Mixing non-Newtonian flows in anaerobic digesters by impellers and pumped recirculation. (January 2018)

• Record Type: Journal Article
• Authors: Meister, Michael; Rezavand, Massoud; Ebner, Christian; Pümpel, Thomas; Rauch, Wolfgang
• Is Part Of: Advances in engineering software. Volume 115(2018)
• Page Start: 194
• Page End: 203
• Publication Date: 2018-01
• Subjects: Anaerobic digester -- Computational Fluid Dynamics -- Egg-shaped digester -- Mechanical mixing -- Non-Newtonian flows -- Pumped recirculation; Computer-aided engineering -- Periodicals; Engineering -- Computer programs -- Periodicals; Engineering -- Software -- Periodicals; Periodicals; 620.0028553
• DOI: 10.1016/j.advengsoft.2017.09.015
• Languages: English
• ISSNs: 0965-9978

Abstract

Highlights: Detailed CFD model for impeller induced mechanical draft tube mixing. Analysis of impeller efficiencies and of the mixing by pumped recirculation. Non-Newtonian flows with different total solids concentrations are investigated. Abstract: In this article, a finite volume method based CFD analysis of the mixing of Newtonian and non-Newtonian flows in anaerobic digesters is conducted. The multiple reference frame method is used to model the mixing which is induced by an impeller rotating within a mechanical draft tube. Moreover, the feeding of biomass is considered in the model formulation. Following the validation of the method against reference data, the mixing of cylindrical and egg-shaped digesters is investigated. The distinguishing feature of this article is that the theoretical findings are adopted for the operation of a real-life anaerobic digester. In the context of a case study slurry flows with high total solids concentrations are investigated.