W/m2 K, the corresponding shell side pressure drop is 91 kPa. The preliminary heat transfer enhancement mechanisms were discussed for oil flow helically on outside surface of petal-shaped finned tubes.