Investigation into cavitational intensity and COD reduction performance of the pinned disc reactor with various rotor-stator arrangements

Gostiša, Jurij (author), Zupanc, Mojca (author), Dular, Matevž (author), Širok, Brane (author), Levstek, Meta (author), Bizjan, Benjamin (author)

In this study, the hydrodynamic cavitation and wastewater treatment performance of a rotary generator with pin disk for hydrodynamic cavitation are investigated. Various geometrical features and arrangements of rotor and stator pins were evaluated to improve the configuration of the cavitation device. The pilot device used to perform the experiments was upgraded with a transparent cover that allows visualization of the hydrodynamic cavitation in the rotor-stator region with high-speed camera and simultaneous measurement of pressure fluctuations. Based on the hydrodynamic characteristics, three arrangements were selected and evaluated with respect to the chemical effects of cavitation on a 200-liter wastewater influent sample. The experimental results show that the rotational speed and the spacing of the rotor pins have the most significant effect on the cavitation intensity and effectiveness, while the pin diameter and the surface roughness are less significant design parameters. Cavitation intensity increases with pin velocity, but can be inhibited if the pins are arranged too close together. At best configuration, COD was reduced by 31% in 15 liquid passes, consuming 8.2 kWh/kg COD. The number of liquid passes also proved to be an important process parameter for improving the energy efficiency.

• Language: English
• Keywords: hydrodynamic cavitation, wastewater treatment, pinned disc reactors, flow visualization, performance evaluation
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2021
• Number of pages: 11 str.
• Numbering: Vol. 77, art. 105669
• PID: 20.500.12556/RUL-128668
• UDC: 532.528
• ISSN on article: 1350-4177
• DOI: 10.1016/j.ultsonch.2021.105669
• COBISS.SI-ID: 70807811
• Publication date in RUL: 22.07.2021

Record is a part of a journal

• Title: Ultrasonics sonochemistry
• Shortened title: Ultrason. sonochem.
• Publisher: Elsevier
• ISSN: 1350-4177
• COBISS.SI-ID: 707668

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

• Language: Slovenian
• Keywords: hidrodinamska kavitacija, odpadne vode, kavitacijski reaktorji, turbostroji, vizualizacija, kemijska potreba po kisiku, KPK, učinkovitost razgradnje KPK

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0401
• Name: Energetsko strojništvo

• Funder: Other - Other funder or multiple funders
• Funding programme: University of Ljubljana, UL Innovation Fund
• Project number: 820-1/2020-35