Abstract
The performance of a low-profile radial countercurrent heat sink driven by an integrated synthetic jet actuator is investigated experimentally. A packaged thermal test die is cooled using an array of synthetic jets normally impinging on the extended surface. A power dissipation of 50 W is accomplished at the nominal case temperature of Tc = 70 °C.
The heat sink design is driven by the flow and heat transfer analysis of normal jet impingement in a confined flow geometry consisting of two parallel circular plates having a diameter that is typically an order of magnitude larger than the spacing between the plates. The velocity and temperature distributions are measured using particle image velocimetry and arrays of thermocouple sensors. A jet actuator is integrated into one of the plates and cools a test heater attached to the opposite surface. The jet draws its makeup air from ambient, impinges on the heater, and ultimately rejects the heat to ambient. This introduces a radial countercurrent flow in the gap between the plates that includes a layer of hot air dispensed along the top plate and a layer of cooler ambient air entrained along the jet exit plane. When the jet is activated the heater temperature drops substantially. Although the global heat transfer coefficient decreases with decreasing gap height, flow pathlines show that the jet can still entrain cool air from ambient and effect substantial cooling even when the spacing between the plates is of the order of the jet orifice diameter.
