The Numerical Simulation And Optimization Of The Wave-plate Mist Eliminator With Auxiliary Capture

In the process industry, the process stability will be affected once droplets in the gas phase was entrained into the subsequent process, and the damage will be caused once droplets into the subsequent device. Droplets released into the atmosphere may pollute the environment or result in material damage. It is of great significance how to deal with this problem in the economical and efficient way. The wave-plate mist eliminator has been widely used because of its simple structure, low pressure drop,uneasiness to be blocked, and easiness to clean. The traditional wave-plate mist eliminator, however, applies only the droplets trapped of particle-size larger than10?m. The paper intends to make improvements in the structure and to expand its range of applications to improve the trapping efficiency. With the rapid development of computer technology, numerical simulation methods has been recognized for its application effects in the development process of the wave-plate mist eliminator. In this paper, the computational fluid dynamics software FLUENT6.3 will be utilized for numerical simulation and structural optimization in connection with the flow field and the droplet trajectory in the wave-plate mist eliminator, in order to provide guidance to industrial design.Eulerian-Lagrangian approach was adopted to simulation the two-phase flow in the wave-plate mist eliminator, in which the SST k-? was used for turbulent flow and DPM was for dispersed phase without regard to the gas-liquid coupling. The reliability of the simulation method was verified by the contrast between the simulation results and experimental data. Then the variation condition of flow field and droplet tracks after the introduction of the auxiliary capture was discussed by the contrast of the separation efficiency and pressure drop at the inlet speed of 2~5m/s. It turned out that in the situation of different inlet velocities the eddies was found near the tip of the auxiliary capture, which increased the turbulent energy. At the same time,the high speed region expanded obviously which was in favor of the capture of the droplets and the pressure drop increased.Through analysis and discussion, it is found that the capture height was the main factor to influence the flow field, separation efficiency and pressure drop. The impact of the structure parameter above on the maximum gas speed, high speed region, low speed region, separation efficiency and pressure drop was discussed in a moresystematic way to obtain the optimization of the structural parameter. The capture heights were chosen to be 35%, 48%, 60% of the channel width respectively, then there should be 27 combination modes for mist eliminator with three stages. It turned out that when the capture height was transformed from 48% to 60% of the channel width, it had better to change the second height rather than the first and third stage height at the inlet speed of 2~5m/s, meantime, it was suggested that it had better to change the first and third stage height rather than the second height when the capture height was transformed from 35% to 48% of the channel width. The capture height at different stages were also suggested to be adopted for different droplet size distribution at the inlet. At last, the overall performance was best when the capture heights were 48%, 35%, 48% of the channel width respectively at the inlet speed of2m/s, and the overall performance was best when the capture heights at different stages were all 48% of the channel width at the inlet speed of 4m/s.