Oscillating piezofan effects on natural and forced convection flow in a vertical channel with protruding heat sources

The current work investigates the flow characteristics and convective heat transfer performance of a vertically-oriented piezofan in a channel with wall-mounted protruding heat sources.A 2D numerical model is developed in COMSOL Multiphysics to simulate the temperature variations on the heated protrudes under forced and natural convection scenarios, with and without oscillation of the piezofan.A vertical channel with dimensions of L ch = 300 mm × S = 35 mm is considered with four protruding heat sources (H hs = 25 mm × b = 7 mm), which are positioned on the same side of the channel, with a frontal surface heat flux of q w = 600 W/m 2 .The results reveal that active and passive vortices generated by piezofan and protruding objects in the flow domain provide higher momentum and heat exchange.It was found that implementing piezofan inside the channel significantly enhances cooling performance and reduces the surface temperatures of the protrudes.Compared to the pure natural convection within the channel, the average convective heat transfer coefficient on the protrudes increased more than three times using piezofan.Besides, in the case of forced convection, the maximum increments in mean convective heat transfer are obtained as 74% and 59% at Reynolds numbers 1000 and 2000, respectively.