Calibration of a Macro-Viscosimeter using CFD Methods

The aim of this work was the identification of the rheological behaviour of typical slurries used in biogas digesters. To optimise the mixing performance of large-scale biogas fermenters using CFD-Methods it is necessary to have data that describe the properties of the fluid. Typical slurries contain a large amount of organic and inorganic particles (up to 12 %) with particle sizes and fibre lengths varying in a large range and display a non-Newtonian behaviour. It is shown that CFD combined with other methods is a suitable tools to calibrate a macro-viscosimeter.

Comparison of the shearrate measured, non-Newtonian fluids

Three different methods were applied to calibrate the macro-viscosimeter:

  • Metzner-Otto method
  • Metzner-Otto method, modified shear distribution
  • numerical investigation