Computational fluid dynamics modeling of effect of dipleg geometry on separation efficiency of a square cyclone

Document Type : Research Article


Department of Mechanical Engineering, Nour Branch, Islamic Azad University, Nour, Iran


In the present work, an effective way is introduced to improve the efficiency of a square cyclone separator. For this aim, a dipleg is attached under the square cyclone to investigate its geometry effect on the performance of square cyclone separator. A three-dimensional computational fluid dynamics simulation is done by solving the Reynolds averaged Navier Stokes equations with the Reynolds stress model turbulence model and using the Eulerian-Lagrangian two phase method. The particle dispersion due to turbulence in the gas phase is predicted using the discrete random Walk model. The predicted results show that using a dipleg although produces an increase in pressure drop but it positively enhances the separation efficiency of the square cyclone. In the present results, the pressure drop is increased by about 19% by using dipleg at an inlet velocity of 28 m/s. Using dipleg significantly increases the separation efficiency of square cyclone especially at higher inlet velocity. This can be more obvious when using dipleg 1 which is minimized the 50% cut size of square cyclone by about 35.5%. Also, in higher inlet velocity, the reduction value of 50% cut size is higher which is proved that using dipleg is more effective due to stronger swirl flow.


Main Subjects

W. P. Martignoni, S. Bernardo, C. L. Quintani, Evaluation of cyclone geometry and its influence on performance parameters by computational fluid dynamics (CFD), Brazilian journal of chemical engineering, 24(1) (2007) 83-94.
F. Zhou, G. Sun, X. Han,  Y. Zhang, W. Bi, Experimental and CFD study on effects of spiral guide vanes on cyclone performance, Advanced Powder Technology, 29(12) (2018) 3394-3403.
A. C. Hoffmann, M. De Groot, W. Peng, H. W. Dries, J. Kater, Advantages and risks in increasing cyclone separator length, AIChE journal, 47(11) (2001) 2452-2460.
M. Shin, H. Kim, D. Jang, J. Chung, M. Bohnet, A numerical and experimental study on a high efficiency cyclone dust separator for high temperature and pressurized environments, Applied Thermal Engineering, 25(11) (2005) 1821-1835.
H. Fatahian, E. Hosseini, E. Fatahian, CFD simulation of a novel design of square cyclone with dual-inverse cone, Advanced Powder Technology, 31(4) (2020) 1748-1758.
B. Zhao, Y. Su, J. Zhang, Simulation of gas flow pattern and separation efficiency in cyclone with conventional single and spiral double inlet configuration, Chemical Engineering Research and Design, 84(12) (2006) 1158-1165.
E. Balestrin, R. Decker, D. Noriler, J. Bastos, H, Meier, An alternative for the collection of small particles in cyclones: Experimental analysis and CFD modeling, Separation and Purification Technology, 184 (2017) 54-65.
H. Safikhani, P. Mehrabian, Numerical study of flow field in new cyclone separators, Advanced Powder Technology, 27(2) (2016) 379-387.
Y. Su, A. Zheng, B. Zhao, Numerical simulation of effect of inlet configuration on square cyclone separator performance, Powder technology, 210(3) (2011) 293-303.
S. Wang, M. Fang, Z. Luo, X. Li, M. Ni, K. Cen, Instantaneous separation model of a square cyclone, Powder Technology, 102(1) (1999) 65-70.
G. Yue, X. Y. Zhang, Y. Li, The water cooled square separator with an acceleration inlet, Chinese Patent, No. 93235842 (1995) 2-15.
L. Jun-Fu, G.Yue, Q. Liu, The design and operation of 75 t/h circulating fluidized bed boiler with water cooled separator, Chinese Electrical Power, 32(4) (1999) 61-75.
J. Li, G.Yue, Q. Liu, The operation experience of a 130 t/h circulating fluidized bed boiler with water cooled square cyclone, Chinese Electrical Power, 32(4) (2001) 19-33.
L. Junfu, Z. Jiansheng, Z. Hai, L. Qing, Y. Guangxi, Performance evaluation of a 220t/h CFB boiler with water-cooled square cyclones, Fuel processing technology, 88(2) (2007) 129-135.
A. Huang, N, Maeda, D. Shibata, T. Fukasawa, H. Yoshida, H. Kuo, K. Fukui, Influence of a laminarizer at the inlet on the classification performance of a cyclone separator, Separation and Purification Technology, 174 (2017) 408-416.
H. Fatahian, E. Fatahian, M. E. Nimvari, Improving efficiency of conventional and square cyclones using different configurations of the laminarizer, Powder technology, 339 (2018) 232-243.
S. Obermair, J. Woisetschläger, G. Staudinger, Investigation of the flow pattern in different dust outlet geometries of a gas cyclone by laser Doppler anemometry, Powder Technology, 138(2) (2003) 239-251.
A. C. Hoffmann, M. De Groot, A. Hospers, The effect of the dust collection system on the flowpattern and separation efficiency of a gas cyclone, The Canadian Journal of Chemical Engineering, 74(4) (1996) 464-470.
C. Cortes, A. Gil, Modeling the gas and particle flow inside cyclone separators, Progress in energy and combustion Science, 33(5) (2007) 409-452.
A. Gil, C. Cortes, L. Romeo, J. Velilla, Gas-particle flow inside cyclone diplegs with pneumatic extraction, Powder Technology, 128(1) (2002) 78-91.
K. Elsayed, C. Lacor, The effect of the dust outlet geometry on the performance and hydrodynamics of gas cyclones, Computers & Fluids, 68 (2012) 134-147.
J. Wang, J. Bouma, H. Dries, An experimental study of cyclone dipleg flow in fluidized catalytic cracking, Powder technology, 112(3) (2000) 221-228.
S. Kim, J. Lee, J. Koh, G. Kim, S. Choi, I. Yoo, Formation and characterization of deposits in cyclone dipleg of a commercial residue fluid catalytic cracking reactor, Industrial & Engineering Chemistry Research, 51(43) (2012) 14279-14288.
F. Qian, J. Zhang, M. Zhang, Effects of the prolonged vertical tube on the separation performance of a cyclone, Journal of hazardous materials, 136(3) (2006) 822-829.
A. Zheng, Y. Su, X. Wan, Experimental study of a square-shaped separator with different inlet forms, Journal of Engineering Thermal Energy Power, 23 (2008) 293-297.
H. Safikhani, M. Akhavan-Behabadi, M. Shams, M. Rahimyan, Numerical simulation of flow field in three types of standard cyclone separators, Advanced Powder Technology, 21(4) (2010) 435-442.
F. Kaya, I. Karagoz, A. Avci, Effects of surface roughness on the performance of tangential inlet cyclone separators, Aerosol science and technology, 45(8) (2011) 988-995.
I. Karagoz, F. Kaya, CFD investigation of the flow and heat transfer characteristics in a tangential inlet cyclone, International Communications in Heat and Mass Transfer, 34(9) (2007) 1119-1126.
T. Chuah, J. Gimbun, T. Choong, A CFD study of the effect of cone dimensions on sampling aero-cyclones performance and hydrodynamics, Powder technology, 162(2) (2006) 126-132.
G. Wan, G. Sun, X. Xue, M. Shi, Solids concentration simulation of different size particles in a cyclone separator, Powder Technology, 183(1) (2008) 94-104.
K. Elsayed, C. Lacor, Optimization of the cyclone separator geometry for minimum pressure drop using mathematical models and CFD simulations, Chemical Engineering Science, 65(22) (2010) 6048-6058.
H. Fatahian, E. Fatahian, M. E. Nimvari, G. Ahmadi, Novel designs for square cyclone using rounded corner and double-inverted cones shapes, Powder Technology, 380 (2020) 67-79.
L. Huang, K. Kumar, A. S. Mujumdar, Simulation of a spray dryer fitted with a rotary disk atomizer using a three-dimensional computational fluid dynamic model, Drying Technology, 22(6) (2004) 1489-1515.
M. Azadi, M. Azadi, A. Mohebbi, A CFD study of the effect of cyclone size on its performance parameters, Journal of hazardous materials, 182(1) (2010) 835-841.
K. Elsayed, C. Lacor, Modeling and Pareto optimization of gas cyclone separator performance using RBF type artificial neural networks and genetic algorithms, Powder Technology, 217 (2012) 84-99.
B. Launder, G. Reece, W. Rodi, Progress in the development of a Reynolds-stress turbulence closure, Journal of fluid mechanics, 68(3) (1975) 537-566.
S. Wang, M. Fang, Z. Luo, X. Li, M. Ni, K. Cen, Instantaneous separation model of a square cyclone, Powder Technology, 102(1) (1999) 65-70.
A. Hoekstra, J. J. Derksen, H. E. A. Van Den Akker, An experimental and numerical study of turbulent swirling flow in gas cyclones, Chemical Engineering Science, 54(13) (1999) 2055-2065.
H. Erol, O. Turgut, R. Unal, Experimental and numerical study of Stairmand cyclone separators: a comparison of the results of small-scale and large-scale cyclones, Heat and Mass Transfer (2019) 1-14.
S. Morsi, A. J. Alexander, An investigation of particle trajectories in two-phase flow systems, Journal of Fluid mechanics, 55(2) (1972) 193-208.
A. Raoufi, M. Shams, M. Farzaneh, R. Ebrahimi, Numerical simulation and optimization of fluid flow in cyclone vortex finder, Chemical Engineering and Processing: Process Intensification, 47(1) (2008) 128-137.
B. Zhao, Y. Su, J. Zhang, Simulation of gas flow pattern and separation efficiency in cyclone with conventional single and spiral double inlet configuration, Chemical Engineering Research and Design, 84(12) (2006) 1158-1165.
S. Shukla, P. Shukla, P. Ghosh, Evaluation of numerical schemes for dispersed phase modeling of cyclone separators, Engineering Applications of Computational Fluid Mechanics, 5.(2) (2011) 235-246.
T. Mothilal, K. Pitchandi, Influence of inlet velocity of air and solid particle feed rate on holdup mass and heat transfer characteristics in cyclone heat exchanger, Journal of Mechanical Science and Technology, 29(10) (2015) 4509-4518.
C. B. Shephered, C. E. Lapple, Flow pattern and pressure drop in cyclone dust collectors, Industrial & Engineering Chemistry, 31(8) (1939) 972-984.
S. Wang, H. Li, R. Wang, X. Wang, R. Tian, Q. Sun, Effect of the inlet angle on the performance of a cyclone separator using CFD-DEM, Advanced Powder Technology, 30(2) (2019) 227-239.
Z. Liu, J. Jiao, Y. Zheng, Q. Zhang, L. Jia, Investigation of turbulence characteristics in a gas cyclone by stereoscopic PIV, AIChE journal, 52(12) (2006) 4150-4160.
A. Raoufi, M. Shams, H. Kanani, CFD analysis of flow field in square cyclones, Powder Technology, 191(3) (2009) 349-357.