Počet záznamů: 1  

The effect of shear rate on properties of aggregates formed in the water treatment process

  1. 1.
    0378896 - ÚH 2013 HU eng C - Konferenční příspěvek (zahraniční konf.)
    Bubáková, Petra - Pivokonská, Lenka - Pivokonský, Martin
    The effect of shear rate on properties of aggregates formed in the water treatment process.
    Proceedings of the 6th IWA International Conference for Young Water Professionals. Budapest: IWA, 2012, IWA-9867.
    [IWA International Conference for Young Water Professionals /6./ (IWA YWPC 2012). Budapest (HU), 10.07.2012-13.07.2012]
    Grant CEP: GA AV ČR IAA200600902
    Výzkumný záměr: CEZ:AV0Z20600510
    Klíčová slova: aggregate size * fractal dimension * shear rate * water treatment
    Kód oboru RIV: BK - Mechanika tekutin

    The paper deals with the dependence of aggregate properties on the shear rate (G) at steady state. Natural raw water and ferric sulphate were aggregated in a laboratory Taylor-Couette reactor (TC) and continuous flow mixing tank (MT) with a paddle stirrer. The shear rates in the range of approximately 20-350 s-1 were used and the aggregation time corresponded to 15 min (steady state). The methods of image and fractal analysis were used to determine the aggregate size and structure, respectively. It was found that the aggregate size decreased with increasing shear rate. There was a small difference in sizes of aggregates formed in TC and MT at G < 150 s-1, but at higher shear rates, almost no difference between TC and MT was observed. The D2 fractal dimension increased with increasing shear rate indicating that the aggregates became less porous and more compact. Moreover, the very precise match in D2 values was attained for both mixing devices. The Dpf fractal dimension decreased with increasing shear rate meaning that aggregates were more regular at higher shear rates, but jagged on the surface with irregular shape at lower shear rates. Contrary to D2, aggregates formed in MT were much more irregular or jagged than those formed in TC.
    Trvalý link: http://hdl.handle.net/11104/0210217
    Název souboruStaženoVelikostKomentářVerzePřístup
    Bubakova_Pivokonska_Pivokonsky_The effect of shear rate on properties of aggregates_IWA Budapest_9867.pdf0323.1 KBAutorský preprintvyžádat