Bubble Movement in Downward-Inclined Pipes |
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Authors: | Stephan Glauser Martin Wickenh?user |
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Affiliation: | 1VAW, ETH Zurich, CH-8092 Zurich, Switzerland. E-mail: stephan.glauser@gmail.com 2ETH Zurich, STUCKY LTD, CH-1020 Renens, Switzerland; formerly, VAW, ETH Zurich, CH-8092 Zurich, Switzerland (corresponding author). E-mail: mwickenhaeuser@stucky.ch
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Abstract: | An experimental investigation with large-scale model tests of bubbles moving upward and downward in downward-inclined pipes is presented. The shape, velocity, and drag coefficient of single nonspherical air bubbles in continuous air-water flows are discussed. The bubble height depends mainly on the approach flow water velocity and the pipe slope. For stagnant bubbles, the bubble height is determined depending on these two parameters. Equilibrium of the drag and buoyancy forces is applied on single air bubbles in downward-inclined pipes. In pipes with pipe slope ranging from 0.052–0.087, the bubble drag coefficient is independent of the bubble Reynolds number. However, the bubble drag coefficient depends on the pipe slope and the approach flow water velocity. Using the approach of the equilibrium of the main forces the volume of stagnant bubbles can be predicted. |
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Keywords: | Bubbles Velocity Drag Coefficients Pipe flow Two phase flow Model tests |
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