INVESTIGATION OF DYNAMIC ENHANCEMENT OF LAMINAR NATURAL CONVECTION COOLING OF ELECTRONICS

Laurie Florio

Advisor: Dr. Avraham Harnoy

With the proliferation of consumer electronics devices and the increasingly demanding thermal control requirements for such devices, more effective and efficient means of cooling electronics are needed.  The feasibility of alternative approaches of enhancing pure natural convection cooling is investigated in the current research.  These cooling methods are intended to operate in the regime for which natural convection cooling is inadequate, yet conventional fan driven cooling is inefficient.

            This presentation will focus on the results of a two-dimensional laminar flow numerical investigation into the feasibility of the use of transversely oscillating vibration sources placed in the immediate vicinity of heat sources for localized enhancement of laminar natural convection in a vertically oriented channel.  Both a constant heat flux plate heat source and a constant volumetric heat source rectangular solid are used.  For a given channel geometry, the oscillation parameters and oscillation source location are varied to determine their impact on any potential cooling effect. The results of these parametric numerical studies allow for the determination of measures of the potential cooling effect of the method including the time averaged local heat transfer coefficients and time averaged average heat transfer coefficients.  Based on the information gathered in the study, a well-informed judgment as to the feasibility of such a cooling enhancement technique can be made.

            The results of this investigation indicate that the use of transverse oscillation sources placed in the immediate vicinity of the heat sources has the potential for significant heat transfer enhancement over a range of viable oscillation and geometric parameters.  By promoting improved fluid mixing in the heat source vicinity, the oscillation sources act to increase the velocity gradients in the fluid nearby the heat source, causing increased temperature gradients in the nearby fluid and increased heat removal.  Improvement in the local heat transfer coefficients of as much as 83% was found for certain parameter values.  In addition, the cooling effect was found to be localized, and, thus, this method may be useful in the cooling of specifically targeted locations.