Abstract
The present paper deals with the mixing of a highly viscous fluid by close-clearance impellers in cylindrical vessels. The study is performed via numerical simulations. Calculations are achieved by the discretization of continuity and momentum equations with the finite volume method. The effect of blade diameter and its shape on the well-stirred region size and the power consumption is investigated. For highly viscous fluids, the obtained results suggest the use of impellers rotating at low Reynolds number, and having a blade with the same shape of the tank to ensure mixing near the vessel base. A comparison is made between the performance of a simple helical ribbon (HR), a simple small screw (SS), helical ribbon-small screw (HR-SS) and a large screw (LS) impeller. The predicted results allow the following classification of impellers studied, based on less power requirements and small size of well-agitated region: SS < HR < HR-SS < LS.
Highlights
Mixing of highly viscous fluids is widely used in many industrial processes, e.g., for the production of foods, polymers or paints
We note the plane passing through the blade tip represents θ = 0°
While the impeller is rotating at low speeds and thCaese Nflou2 id flow is laminar, the mixing is ensured by chaotic folding and stretching actions 0o.2n0 the fluid, which is necessary in any agitation process that does not based on diffusion [27]
Summary
Mixing of highly viscous fluids is widely used in many industrial processes, e.g., for the production of foods, polymers or paints. Driss et al [12] simulated the Newtonian laminar flows in vessels stirred by double helical ribbons (DHR) and double helical screws (DHS) impellers. Ameur et al [13] compared, via numerical simulations, the performance of a Simple Helical Ribbon (SHR) and Double Helical Ribbon (DHR) impellers for mixing shear thinning fluids. They found that the DHR impeller enhances the fluid circulation but an additional power is consumed. In this paper, we compare the efficiency of HR and HS impellers used alone and in combination
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
