摘要
气升式反应器内气液两相流动力学特性对提高传质效率和降低运行成本有重要意义。基于粒子图像测速(PIV)技术,在改变曝气强度的条件下,分析距曝气管不同位置处反应器轴向各区域的液相流场、雷诺应力以及气泡动力学特性。结果表明,曝气强度对液相流场和雷诺应力的影响较大,在一定范围内增加曝气强度可以使得液相速度和雷诺应力值增加。同时分析了4mm孔径下圆帽状气泡的动力学特性。
This paper aims to provide an experimental basis and re- search experience for the analysis of the dynamic features of gas- liquid two phase flow on the surface of the membrane module in an airlifting reactor. The dynamic features of gas-liquid two phase flow in the air-lifting reactor are of great significance to raising the efficiency of mass transfer and lowering of the operation cost. For this purpose, we have set up a pilot scale airlift reactor system with the entire glass- ware, whereas the Particle Image Velocimetry （PIV） technology is oriented for measuring and calculating the dynamic features of gas- liquid two phase flow in the airlift reactor. In this paper we have ana- lyzed the liquid phase flow field, the Reynolds stress and the dynamic feature of the bubbles under the condition of aeration intensity of 3.5 m3/h, 4.5 m3/h, 5.5 m3/h, 6.5 m3/h and 7.5 m3/h, and its five laser sections in the bore diameter of4mm. The results of our analysis show that the aeration intensity in some ways strongly influences the liquid flow field and in turn increases the aeration intensity in a cer- tain range, which is likely to speed up the flow of the liquid. Under the experimental conditions, the optimal aeration intensity can be i- dentified as 5.5 m3/h. whereas the Reynolds stress can be found to account for the turbulent degree of gas-liquid two phase flow field. The experimental results of ours also show that the Reynolds stress is in a position to enhance the aeration intensity of each laser section. At the same time, we have also analyzed the dynamic features of the 4mm bore diameter round the cap bubble, whose movement can gen- erate a secondary flow behind the bubble to form a so-called ＂the wake region＂. The experiments we have done prove that it is realistic and feasible for the PIV technology to be used for measuring the gas- liquid two phase flow features in the airlift reactor. As the same time, the results help to lay out a basis for further research in the flow field of membrane surface so as to establish the membrane module form of MBR in the study of the air-lift reactor area.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2012年第6期77-81,共5页
Journal of Safety and Environment
基金
内蒙古工业大学科学研究基金项目(X200629)
关键词
工程热物理
气升式反应器
气液两相流
粒子图像测速技术
雷诺应力
engineering thermophysics
air-lift reactor
gas-liquid two phase flow
particle image velocimetry
Reynolds stress
