Detail publikace

INFLUENCE OF SHEAR STRESS ON THE LIQUID FILM FLOW IN VERTICAL TUBE

Originální název

INFLUENCE OF SHEAR STRESS ON THE LIQUID FILM FLOW IN VERTICAL TUBE

Anglický název

INFLUENCE OF SHEAR STRESS ON THE LIQUID FILM FLOW IN VERTICAL TUBE

Jazyk

en

Originální abstrakt

When a vapour is condensing in the vertical tube, the resulting condensate produces a resistance to heat and mass transfer. The thermal resistance is dependent on the thickness and character of the flow of the condensate liquid film. The integrity of film collapse due to gravity when it flows down along the tube walls and thereby waves are created in film. Because of this waves, the shear stress is produced at steam-liquid interface by vapour movement. Due to this stress, concurrent flow of the steam accelerates the film and slows down in case of countercurrent flow. This work deals with the experimental verification of theoretical mathematical models describing the behaviour of the film. The experiment was focused on the effect of shear stress of the flowing gaseous medium (air) on the thin liquid film flowing on the wall of the glass tube. The influence of shear stress has been investigated by increase of water film flow so as to maintain a constant film thickness. The influence of the flow was tested for three different pipe diameters and for the concurrent and countercurrent flow configuration. The experiment includes the determination of the upper limit of film flow for a given velocity of air flow when the film starts to pulse and the lower limit of the film flow when the condensate film breaks down and does not flow by the whole circumference of the tube.

Anglický abstrakt

When a vapour is condensing in the vertical tube, the resulting condensate produces a resistance to heat and mass transfer. The thermal resistance is dependent on the thickness and character of the flow of the condensate liquid film. The integrity of film collapse due to gravity when it flows down along the tube walls and thereby waves are created in film. Because of this waves, the shear stress is produced at steam-liquid interface by vapour movement. Due to this stress, concurrent flow of the steam accelerates the film and slows down in case of countercurrent flow. This work deals with the experimental verification of theoretical mathematical models describing the behaviour of the film. The experiment was focused on the effect of shear stress of the flowing gaseous medium (air) on the thin liquid film flowing on the wall of the glass tube. The influence of shear stress has been investigated by increase of water film flow so as to maintain a constant film thickness. The influence of the flow was tested for three different pipe diameters and for the concurrent and countercurrent flow configuration. The experiment includes the determination of the upper limit of film flow for a given velocity of air flow when the film starts to pulse and the lower limit of the film flow when the condensate film breaks down and does not flow by the whole circumference of the tube.

Dokumenty

BibTex


@proceedings{BUT157372,
  author="Filip {Toman} and Petr {Kracík} and Jiří {Pospíšil}",
  title="INFLUENCE OF SHEAR STRESS ON THE LIQUID FILM FLOW IN VERTICAL TUBE",
  annote="When a vapour is condensing in the vertical tube, the resulting condensate produces a resistance to heat and mass transfer. The thermal resistance is dependent on the thickness and character of the flow of the condensate liquid film. The integrity of film collapse due to gravity when it flows down along the tube walls and thereby waves are created in film. Because of this waves, the shear stress is produced at steam-liquid interface by vapour movement. Due to this stress, concurrent flow of the steam accelerates the film and slows down in case of countercurrent flow. This work deals with the experimental verification of theoretical mathematical models describing the behaviour of the film. The experiment was focused on the effect of shear stress of the flowing gaseous medium (air) on the thin liquid film flowing on the wall of the glass tube. The influence of shear stress has been investigated by increase of water film flow so as to maintain a constant film thickness. The influence of the flow was tested for three different pipe diameters and for the concurrent and countercurrent flow configuration. The experiment includes the determination of the upper limit of film flow for a given velocity of air flow when the film starts to pulse and the lower limit of the film flow when the condensate film breaks down and does not flow by the whole circumference of the tube.",
  address="Brno University of Technology, Faculty of Mechanical Engineering",
  booktitle="13th International Conference for Young Researchers and PhD Students, Proceedings of the abstracts",
  chapter="157372",
  edition="1",
  howpublished="print",
  institution="Brno University of Technology, Faculty of Mechanical Engineering",
  year="2019",
  month="april",
  pages="56--56",
  publisher="Brno University of Technology, Faculty of Mechanical Engineering",
  type="conference proceedings"
}