Experimental study of heat transfer of parallel louvered fins by laser holographic interferometry

Recently many compact air-cooled heat exchanger begin to utilize the enhanced fins to upgrade the performance of a heat exchanger. The study of heat transfer characteristics of these enhanced fins has been focused on as calculated by heat transfer performances in two-dimensional plate array neglecting the effects of tubes. Proposed correlations of the Colburn j-factor and the friction factor for triangular tube arrangement to design the heat exchanger are made. The effects of louver's geometry and their arrangement on heat transfer of louvered fins are studied. A number of informations are available concerning theoretical analyses and global heat transfer performances in a heat exchanger with louvered fins; however, little amount of experimental information to clarify the mechanism of heat transfer around louvers so far has prevailed. The objectives of this paper are experimentally to study the mechanism of heat transfer in a louver-array and to develop the preferable geometrical arrangement of louvers from the point of view of improving the performance of a heat exchanger