ARTICLE:

• CONVECTION RESONANCE AND HEAT TRANSFER ENHANCEMENT OF PERIODICALLY HEATED FLUID ENCLOSURES  download article

Jose L. Lage
Laboratory for Porous Materials Applications, Mechanical Engineering Department, Box 750337, School of Engineering, Southern Methodist University, Dallas, TX, USA, 75275-0337

Bogdan V. Antohe
Mechanical Engineering Department, Southern Methodist University, Dallas, TX 75275-0337, USA

ABSTRACT

We report on the theoretical and numerical analysis of the heat and momentum transport inside a rectangular enclosure filled with fluid, or with a fully saturated porous medium, under time-periodic horizontal heating. Numerical simulations indicate that the natural convection activity within the enclosure peaks at several discrete frequencies, with the climax attained at a heating frequency referred to as resonance frequency. We tested a general theory for predicting this resonance frequency against numerical results considering the Prandtl number effect Results of experiments considering a fluid system under time periodic horizontal heating are also reported. Heating period from 32 to 1600 seconds, and time averaged heat-flux from 355 to 1420 W/m² , were considered. For high heat fluxes, the oscillatory heating yielded a time averaged heat transfer coefficient 20 percent higher than obtained with steady heating at a critical pulsating frequency, in good agreement with the numerical and theoretical predictions. .

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