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Affiliation of Author(s):能源与动力学院

Journal:HEAT AND MASS TRANSFER

Key Words:BOUNDED OSCILLATING CANTILEVERS VIBRATING CANTILEVER THERMAL PERFORMANCE PLATE AMPLITUDE ENHANCEMENT PREDICTION POSITION VORTEX BEAMS

Abstract:Experimental tests are carried out to investigate the convective heat transfer performances on a flat surface around the vibration envelope of a vertically-oriented piezoelectric fan in the presence of cross flow. Distinct behaviors of convective heat transfer are illustrated under the present conditions of piezoelectric-fan excitation voltage (U = 50, 150, 250 V) or characteristic velocity (u (PF) = 0.83, 1.67, 2.34 m/s) fan tip-to-heated surface gap (G = 3, 5, 7 mm) and cross flow velocity (u (CH) = 0.94, 1.56 m/s). In addition, three-dimensional flow field simulations are conducted to illustrate the instantaneous flow fields around the vibrating fan. By comparing with the pure piezoelectric fan, the vortex induced by the vibrating fan is pushed downward by the cross flow and a series of vortices are displayed down the vibrating fan. It is confirmed that the presence of cross flow is contributive to the improvement of convective heat transfer in the rear zone downstream fan vibration envelope. The impingement role of streaming flow induced by piezoelectric fan is reduced by the presence of cross flow in the fan vibration envelope. On the other hand, the oscillating movement of the piezoelectric fan promotes the disturbance intensity of cross flow passing through the fan vibration envelope. These two aspects make the conjugated convective heat transfer in the vicinity of fan vibration envelope complicated. In general, the convective heat transfer in the vicinity of fan vibration envelope is mostly improved by the combined action of fan-excited steaming flow and cross flow in the situation where the piezoelectric fan is placed very close to the heated surface.

ISSN No.:0947-7411

Translation or Not:no

Date of Publication:2017-09-01

Co-author:Li, Xin-Jun,TAN Xiaoming

Correspondence Author:zjz