Flat plate heat transfer with impinging axial fan flows

Axial flow fans are widely used for the augmentation of heat transfer. One such use is an axial flow fan impinging air on to a heated flat plate which has many practical applications and has been experimentally investigated to characterize local heat transfer distribution. Using infrared thermography, a two-dimensional profile of the heat transfer coefficient on a flat plate is quantified for a range of fan speeds, from 2000 to 6000 rpm, and fan to plate distances of 5–15 mm. The influence of air flow interaction with motor supports on the exit flow plane of an axial fan was shown to result in substantial gradients in heat transfer coefficient in addition to non-uniform fluctuations in heat transfer coefficient on the plate surface. Local maxima in the heat transfer distribution were identified, and shown in some cases to be a function of fan to plate distance, promoting heat dissipation significantly for discrete heat sources.