Next Article in Journal
Treatment Wetland Aeration without Electricity? Lessons Learned from the First Experiment Using a Wind-Driven Air Pump
Next Article in Special Issue
Assessment of Non-Point Source Total Phosphorus Pollution from Different Land Use and Soil Types in a Mid-High Latitude Region of China
Previous Article in Journal
Rainfall Characteristics and Regionalization in Peninsular Malaysia Based on a High Resolution Gridded Data Set
Previous Article in Special Issue
Reconstructing Historical VOC Concentrations in Drinking Water for Epidemiological Studies at a U.S. Military Base: Summary of Results
Article Menu

Export Article

Open AccessArticle
Water 2016, 8(11), 495; doi:10.3390/w8110495

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

1
Department of Civil Engineering, Eskisehir Osmangazi University, Eskisehir 26000, Turkey
2
Multimedia Environmental Simulations Laboratory, School of Civil and Environmental Engineering Georgia Institute of Technology, Atlanta, GA 30332, USA
*
Author to whom correspondence should be addressed.
Academic Editors: Clelia Luisa Marti and Yung-Tse Hung
Received: 15 August 2016 / Revised: 9 October 2016 / Accepted: 24 October 2016 / Published: 2 November 2016
(This article belongs to the Special Issue Water Quality and Health)
View Full-Text   |   Download PDF [8681 KB, uploaded 2 November 2016]   |  

Abstract

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. View Full-Text
Keywords: ozone contact tank; hydraulic efficiency; computational fluid dynamics (CFD); Reynolds averaged Navier–Stokes (RANS); large eddy simulation (LES); vorticity ozone contact tank; hydraulic efficiency; computational fluid dynamics (CFD); Reynolds averaged Navier–Stokes (RANS); large eddy simulation (LES); vorticity
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Scifeed alert for new publications

Never miss any articles matching your research from any publisher
  • Get alerts for new papers matching your research
  • Find out the new papers from selected authors
  • Updated daily for 49'000+ journals and 6000+ publishers
  • Define your Scifeed now

SciFeed Share & Cite This Article

MDPI and ACS Style

Demirel, E.; Aral, M.M. Unified Analysis of Multi-Chamber Contact Tanks and Mixing Efficiency Based on Vorticity Field. Part I: Hydrodynamic Analysis. Water 2016, 8, 495.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Water EISSN 2073-4441 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top