Numerical simulation of water spray transport along a plate of a heat exchanger

Abstract

Water spraying is widely being used in many industrial applications because of the benefits it has shown over cooling. This paper presents a numerical investigation to simulate evaporating water spray along a plate of an exchanger. Indeed, we were interested in a horizontal channel whose lower wall is the plate of the exchanger maintained at a heating flow. This plate is exposed to a turbulent airflow in which water droplets were injected. The equations governing the continuous phases (air) and the dispersed phase (water) were developed. These equations were solved using Comsol Multiphysics. A comparison of the simulation results and those of the experiment reveals an acceptable concordance. Therefore, the numerical results present the thermal behavior by studying transversal and longitudinal evolution of temperature. Moreover, the maximum evaporated water flow (mmaxew) and the plate temperature are investigated for several physical parameters of the continuous phase, such as velocity, relative humidity and inlet temperature. The results show that these parameters have significant impact on the cooling of the plate. In addition, mmaxew witnesses a remarkable decrease by increasing relative humidity. However, increasing air velocity and inlet air temperature could improve mmaxew.