SIMULATED CONDENSATE FILM THICKNESS AND DRAINAGE STUDIES

1984 ◽  
pp. 649-658
Author(s):  
A.A. Nicol ◽  
Z.L. Aidoun
Keyword(s):  
Film Thickness ◽  
Condensate Film

Condensation of a Vapor Flowing Inside a Horizontal Rectangular Duct

1995 ◽  
Vol 117 (2) ◽  
pp. 418-424 ◽  
Author(s):  
Q. Lu ◽  
N. V. Suryanarayana
Keyword(s):  
Heat Transfer ◽  
Shear Stress ◽  
Heat Transfer Coefficient ◽  
Film Thickness ◽  
Transfer Coefficient ◽  
Interfacial Shear Stress ◽  
Interfacial Shear ◽  
Rectangular Duct ◽  
Interfacial Waves ◽  
Condensate Film

Condensation of a vapor flow inside a horizontal rectangular duct, using the bottom plate as the only condensing surface, was experimentally investigated. The experimental measurements included condensate film thickness and heat transfer coefficients with R-113 and FC-72. The condensate film thickness, measured with an ultrasonic transducer, was used to obtain the local heat transfer coefficient. The heat transfer coefficient increased with increasing inlet vapor velocity. The rate of increase was enhanced noticeably after the appearance of interfacial waves. Within the limited range of the experimental variables, a correlation between St and RegL was developed by a linear regression analysis. However, because of the effect of the interfacial waves, instead of a single correlation for the entire range of RegL, two separate equations (one for the wave-free regime and another for the regime with waves) were found. Analytical predictions of heat transfer rates in the annular condensation regime require the proper modeling of the interfacial shear stress. A properly validated interfacial shear stress model with condensation is not yet available. The measurement of condensate film thickness at several axial locations opens the door for determining the local interfacial stress and, hence, a model for the interfacial shear stress.

Effect of Vapour Drag on Laminar Film Condensation on a Vertical Rectangular Fin

1993 ◽  
Vol 207 (1) ◽  
pp. 63-69
Author(s):  
H Kazeminejad
Keyword(s):  
Heat Transfer ◽  
Film Thickness ◽  
Transfer Rate ◽  
Relative Effect ◽  
Film Condensation ◽  
Friction Drag ◽  
Condensate Film ◽  
Fin Efficiency ◽  
Laminar Film ◽  
Laminar Film Condensation

A simple theory is presented for laminar film condensation of a pure vapour on a vertical rectangular fin which takes account of drag induced on the liquid film by the flow of the condensing vapour. Under these conditions, the governing conjugate differential equations for the fin and condensate flow are solved numerically to determine the fin temperature and condensate film thickness distributions. For the range of parameters investigated, it was found that the reduction in condensate thermal resistance due to vapour shear significantly enhances the heat-transfer rate to the fin and decreases the fin efficiency. The model also provides a clear picture of the relative effect of the gravity force, friction drag and momentum drag on the performance of the fin.

Flow Dynamics and Heat Transfer of Wavy Condensate Film

2000 ◽  
Vol 123 (3) ◽  
pp. 492-500 ◽  
Author(s):  
Akio Miyara
Keyword(s):  
Heat Transfer ◽  
Film Thickness ◽  
Random Perturbation ◽  
Vertical Wall ◽  
Leading Edge ◽  
Capillary Waves ◽  
Staggered Grid ◽  
Thickness Variation ◽  
Large Wave ◽  
Condensate Film

Wave evolution and heat transfer behavior of a wavy condensate film down a vertical wall have been investigated by a finite difference method, in which the algorithm is based on the HSMAC method, and a staggered grid fixed on a physical space is employed. For the moving interface, newly proposed methods are used. A random perturbation of the film thickness is generated near the leading edge. The perturbation quickly diminishes once and small-amplitude long waves are propagated downstream. Then the amplitude of the wave increases rapidly at a certain position, and the wave shape changes from a sinusoidal wave to a pulse-like solitary wave which is composed of a large-amplitude wave and capillary waves. A circulation flow occurs in the large wave and it affects the temperature field. The heat transfer is enhanced by space-time film thickness variation and convection effects.

scholarly journals Ultrasonic measurement of condensate film thickness

2008 ◽  
Vol 124 (4) ◽  
pp. EL196-EL202 ◽  
Author(s):  
Jeramy T. Kimball ◽  
Michael R. Bailey ◽  
James C. Hermanson
Keyword(s):  
Film Thickness ◽  
Ultrasonic Measurement ◽  
Condensate Film
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