Study and Investigation of Secondary Sedimentation Tank Equipped with Lamella using Discrete Phase Model (DPM)

Authors

1 M.Sc. Graduate , Energy Conversion Department,Mechanical Engineering Faculty, Tarbiat Modares University, Tehran, Iran

2 Assoc. Prof., Energy Conversion Department, Mechanical Engineering Faculty, Tarbiat Modares University, Tehran, Iran

Abstract

Water softening and preventing of scaling in evaporators are very important in industrial water treatment processes. Lamella clarifiers improve the treatment process and decrease its related costs. In the present study, by using a CFD approach, the flow inside the sedimentation tank equipped with lamella has been studied. By using the Discrete Phase Model (DPM) and due to the two-way coupling between the main phase (fluid) and the discrete phase (particles), the particles motion has been traced. The turbulence model k-ε RNG is used to simulate the flow inside the sedimentation tank. The influence of employing lamella plates and their inclination angle as well as size of particles have been conducted. Results showed that using lamella inside the tank, by tuning the rising velocity of water, turbulent flow energy, and reduction of the rotational area volume, leads to increase of the tank particle removal efficiency by 6.47 percent. In addition, the presence of lamella causes a stability in the removal efficiency of sedimentation tank at different flow rates. A parametric study with the aim of investigating the effect of different angles of lamella on the tank efficiency shows that changing the angles of the plates from 60 to 45 degrees increases the efficiency by 14.66 percent.

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Main Subjects

References

[1] پورموید ع، رحمتی ر، برخورداری هـ (1396) آنالیز تولید آنتروپی موضعی برای یک آب شیرین‌کن خورشیدی شیب‌دار یک طرفه (بررسی عددی). مجله علمی پژوهشی مکانیک سازه‌ها و شاره‌ها 291-279 :(4)7.
[2] پورموید ع، رحمتی ر، غلامی م (1397) یک مدل‌ جدید برای جریان دو فازی درون یک آب شیرین کن خورشیدی اصلاح شده با یک لایه متخلخل. مجله علمی پژوهشی مکانیک   سازه­ها و شاره‌ها 182-171 :(1)8.
[3] Plum V, Dahl CP, Bentsen L, Petersen CR, Napstjert L, Thomsen N (1998) The actiflo method. Water Sci Technol 37(1): 269-275.
[4] Tarpagkou R, Pantokratoras A (2014) The influence of lamellar settler in sedimentation tanks for potable water treatment—a computational fluid dynamic study. Powder Technol 268: 139-149.
[5] Ueberl J, Hager WH (1997) Improved design of final settling tanks. J Environ Eng 123(3): 259-268.
[6] Asgharzadeh H, Firoozabadi B, Afshin H (2011) Experimental investigation of effects of baffle configurations on the performance of a secondary sedimentation tank. Scientia Iranica 18(4): 938-949.
[7] Goula AM, Kostoglou M, Karapantsios TD, Zouboulis AI (2008) The effect of influent temperature variations in a sedimentation tank for potable water treatment—A computational fluid dynamics study. Water Res 42(13): 3405-3414.
[8] Tamayol A, Firouzabadi B (2006) Effects of turbulent models and baffle position on the hydrodynamics of settling tanks.
[9] Tarpagkou R, Pantokratoras A (2013) CFD methodology for sedimentation tanks: The effect of secondary phase on fluid phase using DPM coupled calculations. Appl Math Model 37(5): 3478-3494.
[10] Liu Y, Zhang P, Wei WJD, Treatment W (2016) Simulation of effect of a baffle on the flow patterns and hydraulic efficiency in a sedimentation tank. 57(54): 25950-25959.
[11] Shahrokhi M, Rostami F, Said MAM (2013) Numerical modeling of baffle location effects on the flow pattern of primary sedimentation tanks. Appl Math Model 37(6): 4486-4496.
[12] Ramin E et al. (2014) A new settling velocity model to describe secondary sedimentation. 66: 447-458.
[13] Gkesouli A, Stamou AJEW (2017) CFD modelling of wind effect on rectangular settling tanks of water treatment plants. 58: 61-67.
[14] Deldar S, Jafarian Dehkordi A, Kharinezhad Arani HJTPNMS (2018) Investigating the effect of flow entrance and existence of baffle on sedimentation efficiency using Discrete Phase Model (DPM). 6: 29-36.
[15] Saleh AM, Hamoda MF (1999) Upgrading of secondary clarifiers by inclined plate settlers. Water Sci Technol 40(7): 141-149.
[16] Sarkar S, Kamilya D, Mal B (2007) Effect of geometric and process variables on the performance of inclined plate settlers in treating aquacultural waste. Water Res 41(5): 993-1000.
[17] Salah AL-kizwini R (2015) Improvement of sedimentation process using inclined plates. Mesop Environ J 2(1): 100-114.
[18] Gouesbet G, Berlemont AJPIE, Science C (1999) Eulerian and lagrangian approaches for predicting the behaviour of discrete particles in turbulent flows. 25(2): 133-159.
[19] Mahdavimanesh M, Noghrehabadi A, Behbahaninejad M, Ahmadi G, Dehghanian MJLSJ (2013) Lagrangian particle tracking: Model development. 10(8s): 34-41.
[20] Song G, Song B, Guo Z, Yang Y, MJM Song (2018) Separation of non-metallic inclusions from a Fe-Al-O melt using a super-gravity field. 49(1): 34-44.
[21] Odar F, Hamilton WSJJOFM (1964) Forces on a sphere accelerating in a viscous fluid. 18(2): 302-314.
[22] Choudhury D (1973) Introduction to the renormalization group method and turbulence modeling. Fluent incorporated.
[23] Graham D, James PJIJOMF (1996) Turbulent dispersion of particles using eddy interaction models. 22(1): 157-175.
[24] Hendricks DW (2006) Water treatment unit processes: physical and chemical. CRC press.
[25] Jover-Smet M, Martín-Pascual J, Trapote AJW (2017) Model of suspended solids removal in the primary sedimentation tanks for the treatment of urban wastewater. 9(6): 448.
Journal of Solid and Fluid Mechanics
Volume 9, Issue 1
April 2019
Pages 173-186

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