Venturi式掺混器几何参数对性能的影响

微气泡发生器在污水处理中具有重要用途, Venturi式气液两相掺混器在微气泡生成方面具有众多优良特性.采用数值模拟方法研究了Venturi式掺混器结构几何参数对其掺混性能的影响.运用单一变量法分别研究了不同收缩段曲线,进气孔数目,扩张角的角度对掺混性能的影响,通过对比不同模型仿真结果的出口段气体体积分数、沿轴向压力变化及沿轴向湍动能变化,得出掺混性能最佳的几何参数.研究收缩段曲线时,发现一次直线的气液掺混性能在所选的5条收缩段曲线中最好;研究进气孔数量时,比较了1, 2, 4个进气孔对掺混性能的影响,发现在一定的进气孔数目范围内,进气孔数目的增加可以提高气液掺混效率;研究扩张角变化对掺混效率的影响时,得出在6～9°的范围内,随着扩张角的增大,气液掺混效率随之显著增大.

Influence of Geometric Parameters of Venturi Mixer on Performance

Microbubble generators have important applications in wastewater treatment. The Venturi gas-liquid two-phase blender has many excellent characteristics in the generation of microbubbles. In this paper, numerical simulation method was used to study the influence of geometric parameters of the Venturi-type blender on its blending performance. A single variable method was used to study the influence of the different shrinkage curves, the number of inlet holes, and the angles of expansion on the blending performance. By comparing the gas volume fraction of the outlet section, the pressure and turbulent kinetic energy variations along the axial of different models, the optimum geometric parameters of mixing performance were obtained. When studying the contraction curves, it was found that the gas-liquid blending performance of a straight line was the best among the five selected contraction curves. The number of intake holes was studied. The effects of one, two and four intake holes on the mixing performance were compared. It was found that the increase of the number of intake holes could improve the mixing efficiency within a certain range and the effect of the change in the expansion angle on the blending efficiency was found in this paper. In the studied range of 6 to 9°, with the increase of the expansion angle, the gas-liquid mixing efficiency increases significantly.