(Dr.Ari Glezer, advisor)

"Local and System Level Thermal Management of a Single Level Integrated Module (SLIM) using Synthetic Jet Actuators"

Abstract

System level thermal management of integrated circuits relies on both local, device-level passive and active heat conduction (e.g., using heat sinks, heat pipes, and thermoelectric heat pumps) and global, system-level heat removal by means of natural or forced convection (e.g., using fans).  A critical element of the thermal path from the device to the system level is the coupling between the local and global cooling processes that can limit efficient heat transfer at both levels.  Such coupling can be effectively achieved using synthetic jet actuator technology that has been developed at Georgia Tech.  Highly efficient, localized, on-demand cooling is accomplished using fluidic actuators that synthesize intense jets directly from the working fluid (gas or liquid) of the flow system in which they are embedded.  Each jet is synthesized by the motion of a train of vortices that form at the edge of an orifice in a shallow cavity as a result of the time harmonic ejection of fluid from the cavity by a diaphragm that is built into one of the cavity surfaces.  These zero net mass flux jets (since no new fluid is injected into the system), operate at relatively high frequencies and thus are inherently more effective than conventional jets in direct impingement cooling applications owing to enhanced small-scale heat transfer at solid surfaces.  The concomitant entrainment and mixing of ambient air (that is necessary to form the jet) provide an extremely efficient coupling between device-level and global, system-level cooling and can lead to a substantial reduction in the capacity of the global cooling system.

The feasibility of synthetic jet technology for interactive cooling of a single level integrated module (SLIM) has been examined in both open- and low flow rate (enclosed) test section designs.  Novel low-profile and normal impingement cooling of a SLIM module using synthetic jet actuators is achieved with and without the assistance of a miniature heat sink in an open flow test section.  Furthermore, the utility of the low-profile synthetic jet actuator for cooling of a SLIM module (with and without a miniature heat sink) is also investigated within a confined enclosure in the presence of a cross-flow that simulates the effect of global cooling.