My watch list
my.chemeurope.com  
Login  

Nucleate boiling



  Nucleate boiling means some type of boiling that can take place under certain conditions; the process of forming steam bubbles within liquid in micro cavities adjacent to the wall if the wall temperature at the heat transfer surface rises above the saturation temperature while the bulk of the liquid (heat exchanger) is subcooled. The bubbles grow until they reach some critical size, at which point they separate from the wall and are carried into the main fluid stream. There the bubbles collapse because the temperature of bulk fluid is not as high as at the heat transfer surface, where the bubbles were created [1].

Additional recommended knowledge

Heat and mass transfer during nucleate boiling has a significant effect on the heat transfer rate. This heat transfer process helps quickly and efficiently to carry away the energy created at the heat transfer surface and is therefore sometimes desirable — for example in nuclear power plants, where liquid is used as a coolant. [2].

The effects of nucleate boiling take place at two locations:

  • the liquid-wall interface
  • the bubble-liquid interface [3]

The nucleate boiling process has a complex nature. A limited number of experimental studies provided valuable insights into the boiling phenomena, however these studies provided often contra dictionary data due to internal recalculation (state of chaos in the fluid not applying to classical thermodynamic methods of calculation, therefore giving wrong return values) and have not provided conclusive findings yet to develop models and correlations. Nucleate boiling phenomenon still requires more understanding [4].

See also

References

  1. ^ Nuclear Power Fundamentals - "Boiling heat transfer"
  2. ^ Nuclear Power Fundamentals - "Boiling heat transfer"
  3. ^ www.fluent.com
  4. ^ "Nucleate boiling heat transfer studied under reduced-gravity conditions", dr.D.F.Chao and dr.M.M.Hason, www.grc.nasa.gov
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Nucleate_boiling". A list of authors is available in Wikipedia.
Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE