Experimental and numerical investigation on the evaporation performance of a cyclone-type spray desalination chamber

Abstract

Complex heat and mass transfer in spray evaporators are areas of intense research due to their increasing predominance in thermal desalination industries. To improve evaporation performance, a cyclone-type spray desalination chamber is developed in this study. Influences of gas-to-liquid volume ratio, temperature and velocity of intake hot air, feeding liquid temperature and nozzle pressure upon evaporation are investigated experimentally and numerically. Thermocouples are used to obtain temperature distribution. Liquid flowmeter and hydrometer are equipped to record evaporation data. Results indicate that swirling flow prolongs the residence time of droplets in the chamber, thus evaporation efficiency can be improved. The rapid development of thermal field is closely related to the two-phase flow and intense phase change heat transfer. Evaporation increases and tends to be stable with gas-liquid ratio, intake air velocity and feeding liquid temperature. Evaporation performance can be improved significantly by increasing temperature of intake hot air. It is highly recommended to control the temperature of feeding liquid and intake air to balance between evaporation performance and energy efficiency. The two-phase flow field can be well organized by matching the spray cone angle and the swirling air flow, thus, a moderate nozzle pressure is suggested to obtain optimal evaporation performance.