24 June 2014

OPTIMIZATION ANALYSIS FOR LOUVER-FINNES HEAT EXCHANGERS


A series of 3-D computational fluid dynamics analyses along with the simplified conjugate-gradient
method were carried out to study the thermal-hydraulic characteristics for the louver-finned heat exchanger. The
effects of different louver angles (? = 20o to 28o), and louver pitches (Lp = 0.8 to 1.2 mm) on the heat transfer
phenomenon and pressure drop (in terms of Colburn j factor and friction f factor) were investigated in detail. The
optimization of the louver angle and louver pitch is carried out by using the simplified conjugate-gradient
method. The area reduction ratio using a louver fin relative to the plain surface is the objective function to be
maximized. The numerical results showed that both the f and j factors are increased with the increase of the
louver angle; while, for a given louver angle, as the louver pitch (Lp) is creased, both the f and j factors are
increased. It is also found that, under the optimum conditions, the area reduction ratio could reach up to 28 % to 37% with Reynolds number (based on the fin pitch ) ReFp ranging from 400 to 1600.