Numerical simulation on flow and evaporation characteristics of desulfurization wastewater in a bypass flue

Abstract

Owing to the oversimplification of the evaporation model, existing numerical analysis cannot accurately characterize the evaporation characteristics, which has limited its significance for engineering. Therefore, by user-defined programming, a droplet evaporation model in line with the properties of desulfurization wastewater was implemented in numerical simulation. The effects of guiding measures, nozzle arrangement, nozzle layer, flue gas temperature, moisture and droplet diameter on the droplet evaporation in a bypass flue were explored. The numerical results show that the fluctuation of evaporativity due to moisture can be neglected. The uniformity of the flow field with guiding measures is good and the phenomenon of droplets impinging on the wall surface can be prevented. The droplet collision probability without guiding measures may be nearly 60 times higher than that with guiding measures. A reasonable nozzle arrangement increases the droplet evaporation rate and reduces the probability of droplets colliding with the wall surface. An increased number of nozzle layers enhances the droplet evaporation rate and the average temperature in the flue; by estimation, the average temperature in the flue with three nozzle layers is 10.7 K higher than that for two nozzle layers, and 15.8 K higher than that for one nozzle layer. In the condition of higher temperature and smaller diameter, droplets evaporate more rapidly. These research results can provide a reliable reference for engineering practice.

Keywords

• desulfurization wastewater
• bypass flue
• evaporation characteristics
• numerical simulation