旋线除雾器切向速度分布建模及除雾效率影响分析  

Mathematical model establishment of tangential velocity distribution and effect analysis on rotary thread demisting efficiency

作　　者：向晓东[1,2] 詹旻钧 钟杰 刘涛 XIANG Xiao-dong;ZHAN Min-jun;ZHONG Jie;LIU Tao(School of Resource and Environmental Engineering,Wuhan University of Science and Technology,Wuhan 430081,China;State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control,Wuhan 430081,China)

机构地区：[1]武汉科技大学资源与环境工程学院,武汉430081 [2]国家环境保护矿冶资源利用与污染控制重点实验室,武汉430081

出　　处：《安全与环境学报》2021年第6期2820-2827,共8页Journal of Safety and Environment

基　　金：国家重点研发计划项目(2017YFC0210404)。

摘　　要：旋线除雾器是一种利用高速旋转的纤维线(旋线)实现气液分离的除雾设备,其除雾机理是旋线与雾滴的惯性碰撞和旋线产生的旋流离心分离。为定量分析旋流的离心分离作用,必须给出切向速度分布的数学表达式。为此,利用Fluent 18.1软件对旋线除雾器内切向速度分布进行数值模拟。模拟结果发现,旋流切向速度随半径的变化近似呈线性关系,相关系数为0.984;随旋线转速和旋线根数的变化呈幂指数函数关系,相关系数均超过0.999。通过上述函数关系建立了切向速度分布数学模型,进而确定了旋线除雾器离心分离效率的计算公式。最后探讨了旋线除雾器除雾效率的主要影响因素。结果表明:旋线的惯性碰撞占主导地位,离心分离对除雾效率的贡献低。对于粒径20μm的雾滴,惯性碰撞除雾效率为77%,离心分离除雾效率为5%;旋流段长度的改变对旋线除雾器的效率影响很小;增加旋线转速或旋线根数是提高旋线除雾器除雾效率的有效途径。To quantitatively analyze the centrifugal separation of swirl flow in the rotary thread demister,the tangential velocity distribution of rotary thread demister was simulated by Fluent 18.1.ICEM was used to divide the model into unstructured grids,and the number of grids was 8.7 million.The κ-ε RNG turbulence model was used to simulate the flow field of the demister with the rotary thread number of 50,75,100 and the rotation speed of 300-1 200 r/min.The velocity distribution contour shows that the axial flow of the airflow becomes swirl flow under the influence of the rotary threads,and the tangential velocity increases sharply.Analyzing the tangential velocity distribution in the 6 cross-sections equally apart after the rotary thread layer found that,the peak tangential velocity of swirl flow in each cross-section decreases obviously,but the tangential velocities are close when the radius r is less than 0.9r_(0).According to the simulation results,a linear relation is found between the tangential velocity and the vortex flow radius with a correlation coefficient of 0.984.It is also found that the tangential velocity is a power exponential function of the thread rotating speed and the thread number and their correlation coefficients are larger than 0.999.Thus,the tangential velocity distribution mathematical model is established based on the above function relation,and the calculation formula of centrifugal separation efficiency of the rotary thread demister is determined.Finally,the main factors affecting the rotary thread demisting efficiency are discussed.The results show that inertial impaction is predominant.The contribution of centrifugal separation to the rotary thread demisting efficiency is quite low.For the droplet size of 20 μm,the efficiency of inertial collision and centrifugal separation are 77% and 5% respectively.The vortex flow length has little effect on the demisting efficiency of the rotary thread demister.It can be an effective way to increase the thread rotating speed or the thread number

关 键 词：环境工程学 旋线除雾器 数值模拟 切向速度 离心分离 除雾效率 

分 类 号：X701.7[环境科学与工程—环境工程]