Bulk fluidity and apparent wall slip of aqueous kaolin suspensions studied using the cone-cone (KK) sensor: The effect of concentration and temperature
| Autor: | V. Pěnkavová, O. Wein, J. Tihon |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Aqueous solution
010304 chemical physics Relative slip Chemistry Slip coefficient Thermodynamics Viscometer Mineralogy 02 engineering and technology Slip (materials science) 021001 nanoscience & nanotechnology 01 natural sciences Rotational viscometry Shear (sheet metal) Colloid and Surface Chemistry Wall slip 0103 physical sciences 0210 nano-technology |
| Zdroj: | Colloids and Surfaces A: Physicochemical and Engineering Aspects. 511:272-284 |
| ISSN: | 0927-7757 |
| DOI: | 10.1016/j.colsurfa.2016.09.082 |
| Popis: | The material viscometric functions of aqueous kaolin suspensions were measured using rotational viscometry with an unconventional cone-cone (KK) sensor. The fluidity φ [ σ ] and slip χ [ σ ] functions were obtained for various concentrations (30 ÷ 40 wt.%) and temperatures (10 ÷ 40 °C), applying different gap thicknesses (0.6 ÷ 1.6 mm) of a smooth stainless sensor. Both the fluidity and slip functions decrease with increasing kaolin concentration. The fluidity of suspensions decreases also with rising temperature, which is a highly unusual trend. On the contrary, the slip coefficient follows a temperature rise of the fluidity of continuous phase, which supports the hypothesis on existence of a totally depleted slip layer. The relative slip contribution to overall kinematic effect, A , was found to vary over a broad interval. The apparent wall slip dominates at low shear stresses ( A ≅ 90%), whereas the bulk fluidity prevails at high shear stresses ( A ≅ 10%). |
| Databáze: | OpenAIRE |
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