The paper is concerned with the constant pressure cake filtration of suspensions in viscoelastic fluids. The filtration equations, based on the capillary hybrid model for power law fluid flow, were used for the description of this type of filtration. Filtration experiments with suspensions of nearly spherical polystyrene particles Krasten in viscoelastic aqueous solutions of polyacrylamide Praestol were carried out at constant pressure in a laboratory cylindrical filtration unit. The fluid rheological properties were measured on a rotational rheometer Haake RheoStress 150. Elastic effects manifested themselves predominantly at the early period of the filtration due to higher filtration velocity which resulted in an evidently increased filtration resistance. Analysing the experimental data, procedures for the evaluation of the effective specific filter cake resistance γ ef, filter screen resistance R fs, and the elongation flow coefficient E have been proposed. The filtration process predicted using the proposed filtration equation agrees very well with that determined experimentally.

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Development of wavy texture in startup flows of liquid crystalline polymer solution through a slit cellAbstract. In this contribution, the measurements are presented of the pressure drop in the creeping flow of viscoelastic solution of polyacrylamides through metal wire screens, differing in wire diameter, aperture dimension, and type of weaving. In this flow, a strong elastic pressure drop excess manifest itself. Analysing the extensive set of experimental data, it was verified that for engineering estimation of the pressure drop excess, a simple form of the corrective Deborah number function can be used.

Sliding plate rheometer studies of concentrated polystyrene solutions: Nonlinear viscoelasticity and wall slip of two high molecular weight polymers in tricresyl phosphate Abstract. In this contribution, the filtration equations for a cake filtration in viscoelastic fluids are presented. They are based on a capillary hybrid model for the flow of a power law fluid. In order to express the elastic pressure drop excess in the flow of viscoelastic filtrate through the filter cake and filter screen, modified Deborah number correction functions are included into these equations. Their validity was examined experimentally. Filtration experiments with suspensions of hardened polystyrene particles (Krasten) in viscoelastic aqueous solutions of polyacryl amides (0.4 % and 0.6 %wt. Kerafloc) were carried out at a constant pressure on a cylindrical filtration unit using filter screens of different resistance.