Examining the effects of velocity ratio of the pressurized flow to the main inlet flow on coagulants dispersion in pump diffusion mixer

No-Suk Park; Seong-Su Kim; Kwan-Yeop Kim; Sangyoung Park

Korean Journal of Chemical Engineering, Vol.28, No.2, 519-526, February, 2011

DOI10.1007/s11814-010-0384-3 Export Citation

Examining the effects of velocity ratio of the pressurized flow to the main inlet flow on coagulants dispersion in pump diffusion mixer

No-Suk Park^†, Seong-Su Kim, Kwan-Yeop Kim, and Sangyoung Park

Water Research Center, K-water Institute, Korea Water Resources Corporation (K-water), 462-1, Jeonmin-dong, Yusung-gu, Daejeon 305-730, Korea

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This study was conducted to evaluate the ratio of the pressurized flow to the main inlet flow, which has been considered one of the most important parameters for operating the pump diffusion mixer (PDM). Computational fluid dynamics (CFD) simulation was employed to evaluate the conventional operation rule of PDM and to propose a supplementary operating parameter and criterion. Test simulation of CFD was carried out for the 21 cases of flow ratio in a full scale PDM. The values of local velocity gradient were calculated in each case to analyze the simulation results in more detail. A wet test was conducted to verify CFD simulation results, which measures the factual coagulant dispersion distribution at a distance of 5.4 m from deflector. From results of both CFD simulation and wet test, the flow ratio was adequate as an operating parameter or criterion; also, the velocity ratio (dimensionless) of the pressurized flow to the main inlet was useful in predicting the performance of PDM. In addition, the injected coagulant could be dispersed evenly in overall cross section on the condition that the velocity ratio is at least over 20.

Keywords:Pump Diffusion Mixer;Flow Ratio;Velocity Ratio;Computational Fluid Dynamics;Wet Test

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Park NS, Park H, Kim JS, J. Water Supply: Research & Technology-AQUA- ., 52(2), 95 (2003)
Versteeg HK, Malalasekera W, An introduction to computational fluid dynamics, Prentice-Hall, New Jersey (1995)
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[1] Amirtharajah A, Mills P, J. AWWA., 74(5), 210 (1994)

[2] Hudson HE, Wolfner JP, J. AWWA., 59(10), 1257 (1967)

[3] Vrale L, Jorden RM, J. AWWA., 63(1), 52 (1971)

[4] Kawamura S, Integrated design of water treatment facilities., John Wiley & Sons (1991)

[5] Kim HC, Lee S, Sep. Purif. Technol., 52(1), 117 (2006)

[6] Clark MM, Srivastava RM, Lang RR, Trussell RR, McCollum LJ, Bailey D, Christie JD, Stolarik G, Selection and design of mixing processes for coagulation., AWWA Research Foundation, Denver, USA (1994)

[7] ANSYS, CFX 10.0 Application manual, Oxfordshire, United Kingdom (2006)

[8] Park NS, Park H, Kim JS, J. Water Supply: Research & Technology-AQUA- ., 52(2), 95 (2003)

[9] Versteeg HK, Malalasekera W, An introduction to computational fluid dynamics, Prentice-Hall, New Jersey (1995)

[10] Park NS, Park H, Water Sci.Technol.: Water Supply., 2(5-6), 47 (2002)