This experimental study investigates the heat transfer in a narrow, rib-roughened, rectangular channel with the width-to-height ratio of 10 for its cross-sectional shape. Two flow entrances with equal areas are respectively opened at the upper and side ends of this channel that allows for increasing the coolant-flow fed into the enhanced channel without increasing the height of cooling device. At a fixed total coolant mass flow rate, three test scenarios, namely the single-blow from the side or upper entrance and the twin-blow with the coolant mass flow ratio of 2:1 between the side and upper blows are performed. A selection of detailed heat transfer measurements, evaluated from infrared thermal images over the rib-roughened surface, illustrates the manner by which the flow entry direction and the twin-blow condition affect the local and spatially averaged heat transfers. Relative to the heat transfer results acquired from the single-blow tests, the present twin-blow entry condition could augment the spatially averaged heat transfers to the levels of 150–180% of the single-blow reference levels. A regression-type analysis is subsequently performed to develop the correlation of spatially-averaged Nusselt numbers over rib-roughened surface, which permits the effect of Reynolds number, evaluated from the total amount of coolant consumption, on heat transfer to be determined for three test scenarios.
Heat transfer characteristics in forced convection through a rectangular channel with broken V-shaped rib roughened surface
