Film Condensation Heat Transfer Research Articles

Erratum: “Laminar Film Condensation Heat Transfer in the Presence of Electric and Magnetic Fields” (Journal of Heat Transfer, 1975, 97, pp. 628–629)

Erratum: “Laminar Film Condensation Heat Transfer in the Presence of Electric and Magnetic Fields” (Journal of Heat Transfer, 1975, 97, pp. 628–629)

Film condensation heat transfer of helium in a vertical tube

Helium was condensed on the wall of a vertical copper tube (14 mm in diameter, 32 mm long) in the experimental range: vapour temperature in the tube − 4.1–5.0 K; heat flux − 0.5–86 mW cm −2; temperature differences across a liquid film − 0.01–1.3 K ;film Reynolds numbers − 3–380. It was found that the heat flux increased linearly with the film temperature difference, yielding a constant heat transfer coefficient of about 0.065 W cm −2 K −1. The discrepancy between the experimental results and the laminar condensation theory is also considered.

Laminar Film Condensation Heat Transfer in the Presence of Electric and Magnetic Fields

Technical Briefs Laminar Film Condensation Heat Transfer in the Presence of Electric and Magnetic Fields A. S. El-Ariny, A. S. El-Ariny Mechanical Engineering Department, University of Riyad, Riyad, Saudi Arabia Search for other works by this author on: This Site PubMed Google Scholar J. A. Sabbagh, J. A. Sabbagh Mechanical Engineering Department, University of Riyad, Riyad, Saudi Arabia Search for other works by this author on: This Site PubMed Google Scholar M. A. Obeid M. A. Obeid Electrical Engineering Department, University of Riyad, Riyad, Saudi Arabia Search for other works by this author on: This Site PubMed Google Scholar Author and Article Information A. S. El-Ariny Mechanical Engineering Department, University of Riyad, Riyad, Saudi Arabia J. A. Sabbagh Mechanical Engineering Department, University of Riyad, Riyad, Saudi Arabia M. A. Obeid Electrical Engineering Department, University of Riyad, Riyad, Saudi Arabia J. Heat Transfer. Nov 1975, 97(4): 628-629 (2 pages) https://doi.org/10.1115/1.3450447 Published Online: November 1, 1975 Article history Online: August 11, 2010

Film Condensation on Inclined Plane Surfaces

An experimental investigation of the effect of reduced gravity forces on film condensation heat transfer rates was carried out. Reduced gravity conditions parallel to the condensing surface were obtained by condensing saturated steam at atmospheric pressure on one surface of a copper block whose inclination to the vertical could be varied giving effective body forces from 0.1g to 1g in several discrete steps. Condensation heat transfer data were higher than predicted by Nusselt’s correlation. Such increases in heat transfer are shown to be well correlated by an empirical correlation suggested by Kutateladze.

Film-Condensation Heat Transfer of Helium in a Vertical Tube

Helium was condensed on the wall of a vertical copper tube (14mm i. d., 32mm long) in the experimental range, Vapor temperatures in a tube 4.1-5.0K Heat fluxes 0.5-86mW/cm2 Temperature differences across a liquid film 0.01-1.3K Film Reynolds numbers 3-380 The heat flux was found to increase linearly with the film temperature difference, yielding a constant heat transfer coefficient of about 0.065W/cm2K. The discrepancy between the experimental results and the laminar condensation theory is also discussed.

The Effect of an Electric Field in the Presence of Noncondensable Gas on Film Condensation Heat Transfer

The Effect of an Electric Field in the Presence of Noncondensable Gas on Film Condensation Heat Transfer

Heat transfer in laminar film condensation; local film resistance and local enthalpy allowing for variable viscosity and subcooling

In contrast to the conventional method of calculation account was taken of the dependence of viscosity on temperature and of the non-linear temperature profile due to subcooling of the condensate. Fully developed velocity and temperature profiles and a constant heat flux along the flow path are assumed.

The Influence of Thermocapillary Flow on Heat Transfer in Film Condensation

The influence of fluid flow—induced by surface-tension forces—on heat transfer through a condensate film broken by non-wetting strips was considered. The film was modeled as a two-dimensional layer on an isothermal, vertical flat surface; the layer has a flat midsection with circular arcs at the edges. The solution was obtained by a finite-difference technique for several values of the Marangoni number (Nm) which provides a relative measure of the surface-tension forces and of the Biot number (Bi) which provides a relative measure of the heat transfer at the liquid–vapor interface. The range of parameters covered by this work transcends the limits of most practical interest for water. The results show that internal thermocapillary circulation causes modest increases in heat transfer. It is concluded that thermocapillary flow might be an important factor in determining the geometry of channeled condensate films.

Effect of regularly spaced surface ridges on film condensation heat transfer coefficients for condensation in the presence of noncondensable gas

Effect of regularly spaced surface ridges on film condensation heat transfer coefficients for condensation in the presence of noncondensable gas

Film Condensation Heat Transfer on a Vertical Surface : In the Case of Combined Body Force and Forced Convection

Film Condensation Heat Transfer on a Vertical Surface : In the Case of Combined Body Force and Forced Convection

An Analysis of Film Condensation, Film Evaporation, and Single-Phase Heat Transfer for Liquid Prandtl Numbers From 10−3 to 104

Annular two-phase flow inside of circular tubes is analyzed for a wide range of film Reynolds and Prandtl numbers. This analysis is applied to the prediction of film heat transfer coefficients and film thicknesses for the cases of condensation and evaporation of pure substances inside tubes, two-component flow in tubes, and condensing falling films on vertical surfaces. The analysis is also extended to single-phase flow in tubes. Extensive comparisons are made with experimental and theoretical results of other investigators, indicating good agreement if consideration is given to liquid-vapor interfacial resistance to heat flow for cases involving phase transformation.

Enhancement of film condensation rate on vertical tubes by longitudinal fins

AbstractLongitudinal rectangular fins loosely clamped to vertical tubes markedly increase the film condensation heat transfer coefficient. At a heat flux of 2×104B.t.u./hr.sq.ft., twelve ⅛×0.013 fins clamped to a ½ in. O.D. vertical tube 42 ½ in. long (thus doubling the surface area of the tube) gave a condensation coefficient of 15,000 ± 15% B.t.u./hr.sq.ft. °F. compared with 1,620 B.t.u./hr.sq.ft. °F. for the same tube without fins, a ratio ofh/hoof 9.2. The enhancement of the film condensation coefficient decreases as the heat flux increases and as the number of fins decreases.A model based on the effect of fin shape on film and rivulet hydrodynamics explains the observed behavior.

Enhancement of Film Condensation Heat Transfer Rates on Vertical Tubes by Vertical Wires

Enhancement of Film Condensation Heat Transfer Rates on Vertical Tubes by Vertical Wires

Heat transfer in film condensation

AbstractIn this theoretical analysis of heat transfer in film condensation the total vapor‐side resistance to heat transfer is obtained by adding the resistance to conduction through the condensate film to the resistance due to the condensation process at the vapor‐liquid interface.The analysis shows that under ordinary conditions conduction in the condensate film is controlling, provided the condensation coefficient is greater than about 0.10. However, under conditions of low total pressure, low heat flux, or low condensation coefficient, the resistances of both processes must be considered.Experiments carried out on the condensation of methanol are in good agreement with the theory. Furthermore, values of the condensation coefficient for methanol are reported which show that small quantities of air will greatly reduce its magnitude. This is offered as an explantion of the commonly observed phenomenon of reduction of heat transfer rates when noncondensable gases enter a system.