(448ag) Experimental Study on the Velocity Distribution in a Hydrocyclone with a Highly Viscous Fluid

Hydrocyclones are widely used in chemical or mineral industry to separate solid particles from liquid media. Therefore, several studies in the past six decades were dealing with the velocities inside hydrocyclones [1-4]. These investigations mainly focused on water, which is the most common liquid media by using hydrocyclones. In the field of purification technology such as wastewater and sludge treatment, the rheological characteristics of the liquid media are significantly different from water [5]. As a result, most hydrocyclone calculation models [6-8] are not suitable for these applications. For the modelling of the rheological characteristics of sludges in the wastewater sector glycerin and water with different mixing ratios are used. A hydrocyclone with a diameter of 100 mm and a length of 500 mm was manufactured of transparent material to allow non-invasive optical measurements by using PIV (Particle Image Velocimetry). The light source for the measurement is carried out by a high-power LED, which is mounted on a linear-guiding unit what allows measuring all areas of interest. Since the viscosity of the water-glycerin mixture is strongly depending on the shear forces, the local velocities in the hydrocyclone will have a strong influence on the efficiency and pressure loss of the separator system, respectively. By measuring the velocity distribution, these investigations should help to define operation parameters for the application of hydrocyclones in wastewater treatment plants in order to minimize the pressure drop and maximize separation efficiency.

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[8] Braun, T., Theoretische und experimentelle Untersuchungen des Einflusses der Feststoff-konzentration und der Partikelgrößenverteilung auf das Trennverhalten von Hydrozyklonen, Dissertation, TU Carolo-Wilhelmina, Braunschweig, 1989.