The effect of inclination on the heat-transfer coefficients for film condensation of steam on an inclined cylinder

1964 ◽  
Vol 7 (12) ◽  
pp. vi ◽  
Author(s):  
T.W. Garrett ◽  
J.L. Wighton
Keyword(s):  
Heat Transfer ◽  
Film Condensation ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

scholarly journals Condensation inside smooth horizontal tubes: Part 1. Survey of the methods of heat-exchange prediction

2015 ◽  
Vol 19 (5) ◽  
pp. 1769-1789 ◽  
Author(s):  
Volodymyr Rifert ◽  
Volodymyr Sereda
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Film Condensation ◽  
Experimental Investigations ◽  
Phase Flow ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Horizontal Tubes

Survey of the works on condensation inside smooth horizontal tubes published from 1955 to 2013 has been performed. Theoretical and experimental investigations, as well as more than 25 methods and correlations for heat transfer prediction are considered. It is shown that accuracy of this prediction depends on the accuracy of volumetric vapor content and pressure drop at the interphase. The necessity of new studies concerning both local heat transfer coefficients and film condensation along tube perimeter and length under annular, stratified and intermediate regimes of phase flow was substantiated. These characteristics being defined will allow determining more precisely the boundaries of the flow regimes and the methods of heat transfer prediction.

scholarly journals Film Condensation of R-22 and R-410A on Horizontal Enhanced Tubes

1997 ◽  
Author(s):  
W. Y. Cheng ◽  
Y. Z. Robert Hu ◽  
C. C. Wang
Keyword(s):  
Heat Transfer ◽  
Energy Balance ◽  
Air Conditioning ◽  
Film Condensation ◽  
Transfer Coefficients ◽  
Average Heat ◽  
Heat Transfer Coefficients ◽  
Enhanced Tubes

This study experimentally investigates the film condensation of R-22 and R-410A on two horizontal enhanced tubes. The test tubes include a GEWA-C and a GEWA-TWX. Data was measured at three different saturation temperatures (35°C, 40°C and 45°C) in accordance with the range of practical condensation conditions in the air-conditioning and refrigeration applications. Average heat transfer coefficients were determined by overall heat transfer coefficients based on energy balance. The comparisons of heat transfer coefficients between R-22 and R-410A for both test tubes were presented.

A Theory of Film Condensation in Horizontal Noncircular Section Microchannels

2005 ◽  
Vol 127 (10) ◽  
pp. 1096-1105 ◽  
Author(s):  
Hua Sheng Wang ◽  
John W. Rose
Keyword(s):  
Heat Transfer ◽  
Channel Wall ◽  
Interfacial Shear Stress ◽  
Interfacial Shear ◽  
Film Condensation ◽  
Transfer Coefficients ◽  
Condensate Film ◽  
Heat Transfer Coefficients ◽  
Flow Parameters ◽  
Local Mean

The paper presents a theoretical model to predict film condensation heat transfer from a vapor flowing in horizontal square and equilateral triangular section minichannels or microchannels. The model is based on fundamental analysis which assumes laminar condensate flow on the channel walls and takes account of surface tension, interfacial shear stress, and gravity. Results are given for channel sizes (side of square or triangle) in the range of 0.5–5 mm and for refrigerants R134a, R22, and R410A. The cases considered here are where the channel wall temperature is uniform and the vapor is saturated at the inlet. The general behavior of the condensate flow pattern (spanwise and streamwise profiles of the condensate film), as well as streamwise variation of local mean (over section perimeter) heat-transfer coefficient and vapor mass quality, are qualitatively in accord with expectations on physical grounds. The magnitudes of the calculated heat-transfer coefficients are in general agreement with experimental data for similar, but nonidentical, channel geometry and flow parameters.

scholarly journals Roles of Flue Gas in Promoting Steam Flow and Heat Transfer in Multithermal Fluid Flooding

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Zhuangzhuang Wang ◽  
Zhaomin Li
Keyword(s):  
Heat Transfer ◽  
Flue Gas ◽  
Film Condensation ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Flow And Heat Transfer ◽  
Steam Flooding ◽  
Heat Injection ◽  
The Heat Transfer Coefficient ◽  
Steam Heat

Multithermal fluid technology is becoming an important method in the field of heavy oil development. However, because of insufficient investigation on the heat transfer for the multithermal fluid, some development phenomena and characteristics still cannot be well explained. In order to determine the effect of flue gas on the thermal swept scope, multithermal fluid flooding experiments were carried out through 1D sandpack. The temperatures along the sandpack were measured. On this basis, steam heat transfer simulation experiments were conducted and the heat transfer coefficients were calculated. The mechanism of flue gas on steam heat transfer was analyzed. The results show that at the same heat injection conditions, the thermal swept scope for the multithermal fluid flooding was larger than that for the steam flooding. With the increase of flue gas proportion in the multithermal fluid, the heat transfer coefficient decreased and the condensation pattern was transformed from drop condensation to film condensation gradually. The flue gas can form gas film on the surface of the cold body and inhibit the heat transfer between steam and the cold body. Because of the inhibiting effect of flue gas on steam heat transfer, flue gas can reduce the heat transferred to the rock matrix in flooding and thus promote steam to carry more heat further. Meanwhile, flue gas can accelerate the flow of steam in porous media, which also leads to the expansion of the thermal swept scope for the multithermal fluid flooding.

Film Condensation of R-134a on Tube Arrays With Plain and Enhanced Surfaces: Part I—Experimental Heat Transfer Coefficients

2005 ◽  
Vol 128 (1) ◽  
pp. 21-32 ◽  
Author(s):  
D. Gstoehl ◽  
J. R. Thome
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Finned Tube ◽  
Surface Structures ◽  
Film Condensation ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Tube Arrays ◽  
R 134A ◽  
Enhanced Surface

The aim of the present investigation was to study the effect of condensate inundation on the thermal performance of a vertical array of horizontal tubes with plain and enhanced surfaces. Refrigerant R-134a was condensed at a saturation temperature of 304K on tube arrays with up to ten tubes at pitches of 25.5,28.6,and44.5mm. Notably, local condensing heat transfer coefficients were measured at the midpoint of each tube, as opposed to mean values. Four commercially available copper tubes with a nominal diameter of 19.05mm(0.75in.) were tested: a plain tube, a 26fpi∕1024fpm low finned tube, and two tubes, with three-dimensional (3D) enhanced surface structures. At low liquid inundation rates, the tubes with 3D enhanced surface structures significantly outperformed the low finned tube. Increasing liquid inundation deteriorated the thermal performance of the 3D enhanced tubes, whereas it had nearly no affect on the low finned tube, resulting in a higher heat transfer coefficients for the low finned tube at high liquid film Reynolds numbers. All the tests were performed with minimal vapor shear.

Numerical Modeling of Film Condensation in Horizontal Mini- and Macrocircular Tubes

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Jun-De Li
Keyword(s):  
Heat Transfer ◽  
Film Thickness ◽  
Numerical Differentiation ◽  
Vapor Condensation ◽  
High Order ◽  
Film Condensation ◽  
Thickness Variation ◽  
Condenser Tube ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

A partial differential–integral equation has been derived to connect vapor condensation and the development of condensate film thickness in both the tangential and axial directions in a horizontal circular condenser tube. A high-order explicit numerical scheme is used to solve the strongly nonlinear equation. A simple strategy is applied to avoid possible large errors from high-order numerical differentiation when the condensate becomes stratified. A set of empirical friction factor and Nusselt number correlations covering both laminar and turbulent film condensation have been incorporated to realistically predict film thickness variation and concurrently allow for the predictions of local heat transfer coefficients. The predicted heat-transfer coefficients of film condensation for refrigerant R134a and water vapor in horizontal circular mini- and macrotubes, respectively, have been compared with the results from experiments and the results from the simulations of film condensation using computational fluid dynamics (CFD), and very good agreements have been found. Some of the predicted film condensations are well into the strong stratification regime, and the results show that, in general, the condensate is close to annular near the inlet of the condenser tube and becomes gradually stratified as the condensate travels further away from the inlet for all the simulated conditions. The results also show that the condensate in the minitubes becomes stratified much earlier than that in the macrotubes.

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