Numerical and experimental analysis on air/water direct contact heat and mass transfer in the humidifier

This study presents the numerical and experimental investigations of air/water direct contact heat and mass transfer in the humidifier. The mathematical model of humidifier is developed based on the Multiphase-Eulerian model. The regression equation for Merkel number utilized in the numerical model was proposed on the basis of experimental results. According to the numerical simulation results, the error between the numerical and experimental results is within 12%. The distributions of air temperature, the mass fraction of vapour in the air and total pressure have been studied to reveal the heat and mass transfer characteristics in the humidifier. And, the distributions of the relative humidity at different water inlet temperature and air-and-water mass flow ratio are investigated. It is found that the evaporation rate of the humidifier increases with the increase in the air mass flow rate, water inlet temperature and water mass flow rate. Comparing with the previous theoretical calculation results based on the Poppe model, the numerical results are closer to the experimental results. This study has important significance on the development of humidification-dehumidification desalination technology.