Study on Heat Transfer Enhancement of a Coil Zone for Closed Wet Cooling Towers Equipped with Longitudinal Fin Tubes

Abstract

In this paper, we numerically investigate the structural parameters and operating parameters of a closed wet cooling tower (CWCT) installed with longitudinal fin tubes using a CFD species transport model. A two- dimensional model of the CWCT is established, the Navier-Stokes equation and κ-ε model are employed to calculate the vapour-phase flow and Reynolds number of the coil zone. In particular, we explore the approaches of heat transfer enhancement and the resulting CWCTs installed with different types of tubes. The results show that the fin tube case-3 (8 fins on one tube) is the optimal one. The heat and mass transfer coefficients of fin tube case-3 are 1.25 ~ 1.7 times that of a plain tube case with an inlet air flow rate of 3.7 kg·m^-2·s^-1. The heat and mass transfer show a decreasing trend with the increase of the inlet air wet-bulb temperature. Remarkably, the heat transfer coefficient of the plain tube case decreases by about 20 %.