Squeeze flow rheometry of paste and slurry

摘要

A squeeze flow analysis method of sticking viscoplastic fluids as mud, mineral pastes or slurry isdeveloped. This method allows an equivalent flow curve to be extracted from squeeze data. Forthis purpose, it is assumed that the fluids stick on both plates and the flow field is essentiallyextensional around the plane of symmetry. Furthermore, we consider a Bingham model todescribe the squeeze flow of any fluids and specify an equivalent stress-strain state at any time.For this, we have calculated an instantaneous average strain rate. This average strain rate isdefined by means of a dimensional analysis coupled with energy balance. The constitutiveparameters of the Bingham model are evaluated by confronting squeeze data and analyticalsolution of the Bingham squeeze force which included the outcoming sample effects. Thisprovides also the average strain rate value and one point of the equivalent flow curve. Inconsequence, we developed an algorithm that enables the construction of an equivalent flowcurve with step-by-step computation. The algorithm, preliminary tested and validated onsimulated data of complex fluids in sticking squeeze flow, is applied on experimental squeezedata. It is finally shown that the equivalent flow curve obtained from squeeze data are inagreement with conventional shear flow curve.