旋风分离器有无灰斗对气相流场动态特性的影响
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摘要
旋风分离器底端的排尘口依据气固分离工艺的要求分别采用有灰斗或无灰斗结构。但灰斗是否存在对旋风分离器内部流场影响的研究尚显不足。为此,采用热线风速仪对排尘口有灰斗和无灰斗的旋风分离器气相流场的切向速度进行了测量。结果表明旋风分离器内旋转流具有较强的不稳定性,表现为瞬时切向的速度低频高幅值波动变化。灰斗的存在进一步导致了排尘口附近瞬时切向速度的强烈波动。通过对瞬时切向速度的频谱分析表明,有灰斗结构的旋风分离器瞬时切向速度有2个主频,分别是存在于整个空间的全空间主频和出现在锥体下端排尘口附近区域的局部主频。无灰斗结构的旋风分离器仅有1个全空间主频。全空间主频是气体旋流中心围绕旋风分离器几何中心摆动造成的,而局部主频是灰斗气体回流造成的。灰斗气体回流主频与全空间旋转流摆动的主频叠加形成了锥体下端排尘口附近区域瞬时切向速度的2个主频。
The dust exhaust port at the bottom end of the cyclone separator adopts an ash or ashless bucket structure according to the requirements of the gas-solid separation process. The existence of the hopper has an important influence on the flow field inside the cyclone separator, and then the separating performance. But the research of this aspect is few. Therefore, the tangential velocity of gas flow field in the cyclone separator with and without hopper was measured by using hot wire anemometry(HWA). The results show that the swirling flow in the cyclone is highly instability, and the real tangential velocity fluctuates with low frequency and high amplitude.Further, the existence of hopper leads to strong instability of swirling flow field near the dust outlet, which is characterized by intense fluctuation of real tangential velocity. Fast Fourier transform analysis of measured data shows that the real tangential velocity of cyclone separator with hopper has two dominant frequencies, one exists in the whole space and another one presents in the local area near the dust outlet. However there is only one dominant frequency in the whole space of the cyclone without hopper. The dominant frequency of the whole space is caused by the swing of the swirling flow center around the geometric center, while the local dominant frequency is caused by the backflow from the hopper. So, the swing of the swirling flow from the hopper is superimposed on the swing of the swirling flow in the separation space, which forms two dominant frequencies near the dust outlet region.
The dust exhaust port at the bottom end of the cyclone separator adopts an ash or ashless bucket structure according to the requirements of the gas-solid separation process. The existence of the hopper has an important influence on the flow field inside the cyclone separator, and then the separating performance. But the research of this aspect is few. Therefore, the tangential velocity of gas flow field in the cyclone separator with and without hopper was measured by using hot wire anemometry(HWA). The results show that the swirling flow in the cyclone is highly instability, and the real tangential velocity fluctuates with low frequency and high amplitude.Further, the existence of hopper leads to strong instability of swirling flow field near the dust outlet, which is characterized by intense fluctuation of real tangential velocity. Fast Fourier transform analysis of measured data shows that the real tangential velocity of cyclone separator with hopper has two dominant frequencies, one exists in the whole space and another one presents in the local area near the dust outlet. However there is only one dominant frequency in the whole space of the cyclone without hopper. The dominant frequency of the whole space is caused by the swing of the swirling flow center around the geometric center, while the local dominant frequency is caused by the backflow from the hopper. So, the swing of the swirling flow from the hopper is superimposed on the swing of the swirling flow in the separation space, which forms two dominant frequencies near the dust outlet region.
引文
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[2] Swamee P K, Aggarwal N, Bhobhiya K. Optimum design of cyclone separator[J]. AIChE Journal, 2010, 55(10):2279-2283.
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[4]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-averaged flow structure in cyclone separator with volute inlet[J]. Journal of Chemical Industry and Engineering(China), 2003, 54(4):549-556.
[5]吴小林,姬忠礼,田彦辉,等. PV型旋风分离器内流场的试验研究[J].石油学报(石油加工), 1997, 13(3):93-99.Wu X L, Ji Z L, Tian Y H, et al. Experimental study on flow field of PV type cyclone separator[J]. Acta Petrolei Sinica(Petroleum Processing Section), 1997, 13(3):93-99.
[6] Hu L, Zhou L, Zhang J, et al. Studies on strongly swirling flows in the full space of a volute cyclone separator[J]. AIChE Journal,2010, 51(3):740-749.
[7]高雪琦,金有海,许伟伟,等.结构参数对小型旋风分离器分离性能的影响[J].中国粉体技术, 2017, 23(2):1-5.Gao X Q, Jin Y H, Xu W W, et al. Numerical study on separation performance of small cyclone separator with different structure parameters[J]. China Powder Science and Technology, 2017, 23(2):1-5.
[8]魏耀东,宋健斐,陈建义,等.旋风分离器内气相流场的相似模化分析(Ⅰ):流动参数[J].化工学报, 2010, 61(9):2265-2273.Wei Y D, Song J F, Chen J Y, et al. Similarity analysis on modeling of gas phase flow field in cyclone separator(Ⅰ):Flow parameters[J]. CIESC Journal, 2010, 61(9):2265-2273.
[9] Brar L S, Sharma R P, Elsayed K. The effect of the cyclone length on the performance of Stairmand high-efficiency cyclones[J].Powder Technology, 2015, 286:668-677.
[10] Elsayed K, Lacor C. The effect of cyclone vortex finder dimensions on the flow pattern and performance using LES[J].Computers&Fluids, 2013, 71:224-239.
[11] 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(1):30-38.
[12] Safikhani H, Zamani J, Musa M. Numerical study of flow field in new design cyclone separators with one, two and three tangential inlets[J]. Advanced Powder Technology, 2018, 29(3):611-622.
[13]高翠芝,孙国刚,董瑞倩.排气管对旋风分离器轴向速度分布形态影响的数值模拟[J].化工学报, 2010, 61(9):2409-2416.Gao C Z, Sun G G, Dong R Q. Effect of vortex finder on axial velocity distribution patterns in cyclones[J]. CIESC Journal, 2010,61(9):2409-2416.
[14] Parvaz F, Hosseini S H, Ahmadi G, et al. Impacts of the vortex finder eccentricity on the flow pattern and performance of a gas cyclone[J]. Separation&Purification Technology, 2017, 187:1-13.
[15]钱付平,章名耀.不同排尘结构旋风分离器的分离特性[J].燃烧科学与技术, 2006, 2:169-174.Qian F P, Zhang M Y. Separation characteristics of cyclone separators with different dust outlet geometries[J]. Journal of Combustion Science and Technology, 2006, 2:169-174.
[16] Obermair S, Woisetschl?ger J, Staudinger G. Investigation of the flow pattern in different dust outlet geometries of a gas cyclone by laser Doppler anemometry[J]. Powder Technology, 2003, 138(2):239-251.
[17] Gioliu S, Aldo C. Experimental fluid dynamic characterization of a cyclone chamber[J]. Experimental Thermal&Fluid Science,2002, 27(1):87-96.
[18]王甜,徐俊,宋健斐,等.旋风分离器内旋转流的不稳定性[J].化工学报, 2010, 61(2):317-322.Wang T, Xu J, Song J F, et al. Instability of swirling flow in cyclone[J]. CIESC Journal, 2010, 61(2):317-322.
[19]宋健斐,王甜,徐国,等. D300 mm×2000 mm圆管内旋转流切向速度特征的实验研究[J].实验流体力学, 2010, 24(6):41-46.Song J F, Wang T, Xu G, et al. Experimental study of the real tangential velocity in the circular pipe with D300mm×2000mm by HWA[J]. Journal of Experiments in Fluid Mechanics, 2010, 24(6):41-46.
[20]蔡香丽,杨智勇,马玉苗,等.旋风分离器内旋转流湍流特性的实验分析[J].石油学报(石油加工), 2015, 31(4):983-990.Cai X L, Yang Z Y, Ma Y M, et al. Experimental analysis of turbulence characteristics of swirling flow in cyclone[J]. Acta Petrolei Sinica(Petroleum Processing Section), 2015, 31(4):983-990.
[21] Liu Z, Jiao J, Zheng Y, et al. Investigation of turbulence characteristics in a gas cyclone by stereoscopic PIV[J]. AIChE Journal, 2010, 52(12):4150-4160.
[22] Wu X L, Shi M X. Visualization of the precessing vortex core in a cyclone separator by PIV[J]. Chinese Journal of Chemical Engineering, 2003, 11(6):633-637.
[23] Gu X, Song J, Wei Y. Experimental study of pressure fluctuation in a gas-solid cyclone separator[J]. Powder Technology, 2016,299:217-225.
[24]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.
[25]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.
[26]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.
[27]龙薪羽,刘根凡,毛锐,等.旋风分离器旋进涡核的大涡数值模拟[J].石油学报(石油加工), 2016, 32(4):734-740.Long X Y, Liu G F, Mao R, et al. Large eddy simulation of vortex core processing in cyclone separator[J]. Acta Petrolei Sinica(Petroleum Processing Section), 2016, 32(4):734-740.
[28] Lakhbir S B, Khairy E. Analysis and optimization of multi-inlet gas cyclones using large eddy simulation and artificial neural network[J]. Powder Technology, 2017, 311:465-483.
[29] Derksen J J, van den Akker H E A. Simulation of vortex core precession in a reverse-flow cyclone[J]. AIChE Journal, 2000, 46(7):1317-1331.
[30]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.
[31] Qian F, Zhang J, Zhang M. Effects of the prolonged vertical tube on the separation performance of a cyclone[J]. Journal of Hazardous Materials, 2006, 136(3):822-829.
[32] Obermair S, Woisetschl?ger J, Staudinger G. 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.
[33] Hoffmann A C, Groot M D, Hospers A. The effect of the dust collection system on the flow pattern and separation efficiency of a gas cyclone[J]. The Canadian Journal of Chemical Engineering,1996, 74(4):464-470.
[34] Elsayed K, Lacor C. The effect of the dust outlet geometry on the performance and hydrodynamics of gas cyclones[J]. Computers&Fluids, 2012, 68(68):134-147.
[2] Swamee P K, Aggarwal N, Bhobhiya K. Optimum design of cyclone separator[J]. AIChE Journal, 2010, 55(10):2279-2283.
[3] Hoekstra A 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(s13/14):2055-2065.
[4]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-averaged flow structure in cyclone separator with volute inlet[J]. Journal of Chemical Industry and Engineering(China), 2003, 54(4):549-556.
[5]吴小林,姬忠礼,田彦辉,等. PV型旋风分离器内流场的试验研究[J].石油学报(石油加工), 1997, 13(3):93-99.Wu X L, Ji Z L, Tian Y H, et al. Experimental study on flow field of PV type cyclone separator[J]. Acta Petrolei Sinica(Petroleum Processing Section), 1997, 13(3):93-99.
[6] Hu L, Zhou L, Zhang J, et al. Studies on strongly swirling flows in the full space of a volute cyclone separator[J]. AIChE Journal,2010, 51(3):740-749.
[7]高雪琦,金有海,许伟伟,等.结构参数对小型旋风分离器分离性能的影响[J].中国粉体技术, 2017, 23(2):1-5.Gao X Q, Jin Y H, Xu W W, et al. Numerical study on separation performance of small cyclone separator with different structure parameters[J]. China Powder Science and Technology, 2017, 23(2):1-5.
[8]魏耀东,宋健斐,陈建义,等.旋风分离器内气相流场的相似模化分析(Ⅰ):流动参数[J].化工学报, 2010, 61(9):2265-2273.Wei Y D, Song J F, Chen J Y, et al. Similarity analysis on modeling of gas phase flow field in cyclone separator(Ⅰ):Flow parameters[J]. CIESC Journal, 2010, 61(9):2265-2273.
[9] Brar L S, Sharma R P, Elsayed K. The effect of the cyclone length on the performance of Stairmand high-efficiency cyclones[J].Powder Technology, 2015, 286:668-677.
[10] Elsayed K, Lacor C. The effect of cyclone vortex finder dimensions on the flow pattern and performance using LES[J].Computers&Fluids, 2013, 71:224-239.
[11] 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(1):30-38.
[12] Safikhani H, Zamani J, Musa M. Numerical study of flow field in new design cyclone separators with one, two and three tangential inlets[J]. Advanced Powder Technology, 2018, 29(3):611-622.
[13]高翠芝,孙国刚,董瑞倩.排气管对旋风分离器轴向速度分布形态影响的数值模拟[J].化工学报, 2010, 61(9):2409-2416.Gao C Z, Sun G G, Dong R Q. Effect of vortex finder on axial velocity distribution patterns in cyclones[J]. CIESC Journal, 2010,61(9):2409-2416.
[14] Parvaz F, Hosseini S H, Ahmadi G, et al. Impacts of the vortex finder eccentricity on the flow pattern and performance of a gas cyclone[J]. Separation&Purification Technology, 2017, 187:1-13.
[15]钱付平,章名耀.不同排尘结构旋风分离器的分离特性[J].燃烧科学与技术, 2006, 2:169-174.Qian F P, Zhang M Y. Separation characteristics of cyclone separators with different dust outlet geometries[J]. Journal of Combustion Science and Technology, 2006, 2:169-174.
[16] Obermair S, Woisetschl?ger J, Staudinger G. Investigation of the flow pattern in different dust outlet geometries of a gas cyclone by laser Doppler anemometry[J]. Powder Technology, 2003, 138(2):239-251.
[17] Gioliu S, Aldo C. Experimental fluid dynamic characterization of a cyclone chamber[J]. Experimental Thermal&Fluid Science,2002, 27(1):87-96.
[18]王甜,徐俊,宋健斐,等.旋风分离器内旋转流的不稳定性[J].化工学报, 2010, 61(2):317-322.Wang T, Xu J, Song J F, et al. Instability of swirling flow in cyclone[J]. CIESC Journal, 2010, 61(2):317-322.
[19]宋健斐,王甜,徐国,等. D300 mm×2000 mm圆管内旋转流切向速度特征的实验研究[J].实验流体力学, 2010, 24(6):41-46.Song J F, Wang T, Xu G, et al. Experimental study of the real tangential velocity in the circular pipe with D300mm×2000mm by HWA[J]. Journal of Experiments in Fluid Mechanics, 2010, 24(6):41-46.
[20]蔡香丽,杨智勇,马玉苗,等.旋风分离器内旋转流湍流特性的实验分析[J].石油学报(石油加工), 2015, 31(4):983-990.Cai X L, Yang Z Y, Ma Y M, et al. Experimental analysis of turbulence characteristics of swirling flow in cyclone[J]. Acta Petrolei Sinica(Petroleum Processing Section), 2015, 31(4):983-990.
[21] Liu Z, Jiao J, Zheng Y, et al. Investigation of turbulence characteristics in a gas cyclone by stereoscopic PIV[J]. AIChE Journal, 2010, 52(12):4150-4160.
[22] Wu X L, Shi M X. Visualization of the precessing vortex core in a cyclone separator by PIV[J]. Chinese Journal of Chemical Engineering, 2003, 11(6):633-637.
[23] Gu X, Song J, Wei Y. Experimental study of pressure fluctuation in a gas-solid cyclone separator[J]. Powder Technology, 2016,299:217-225.
[24]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.
[25]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.
[26]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.
[27]龙薪羽,刘根凡,毛锐,等.旋风分离器旋进涡核的大涡数值模拟[J].石油学报(石油加工), 2016, 32(4):734-740.Long X Y, Liu G F, Mao R, et al. Large eddy simulation of vortex core processing in cyclone separator[J]. Acta Petrolei Sinica(Petroleum Processing Section), 2016, 32(4):734-740.
[28] Lakhbir S B, Khairy E. Analysis and optimization of multi-inlet gas cyclones using large eddy simulation and artificial neural network[J]. Powder Technology, 2017, 311:465-483.
[29] Derksen J J, van den Akker H E A. Simulation of vortex core precession in a reverse-flow cyclone[J]. AIChE Journal, 2000, 46(7):1317-1331.
[30]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.
[31] Qian F, Zhang J, Zhang M. Effects of the prolonged vertical tube on the separation performance of a cyclone[J]. Journal of Hazardous Materials, 2006, 136(3):822-829.
[32] Obermair S, Woisetschl?ger J, Staudinger G. 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.
[33] Hoffmann A C, Groot M D, Hospers A. The effect of the dust collection system on the flow pattern and separation efficiency of a gas cyclone[J]. The Canadian Journal of Chemical Engineering,1996, 74(4):464-470.
[34] Elsayed K, Lacor C. The effect of the dust outlet geometry on the performance and hydrodynamics of gas cyclones[J]. Computers&Fluids, 2012, 68(68):134-147.