ENHANCED HEAT-TRANSFER IN CHANNELS WITH STAGGERED FINS OF DIFFERENT SPACINGS

The flow pattern and heat transfer acrOsS staggered fins inside a rect angular duct are presented. The influence of Reynolds number, fin spac ing, fin material, and wall heat flux on local and average heat transf er coefficients are studied. Fin spacings ranged from 0.8 to 2.0 times the channel height The fin height was 0.7 times the channel height. T he investigated Reynolds number ranged from 8,000 to 18,000. The exper imental results show that the flow must pass over three to six fins be fore it appears to be a thermally periodic, fully developed flow The f ins enhance the heat transfer significantly due to flow deflection and impingement upon the fins. Augmentation of heat transfer was obtained with increase in Reynolds number, thermal conductivity of fins, and d ecrease in fin spacing and wall heat flux.