旋流板塔内两相流场的CFD模拟与分析
|
摘要
旋流板塔(RST)是浙江大学发明的一种高效通用型传质设备，其综合性能优于国外常用的吸收器，作为主设备已成功应用于大中型燃煤工业锅炉的烟气脱硫除尘工程上。旋流塔板上的气液运动是决定塔板效率的主要因素，因此研究气液两相流场将对塔板操作的优化及结构的放大具有重要而现实的指导意义。
本文以商用软件FLUENT为求解软件，拥有双CPU及2G内存的服务器为硬件基础，生成了含有大量网格的Φ150mm和Φ34000mm的旋流板塔的三维模型，用双方程RNG K-ε湍流模型、Eulerian多相流模型和Granular流体模型，对RST内气液运动进行了较为深入的仿真研究。
研究并优化了旋流板塔的绘制方法与网格的生成，为本文模拟所涉及的各种小型、大型及各种板型参数的RST生成了计算所需的三维网格。
用双方程RNG K-ε模型模拟湍流，Eulerian模型模拟气液两相流动，得到了Φ150mm及Φ4000mmRST内一定空塔气速下两相流场的分布及特征，发现RST经放大后液相流场分布的一些问题。
通过改进数学模型，引进Granular流体模型对液体的湍流粘性进行修正，并选用相应的流体-固体交换系数，选用几种特定的液滴粒径，得到了Φ150mm及Φ34000mmRST内更为合理的流场分布结果，发现大型RST内气液流场受液滴粒径影响较大，对较小颗粒(小于300μm)的去除能力较小型RST要低。
本文为RST内两相流场的数值模拟提供了有效的方法，模拟结果有助于旋流板塔的结构优化和放大设计。本文工作也为进一步的研究打下了良好的基础，在RST流场CFD数值模拟的基础上可以进一步进行传热及化学反应过程的CFD数值模拟研究。
Rotating-stream-tray (RST) absorber, which was invented by Zhejiang University, is a high-efficient equipment for mass transfer. Its performance is better than that of commercial absorbers used in developed countries. It has been successfully implemented in fuel gas desulfurization project for large and medium scale coal-burning boiler. The motion of the gas and liquid phases in RST absorber is the main factor affecting its efficiency. The study of the two-phase velocity field in RST absorber is very important and instructive to the further optimization of RST and the amelioration of operating conditions.
Based upon powerful computers and commercially available Computational Fluid Dynamics (CFD) software (FLUENT), 3D models of 0150mm and 04000mm RST with plenty numbers of meshes were generated and the two-phase flow fields in RST absorbers were simulated using Eulerian multiphase theory, two-equation RNG K-e turbulence model and granular flow model in this work.
Method for mesh generation of RST was studied and optimized. The computational RST models studied in this paper were strictly build and finely meshed.
Two phase flow distribution under certain operating condition in 0150mm and 04000mm RST was obtained by using RNG K-e and Eulerian model. The flow field of RST after amplify was questioned for the distribution of water being abnormal.
The model of turbulence viscosity of water phase was improved by adopting granular flow model and the model for interphase exchange coefficient was changed. After setting some characteristic droplet diameters, the new flow fields of 0150mm and 04000mm RST were obtained. It was found that the ability of removing small diameter (less than 300um) droplets of large scale RST was relatively limited.
The research carried out in this work provided an effective method for the simulation of two phase flow field in RST. The results are helpful to the structural optimization and large-scale designing. Also, the work provided the foundation for further research. Based on this foundation, the CFD simulation of heat transfer and chemical reaction process in RST can be carried out.
本文以商用软件FLUENT为求解软件，拥有双CPU及2G内存的服务器为硬件基础，生成了含有大量网格的Φ150mm和Φ34000mm的旋流板塔的三维模型，用双方程RNG K-ε湍流模型、Eulerian多相流模型和Granular流体模型，对RST内气液运动进行了较为深入的仿真研究。
研究并优化了旋流板塔的绘制方法与网格的生成，为本文模拟所涉及的各种小型、大型及各种板型参数的RST生成了计算所需的三维网格。
用双方程RNG K-ε模型模拟湍流，Eulerian模型模拟气液两相流动，得到了Φ150mm及Φ4000mmRST内一定空塔气速下两相流场的分布及特征，发现RST经放大后液相流场分布的一些问题。
通过改进数学模型，引进Granular流体模型对液体的湍流粘性进行修正，并选用相应的流体-固体交换系数，选用几种特定的液滴粒径，得到了Φ150mm及Φ34000mmRST内更为合理的流场分布结果，发现大型RST内气液流场受液滴粒径影响较大，对较小颗粒(小于300μm)的去除能力较小型RST要低。
本文为RST内两相流场的数值模拟提供了有效的方法，模拟结果有助于旋流板塔的结构优化和放大设计。本文工作也为进一步的研究打下了良好的基础，在RST流场CFD数值模拟的基础上可以进一步进行传热及化学反应过程的CFD数值模拟研究。
Rotating-stream-tray (RST) absorber, which was invented by Zhejiang University, is a high-efficient equipment for mass transfer. Its performance is better than that of commercial absorbers used in developed countries. It has been successfully implemented in fuel gas desulfurization project for large and medium scale coal-burning boiler. The motion of the gas and liquid phases in RST absorber is the main factor affecting its efficiency. The study of the two-phase velocity field in RST absorber is very important and instructive to the further optimization of RST and the amelioration of operating conditions.
Based upon powerful computers and commercially available Computational Fluid Dynamics (CFD) software (FLUENT), 3D models of 0150mm and 04000mm RST with plenty numbers of meshes were generated and the two-phase flow fields in RST absorbers were simulated using Eulerian multiphase theory, two-equation RNG K-e turbulence model and granular flow model in this work.
Method for mesh generation of RST was studied and optimized. The computational RST models studied in this paper were strictly build and finely meshed.
Two phase flow distribution under certain operating condition in 0150mm and 04000mm RST was obtained by using RNG K-e and Eulerian model. The flow field of RST after amplify was questioned for the distribution of water being abnormal.
The model of turbulence viscosity of water phase was improved by adopting granular flow model and the model for interphase exchange coefficient was changed. After setting some characteristic droplet diameters, the new flow fields of 0150mm and 04000mm RST were obtained. It was found that the ability of removing small diameter (less than 300um) droplets of large scale RST was relatively limited.
The research carried out in this work provided an effective method for the simulation of two phase flow field in RST. The results are helpful to the structural optimization and large-scale designing. Also, the work provided the foundation for further research. Based on this foundation, the CFD simulation of heat transfer and chemical reaction process in RST can be carried out.
引文
[1] 孙文寿．双程旋流板分离器三维流场的测定及其与单程旋流板分离器的比较[D]．杭州：浙江大学化学工程系，1989．
[2] 顾永祥，谭天恩．旋流塔板气液接触状态及塔板压降[J]．高校化学工程学报，1990，4(1)：39-49．
[3] 史小农，谭天恩，陈建孟．旋流塔板的操作工况及其区域划分[J]．化学工程，1994，22(5)：20-25．
[4] 汪大翠，贾缨，杜有根，鲍慧敏，谭天恩．旋流板塔的效率[J]．化工学报，1983，(3)：212-220．
[5] 顾永祥，谭天恩．旋流塔板的气相传质系数[J]．高校化学工程学报，1990，4(3)：263-272．
[6] 浙江大学化工原理组．关于旋流板除雾器在湍球塔内除雾问题的研究[J]．化学工程，1972，(4．5)：79-84．
[7] 张国干．双程叶片旋流塔板在大直径脱硫塔上的应用[J]．化肥工业，1989，16(3)：15-17．
[8] 谭天恩，汪大翚，金一中．旋流板塔的应用及其近期研究进展[J]．石油化工设备，1991，20(2)：13-16．
[9] 四川化肥总厂，浙江大学．中氮肥，1987，(1)：21．
[10] 周玉昆．湿法烟气脱硫(WFGD)的技术现状和发展趋势[J]．大气环境，1991，6(3)：10-14．
[11] 瞿治诚，黄秉忠．国外烟道气和废气脱硫的现状[J]．重庆环境科学，1983，(5)：34-44．
[12] 吴忠标，刘越，谭天恩．双碱法烟气脱硫工艺的研究[J]．环境科学学报，2001，21(5)：534-537．
[13] 晏乃强，施耀，吴忠标，李玉平，李松，谭天恩．双碱法旋流板塔烟气脱硫工艺[J]．环境科学，1998，19(5)：72-74．
[14] 浙江大学化工原理教研组．旋流板塔的试验和设计[J]．化学工程，1975，(3)：13-45．
[15] 吴忠标，谭天恩．钙基湿法烟气脱硫主要参数的影响规律[J]．中国环境科学，2000，20(6)：557-560．
[16] 吴忠标，潘学良，钟丽，施耀，谭天恩．钢渣湿法脱硫试验研究[J]．环境工程，1996，14(6)：17-22．
[17] 吴忠标，刘越，余世清，莫建松，王栋，陈春平．废大理石粉湿法烟气脱硫工
艺实验[J]．环境科学，2002，23(1)：35-44．
[18] 刘越，吴忠标，谭天恩．旋流板塔廉价脱硫剂湿法烟气脱硫工艺[J]．环境科学学报，2001，21(5)：530-533．
[19] 吴忠标，余世清．飞灰和废大理石烟气脱硫的传质一反应研究[J]．环境科学学报，2002，22(6)：768-773．
[20] 吴忠标，余世清，莫建松．己二酸强化石灰石浆液脱硫工艺过程研究[J]．高校化学工程学报，2003，17(5)：540-544．
[21] 孙文寿 吴忠标，谭天恩．旋流板塔镁强化石灰脱硫过程研究[J]．环境科学，2001，22(3)：104-107．
[22] 孙文寿，吴忠标，李悦，谭天恩．旋流板塔钠强化石灰石湿式烟气脱硫研究[J]．环境科学，2002，23(5)：105-108．
[23] 孙文寿，吴忠标，谭天恩．石灰石湿式烟气脱硫工艺中添加剂的研究[J]．环境工程，2002，19(4)：30-33．
[24] B.J. Marshall, R. Marwood, R. E. Belcher, C. J. Wood. Laser doppler anemometry and conditional sampling[J]. J. Wind Eng. 1rid Aerodyn., 1999, 79(3): 209-231.
[25] 陈建孟，谭天恩，史小农．旋流塔板上的两相流场[J]．化工学报，1993，44(5)：507-514．
[26] 陈建孟，谭天恩．旋流板上流场的LDA实验研究[J]．纪学工程，1996，24(3)：59-64．
[27] 陶文铨．数值传热学[M]．西安：西安交通大学出版社，1988．
[28] D.J. Mavriplis, Mesh generation and adaptivity for complex geometries and flows. In: Peyret R. Ed. Handbook of computational fluid mechanics[M]. London: Academic Press, 1996.
[29] J.F. Thompson. A reflection of grid generation in the 90's: trends, needs and influences[D]. Mississippi State University, Mississippi State, 1996.
[30] S.V. Patankar. Numerical heat transfer and fluid flow[M]. Washington, D.C.: Hemisphere, 1980.
[31] 陈建孟．旋流塔板上的气液运动[D]．杭州：浙江大学化学工程系，1992．
[32] D.A. Drew. S. L. Passman. Theory of multicomponent fluids: applied mathematical sciences[M]. New York: Springer, 1999.
[33] G.T. Analytis. Implementation of the renormalization group (RNG) k-ε turbulence model in GOTHIC/6.1b: solution methods and assessment[J]. Ann. Nucl. Energy, 2003, 30(3): 349-387.
[34] 周力行．湍流两相流动与燃烧的数值模拟[M]．北京：清华大学出版社，1991．
[35] R.M. Bowen. Theory of mixtures[M]. Academic Press, New York, 1976.
[36] L. Schiller, Z. Naumann. Z. Ver. Deutsch. Ing., 1935, 77:318.
[37] P.J. Coelho, M. G. Carvalho. Modelling of soot formation and oxidation in turbulent diffusion flames[J]. J. of Thermophysics and Heat Transfer, 1995, 9(4):644-652.
[38] S.A. Vasquez, V. A. Ivanov. A phase coupled method for solving multiphase problems on unstructured meshes[C]. Boston: ASME FEDSM'O0: ASME 2000 Fluids Engineering Division Summer Meeting, 2000.
[39] J.O. Hinze. Turbulence[M]. New York: McGraw-Hill Publishing Co., 1975.
[40] J.M. Weiss, J. E Maruszewski, W. A. Smith. Implicit solution of preconditioned Navier-Stokes equations using algebraic multigrid[J]. AIAA J., 1999, 37(1): 29-36.
[41] C.Y. Wen, Y. H. Yu. Mechanics of fluidization[J]. Chem. Eng. Prog. Symp. Series, 1966, 62:100-111.
[42] J. Ding, D. Gidaspow. A bubbling fluidization model using kinetic theory of granular flow[J]. AIChE J., 1990, 36(4): 523-538.
[43] C.K.K. Lun, S. B. Savage, D. J. Jeffrey, N. Chepumiy. Kinetic theories for granular flow: inelastic particles in couette flow and slightly inelastic particles in a general flow field[J]. J. Fluid Mech., 1984, 140: 223-256.
[44] D. Gidaspow, R. Bezburuah, J. Ding. Hydrodynamics of circulating fluidized beds, kinetic theory approach[A]. In Fluidization VII[C]. Proceedings of the 7th Engineering Foundation Conference on Fluidization, 1992.75-82.
[45] S. Chapman, T. G. Cowling. The mathematical theory of non-uniform gases[M]. England, Cambridge: Cambridge University Press, 3rd edition, 1990.
[46] S. Ogawa, A. Umemura, N. Oshima. On the Equation of fully fluidized granular materials[J]. J. Appl. Math. Phys., 1980, 31: 483.
[47] M. Syamlal, W. Rogers, O'Brien T. J.. MFIX documentation: volume 1, theory guide[M]. National Technical Information Service, Springfield, VA, 1993.
[48] 史惠祥．旋流塔板上气液运动及板效率模型研究[D]．杭州：浙江大学化学工程系，1994．
[2] 顾永祥，谭天恩．旋流塔板气液接触状态及塔板压降[J]．高校化学工程学报，1990，4(1)：39-49．
[3] 史小农，谭天恩，陈建孟．旋流塔板的操作工况及其区域划分[J]．化学工程，1994，22(5)：20-25．
[4] 汪大翠，贾缨，杜有根，鲍慧敏，谭天恩．旋流板塔的效率[J]．化工学报，1983，(3)：212-220．
[5] 顾永祥，谭天恩．旋流塔板的气相传质系数[J]．高校化学工程学报，1990，4(3)：263-272．
[6] 浙江大学化工原理组．关于旋流板除雾器在湍球塔内除雾问题的研究[J]．化学工程，1972，(4．5)：79-84．
[7] 张国干．双程叶片旋流塔板在大直径脱硫塔上的应用[J]．化肥工业，1989，16(3)：15-17．
[8] 谭天恩，汪大翚，金一中．旋流板塔的应用及其近期研究进展[J]．石油化工设备，1991，20(2)：13-16．
[9] 四川化肥总厂，浙江大学．中氮肥，1987，(1)：21．
[10] 周玉昆．湿法烟气脱硫(WFGD)的技术现状和发展趋势[J]．大气环境，1991，6(3)：10-14．
[11] 瞿治诚，黄秉忠．国外烟道气和废气脱硫的现状[J]．重庆环境科学，1983，(5)：34-44．
[12] 吴忠标，刘越，谭天恩．双碱法烟气脱硫工艺的研究[J]．环境科学学报，2001，21(5)：534-537．
[13] 晏乃强，施耀，吴忠标，李玉平，李松，谭天恩．双碱法旋流板塔烟气脱硫工艺[J]．环境科学，1998，19(5)：72-74．
[14] 浙江大学化工原理教研组．旋流板塔的试验和设计[J]．化学工程，1975，(3)：13-45．
[15] 吴忠标，谭天恩．钙基湿法烟气脱硫主要参数的影响规律[J]．中国环境科学，2000，20(6)：557-560．
[16] 吴忠标，潘学良，钟丽，施耀，谭天恩．钢渣湿法脱硫试验研究[J]．环境工程，1996，14(6)：17-22．
[17] 吴忠标，刘越，余世清，莫建松，王栋，陈春平．废大理石粉湿法烟气脱硫工
艺实验[J]．环境科学，2002，23(1)：35-44．
[18] 刘越，吴忠标，谭天恩．旋流板塔廉价脱硫剂湿法烟气脱硫工艺[J]．环境科学学报，2001，21(5)：530-533．
[19] 吴忠标，余世清．飞灰和废大理石烟气脱硫的传质一反应研究[J]．环境科学学报，2002，22(6)：768-773．
[20] 吴忠标，余世清，莫建松．己二酸强化石灰石浆液脱硫工艺过程研究[J]．高校化学工程学报，2003，17(5)：540-544．
[21] 孙文寿 吴忠标，谭天恩．旋流板塔镁强化石灰脱硫过程研究[J]．环境科学，2001，22(3)：104-107．
[22] 孙文寿，吴忠标，李悦，谭天恩．旋流板塔钠强化石灰石湿式烟气脱硫研究[J]．环境科学，2002，23(5)：105-108．
[23] 孙文寿，吴忠标，谭天恩．石灰石湿式烟气脱硫工艺中添加剂的研究[J]．环境工程，2002，19(4)：30-33．
[24] B.J. Marshall, R. Marwood, R. E. Belcher, C. J. Wood. Laser doppler anemometry and conditional sampling[J]. J. Wind Eng. 1rid Aerodyn., 1999, 79(3): 209-231.
[25] 陈建孟，谭天恩，史小农．旋流塔板上的两相流场[J]．化工学报，1993，44(5)：507-514．
[26] 陈建孟，谭天恩．旋流板上流场的LDA实验研究[J]．纪学工程，1996，24(3)：59-64．
[27] 陶文铨．数值传热学[M]．西安：西安交通大学出版社，1988．
[28] D.J. Mavriplis, Mesh generation and adaptivity for complex geometries and flows. In: Peyret R. Ed. Handbook of computational fluid mechanics[M]. London: Academic Press, 1996.
[29] J.F. Thompson. A reflection of grid generation in the 90's: trends, needs and influences[D]. Mississippi State University, Mississippi State, 1996.
[30] S.V. Patankar. Numerical heat transfer and fluid flow[M]. Washington, D.C.: Hemisphere, 1980.
[31] 陈建孟．旋流塔板上的气液运动[D]．杭州：浙江大学化学工程系，1992．
[32] D.A. Drew. S. L. Passman. Theory of multicomponent fluids: applied mathematical sciences[M]. New York: Springer, 1999.
[33] G.T. Analytis. Implementation of the renormalization group (RNG) k-ε turbulence model in GOTHIC/6.1b: solution methods and assessment[J]. Ann. Nucl. Energy, 2003, 30(3): 349-387.
[34] 周力行．湍流两相流动与燃烧的数值模拟[M]．北京：清华大学出版社，1991．
[35] R.M. Bowen. Theory of mixtures[M]. Academic Press, New York, 1976.
[36] L. Schiller, Z. Naumann. Z. Ver. Deutsch. Ing., 1935, 77:318.
[37] P.J. Coelho, M. G. Carvalho. Modelling of soot formation and oxidation in turbulent diffusion flames[J]. J. of Thermophysics and Heat Transfer, 1995, 9(4):644-652.
[38] S.A. Vasquez, V. A. Ivanov. A phase coupled method for solving multiphase problems on unstructured meshes[C]. Boston: ASME FEDSM'O0: ASME 2000 Fluids Engineering Division Summer Meeting, 2000.
[39] J.O. Hinze. Turbulence[M]. New York: McGraw-Hill Publishing Co., 1975.
[40] J.M. Weiss, J. E Maruszewski, W. A. Smith. Implicit solution of preconditioned Navier-Stokes equations using algebraic multigrid[J]. AIAA J., 1999, 37(1): 29-36.
[41] C.Y. Wen, Y. H. Yu. Mechanics of fluidization[J]. Chem. Eng. Prog. Symp. Series, 1966, 62:100-111.
[42] J. Ding, D. Gidaspow. A bubbling fluidization model using kinetic theory of granular flow[J]. AIChE J., 1990, 36(4): 523-538.
[43] C.K.K. Lun, S. B. Savage, D. J. Jeffrey, N. Chepumiy. Kinetic theories for granular flow: inelastic particles in couette flow and slightly inelastic particles in a general flow field[J]. J. Fluid Mech., 1984, 140: 223-256.
[44] D. Gidaspow, R. Bezburuah, J. Ding. Hydrodynamics of circulating fluidized beds, kinetic theory approach[A]. In Fluidization VII[C]. Proceedings of the 7th Engineering Foundation Conference on Fluidization, 1992.75-82.
[45] S. Chapman, T. G. Cowling. The mathematical theory of non-uniform gases[M]. England, Cambridge: Cambridge University Press, 3rd edition, 1990.
[46] S. Ogawa, A. Umemura, N. Oshima. On the Equation of fully fluidized granular materials[J]. J. Appl. Math. Phys., 1980, 31: 483.
[47] M. Syamlal, W. Rogers, O'Brien T. J.. MFIX documentation: volume 1, theory guide[M]. National Technical Information Service, Springfield, VA, 1993.
[48] 史惠祥．旋流塔板上气液运动及板效率模型研究[D]．杭州：浙江大学化学工程系，1994．