蜗壳式旋风分离器内部流场空间的涡分析

doi:10.11949/j.issn.0438-1157.20170260

摘要/Abstract

摘要：

为了研究旋风分离器内部空间涡的特性，采用改进的RNG k-ε模型对单入口蜗壳式旋风分离器进行气相流场数值模拟。同时，引入Q判据识别涡的结构，并做出三维涡等值面，使空间涡的结构更加直观和具体；结果表明，利用Q判据做出的涡等值面在筒体上部区域等效直径较大，沿轴线向下，涡面等效直径逐渐减小，表明涡携带能量逐渐衰减；涡等值面并不是绕中心轴线呈规则圆周分布，而是扭曲的。在边壁处，因摩擦阻力存在，涡量急剧变小，涡的能量损失加剧。此外，涡核中心偏离几何中心的变化趋势，呈现先增大后逐渐减小直至较为平稳的过程，在此过程中，涡迅速发展，甚至破裂，产生动能损失。因此，提高涡结构的平衡，有利于改善旋流的不稳定性，降低能量损失，从而提高分离效率。

关键词: 旋风分离器, 涡结构, Q判据, 涡等值面, 涡核中心

Abstract:

To study vortex characteristics in cyclone separator, advanced RNG k-ε turbulence model was applied to numerical simulation of strongly rotational gas flow in cyclone separators with single volute inlet. In addition, Q criterion was used to identify vortex structure and to plot more obvious and highly detailed 3D iso-surface of vortex structure. The results showed that equivalent diameter of Q criterion iso-surface was large in upper cylinder and became smaller downward along the axis, indicating gradual decay of vortex-carrying energy. The vorticity iso-surface was not distributed regularly but distorted around central axis. Because of friction resistance, vorticity magnitude decreased sharply and energy lost rapidly near the wall. Furthermore, the deviation of vortex core center from geometric center exhibited a trending process of enlarging in the upper cyclone cylinder, decreasing downward along the axis gradually, and stabilizing eventually at the bottom of the cyclone cylinder. In this process, vortex developed rapidly, sometimes even ruptured, which caused loss of dynamic energy. Therefore, measures to enhance balance of vortex structure were conducive to reduce energy loss, to curb flow instability, and to increase separation efficiency.

Key words: cyclone separator, vortex structure, Q criterion, vortex iso-surface, vortex core center

中图分类号:

TQ051.8

高助威, 王江云, 王娟, 毛羽, 魏耀东. 蜗壳式旋风分离器内部流场空间的涡分析[J]. 化工学报, 2017, 68(8): 3006-3013.

GAO Zhuwei, WANG Jiangyun, WANG Juan, MAO Yu, WEI Yaodong. Vortex analysis in flow field of cyclone separator with single volute inlet[J]. CIESC Journal, 2017, 68(8): 3006-3013.

参考文献 31

[1]	KHAIRY E. Design of a novel gas cyclone vortex finder using the adjoint method[J]. Separation and Purification Technology,2015, 142:274-286.
[2]	HOFFMANN A C, JOUGE R D E, ARENDS H, et al. Evidence of the natural vortex length and its effect on the separation efficiency of gas cyclone[J]. Filtration & Separation, 1995, 32(8):799-804.
[3]	HOFFERMANN A C, PENG W, DRIES H, et al. Effect of pressure recovery vanes on the performance of a swirl tube with emphasis on the flow pattern and separation efficiency[J]. Energy Fuel, 2006, 20(4):1691-1697.
[4]	GU X F, SONG J F, WEI Y D. Experimental study of pressure fluctuation in a gas-solid cyclone separator[J]. Powder Technology, 2016, 299:217-225.
[5]	高翠芝, 孙国刚, 董瑞倩. 旋风分离器旋涡尾端测量及压力特性分析[J]. 化工学报, 2010, 61(6):1399-1405. GAO C Z, SUN G G, DONG R Q. Analysis on location and pressure of vortex end in gas cyclone[J]. CIESC Journal, 2010, 61(6):1399-1405.
[6]	姬忠礼, 时铭显. 旋风分离器内流场的测试技术[J]. 中国石油大学学报, 1991, 15(6):52-58. JI Z L, SHI M X. Flow fluid measurement in cyclone separator[J]. Journal of the China University of Petrolem, 1991, 15(6):52-58.
[7]	王娟, 毛羽, 钟安海, 等. FCC沉降器全部空间三维流场的数值模拟[J]. 石油学报(石油加工), 2007, 23(5):15-21. WANG J, MAO Y, ZHONG A H, et al. Numerical simulation of 3D turbulent flow in a FCC disengage[J]. Acta Petrolei Sinica (Petroleum Processing Section), 2007, 23(5):15-21.
[8]	梁邵青, 王铖健. 旋风分离器流场数值模拟及其涡结构识别[J]. 煤炭学报, 2014, 39(1):262-266. LIANG S Q, WANG C J. Numerical simulation of the flow field in a cyclone separator and vortex identification[J]. Journal of China Coal Society, 2014, 39(1):262-266.
[9]	TER LINDEN A J. Investigations into cyclone dust collectors[J]. Proceedings of the Institution of Mechanical Engineers, 1949, 160(1):233-251.
[10]	BOYSAN F, AYERS W H, SWITHENBANK J, et al. A fundamental mathematical modeling approach to cyclone design[J]. Transactions of the Institution of Chemical Engineers, 1982, 60:222-230.
[11]	BOYSAN F, EWAN B C R, SWITHENBANK J, et al. Experimental and Theoretical Studies of Cyclone Separator Aerodynamics[M]//Powtech Particle Technology. Elsevier, 1983:305-306.
[12]	YAZDABADI P A, GRIFFITHS A J. Alternate eddy shedding set up by the non-axisymmetric recirculation zone at the exhaust of a cyclone dust separator[J]. Trans. I. Chem. E, 1996, 74A:363-368.
[13]	STEFEN O, JAKOB W, GEMOT S. Investigation of the flow pattern in different dust outlet geometries of a gas cyclone by laser Doppler anemometry[J]. Powder Technology, 2003, 138(2/3):239-251.
[14]	DERKSEN J J, VANDEN AKKER H E A. Simulation of vortex core precession in a reverse-flow cyclone[J]. AIChE Journal, 2000, 46(7):1317-1331.
[15]	HOEKSTRA A J, ISRAEL A T, DERKSEN J J, et al. The application of laser diagnostics to cyclonic flow with vortex precession[C]//Proceedings of the 9th International Symposium on Applications of Laser Techniques to Fluid Mechanics. Lisbon, 1998:431-435.
[16]	吴小林, 熊至宜, 姬忠礼, 等. 旋风分离器旋进涡核的数值模拟[J]. 化工学报, 2007, 58(2):383-390. WU X L, XIONG Z Y, JI Z L, et al. Numerical simulation of precessing vortex core in cyclone separator[J]. Journal of Chemical Industry and Engineering (China), 2007, 58(2):383-390.
[17]	严超宇, 吴小林, 时铭显. 旋风分离器非稳态流场的简化分析[J]. 流体机械, 2002, 30(3):18-21. YAN C Y, WU X L, SHI M X. Simplified analysis of the unsteady flow field in a cyclone separator[J]. Flow Machinery, 2002, 30(3):18-21.
[18]	王江云, 毛羽, 孟文, 等. 旋风分离器内非轴对称旋转流场的测量[J]. 石油学报(石油加工), 2015, 31(4):920-928. WANG J Y, MAO Y, MENG W, et al. Experimental measurement of non-axisymmetric rotating flow field in cyclone separator[J]. Acta Petrolei Sinica (Petroleum Processing Section), 2015, 31(4):920-928.
[19]	王江云, 毛羽, 王娟, 等. FCC沉降器内粗旋与顶旋分离器连接结构的优化[J]. 石油学报(石油加工), 2008, 24(3):251-255. WANG J Y, MAO Y, WANG J, et al. Optimization of linkage structure between primary and secondary separator in FCC disengagers[J]. Acta Petrolei Sinica (Petroleum Processing Section), 2008, 24(3):251-255.
[20]	孟文, 王江云, 毛羽, 等. 排气管直径对旋风分离器非轴对称旋转流场的影响[J]. 石油学报(石油加工), 2015, 31(6):1309-1316. MENG W, WANG J Y, MAO Y, et al. Effect of vortex finder diameter on non-axisymmetric rotating flow field in cyclone separator[J]. Acta Petrolei Sinica (Petroleum Processing Section), 2015, 31(6):1309-1316.
[21]	王江云, 毛羽, 王娟. 单入口双进气道旋风分离器内流体的流动特性[J]. 石油学报(石油加工), 2011, 27(5):780-786. WANG J Y, MAO Y, WANG J. Flow characteristic in a single inlet cyclone separator with double passage[J]. Acta Petrolei Sinica (Petroleum Processing Section), 2011, 27(5):780-786.
[22]	魏耀东, 燕辉, 时铭显. 蜗壳式旋风分离器环形空间流场的研究[J]. 石油炼制与化工, 2000, 31(11):46-50. WEI Y D, YAN H, SHI M X.Study on flow in the annular space of a cyclone separator with a volute inlet[J]. Petroleum Processing and Petrochemical, 2000, 31(11):46-50.
[23]	魏耀东, 张静, 宋健斐, 等. 旋风分离器自然旋风长的试验研究[J]. 热能动力工程, 2010, 25(2):206-209. WEI Y D, ZHANG J, SONG J F, et al. Experimental study of natural cyclone length of a cyclone separator[J]. Journal of Engineering for Thermal Energy and Power, 2010, 25(2):206-209.
[24]	毛羽, 庞磊, 王小伟, 等. 旋风分离器内三维紊流场的数值模拟[J]. 石油炼制与化工, 2002, 33(2):1-6. MAO Y, PANG L, WANG X W, et al. Numerical modeling of three-dimension turbulent field in cyclone separator[J]. Petroleum Processing and Petrochemical, 2002, 33(2):1-6.
[25]	YAKHOT V, ORZAG S A. Renormalization group analysis of turbulence:basic theory[J]. Journal of Scientific Computing, 1986, 1:3-11
[26]	IRFAN K, FUAT K. CFD investigation of the flow and heat transfer characteristics in a tangential inlet cyclone[J]. International Communications in Heat and Mass Transfer, 2007, 34(9/10):1119-1126.
[27]	王江云, 毛羽, 刘美丽, 等. 用改进的RNG k-ε模型模拟旋风分离器内的强旋流动[J]. 石油学报(石油加工), 2010, 26(1):8-13. WANG J Y, MAO Y, LIU M L, et al. Numerical simulation of strongly swirling flow in cyclone separator by using an advanced RNG k-ε model[J]. Acta Petrolei Sinica (Petroleum Processing Section), 2010, 26(1):8-13.
[28]	胡子俊, 张楠, 姚惠之, 等. 涡判据在空腔旋流动拓扑结构分析中的应用[J]. 船舶力学, 2012, 12(8):839-846. HU Z J, ZHANG N, YAO H Z, et al. Vortex identification in the analysis on the topology structure of vertical flow in cavity[J]. Journal of Ship Mechanics, 2012, 12(8):839-846.
[29]	CHONG M S, PERRY A E, CANTWELL B J. A general classification of three-dimensional flow fields[J]. Phys. Fluids A, 1990, 2:765-777.
[30]	MELANDER M V, HUSSAIN F. Coupling between a coherent structure and fine-scale turbulence[J]. Phys. Rev. E, 1993, 48(4):2669-2689.
[31]	HUNT J C, WRAY A A, MOIN P. Eddies stream and convergence zones in turbulent flows[R]. Stanford:Center for Turbulence Research Report CTR-S88, 1988:193-208.