NUMERICAL AND EXPERIMENTAL INVESTIGATION OF SPRAY EVAPORATION BASED ON DROPLET ANALYSIS

The spray evaporation desalination technology has the potential for improving the performance of thermal desalination plants and making thermal desalination more competitive and appealing. For a better understanding of the seawater evaporation process, a mathematical model has been presented with consideration of the motion and heat transfer of the droplet, and performance of the evaporator based on droplet analysis. The model has been validated by using experimental data, and simulation results showed good agreement with experiments with a discrepancy below 10%. The model can be used to evaluate water productivity and thermal utilization accurately, which are critical to the design of the evaporator. Research results revealed that smaller droplets and lower initial velocity lead to a high thermal utilization, while superheat degree has a marginal effect on thermal utilization. The merits of flash evaporation can make it operate at larger superheat with higher thermal utilization and water productivity while multistage flash distillation (MSF) needs more stages to eliminate nonequilibrium temperature differences.