24 research outputs found
Extending acoustic inâline pipe rheometry and friction factor modelling to lowâReynoldsânumber, nonâNewtonian slurries
The rheology of nonâNewtonian slurries are measured in a recirculating pipe loop using an acoustic velocimetryâpressure drop technique at very low flow rates and variable solids loadings. The technique avoids (a) settling at low solids concentration, a shortcoming of bench rheometry, by using a vertical test section, and (b) physical sampling, providing greater safety. Speed of sound in the suspensions is also modelled. Inâline and offâline data are used to assess the suitability of several nonâNewtonian models to describe observed flow behaviour. Measured and predicted values of the friction factor are compared, with the Madlener et al. (2009) HerschelâBulkley Extended model found to be superior. The dependence of yield stress and viscosity on solids loading and particle size is investigated, showing complexities from aggregation on the particle size distribution require more interpretation than the choice of rheological or frictionâfactor model