泡沫发生器数值模拟优化及其阻隔异味物质的效果

Numerical Simulation Optimization of Foam Generator and Its Application in Blocking Odorous Substances

泡沫喷施覆盖技术是解决水体底泥清淤臭气释放、阻隔污水厂面源臭气逸散、控制土壤修复异味的一种新方法。然而以往的参数设计使得泡沫发生器对于高黏度泡沫液难以形成均质的泡沫。以射流式泡沫发生器为基础,设置2 mm孔径的出口多孔网,利用数值模拟进行优化设计。分布云图表明,进气压力对气液混合效果影响不大;气液比为6∶1时,气液混合效果明显提高,边缘液相占比为22.5%;进一步调整喉管长度为180 mm,射流出的泡沫混合更加均匀,边缘液相占比提高至44.1%。优化后的泡沫发生器可以实现气液两相充分混合,气液均质泡沫从出口流出,对典型臭气成分如二甲基二硫醚、硫化氢、氨气的阻隔效果均大于95%,污染物逸散量分别降低66.5%、65.8%、40.2%。

Foam spray technology has been applied to control odorous substances releasing from sediment in water bodies,contaminated soil,and non⁃point sources in sewage treatment plants.However,the previous design of the foam generator was difficult to form homogeneous foam for high⁃viscosity foaming liquid.In this study,numerical simulation was used to optimize the design of the jet foam generator with a 2 mm aperture outlet porous network.The distribution cloud diagram showed that the inlet pressure has little influence on the gas⁃liquid mixing effect.But,the proportion of the edge liquid phase increased to 22.5%showed that the gas⁃liquid mixing effect was obviously improved,when the gas⁃liquid ratio was 6∶1.By further adjusting the length of the throat to 180 mm,the foam produced was mixed more evenly,and the proportion of the edge liquid phase was increased to 44.1%.The optimized foam generator could release thoroughly mixing of the gas phase and the liquid phase,then the homogeneous foam flew out of the outlet.And the foam could block 95%of dimethyl disulfide,hydrogen sulfide,and ammonia,which were typical odorous substances,and the emission amount of pollutants decreased by 66.5%,65.8%,and 40.2%respectively.