Rheology and Mixing

Effect of Fill Level in Mixer Viscometry

“…The rotational rheometer such as concentric cylinder system (also known as Couette) display a well‐defined shear rates and ideal for rheological characterization because absolute rheological data are able to be obtained. In mixer rheometry, absolute rheological data may be difficult to obtained because if complex flow patterns; however, mixer rheometry data may be a good representative of a fluid's rheological characteristics for a fluid whose properties cannot be determined by the concentric cylinder system such as fluid with large particulates, settling problems, slip and time dependency (Cullen and Connelly 2009).…”

Rate of chaotic mixing in localized flows

“…For this purpose, we study the mixing of non-Newtonian viscoplastic fluids, that start to flow only when submitted to a stress larger than a critical value, called yield stress. This behavior affects the mixing performance, due to shear localization that can in the worst case generate dead zones inside the mixing device [14][15][16]. Since mixing yield-stress fluids is an operation involved in several industries such as cosmetic, polymer, petrochemical, pharmaceutical, or food engineering [16][17][18], an abundant literature in engineering [14][15][16][17]19] has focused on design and upscaling of flows in order to reduce such dead zones.…”

“…This behavior affects the mixing performance, due to shear localization that can in the worst case generate dead zones inside the mixing device [14][15][16]. Since mixing yield-stress fluids is an operation involved in several industries such as cosmetic, polymer, petrochemical, pharmaceutical, or food engineering [16][17][18], an abundant literature in engineering [14][15][16][17]19] has focused on design and upscaling of flows in order to reduce such dead zones. A few studies have addressed the description of chaotic advection in flows of viscoplastic [20][21][22] or other types [23,24] of shear-thinning fluids, demonstrating in particular the the shear localization is often responsible for a very scattered distribution of stretching factors [21].…”