Microelectronic Cooling Techniques Using Single and Dual Oscillatory Impinging Air Jets

Abstract

A numerical investigation was performed to compare the flow and heat transfer characteristics for microelectronics cooling scenarios. The first cooling method uses a single unsteady/oscillatory impinging air jet while the second method uses dual unsteady impinging air jets. The unsteady confined impinging jet flow has proven to enhance the heat transfer, thus reducing the prohibitive temperatures in high-powered chips. Past a specific Reynolds number range, the jet core becomes distorted and buckles, leading to a sweeping motion of the jet tip. Due to these combined motions, the effective cooled area is notably enhanced thereby reducing the power needed to cool the components placed on the PCB (Printed Circuit Board). A comparison between the unsteady laminar impinging jet and the dual unsteady impinging jets reveals that at the same flow rate, the heat transfer enhancement provided by the single unsteady jet is at least 5–8 times better than that for the dual jets. This cooling enhancement significantly reduces the temperature increase by almost 50 percent. The oscillatory impinging jet cooling technique does not require the incorporation of costly heat sinks and heat spreaders or the unnecessary increase of blower work. This technique provides effective cooling at significantly lower pumping powers with reduced manufacturing and operating costs.