旋风分离器入口形式对内流场非稳态特性的影响

doi:10.11949/j.issn.0438-1157.20180114

摘要/Abstract

摘要：

旋进涡核（PVC）现象会削弱旋风分离器对细颗粒的捕集效率。利用数值模拟方法研究纯气相流场中涡核的运动频率和偏心程度。结果表明：随着蜗壳包角的增大，排尘口截面涡核的运动频率和偏心程度都逐渐减小，PVC现象被削弱，蜗壳包角大于270°以后，纯气相流场中的PVC现象基本消失。入口切进度对排尘口截面涡核运动特性的影响会因蜗壳包角而有所不同。相比于入口结构的对称性，涡核偏心程度与下行气流的能量损失相关性更强。下行气流的能量损失越多，下行期间汇入内旋流的气流能量越高，内旋上行气流受到的横向扰动越大，汇入气流的能量超过某一阈值后，引发涡核摆动。而涡核旋转频率受下行气流能量损失的影响则较小。

关键词: 旋风分离器, 旋进涡核, 入口结构, 偏心程度, 频率

Abstract:

The processing vortex core phenomenon (PVC) diminished the efficiency of a cyclone in capturing fine particles. In this paper, the numerical simulation method was used to study the motion frequency of vortex core and eccentricity degree from vortex core to geometrical center in a gas-flow field with a spiral inlet. Generally, the surface minimum pressure was regarded as the vortex core, and the PVC phenomenon was swung most heavily at the dust outlet section. Therefore, the variation of minimum pressure over time at dust outlet was analyzed by the fast Fourier transform (FFT), and the location of the vortex core was recorded. The results showed that the frequency and eccentricity degree at the dust outlet were gradually decreased with the increase of volute wrapping angle, and the PVC phenomenon was weakened. While the volute wrapping angle was more than 270°, the PVC phenomenon in the gas-flow field almost disappeared. The influence of the entrance cut-off on the movement characteristics of the vortex core at the dust outlet section would vary depending on the volute wrapping angle. Compared with the symmetry of the inlet structure, the eccentricity degree of vortex core was more strongly related to the energy loss of the down draft. When the energy loss of the downward airflow was greater, the energy getting from outer vortex to inner vortex zones was higher, and upward flow would suffer greater horizontal disturbances. When the energy of the incoming air flow exceeded a certain threshold value, the vortex core oscillation was induced. The vortex core rotation frequency was less affected by the energy loss of the downward airflow.

Key words: cyclone separator, processing vortex core, inlet structure, eccentricity degree, frequency

中图分类号:

TQ051.8

王璐, 张兴芳, 董振洲, 赵忠凯, 杨景轩, 郝晓刚. 旋风分离器入口形式对内流场非稳态特性的影响[J]. 化工学报, 2018, 69(8): 3488-3501.

WANG Lu, ZHANG Xingfang, DONG Zhenzhou, ZHAO Zhongkai, YANG Jingxuan, HAO Xiaogang. Effect of inlet structure on transient properties of gas flow in cyclone separator[J]. CIESC Journal, 2018, 69(8): 3488-3501.

参考文献 33

[1]	孙国刚, 时铭显. 提高旋风分离器捕集细粉效率的技术研究进展[J]. 现代化工, 2008, 28(7):64-69. SUN G G, SHI M X. Progress in improving removal efficiency of gas cyclones for fine particles[J]. Modern Chemical Industry, 2008, 28(7):64-69.
[2]	宋健斐, 魏耀东, 时铭显. 蜗壳式旋风分离器气相流场的非轴对称特性的模拟[J]. 化工学报, 2005, 56(8):1397-1402. SONG J F, WEI Y D, SHI M X. Asymmetry of gas-phase flow field in cyclone separator[J]. Journal of Chemical Industry and Engineering (China), 2005, 56(8):1397-1402.
[3]	DERKSEN J J, AKKER H E A V D. Simulation of vortex core precession in a reverse-flow cyclone[J]. AIChE Journal, 2000, 46(7):1317-1331.
[4]	DERKSEN J J. Simulations of confined turbulent vortex flow[J]. Computers & Fluids, 2005, 34(3):301-318.
[5]	高助威, 王娟, 王江云, 等. 旋风分离器内涡核摆动的特性研究[J]. 工程热物理学报, 2017, 38(12):2610-2618. GAO Z W, WANG J, WANG J Y, et al. Study of the characteristics of vortex core oscillation in cyclone separator[J]. Journal of Engineering Thermophysics, 2017, 38(12):2610-2618.
[6]	吴小林, 申屠进华, 姬忠礼. PV型旋风分离器内三维流场的数值模拟[J]. 石油学报(石油加工), 2003, 19(5):74-79. WU X L, SHENTU J H, JI Z L. Numerical simulation of three-dimension flow filed in a PV cyclone[J]. Acta Petrolei Sinica (Petroleum Processing Section), 2003, 19(5):74-79.
[7]	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.
[8]	PENG W, HOFFMANN A C, DRIES H W A, et al. Experimental study of the vortex end in centrifugal separators:the nature of the vortex end[J]. Chemical Engineering Science, 2005, 60:6919-6928.
[9]	HOEKSTRA A J, ISRAEL A T, DERKSEN J J, et al. The application of laser diagnostics to cyclonic flow with vortex precession[C]//Int. Symp. Applications of Laser Techniques to Fluid Mechanics. 1998.
[10]	HOEKSTRA J, DERKSEN J J, AKKER H E A V D. An experimental and numerical study of turbulent swirling flow in gas cyclones[J]. Chemical Engineering Science, 1999, 54(s 13/14):2055-2065.
[11]	宋健斐, 魏耀东, 时铭显. 蜗壳式旋风分离器内气相流场非轴对称特性分析[J]. 化工学报, 2007, 58(5):1091-1096. SONG J F, WEI Y D, SHI M X. Analysis of asymmetry of gas-phase flow field in volute cyclone[J]. Journal of Chemical Industry and Engineering (China), 2007, 58(5):1091-1096.
[12]	许伟伟, 金有海, 王建军. 两种不同入口形式的旋风分离器内流动分布的对比研究[J]. 流体机械, 2009, 37(10):1-6. XU W W, JIN Y H, WANG J J. Study on gas flow in tangential inlet and spiral inlet cyclone separator[J]. Fluid Machinery, 2009, 37(10):1-6.
[13]	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.
[14]	柳绮年, 贾复, 张蝶丽, 等. 旋风分离器三维流场的测定[J]. 力学学报, 1978, 14(3):182-191. LIU Q N, JIA F, ZHANG D L, et al. Measurement of 3D flow field in cyclone separator[J]. Acta Mechanica Sinica, 1978, 14(3):182-191.
[15]	姬忠礼, 时铭显. 蜗壳式旋风分离器内流场的特点[J]. 中国石油大学学报(自然科学版), 1992, 16(1):47-53. JI Z L, SHI M X. Flow field characteristics of cyclone separator with a spiral inlet[J]. Journal of China University of Petroleum (Edition of Natural Science), 1992, 16(1):47-53.
[16]	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(自然科学版), 1991, 15(6):47-53. JI Z L, SHI M X. Flow field measurement in cyclone separator[J]. Journal of China University of Petroleum (Edition of Natural Science), 1991, 15(6):47-53.
[17]	吴小林, 黄学东, 时铭显. 旋风分离器的颗粒浓度分布的实验研究[J]. 中国石油大学学报(自然科学版), 1993, 17(4):54-59. WU X L, HUANG X D, SHI M X. Experimental research on particle concentration distribution in cyclone[J]. Journal of China University of Petroleum (Edition of Natural Science), 1993, 17(4):54-59.
[18]	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 field in the annular space of a cyclone separator with a volute inlet[J]. Petroleum Processing and Petrochemicals, 2000, 31(11):46-50.
[19]	付烜, 孙国刚, 刘书贤, 等. 单、双入口旋风分离器环形空间流场的数值模拟[J]. 炼油技术与工程, 2010, 40(8):26-30. FU X, SUN G G, LIU S X, et al. Numerical simulation of flow filed in annular space of single-and double-inlet cyclone[J]. Petroleum Refinery Engineering, 2010, 40(8):26-30.
[20]	严超宇, 吴小林, 时铭显. 双入口直切式旋风分离器流场内旋进涡核现象的研究[C]//李大东, 等. 中国石油学会第四届石油炼制学术年会论文集. 北京:石油工业出版社, 2001:674-678. YAN C Y, WU X L, SHI M X. Research on the precession vortex core in the flow field of cyclone separators with double tangential inlets[C]//LI D D, et al. Proceedings of the Fourth Annual Meeting of Petroleum Refining of the Chinese Petroleum Society. Beijing:Petroleum Industry Press, 2001:674-678.
[21]	SUN G G, CHEN J Y, SHI M X. Optimization and applications of reverse-flow cyclones[J].China Particuology, 2005, 3(1):43-46.
[22]	YANG J, SUN G, GAO C Z. Effect of the inlet dimensions on the maximum-efficiency cyclone height[J]. Separation & Purification Technology, 2013, 105(105):15-23.
[23]	胡瓅元, 时铭显. 蜗壳式旋风分离器全空间三维时均流场的结构[J]. 化工学报, 2003, 54(4):549-556. HU L Y, SHI M X. Three dimensional time-average flow structure in cyclone separator with volute inlet[J]. Journal of Chemical Industry and Engineering (China), 2003, 54(4):549-556.
[24]	高翠芝, 孙国刚, 董瑞倩. 旋风分离器旋涡尾端位置的实验测量及其影响因素[J]. 石油学报(石油加工), 2011, 27(6):952-958. GAO C Z, SUN G G, DONG R Q. Analysis on location and pressure of vortex end in gas cyclone[J]. Acta Petrolei Sinica (Petroleum Processing Section), 2011, 27(6):952-958.
[25]	赵海鹏, 张秀欣. 旋风分离器涡核非稳现象的分析与研究[J]. 煤矿机械, 2004, (7):43-45. ZHAO H P, ZHANG X X. Study and analysis on the instable vortex core phenomenon in the flow field of cyclone separators[J]. Coal Mine Machinery, 2004, (7):43-45.
[26]	元少昀, 吴小林, 时铭显. 旋风分离器内旋进涡核的实验研究[J]. 化工机械, 1999, 26(5):249-252. YUAN S Y, WU X L, SHI M X. Experimental investigation on the precessing vortex core in cyclone separator[J]. Chemical Engineering & Machinery, 1999, 26(5):249-252.
[27]	GAO C Z, SUN G G, DONG R Q, et al. Characterizing the dynamic property of the vortex tail in a gas cyclone by wall pressure measurements[J]. Fuel Processing Technology, 2010, 91(8):921-926.
[28]	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.
[29]	刘爱林, 孙国刚, 时铭显, 等. 催化裂化旋风分离器型式的对比试验[J]. 石油炼制与化工, 1988, (7):18-24. LIU A L, SUN G G, SHI M X, et al. Experimental comparison of the configurations of cyclone separators for FCC unit[J]. Petroleum Processing and Petrochemicals, 1988, (7):18-24.
[30]	高翠芝, 孙国刚, 董瑞倩. 旋风分离器旋风长度的分析计算[J]. 石油学报(石油加工), 2012, 28(1):94-98. GAO C Z, SUN G G, DONG R Q. Analysis calculation of the vortex length in a gas cyclone[J]. Acta Petrolei Sinica (Petroleum Processing Section), 2012, 28(1):94-98.
[31]	窦华书, KHOO Boo Cheong. 压力驱动剪切流动中湍流转捩的准则[C]//樊菁. 第七届全国流体力学学术会议. 桂林:中国力学学会, 2012. DOU H S, KHOO B C. Criterion of turbulent transition in pressure driven flows[C]//FAN J. The 7th National Conference on Fluid Mechanics. Guilin:Chinese Society of Theoretical and Applied Mechanics, 2012.
[32]	HOFFMANN A C, GROOT M D, PENG W, et al. Advantages and risks in increasing cyclone separator length[J]. AIChE Journal, 2010, 47(11):2452-2460.
[33]	XIANG R B, LEE K W. Numerical study of flow field in cyclones of different height[J]. Chemical Engineering & Processing Process Intensification, 2005, 44(8):877-883.