Effect of cavity size on confined slot jet impingement cooling

The paper investigates experimentally the heat transfer characteristic for internal flow inside a semicircular channel due to confined slot-jet impingement. The effect of varying the channel diameters to slot-jet width is evaluated. The average and local Nusselt numbers is calculated by reporting the heater thermal map obtained via an infrared camera, the inlet/ outlet flow temperature are measured via thermocouples, the flow rates are reported via rotameter and the pressure drop is measured across the inlet and outlet flow via pressure transducers. The single enclosed jet flow is used to create a double cyclones inside the semicircular channel to promote heat transfer at different jet Reynolds numbers (= 100 to 1,000). A semicircular cavity with variable diameter are used to evaluate the effect of channel size on the cyclone flow which directly affect the heat transfer. It is found that the cavity size has two opposite effects on the heat transfer. In one side, as cavity size decreases, the distance between the jet and the curved surface decreases and hence heat transfer improves. On the other hand, as the cavity size increases the swirl size inside the cavity increases and hence heat transfer improves.