一种内置旋流叶片的旋风分离器性能数值研究
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摘要
提出了一种新的高效旋风分离器构造,在传统分离器的内外涡旋交界面上添加一组与气流旋转方向相同的旋流叶片,来阻挡含尘气流中的颗粒进入内涡旋区.基于计算流体力学(CFD),采用雷诺应力模型和离散相的随机轨道模型来计算分离器的气固两相流,并用试验数据验证了计算模型的正确性;通过数值计算分析、比较了添加旋流叶片前后的分离器性能,对旋流叶片进行了性能优化.结果显示,与传统分离器相比,添加旋流叶片能够使分割粒径减小60%～70%,有效地提高了分离效率,而压降仅增加19.3%,且旋流叶片对于小粒径、小密度颗粒的分离效率提升更为显著.
This paper presented a new efficient cyclone separator,which can block the particles moving to the inner vortex.The new cyclone separator was obtained by setting a group of swirling blades with the same direction as the rotating direction of the air flow in the internal and external vortex interface of the traditional separator. The Reynolds model and discrete phase model were selected to simulate the gas-solid two-phase flow,and the discrete random walk model was used to study the turbulent dispersion of particles.The accuracy of the numerical simulation was verified by comparing with the experimental data. The performance between the traditional cyclone and new efficient cyclone was compared by numerical simulation. Moreover, the optimization of the swirling blades was performed. The results show that, compared with the traditional cyclone, adding the swirling blades effectively improves the separation efficiency,which can decrease the cut-off size by 60%～70% and increase the pressure drop by 19.3% only. Further, the effect of swirling blades on the separation efficiency of small particle size and low density particles was more significant.
This paper presented a new efficient cyclone separator,which can block the particles moving to the inner vortex.The new cyclone separator was obtained by setting a group of swirling blades with the same direction as the rotating direction of the air flow in the internal and external vortex interface of the traditional separator. The Reynolds model and discrete phase model were selected to simulate the gas-solid two-phase flow,and the discrete random walk model was used to study the turbulent dispersion of particles.The accuracy of the numerical simulation was verified by comparing with the experimental data. The performance between the traditional cyclone and new efficient cyclone was compared by numerical simulation. Moreover, the optimization of the swirling blades was performed. The results show that, compared with the traditional cyclone, adding the swirling blades effectively improves the separation efficiency,which can decrease the cut-off size by 60%～70% and increase the pressure drop by 19.3% only. Further, the effect of swirling blades on the separation efficiency of small particle size and low density particles was more significant.
引文
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[12]XIANG R B,LEE K W.Numerical study of flow field in cyclones of different height[J].Chemical Engineering and Process,2005,44:877-883.
[13]LEE J W,YANG H J,LEE D Y. Effect of the cylinder shape of a long-coned cyclone on the stable flow-field establishment[J].Powder Technology,2006,165:30—38.
[14]CORTES C,GIL A. Modeling the gas and particle flow inside cyclone separators[J].Progress in Energy&Combustion Science,2007,33(5):409-452.
[15]VANDOORMAAL J P,RAITHBY G D. Enhancements of the SIMPLE method for predicting incompressible fluid flows[J].Numerical Heat Transfer Applications,1984,7:147—163.
[16]RAOUFI A,SHAMS M,FARZANEH M,et al.Numerical simulation and optimization of fluid flow in cyclone vortex finder[J].Chemical Engineering and Processing:Process Intensification,2008,47(1):128—137.
[17]MORSI S A,ALEXANDER A J. An investigation of particle trajectories in two-phase flow systems[J]. Journal of Fluid Mechanics,1972,55(2):193—208.
[18]RAOUFI A,SHAMS M,FARZANEH M,et al.Numerical simulation and optimization of fluid flow in cyclone vortex finder[J].Chemical Engineering and Processing:Process Intensification,2008,47(1):128—137.
[19]WEI J,ZHANG H,WANG Y,et al.The gas-solid flow characteristics of cyclones[J].Powder Technology,2017,308:178—192.
[20]CHEN J,CHU K,ZOU R,et al. Systematic study of the effect of particle density distribution on the flow and performance of a dense medium cyclone[J].Power Technology,2017,314:510—523.
[21]DIRGO J,LEITH D.Cyclone collection efficiency:comparison of experimental results with theoretical predictions[J]. Aerosol Science and Technology,1958,4(4):401—415.
[2]JO Y,TIEN C,RAY M B.Development of a post cyclone to improve the efficiency of reverse flow cyclone[J]. Powder Technology,2000,113(1/2):97—108.
[3]CHMIELNIAK T,BRYCZKOWSKI A. Method of calculation of a new cyclone-type separator with swirling baffle and bottom take off of clean gas—part I:theoretical approach[J]. Chemical Engineering and Processing:Process Intensification,2000,39(5):441—448.
[4]CHMIELNIAK T,BRYCZKOWSKI A. Method of calculation of new cyclone-type separator with swirling baffle and bottom take off of clean gas-part II:experimental verification[J]. Chemical Engineering and Processing:Process Intensification,2001,40(3):245-254.
[5]LI Q,XU W W,WANG J J,et al.Performance evaluation of a new cyclone separator—part I:experimental results[J].Separation and Purification Technology,2015,141:53—58.
[6]LI Q,XU W W,WANG J J,et al.Performance evaluation of a new cyclone separator-part II simulation results[J]. Separation and Purification Technology,2015,160:112—116.
[7]PEI B B,LIU Y,DONG K J,et al.The effect of cross-shaped vortex finder on the performance of cyclone separator[J]. Powder Technology,2017,313:135—144.
[8]陈海焱.涡轮除尘技术[J].现代化工,2003,23(1):49-51.CHEN H Y.Technique of turbine dusting[J]. Modem Chemical Industry,2003,23(1):49—51.(In Chinese)
[9]潘传九,靳兆文,冯秀.旋风分离器的螺旋导流和防返混[J].化工进展,2012,31(6):1215—1219.PAN C J,JIN Z E,FENG X.Research on the spiral guiding and the back-mixing preventing of cyclone separating devices[J].Chemical Industry and Engineering Progress,2012,31(6):1215—1219.(In Chinese)
[10]孙一坚,沈恒根.工业通风[M].4版.北京:中国建筑工业出版社,2010:77—79.SUN Y J,SHEN H G.Industrial ventilation[M].4th ed.Beijing:China Architecture&Building Press,2010:77—79.(In Chinese)
[11]STAIRMAND C J. The design and performance of cyclone separators[J]. Transactions of the Institution of Chemical Engineers,1951,29:356—383.
[12]XIANG R B,LEE K W.Numerical study of flow field in cyclones of different height[J].Chemical Engineering and Process,2005,44:877-883.
[13]LEE J W,YANG H J,LEE D Y. Effect of the cylinder shape of a long-coned cyclone on the stable flow-field establishment[J].Powder Technology,2006,165:30—38.
[14]CORTES C,GIL A. Modeling the gas and particle flow inside cyclone separators[J].Progress in Energy&Combustion Science,2007,33(5):409-452.
[15]VANDOORMAAL J P,RAITHBY G D. Enhancements of the SIMPLE method for predicting incompressible fluid flows[J].Numerical Heat Transfer Applications,1984,7:147—163.
[16]RAOUFI A,SHAMS M,FARZANEH M,et al.Numerical simulation and optimization of fluid flow in cyclone vortex finder[J].Chemical Engineering and Processing:Process Intensification,2008,47(1):128—137.
[17]MORSI S A,ALEXANDER A J. An investigation of particle trajectories in two-phase flow systems[J]. Journal of Fluid Mechanics,1972,55(2):193—208.
[18]RAOUFI A,SHAMS M,FARZANEH M,et al.Numerical simulation and optimization of fluid flow in cyclone vortex finder[J].Chemical Engineering and Processing:Process Intensification,2008,47(1):128—137.
[19]WEI J,ZHANG H,WANG Y,et al.The gas-solid flow characteristics of cyclones[J].Powder Technology,2017,308:178—192.
[20]CHEN J,CHU K,ZOU R,et al. Systematic study of the effect of particle density distribution on the flow and performance of a dense medium cyclone[J].Power Technology,2017,314:510—523.
[21]DIRGO J,LEITH D.Cyclone collection efficiency:comparison of experimental results with theoretical predictions[J]. Aerosol Science and Technology,1958,4(4):401—415.