Towards optimal design parameters for around-the-end hydraulic flocculators

Research Article| May 01 2001 Towards optimal design parameters for around-the-end hydraulic flocculators Johannes Haarhoff; Johannes Haarhoff 1Department of Civil and Urban Engineering, Rand Afrikaans University, PO Box 524, 2006 Auckland Park, South Africa Fax: + 27 11 489 2148; E-mail: jh@ing1.rau.ac.za Search for other works by this author on: This Site PubMed Google Scholar Jeremia J. van der Walt Jeremia J. van der Walt 2Magalies Water, Private Bag X82327, 0300 Rustenburg, South Africa Search for other works by this author on: This Site PubMed Google Scholar Journal of Water Supply: Research and Technology-Aqua (2001) 50 (3): 149–160. https://doi.org/10.2166/aqua.2001.0014 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Share Icon Share Twitter LinkedIn Tools Icon Tools Cite Icon Cite Permissions Search Site Search nav search search input Search input auto suggest search filter All ContentAll JournalsThis Journal Search Advanced Search Citation Johannes Haarhoff, Jeremia J. van der Walt; Towards optimal design parameters for around-the-end hydraulic flocculators. Journal of Water Supply: Research and Technology-Aqua 1 May 2001; 50 (3): 149–160. doi: https://doi.org/10.2166/aqua.2001.0014 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Hydraulic flocculators are principally characterized by their volume (which determines the time of flocculation) and the water level difference between inlet and outlet (which determines the average energy dissipation). Within these constraints, however, the designer has many degrees of freedom, such as the average water depth, the number and spacing of baffles, the length of the gap at the baffle ends, and the degree to which adjoining baffles overlap. In an earlier paper (Haarhoff 1998), these variables were systematically reduced to a number of critical ratios, and a comprehensive mathematical framework was presented whereby hydraulic flocculators can be designed once these ratios are fixed. In this paper, these ratios are further investigated by computational fluid dynamics (CFD) to find their optimal values. The validity of CFD modelling is first verified by comparing experimentally measured velocities in two flocculators against modelled velocities for similar hydraulic conditions. CFD is then used to systematically optimize the three critical design ratios for flocculator design. The optimal ratios are considered to be those that cause the least deviation from the average G-value; addressing the concern that there may be large G-value differences at different points in the flocculator. baffled flocculators, computational fluid dynamics (CFD), hydraulic flocculation, velocity gradient This content is only available as a PDF.