An in-depth analysis of the hydrodynamic behaviour of a high-rate lamellar DAF tank by means of CFD simulations
| Title: | An in-depth analysis of the hydrodynamic behaviour of a high-rate lamellar DAF tank by means of CFD simulations |
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| Authors: | Dmytro Hlukhov, Gorka S. Larraona, Alejandro Rivas, Juan Carlos Ramos |
| Source: | Applied Water Science, Vol 14, Iss 6, Pp 1-17 (2024) |
| Publisher Information: | SpringerOpen, 2024. |
| Publication Year: | 2024 |
| Collection: | LCC:Water supply for domestic and industrial purposes |
| Subject Terms: | Dissolved Air Flotation, Lamellae, Lamellar DAF, High-rate DAF, Computational Fluid Dynamics, Removal efficiency, Water supply for domestic and industrial purposes, TD201-500 |
| More Details: | Abstract This research is based on computational fluid dynamics simulations of water and microbubble flow within the tank of a lamellar DAF (L-DAF) clarification system operating under high-rate DAF conditions (12–30 m/h). Firstly, performance of the DAF tank with lamellae was evaluated under two operating conditions in which the flow was either short-circuited or stratified in the absence of lamellae. In addition, the improvement in bubble removal efficiency achieved by the incorporation of lamellae in each scenario was assessed. Secondly, an in-depth analysis was conducted of the flow that develops in the separation zone as a result of placing the lamella pack in that part of the tank. The significant density difference that the lamellae cause to exist between the bubble blanket and clarified water below is responsible for the complex three-dimensional flow observed between the two regions. Analysis of this flow showed a previously undescribed mechanism in which the density gradient plays a crucial role in preventing bubbles from passing through the lamellae and ultimately escaping with the effluent. Finally, the effect of hydraulic loading on the bubble removal efficiency of the L-DAF tank under consideration was researched, and it was found that an L-DAF with a height/length ratio of 0.72 is able to operate at hydraulic loading close to 30 m/h, evidencing good debubbling performance. |
| Document Type: | article |
| File Description: | electronic resource |
| Language: | English |
| ISSN: | 2190-5487 2190-5495 |
| Relation: | https://doaj.org/toc/2190-5487; https://doaj.org/toc/2190-5495 |
| DOI: | 10.1007/s13201-024-02197-0 |
| Access URL: | https://doaj.org/article/57b08d76079a49f599ff80a1fa33b3e4 |
| Accession Number: | edsdoj.57b08d76079a49f599ff80a1fa33b3e4 |
| Database: | Directory of Open Access Journals |
| ISSN: | 21905487 21905495 |
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| DOI: | 10.1007/s13201-024-02197-0 |
| Published in: | Applied Water Science |
| Language: | English |