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A Physical Model of the Molecular-Quantum Natural Convection Heat Transfer Mechanism

[+] Author Affiliations
G. Soare

University Politehnica of Bucharest, Bucharest, Romania

Paper No. HT2003-47401, pp. 527-531; 5 pages
doi:10.1115/HT2003-47401
From:
  • ASME 2003 Heat Transfer Summer Conference
  • Heat Transfer: Volume 1
  • Las Vegas, Nevada, USA, July 21–23, 2003
  • Conference Sponsors: Heat Transfer Division
  • ISBN: 0-7918-3693-2 | eISBN: 0-7918-3679-7
  • Copyright © 2003 by ASME

abstract

In this work a physical model of the natural convection heat transfer mechanism, molecular-quantum in nature, is proposed. On the surface of the solid there are a lot of chemical defects (atoms of different chemical elements) and geometrical ones (steps, kinks, terraces, dislocations) at microscopic and nanoscopic scale. All these defects make the surface of the wall to be not an equipotential surface. On the other hand, the existence of a gradient of temperature in a metal wall, which is involved in a heat transfer process, generates a gradient of conduction electrons. On the cool face of the wall there are more electrons as a result of Péltier-Thomson effect. Because of surface’s defects the electrons are not uniformly distributed, on a high defect there are more electrons than on a depth defect and the electrical field is more intense on the high defect. The molecules of the fluid are adsorbed on the surface, and become polar molecules, as a result of the polarization by influence. The absorbed molecules form a multilayer in which take place more elementary processes, molecular-quantum in nature. These elementary processes are: the overlap between the electronic orbital of the solid and fluid, electron clouds perturbation, solid-fluid electron exchange by quantum tunneling effect, the motion under action of the Helmann-Feynman force between adsorbed molecules and a high defect of the wall, the absorption of the phonons from the surface’s atoms and rejection of the molecules from the surface. In this way natural convection is generated. The proposed model needs directly experimental confirmation.

Copyright © 2003 by ASME

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