The thermal-hydraulic characteristics of staggered circular finned-tube heat exchangers under dry and dehumidifying conditions

Fluid flow and heat transfer over four row circular tinned-tube heat exchangers with staggered arrangement are studied experimentally and numerically. Two types of finned-tube configurations have been investigated under the dry and wet conditions for different values of inlet frontal velocity ranging from 1 to 6 m s^-1. The experimental results indicated that the sensible Colburn factor, J_s, and for the friction factor, 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 are considered also. The numerical results for the streamline, isotherm, Nusselt number and fin efficiency are shown and compared with the experiments.