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Title: Combined free and forced convection laminar film condensation on an inclined circular tube with isothermal surface

Abstract

Laminar film condensation on an inclined circular tube, under the condition of combined free and forced convection, is analyzed. The assumptions are as in the analysis of Shekriladze and Gomelauri (1966) for the horizontal tube case. In addition, some approximations are introduced for the determination of the interfacial shear stress. The resultant governing equation, in special cases, yields the known analytical solutions of horizontal and vertical tubes, which were obtained in previous studies. A numerically-obtained solution reveals the effects of vapor velocity and gravity force on local and mean Nusselt numbers. For the case of an infinitely-long tube, an explicit simple expression has been obtained, based on numerical results, to calculate the mean Nusselt number for the whole tube surface.

Authors:
Publication Date:
Research Org.:
Mansoura Univ. (EG)
OSTI Identifier:
20030462
Resource Type:
Conference
Resource Relation:
Conference: 5th ASME/JSME Thermal Engineering Joint Conference, San Diego, CA (US), 03/14/1999--03/19/1999; Other Information: 1 CD-ROM. Operating system required: Windows i386(tm), i486(tm), Pentium (R) or Pentium Pro, MS Windows 3.1, 95, or NT 3.51, 8 MB RAM, MacIntosh and Power MacIntosh with a 68020 or greater processor, System software version 7.1, 3.5 MB RAM (5 MB for PowerMac) 6 MB available hard-disk space, Unix; PBD: 1999; Related Information: In: Proceedings of the 5th ASME/JSME thermal engineering joint conference, [3600] pages.
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; NATURAL CONVECTION; FORCED CONVECTION; LAMINAR FLOW; TUBES; NUSSELT NUMBER; FILM CONDENSATION

Citation Formats

Mosaad, M. Combined free and forced convection laminar film condensation on an inclined circular tube with isothermal surface. United States: N. p., 1999. Web.
Mosaad, M. Combined free and forced convection laminar film condensation on an inclined circular tube with isothermal surface. United States.
Mosaad, M. 1999. "Combined free and forced convection laminar film condensation on an inclined circular tube with isothermal surface". United States. doi:.
@article{osti_20030462,
title = {Combined free and forced convection laminar film condensation on an inclined circular tube with isothermal surface},
author = {Mosaad, M.},
abstractNote = {Laminar film condensation on an inclined circular tube, under the condition of combined free and forced convection, is analyzed. The assumptions are as in the analysis of Shekriladze and Gomelauri (1966) for the horizontal tube case. In addition, some approximations are introduced for the determination of the interfacial shear stress. The resultant governing equation, in special cases, yields the known analytical solutions of horizontal and vertical tubes, which were obtained in previous studies. A numerically-obtained solution reveals the effects of vapor velocity and gravity force on local and mean Nusselt numbers. For the case of an infinitely-long tube, an explicit simple expression has been obtained, based on numerical results, to calculate the mean Nusselt number for the whole tube surface.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1999,
month = 7
}

Conference:
Other availability
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  • An analysis is made of the combined forced and free convection for laminar flow in the entrance region of isothermal, inclined tubes. This involves the numerical calculation of the developing flow with significant buoyancy effects. Three independent parameters are introduced: the Prandtl number Pr, a modified Rayleigh number Ra*, and {Omega}, a parameter that measures the relative importance of free and forced convection. The inclination angle does not appear explicitly in the formulation. Numerical results are obtained for Pr = 0.7, 5, and 10, and representative values of Ra* and {Omega}. The axial development of the velocity profiles, temperature field,more » local pressure gradient, and the Nusselt number are presented. These results reveal that the buoyancy effects have a considerable influence on the fluid flow and heat transfer characteristics of the development flow. A comparison of the numerical results with the available experimental data is also presented.« less
  • Combined free and forced-convection effects by heatgenerating laminar flow inside cylindrical pipes with elements parallel to the direction of the generating body force were investigated by applying the finite Fourier sine transform and finite Harkel transforms when the cross sections of the pipes were circular sectors. A numerical example is provided to show the effects of various parameters. (auth)
  • An approximate analysis is given for miscible displacement in vertical tubes when density differences between the displaced and displacing fluids give rise to buoyancy forces which affect the velocity distribution significantly. The results of this analysis agree with the available experimental data fairly uniformly over th range of parameters studied experimentally. By analogy with studies of heat transfer in vertical tubes, it is concluded that both cases studied, when a lighter fluid displaces a heavier fluid in upflow, or when the heavier fluid is below the lighter fluid, are potentially unstable flows because buoyancy forces can create points of inflectionmore » in the velocity profile; stagnation at the walls also is predicted for upflow when the lighter fluid is on the bottom initially, and this has been observed to induce a sudden transition to turbulence in heat transfer systems.« less