Experimental study of pressure drop and heat transfer characteristics of φ10.07 wave and wave-slit fin-tube heat exchangers with wave depth of 2 mm

Heat transfer and air side pressure drop for empty set 10.07 dry surface fin-tube heat exchanger with wave and wave-slit fins were measured for various fin spacings and number of tube rows. Longitudinal and transverse tube spacings of the heat exchanger are 21.65 mm and 25 mm respectively, and wave depth of the wave fin is 2 mm. Experiments were conducted for 1, 2 and 3 rows and 3 different fin spacings, 1.3, 1.5 and 1.7 mm. An attempt was made to demonstrate advantage of the enhanced fins over the plane fin by introducing the concept of fan power. Effect of the number of tube rows on heat transfer was discussed in connection with general mechanisms of heat transfer enhancement for fin-tube heat exchanger. Also the effect of hydrophilic coating was investigated. Lastly, correlations for Colburn j-factor and friction factor were developed.