Boiling curve

Fig. 2. Boiling curve of a heat-flux-controlled surface with pool boiling.

Fig. 3. Boiling curves for Freon 12 in a heat-flux-controlled uniformly heated tube [from Stevens et al. (SI 3)]. L = 51 in., 4 = 0.633 in.,F = 155 psia, Ah = 13 Btu/lb.

Figure 2.42 shows boiling curves obtained in an annular channel with length 24 mm and different gap size (Bond numbers). The heat flux q is plotted versus the wall excess temperature AT = 7w — 7s (the natural convection data are not shown). The horizontal arrows indicate the critical heat flux. In these experiments we did not observe any signs of hysteresis. The wall excess temperature was reduced as the Bond number (gap size) decreased. One can see that the bubbles grew in the narrow channel, and the liquid layer between the wall and the base of the bubble was enlarged. It facilitates evaporation and increases latent heat transfer. 

Fig. 2.42 Boiling curves of water in restricted space. Squares indicate Bond number Bn = 0.185, circles indicate Bond number Bn = 0.493, triangles indicate Bond number Bn = 0.9, and last symbol (-X-) indicate Bn = 1.52...

Two hypotheses of seafloor depth at the time of mineralization have been proposed based on foraminiferal data, ca. 3500 m (Guber and Ohmoto, 1978 Guber and Merrill, 1983) and 1500 m (Kitazato, 1979). Considering seafloor depth of present-day ore formation at back-arc basins and fluid inclusion data mentioned above, shallow seafloor depth hypothesis (Kitazato, 1979) seems more likely. If the pressm e-temperature condition of Kuroko ore fluids was close to the boiling curve, the depth could be estimated to be 1,000-1,500 m, which is similar to that for present-day back-arc mineralization such as Okinawa Trough. 

Figure 12.54. Typical pool boiling curve (water at 1 bar)...

Figure 2.31 Boiling curve of water at contact angles of 38 and 107°. (From Liaw and Dhir, 1986. Copyright 1986 by Hemisphere Publishing Corp., Washington, DC. Reprinted with permission.)...

Figure 2.33 Boiling curves for acetone boiling on Teflon-coated, mirror-finished, and rough surfaces. (From Ramilison and Lienhard, 1987. Copyright 1987 by American Society of Mechanical Engineers, New York. Reprinted with permission.)...

Figure 4.3 Boiling curve for partial nucleate boiling. 

Chambre, P, and E. Elias, 1977, Rewetting Model Using a Generalized Boiling Curve, EPRI NP-571, Topical Rep. (University of California, Berkeley), Electric Power Research Inst., Palo Alto, CA. (4)... 

Westwater, J. W., J. C. Zinn, and K. J. Brobeck, 1989, Correlation of Pool Boiling Curves for the Nomo-logous Group—Freons, Trans. ASME, J. Heat Transfer 111 204-207. (2)... 

If a mixture of benzene and toluene is heated in a vessel, closed in such a way that the pressure remains atmospheric and no material can escape and the mole fraction of the more volatile component in the liquid, that is benzene, is plotted as abscissa, and the temperature at which the mixture boils as ordinate, then the boiling curve is obtained as shown by ABCJ in Figure 11.5. The corresponding dew point curve ADEJ shows the temperature at which a vapour of composition y starts to condense. 

Table 9.12 Thermal profile of water along boiling curve (from Haas, 1971).

Consider a tube heated uniformly at a heat flux q/A fed with saturated water at the base at a velocity Fo. For this velocity and heat flux, nucleate boiling will take place, and a temperature difference aTo will be established. At some distance up the tube vaporization will occur and increase the volumetric flow of material and hence the velocity to, say, Fi. The line for forced convective heat transfer meets the boiling curve below the heat flux of q/A and so nucleate boiling will still be the mode of heat transfer and the temperature difference AT, and hence the heat transfer... 

Nukiyama s boiling curve is shown in Fig. 1. He concluded that at least two types of boiling occur for water, one was below 300° F. and one above 570° F. He postulated that a third type might exist, represented by the dotted line on the figure. It was obvious that if this third type.existed it would have a.peculiar characteristic any increase in the... 

Fig. 1. The first boiling curve. Nukiyama s results for water boiling on a platinum wire are shown (N2).

Fig. 3. Boiling curve for methanol. The liquid was outside a %-in., steam-heated, horizontal copper tube, at 1 atm. The letters represent the conditions for the photographs, Figs. 4 to 9 (W3).

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