Boiling Heat Transfer Correlations
The nucleate boiling regime is important to engineers because of the high heat fluxes possible with moderate temperature differences. The date can be correlated by equation of the form,
The Nusselt number is defined as,
where q/A is the total heat flux, is the maximum bubble diameter as it leaves the surface, is the excess temperature, is the thermal conductivity of the liquid and is the Prandtl number of the liquid. The bubble Reynolds number, is defined as,
Where is the average mass velocity of the vapor leaving the surface and is the liquid viscosity.
Rohsenow has developed the first and most widely used correlation for nucleate boiling,
Where is the heat capacity of the liquid. is the surface fluid combination and vary for various combinations of fluid and surface. For example, water and nickel have a of 0.006.
| Surface fluid combinations | |
|---|---|
| Water/copper | 0.013 |
| Water/nickel | 0.006 |
| Water/platinum | 0.013 |
| Water/brass | 0.006 |
| Water/Stainless steel, mechanically polished | 0.0132 |
| Water/Stainless steel, Chemically etched | 0.0133 |
| Water/Stainless steel, Ground and polished | 0.0080 |
| /copper | 0.013 |
| Benzene/Chromium | 0.0101 |
| n-Pentane/Chromium | 0.015 |
| Ethyl alcohol/Chromium | 0.0027 |
| Isopropyl alcohol/copper | 0.0025 |
| n-Butyl alcohol/copper | 0.003 |
Read more about this topic: Nucleate Boiling
Famous quotes containing the words boiling, heat and/or transfer:
“Most people hew the battlements of life from compromise, erecting their impregnable keeps from judicious submissions, fabricating their philosophical drawbacks from emotional retractions and scalding marauders in the boiling oil of sour grapes.”
—Zelda Fitzgerald (1900–1948)
“... often in the heat of noonday, leaning on a hoe, looking across valleys at the mountains, so blue, so close, my only conscious thought was, “How can I ever get away from here? How can I get to where they have books, where I can be educated?” I worked hard, always waiting for something to happen to change things. There came a time when I knew I must make them happen; that no one would do anything about it for me. And I did.”
—Belinda Jelliffe (1892–1979)
“If it had not been for storytelling, the black family would not have survived. It was the responsibility of the Uncle Remus types to transfer philosophies, attitudes, values, and advice, by way of storytelling using creatures in the woods as symbols.”
—Jackie Torrence (b. 1944)