Synthetic jet based active heat sink for electronic cooling

The development of an air-cooled heat sink augmented by a synthetic (zero net mass flux) jet actuator for moderate heat flux applications as in mobile electronics is discussed. Since the jet is synthesized without net mass injection, a compact, efficient impingement-cooling module is enabled. An off-the-shelf plate-fin heat sink is integrated with a jet module placed on the heat sink such that the jet impinges on the base plate of the heat sink and flows within the channels between the fins. Entrainment of cool air is forced from regions away from the heated surfaces by a baffle plate that prevents recirculation of the heated air. The cooling performance of the module is assessed using a thermal die and the effects of fin-density, actuation frequency and amplitude are investigated. While under natural convection with a heat sink the package typically dissipates 6W (a thermal resistance of 12.6degreesC/W), the active heat sink enables a power dissipation of 21.9W/cm(2) at 0.4 CFM (a thermal resistance of 3.3degreesC/W). This corresponds to a 250% improvement over natural convection and 35% over a 3-4CFM fan-heat sink combination having similar volume.