THE THERMAL-HYDRAULIC CHARACTERISTICS OF STAGGERED CIRCULAR FINNED-TUBE HEAT-EXCHANGERS UNDER DRY AND DEHUMIDIFYING CONDITIONS

Fluid flow and heal transfer over four row circular finned-tube heat e xchangers with staggered arrangement are studied experimentally and nu merically. Two types of finned-tube configurations have been investiga ted under the dry and wet conditions for different values of inlet fro ntal velocity ranging from 1 to 6 m s(-1). The experimental results in dicated that the sensible Colburn factor, J(s), and for the friction f actor, f, the wet coils are, respectively 20% and 15% higher than that for the dry coils. The three-dimensional numerical results of laminar model for the dry coils are also presented. Conjugate convective heat transfer in the flow field and heat conduction in the circular fins a re considered also. The numerical results for the streamline, isotherm , Nusselt number and fin efficiency are shown and compared with the ex periments. (C) 1988 Elsevier Science Ltd. All rights reserved.