Rheology, Rheometry and Wall Slip

Abstract

In diverse resource, processing and dredging applications wall slip occurs. In hydraulic transport of highly concentrated particulate mixtures, wall slip can be beneficial as it may substantially reduce hydraulic gradients. In other occasions, for instance in rheometry, wall slip may obscure rheology. Rheometric wall slip is not specific to industrial slurries and appears in natural (fluid) mud as well, mostly found in harbours and estuaries. In natural (fluid) muds, in contrary to industrial muds, coarse solids are absent. However, similarly, (clay) colloids govern their non-Newtonian flow characteristics. It is exciting to see that wall slip does not only occur in the case of dispersed coarse materials but also in the absence of those. In this chapter, we elaborate on wall slip in some existing resource industry rheometry data and compare them with typical recent results of fluid mud rheology. Moreover, measurement of a (stationary) fluid mud’s longitudinal profile in a harbour basin is used to examine consequences of utilising slippage data. We finally evaluate measuring element usage and implementation of rheology in calculation methods.