Nucleation, boiling

Boiling Nucleate Natural Circulation (Thermosiphon) Inside Vertical Tubes or Outside Horizontal Tubes... 

Cole R (1974) Boiling nucleation. In Advances in Heat Transfer 10. Academic, New York, pp 86-166... 

Peng XF, Hu HY, Wang BX (1997) Boiling nucleation during liquid flow in micro-channels. Int J Heat Mass Transfer 41 101-106... 

A few of the many contributors to the classical rate theory of boiling nucleation are Volmer (VI), Becker and Doring (B2), Frenkel (F7), Fisher (F3), and Bernath (B4). All agree that a prime requirement for nucleation to occur in a liquid is that the liquid must be superheated. The bubbles formed are cooler than the liquid therefore nucleation is strictly irreversible. Because of the superheat, a temperature driving force exists between liquid and bubble. However, because surface tension forces are immense for tiny bubbles, a collapsing tendency exists which may counteract the tendency of a bubble to grow by absorbing heat. One problem faced by any theory of nucleation is to explain the formation of a bubble which will not collapse. 

Consider the criteria requiredfor nucleate boiling. Nucleate boiling occurs when the difference between the temperature of the hot surface and the bulk fluid temperature is above a certain value. At temperature differences less than this value, heat transfer occurs as a result of natural convection. Nucleate-boiling heat-transfer coefficients for a steel tube may be calculated using the equation... 

Two types of condensation, drop-wise and film-wise, have been known for many years. As soon as the two types of boiling, nucleate and film, were described, certain similarities to condensation became evident. Nucleate boiling and drop-wise condensation were seen to be analogous. This is of little practical value, because no good theory of drop-wise condensation exists. However the analogy between film boiling and film condensation is fruitful, because a good theory of film condensation exists. 

R. Cole, Boiling Nucleation, Advances in Heat Transfer (10) 86-164,1974. 

S. R. Yang and R. H. Kim, A Mathematical Model of the Pool Boiling Nucleation Site Density in Terms of the Surface Characteristics, Int. J. Heat Mass Transfer (31) 1127-1135,1988. 

Natural convective boiling Nucleate boiling Transition boiling... 

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