Investigating the Effect of Multiple Reference Frame Approach on the Modelling of an Oxidation Ditch

Autor: Mohammad-Hossein Sarrafzadeh, Hossein Norouzi-Firouz, Reza Zarghami
Rok vydání: 2018
Předmět:
Zdroj: International Journal of Environmental Research. 12:429-437
ISSN: 2008-2304
1735-6865
DOI: 10.1007/s41742-018-0095-x
Popis: One of the common bioreactors in activated sludge process is oxidation ditch (OD). Since aeration and mixing are the main causes of alteration in flow field, study on hydrodynamics is essential for effective operation and optimization of an OD. Such study has become less-difficult and more cost-effective because computational fluid dynamics as a dominant tool to simulate the hydrodynamics has increasingly improved. Rotation of the impeller and mixer generates fluid flow, so selecting a model that outlines impeller rotation plays a vital role. Based on the proficiency of multiple reference frame (MRF) approach, the flow characteristics associated with several rotational parts can be investigated. However, in most of the previous studies on OD as a wastewater treatment equipment, there is no clear comment on the dimension of rotational zone required for the simulation; therefore, an exclusive investigation is essential and can be supportive for additional studies on processes with moving parts. In this paper, the influence of rotational zone proportions on the precision of OD simulation was analysed and four models were proposed and simulated by (or with) MRF approach. As a result of this investigation, the more the radius of rotating zone is, the greater the exactness of modelling is. Additionally, the semi-circle rotating zone in MRF approach is infeasible.
Databáze: OpenAIRE
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