Numerical simulation of humidification process by spray evaporation under different air pressure and temperature

Abstract

In special industrial fields, when dry compressed air enters process fluids containing radioactive substances, it often carries radioactive water vapour. To effectively solve this problem, it is necessary to humidify the dry compressed air before feeding the liquid. By utilizing computational fluid dynamics software FLUENT, this study employs the Discrete Phase Model (DPM) to depict the trajectory of spray particles and investigates the effects of structural parameters and operational variables such as inlet air temperature, inlet pressure, and spray volume on the humidification process. The optimal design parameters for the humidifying tank are determined. The simulation results show that the humidification effect is significantly improved with the increase of inlet air temperature when 30 μ m water droplets are sprayed at a flow rate of 3.8 g/s in a humidification tank with a diameter of 850 mm and a height of 1500 mm; When the water spray volume is increased to 20 g/s, the relative humidity of outlet gas can reach about 91 %; When the installation height of nozzle is 1200 mm, the outlet relative humidity is close to saturation; When nozzles are added, 27 % of the spray water is not involved in the heat and mass transfer process due to spraying to the wall.