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Bubble curtains with vertical tubes: A way to deter fish from hydro power intakes
Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
2019 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

This project was performed on assigment of Vattenfall R&D in Älvkarleby. The project was a first step in evaluating whether bubble curtains with vertical tubes could be suitable for diverting fish from hydro power intakes into fish passages. To determine this, prototypes were constructed, where one was tested in still water and one in running water. The tests in still water were carried out in a large cylindrical tank and the tests in running water were carried out in Kungsr¨annan in ¨Alvkarleby. A number of test variables were developed to be able to vary the tests. These test variables were hole size, number of holes, tube center-to-center distance, air flow and water velocity. The tests were carried out without fish, but a number of indicators were developed to be able to compare and evaluate the tests. For the tests in still water, these indicators were the width of the bubble curtain created by a single tube and the horizontal movement of the air bubbles, to determine whether the hydrostatic pressure from the surrounding water had any effect on the appearance of the bubble curtain. For the tests in running water, the indicators were the bubble curtain density, the curvature of the tubes and the movement of the tubes. All experiments were documented using cameras and the results were then obtained through image processing in the software MATLAB. The results showed that the width of the bubble curtain created by a single tube varied between 12 and 34 cm for pressures between 0.5 and 2.0 bar. It was concluded that the hydrostatic pressure was of minimal significance for the appearance of the bubble curtain, at least for depths up to 1.95 m. For the tests in running water, the air flow rate and tube center-to-center distance was of the greatest importance for the bubble curtain density. The curvature of the tubes were most affected by the size of the holes and the movement of the tubes were most affected by the number of holes.

Abstract [sv]

Detta projekt utfördes på uppdrag av Vattenfall R&D i Älvkarleby. Projektet var ett första steg i att utvärdera om bubbelridåer med vertikala slangar skulle kunna lämpa sig för att avleda fisk från vattenkraftverk vidare mot fiskpassager. För att avgöra detta konstruerades prototyper, där en testades i stilla vatten och en i rinnande vatten. Testerna i stilla vatten utfördes i en stor cylindrisk tank och testerna i rinnande vatten utfördes i Kungsrännan i Älvkarleby. Ett antal testvariabler togs fram för att kunna variera testerna. Dessa testvariabler var hålstorlek, antal hål, avstånd mellan slangarnas centrum, luftflöde samt vattenhastighet. Testerna gjordes utan fisk, men ett antal indikatorer togs fram för att kunna jämföra och utvärdera testerna. För testerna i stilla vatten var dessa indikatorer bubbelridåns bredd skapad av en enskild slang samt luftbubblornas horisontella förflyttning, för att avgöra om det hydrostatiska trycket från omgivande vattnet hade någon effekt på bubbelridåns utseende. För testerna i rinnande vatten var indikatorerna bubbelridåns täthet, slangens krökning samt slangens rörelser. Alla experiment dokumenterades med hjälp av kameror och resultaten togs sedan fram genom bildhantering i programvaran MATLAB. Resultaten visade att bubbelridåns bredd skapad av en enskild slang varierade mellan 12 och 34 cm för tryck mellan 0,5 och 2,0 bar. Det bedömdes att det hydrostatiska trycket var av minimal betydelse för bubbelridåns utseende, åtminstone för djup upp till 1,95 m. För testerna i rinnande vatten visade resultaten att luftflödet och avståndet mellan slangarnas centrum var av störst betydelse förr bubbelridåns täthet. Slangens krökning påverkades mest av hålens storlek och slangens rörelser påverkades mest av antalet hål.

Place, publisher, year, edition, pages
2019. , p. 56
Keywords [en]
Bubble curtain hydro power intakes fish salmon eel barrier screen deter
Keywords [sv]
vattenkraft bubbelridå ridå bubblor lax ål fisk
National Category
Ocean and River Engineering
Identifiers
URN: urn:nbn:se:umu:diva-161010OAI: oai:DiVA.org:umu-161010DiVA, id: diva2:1331245
External cooperation
Vattenfall R&D
Subject / course
Energiteknik
Educational program
Master of Science Programme in Energy Engineering
Supervisors
Examiners
Available from: 2019-06-27 Created: 2019-06-26 Last updated: 2019-06-27Bibliographically approved

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