Similar Solutions for Laminar Film Condensation with Adverse Pressure Gradients

1973 ◽  
Vol 95 (2) ◽  
pp. 268-270 ◽  
Author(s):  
P. M. Beckett
Keyword(s):  
Numerical Solutions ◽  
Saturated Vapor ◽  
Film Condensation ◽  
Pressure Gradients ◽  
Two Dimensional ◽  
Laminar Film ◽  
Approximate Models ◽  
Laminar Film Condensation ◽  
Similar Solutions

Steady two-dimensional laminar film condensation is investigated when the saturated vapor has the Falkner–Skan mainstream. Numerical solutions and approximate models are discussed with reference to other published work.

Laminar Film Condensation on Nonisothermal and Arbitrary-Heat-Flux Surfaces, and on Fins

1974 ◽  
Vol 96 (2) ◽  
pp. 197-203 ◽  
Author(s):  
J. H. Lienhard ◽  
V. K. Dhir
Keyword(s):  
Heat Flux ◽  
Wide Spectrum ◽  
Film Condensation ◽  
Two Dimensional ◽  
Boundary Layer Equations ◽  
Laminar Film ◽  
Laminar Film Condensation ◽  
Variable Wall ◽  
Similar Solutions ◽  
Axisymmetric Bodies

The class of two-dimensional laminar film condensation problems with variable wall-subcooling, for which the full boundary layer equations admit similar solutions, is identified. The solutions of this problem reveal the limitations of the simple Nusselt-Rohsenow method when it is employed to deal with nonisothermal wall problems. The Nusselt-Rohsenow method is used to treat a wide spectrum of variable wall termpeature problems, and results are compared with the exact solutions. Problems in which the heat flux is arbitrarily specified are considered. Variable wall termperature problems involving axisymmetric bodies and arbitrary variations of gravity are also included. Finally, condensation on fins of various configurations is also treated.

scholarly journals Mixed-convection laminar film condensation on a semi-infinite vertical plate

1995 ◽  
Vol 300 ◽  
pp. 207-229 ◽  
Author(s):  
Jian-Jun Shu ◽  
Graham Wilks
Keyword(s):  
Vertical Plate ◽  
Body Force ◽  
Numerical Solutions ◽  
Force Convection ◽  
Film Condensation ◽  
Approximate Methods ◽  
Saturated Vapour ◽  
Laminar Film ◽  
Laminar Film Condensation ◽  
Infinite Vertical Plate

The flow of a uniform stream of pure saturated vapour past a cold, semi-infinite vertical plate is examined. The formulation incorporates the limits of both pure forcedconvection and pure body-force-convection laminar film condensation. Detailed asymptotic and exact numerical solutions are obtained and comparisons drawn with approximate methods and experimental results reported in the literature.

Laminar Film Condensation of a Flowing Vapor on a Horizontal Cylinder at Normal Gravity

1969 ◽  
Vol 91 (4) ◽  
pp. 495-501 ◽  
Author(s):  
V. E. Denny ◽  
A. F. Mills
Keyword(s):  
Boundary Layer ◽  
Normal Gravity ◽  
Numerical Solutions ◽  
Horizontal Cylinder ◽  
Vertical Surface ◽  
Film Condensation ◽  
Laminar Film ◽  
Laminar Film Condensation ◽  
Fluid Properties ◽  
Finite Difference Analog

An analytical solution, based on the Nusselt assumptions, has been obtained for laminar film condensation of a flowing vapor on a horizontal cylinder. In so doing, a reference temperature for evaluating locally variable fluid properties is defined in the form Tr = Tw + α (Ts − Tw) and accounts for both the effects of fluid property variations and minor errors introduced by the assumptions in the analysis. Verification was obtained by comparison with exact numerical solutions based on a finite-difference analog to the conservation equations in boundary-layer form. In the analytical as well as the numerical developments, vapor drag was accounted for through an asymptotic solution of the vapor boundary layer under strong suction. It was found that, for angles up to 140 deg, there was less than a 2 percent discrepancy between the analytical predictions and the numerical results. As 180 deg is approached an increased discrepancy is expected due to a gross violation of the Nusselt assumptions. The values of the reference parameter α, which were previously derived for condensation on a vertical surface, were found to be appropriate for the horizontal cylinder as well.

Laminar Film Condensation on a Vertical Melting Surface

1976 ◽  
Vol 98 (1) ◽  
pp. 108-113 ◽  
Author(s):  
M. Epstein ◽  
D. H. Cho
Keyword(s):  
Liquid Film ◽  
Saturated Vapor ◽  
Previous Treatment ◽  
Film Condensation ◽  
Full Account ◽  
Component System ◽  
Laminar Film ◽  
Laminar Film Condensation ◽  
Melting Surface ◽  
Prandtl Numbers

Laminar film condensation of a saturated vapor on a vertical melting surface is treated theoretically, with emphasis on departures from a previous treatment produced by: (a) arbitrary liquid Prandtl numbers and (b) condensation-melting systems involving two materials of immiscible liquids. An integral method is utilized which takes full account of the effects of both liquid film inertia and shear force at the condensing vapor-liquid film interface. For a one-component system accurate numerical results for the melting rates are displayed graphically and define the range of validity of a simple treatment of this problem based on Nusselt’s method. For a two-component system, illustrative calculations are made for the condensation of a refrigerant vapor on melting ice.

Effects of Vapor Superheat and Condensate Subcooling on Laminar Film Condensation

1999 ◽  
Vol 122 (1) ◽  
pp. 192-196 ◽  
Author(s):  
J. Mitrovic
Keyword(s):  
Heat Transfer ◽  
Single Phase ◽  
Saturated Vapor ◽  
Interfacial Shear ◽  
Film Condensation ◽  
Sensible Heat ◽  
Laminar Film ◽  
Laminar Film Condensation ◽  
Condensation Model ◽  
The Heat Transfer Coefficient

Nusselt’s model is employed to illustrate the effects of vapor superheat and condensate subcooling on laminar film condensation occurring under simultaneous actions of gravity and interfacial shear. The vapor superheat affects the condensation kinetics in cooperation with heat transfer in both phases. Under comparable conditions, the condensate film is thinner and the heat transfer coefficient larger for superheated than for saturated vapor. The heat flux on the cooling surface arising from the sensible heat of condensate increases as the critical point of the condensing substance is approached and, at this point, the Nusselt condensation model gives the single-phase boundary layer solutions. [S0022-1481(00)00701-5]

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