Walks of bubbles on a hot wire in a liquid bath
| Quand ? |
Le 16/05/2017, de 10:45 à 12:00 |
|---|---|
| Où ? | Centre Blaise Pascal |
| Participants |
Alexis Duchesne |
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When a horizontal resistive wire is heated up to the boiling point in a subcooled liquid bath, some vapor bubbles will nucleate on the wire surface. Traditional nucleate boiling theory predicts that bubbles generated from active nucleate sites, grow up and depart from the heating surface due to buoyancy and inertia.
We observed here a different behavior: the bubbles detached and then slide along the horizontal heated wire. We will first discuss some physical arguments explaining why the bubble is still attracted by the wire. Further, we will described the different states of organization for bubbles at the wire surface:
- A regime called “free” where bubbles freely circulate at the wire surface, interacting each others. We will give an explanation for this propulsion phenomenon and we will also describe the effect of this bubbles circulation on the thermal boundary layer.
- A regime called “clusters” where bubbles aggregate in motionless clusters at the wire surface.
Some videos of these phenomena can be viewed here: https://www.youtube.com/watch?v=KFggBH1jBfQ