Experimental study on gas-liquid mixing and foaming characteristics of Venturi series bubble generator
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摘要:
高效紧凑型微细气泡发生技术和粒径调控技术是微细气泡技术大规模工业应用的前提和基础。通过CFD数值模拟手段和试验测试手段测试两级文丘里串联结构气泡发生器内气液两相混合发泡特性,并利用响应曲面法对关键结构参数进行了优化设计和交互影响分析。结果表明:对两级文丘里串联结构气泡发生器成泡粒径影响最大的参数主要是二级喉管管径,其次为一级喉管管径和二级扩张角,一级扩张角的影响最小。相同工况条件下,单级文丘里管气泡发生器所生成的气泡群中位粒径为543.64 μm,粒径小于100 μm的微细气泡数量占比为8.6%;两级文丘里管串联气泡发生器所生成的气泡中位粒径为515.99 μm,微细气泡数量占比提升至12.1%。因此,可以通过控制水流流量和改变文丘里串联数量实现气泡粒径从毫米级别到微米级别的调控。
Abstract:The efficient and compact microbubble generation technology and particle size control technology are the premise and foundation of large-scale industrial application of microbubble technology. The foaming characteristics of gas-liquid two-phase mixing in two-stage Venturi series bubble generator were studied employing CFD numerical simulation and experimental test, the key structural parameters were optimized, and the interactions were analyzed by Response Surface Method. The results showed that the diameter of the throat in the second stage had the greatest influence on the bubble particle size of the two-stage Venturi series bubble generator, followed by the diameter of the throat in the first stage and the second stage expansion angle, while the expansion angle in the first stage had the least influence. Under the same working conditions, the median particle size of bubbles generated by single-stage Venturi bubble generator was 543.64 μm, and the proportion of fine bubbles with particle size less than 100 μm was 8.6%. The median particle size of bubbles generated by two-stage Venturi series bubble generator was 515.99 μm, and the proportion of fine bubbles increased to 12.1%. Thus by controlling the flow rate and changing the number of Venturis in series, the bubble particle size could be adjusted from millimeter level to micron level.
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Key words:
- fine bubble /
- Venturi /
- CFD numerical simulation /
- response surface method /
- bubble characteristics
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表 1 两级文丘里串联结构气泡发生器关键结构参数尺寸
Table 1. Dimensions of key structural parameters of two-stage Venturi series bubble generator
主要参数 尺寸 主要参数 尺寸 入水口管径/mm 25 注气口直径/mm 8 喉管直径/mm 10 收缩管段角度/(°) 22.5 扩散管段角度/(°) 12 外壁厚度/mm 0.277 表 2 响应曲面法模拟因子和水平
Table 2. Simulation factors and levels of response surface methodology
因子 水平 1 0 −1 一级喉管管径/mm 13 9 5 一级扩张角/(°) 15 11 7 二级喉管管径/mm 13 9 5 二级扩张角/(°) 15 11 7 -
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