Numerical Investigation of the Flow and Heat Transfer Due to a Miniature Piezoelectric Fan

Piezoelectric fans have emerged as a viable alternative for electronics cooling applications requiring low input power and noiseless operation. A piezoelectric fan is a cantilever actuated by a piezoelectric ceramic material bonded to it. The fan oscillates back and forth creating airflow when an alternating electric field is applied to this bonded piezoelectric ceramic. Forced convection induced by such an oscillating fan in an enclosure is numerically investigated. The computational model is capable of sustaining deforming fluid cells that allow large boundary movement. The moving wall boundary, modeled as large-amplitude beam deflection, initiates flow in the fluid domain which enhances convection to varying extents depending on the heat source-to-fan distance and beam deflection amplitude. The effects of these parameters on heat transfer are studied. Transition between distinct convection patterns is observed with changes in the parameters. Results are validated against experimental measurements, with good agreement.Copyright © 2004 by ASME