It is still one of the significant solutions to treat saline wastewater with thermal desalination technology, especially falling film evaporators. To improve the performance of the falling film evaporator, a numerical study on the gas–liquid two-phase flow characteristics of saline wastewater in the vertical pipe was conducted using the VOF model. The results showed that the inlet velocity of the saline wastewater increased under the same operating conditions, resulting in the thickening of the liquid film and the increase of the average convective heat transfer coefficient. Increasing the inlet temperature of the working liquid reduced the temperature difference, which led to a decrease of the average convective heat transfer coefficient. In addition, as the inlet concentration of the working liquid increased, the film flow rate and the average convective heat transfer coefficient first decreased and then increased slightly. The experimental results verified the accuracy of the numerical simulation, and the average error was 9.27%.

热脱盐技术，尤其是降膜蒸发器，仍然是处理含盐废水的重要解决方案之一。为提高降膜蒸发器的性能，利用VOF模型对垂直管道中含盐废水的气液两相流动特性进行了数值研究。结果表明，在相同工况下，含盐废水的入口流速增大，导致液膜增厚，平均对流传热系数增大。提高工作液入口温度，减小了温差，导致平均对流传热系数降低。此外，随着工作液入口浓度的增加，膜流速和平均对流传热系数先降低后略有增加。实验结果验证了数值模拟的准确性，平均误差为9.27%。