Validation of a Three-Dimensional Computational Fluid Dynamics Model of a Contact Tank

Khan, Liaqat Ali; Wicklein, Edward; Teixeira, Edmilson Costa

doi:10.1061/(asce)0733-9429(2006)132:7(741)

Cited by 44 publications

(27 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The significant increase in the solution complex was associated with the decrease of the nozzles' size from 0.127 mm to 0.4 μm [9]. This would confirm the degree of accuracy of the airflow in the cascade impactor by our boundary conditions [5,16].…”

Section: Numerical Validationsupporting

confidence: 69%

See 1 more Smart Citation

The Comparison of Fluid Dynamics Parameters in an Andersen Cascade Impactor Equipped With and Without a Preseparator

et al. 2014

View full text Add to dashboard Cite

Abstract. The fluid dynamic data in Andersen cascade impactor (ACI) are still lacking. Airflows and those affected parameters can be predicted in a preseparator and Andersen cascade impactor (ACI) by computational modeling. This study developed a validated computational fluid dynamic (CFD) model of an ACI and investigated the effects of the preseparator on the CFD parameters. Validation of the computational nozzle velocity for each of the stage 0 to stage 5 of the ACI stages was found to be within a 3.56% error. The flow field indicated that the preseparator accelerated the airflow velocity at the induction tube from 1.13 to 3.71±0.09 m/s and 2.40 to 8.68±0.16 m/s (at 28.3 and 60 L/min of flow rate, respectively). The preseparator produced a nozzle's wall shear stress ranged from 0.08 to 0.34 Pa on a collection plate, while the ex-preseparator spread wall shear from the plate's center was in a range of 0.11 to 0.37 Pa (at 28.3 L/min of flow rate). Moreover, the nozzle velocities increased along the distance from the middle of the collection plate to the periphery. The CFD explained the airflow of the preseparator equipped model by accelerating the airflow along the inlet port to maximize the trapping of desirable particles and the generation of a smooth wall shear stress at the collection plate to reduce the particle reentrainment. While, the ex-preseparator generated an airflow that resulted in a higher wall shear stress occurring on the lower stages.

show abstract

Section: Numerical Validationsupporting

confidence: 69%

“…The validation of the velocities and FTC was carried out to establish the predictive abilities of the CFD models [16]. Airflow velocities across a 200-mm cube were experimented with in a wind tunnel using a probe of laser Doppler anemometers.…”

Section: Introductionmentioning

confidence: 99%

The Comparison of Fluid Dynamics Parameters in an Andersen Cascade Impactor Equipped With and Without a Preseparator

et al. 2014

View full text Add to dashboard Cite

show abstract

“…It should be mentioned here that the effects of wall roughness are not considered in this study in order to be consistent with the previously reported numerical results. However, the effects of wall roughness must be considered at the implementation of wall functions in order to compare the numerical results with the experimental results, which are available for the hydrodynamics of contact tanks [9,[24][25][26][27][28].…”

Section: Hydraulic Simulationsmentioning

confidence: 99%

Unified Analysis of Multi-Chamber Contact Tanks and Mixing Efficiency Based on Vorticity Field. Part I: Hydrodynamic Analysis

Demirel

Aral

2016

Water

View full text Add to dashboard Cite

Multi-chamber contact tanks have been extensively used in industry for water treatment to provide potable water to communities, which is essential for human health. To evaluate the efficiency of this treatment process, flow and tracer transport analysis have been used in the literature using Reynolds averaged Navier-Stokes (RANS) and large-eddy simulations (LES). The purpose of this study is two-fold. First a unifying analysis of the flow field is presented and similarities and differences in the numerical results that were reported in the literature are discussed. Second, the vorticity field is identified as the key parameter to use in separating the mean flow (jet zone) and the recirculating zones. Based on the concepts of vorticity gradient and flexion product, it is demonstrated that the separation of the recirculation zone and the jet zone, fluid-fluid flow separation, is possible. The separation of the recirculation zones and vortex core lines are characterized using the definition of the Lamb vector. The separated regions are used to characterize the mixing efficiency in the chambers of the contact tank. This analysis indicates that the recirculation zone and jet zone formation are three-dimensional and require simulations over a long period of time to reach stability. It is recognized that the characteristics of the jet zones and the recirculation zones are distinct for each chamber and they follow a particular pattern and symmetry between the alternating chambers. Hydraulic efficiency coefficients calculated for each chamber show that the chambers having an inlet adjacent to the free surface may be designed to have larger volumes than the chambers having wall bounded inlets to improve the efficiency of the contact tank. This is a simple design alternative that would increase the efficiency of the system. Other observations made through the chamber analysis are also informative in redefining the characteristics of the efficiency of the contact tank system.

show abstract

“…However, several experimental studies, which have focused on the hydrodynamics of CTs [26,28], have illustrated a complex three-dimensional (3-D) nature to the internal flow structure due to the inlet and outlet configurations. Consequently, accurate reproduction of the flow and transport in such CTs requires 3-D models ( [30]; [20]; [13,31]; [23]; [4,21]). …”

Section: Introductionmentioning

confidence: 99%

Contact Tank Design Impact on Process Performance

Angeloudis

Stoesser

Gualtieri

et al. 2016

Environ Model Assess

View full text Add to dashboard Cite

In this study three-dimensional numerical models were refined to predict reactive processes in disinfection contact tanks (CTs). The methodology departs from the traditional performance assessment of contact tanks via hydraulic efficiency indicators, as it simulates directly transport and decay of the disinfectant, inactivation of pathogens and accumulation of by-products. The method is applied to study the effects of inlet and compartment design on contact tank performance, with special emphasis on turbulent mixing and minimisation of internal recirculation and short-circuiting. In contrast to the conventional approach of maximising the length-to-width ratio, the proposed design changes are aimed at addressing and mitigating adverse hydrodynamic structures, which have historically led to poor hydraulic efficiency in many existing contact tanks. The results suggest that water treatment facilities can benefit from in-depth analyses of the flow and kinetic processes through computational fluid dynamics, resulting in up to 38 % more efficient pathogen inactivation and 14 % less disinfection by-product formation.

show abstract

Validation of a Three-Dimensional Computational Fluid Dynamics Model of a Contact Tank

Cited by 44 publications

References 8 publications

The Comparison of Fluid Dynamics Parameters in an Andersen Cascade Impactor Equipped With and Without a Preseparator

The Comparison of Fluid Dynamics Parameters in an Andersen Cascade Impactor Equipped With and Without a Preseparator

Unified Analysis of Multi-Chamber Contact Tanks and Mixing Efficiency Based on Vorticity Field. Part I: Hydrodynamic Analysis

Contact Tank Design Impact on Process Performance

Contact Info

Product

Resources

About