DOI: 10.1615/ICHMT.1996.TransientConvHeatTransf
ISBN Print: 978-1-56700-084-9
CONVECTION RESONANCE AND HEAT TRANSFER ENHANCEMENT OF PERIODICALLY HEATED FLUID ENCLOSURES
SINOPSIS
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. .