Work Areas

  • Rheology of Non-Brownian Dense Suspensions
  • Optical measurement techniques for multiphase flows

Research Topic

Experimental Investigation on the Rheology of Non-Brownian Dense Suspensions.

automatische Worttrennung mit hyphens

Suspensions are present in many different fields, from biological flows (e.g. blood or micro-organism colonies) to industrial processing (e.g. paper or waste slurries) and consist of suspended particles that can be of different shape or material being suspended in a carrier fluid that can be Newtonian or non-Newtonian. Numerous efforts have been made to understand the rheological behavior of suspensions during the last decades [Mewis et. al]. For dense suspensions, where particle-particle interactions play a vital role, complex behaviors such as shear thinning and shear thickening may occur [Stickel and Powell]. However, experimental studies on the rheological properties of dense suspensions at finite Reynolds number are extremely scarce.

Research Goal
In the present project, the rheological and microrheological features of dense suspensions under inertial effects will be investigated experimentally. Measurements of the effective bulk viscosity shall be accompanied by optical measurements to access microrheological features such as local particle concentrations and shear rate distributions. This allows to work out the local effective viscosity as function of radial gap position.

Methods and Outlook
Measurements will be carried out in a Taylor-Couette (TC) set-up which consists of two concentrically arranged glass cylinders as shown in Figure 1a with a gap-width of 1 mm. The wall driven rotational flow can be superposed by a pressure driven axial flow. For this, the TC set-up is integrated into a fluid cycle where temperatures and pressures are monitored at the inlet and the outlet of the TC cell.
To access microrheological features of the flow such as local particle concentrations and shear rate distributions MicroPIV measurements will be combined by Laser induced Fluoresence (LiF) Imaging as depicted schematically in Figure 1b. This investigation will help us to gain a better understanding of bulk and microscopic properties of dense suspensions at finite particle Reynolds number.

M. Sc. Seyed Hamid Tabaeikazerooni

Ruhr-Universität Bochum
Raum IC 3 / 81
Universitätsstraße 150
44801 Bochum

Telefon +49 (0)234 / 32-28410


Figure 1: a) 3D sketch of the TC flow cell; b) Sketch of the measurement set-up