Effect of circumferential pin thickness on condensate retention as a function of vapor velocity on horizontal pin-fin tubes

2015 ◽  
Vol 91 ◽  
pp. 245-251 ◽  
Author(s):  
Hafiz Muhammad Ali ◽  
Muhammad Abubaker
Keyword(s):  
Vapor Velocity ◽  
Pin Fin ◽  
Fin Tubes

EFFECT OF CONDENSATE FLOW RATE AND VAPOR VELOCITY ON CONDENSATE RETENTION FOR PIN-FIN TUBES

2019 ◽  
Vol 26 (6) ◽  
pp. 619-630
Author(s):  
Hassan Ali ◽  
Nasir Rafique ◽  
Amjad Hussain ◽  
Muazzam Ali ◽  
Haroon Farooq
Keyword(s):  
Flow Rate ◽  
Vapor Velocity ◽  
Pin Fin ◽  
Fin Tubes

Effect of vapour velocity on condensate retention on horizontal pin-fin tubes

2014 ◽  
Vol 86 ◽  
pp. 1001-1009 ◽  
Author(s):  
Hafiz Muhammad Ali ◽  
Muhammad Abubaker
Keyword(s):  
Pin Fin ◽  
Fin Tubes

Forced-Convection Condensation of Ethylene Glycol on Integral-Fin Tubes

2004 ◽  
Author(s):  
Satesh Namasivayam ◽  
Adrian Briggs
Keyword(s):  
Ethylene Glycol ◽  
Forced Convection ◽  
Experimental Studies ◽  
Heat Fluxes ◽  
Slight Reduction ◽  
Enhancement Ratio ◽  
Vapor Velocity ◽  
Wide Range ◽  
Plain Tube ◽  
Fin Tubes

This paper reports new experimental data for forced-convection condensation of ethylene glycol on a set of five single, copper, integral-fin tubes. The five tubes had fin root diameter of 12.7 mm, fin height and thickness of 1.6 mm and 0.25 mm respectively. Fin spacings were 0.25, 0.5, 1.0, 1.5 and 2.0 mm. A plain tube of outside diameter 12.7 mm was also tested. The tests, which were performed at near constant pressure of approximately 15 kPa, covered vapor velocities between 10 and 22 m/s and a wide range of heat fluxes. The best performing tube was that with a fin spacing of 0.5 mm, which had an enhancement ratio (compared to the plain tube at the same vapor-side temperature difference and vapor velocity) of 2.5 at the lowest vapor velocity tested, increasing to 2.7 at the highest. The increase in enhancement ratio with increasing vapor velocity, which is the opposite trend to that found in most earlier experimental studies, was thought to be due to a slight reduction in condensate flooding between the fins due to increased vapor shear.

Enhanced Condensation of Ethylene Glycol on Single Pin-Fin Tubes: Effect of Pin Geometry

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Hafiz Muhammad Ali ◽  
Adrian Briggs
Keyword(s):  
Heat Transfer ◽  
Surface Tension ◽  
Ethylene Glycol ◽  
Heat Transfer Enhancement ◽  
Surface Area ◽  
Two Dimensional ◽  
Transfer Enhancement ◽  
Pin Fin ◽  
Fin Tube ◽  
Fin Tubes

This paper presents a fundamental study into the underlying mechanisms influencing heat transfer during condensation on enhanced surfaces. New experimental data are reported for condensation of ethylene glycol at near atmospheric pressure and low velocity on 11 different 3-dimensional pin-fin tubes tested individually. Enhancements of the vapor-side, heat-transfer coefficients were found between 3 and 5.5 when compared to a plain tube at the same vapor-side temperature difference. Heat-transfer enhancement was found to be strongly dependent on the active surface area of the tubes, i.e., on the surface area of the parts of the tube and pin surface not covered by condensate retained by surface tension. For all the tubes, vapor-side, heat-transfer enhancements were found to be approximately twice the corresponding active-area enhancements. The best performing pin-fin tube gave a heat-transfer enhancement of 5.5; 17% higher than obtained from “optimised” two-dimensional fin-tubes reported in the literature and about 24% higher than the “equivalent” two-dimensional integral-fin tube (i.e., with the same fin-root diameter, longitudinal fin spacing and thickness, and fin height). The effects of surface area and surface tension induced enhancement and retention are discussed in the light of the new data and those of previous investigations.

Effect of Vapour Velocity on Condensation of Ethylene Glycol on Horizontal Integral Fin Tubes: Heat Transfer and Retention Angle Measurements

2010 ◽  
Author(s):  
Claire L. Fitzgerald ◽  
Adrian Briggs ◽  
Huasheng Wang ◽  
John W. Rose
Keyword(s):  
Heat Transfer ◽  
Ethylene Glycol ◽  
Root Diameter ◽  
Transfer Coefficients ◽  
Vapor Velocity ◽  
Finned Tubes ◽  
Tube Wall Temperature ◽  
Transfer And Retention ◽  
Plain Tube ◽  
Fin Tubes

Heat-transfer data are reported for forced-convection filmwise condensation of ethylene glycol flowing vertically downward over two single, horizontal instrumented integral-fin tubes and one plain tube. Vapor-side, heat-transfer coefficients were obtained by direct measurement of the tube wall temperature using two specially manufactured, instrumented tubes with thermocouples embedded in the tube walls. Both tubes have fin height of 1.6 mm and fin root diameter and 12.7 mm, with fin thickness and spacings of 0.3 mm and 0.6 mm, respectively for one of the tubes and 0.5 mm and 1 mm, respectively for the other. Tests were performed at low pressures; 5.59kPa, 8.15kPa and 11.23kPa, at nominal vapour velocities from 13m/s to 82 m/s. All the data show that both of the finned tubes provided an increase in heat flux at the same vapour-side temperature difference with increasing vapour velocity. Visual observations were made and photographs obtained of the fluid retention angle φf at each combination of vapor velocity and pressure tested. It was observed that the curvature of the meniscus was distorted by the increase in vapor velocity and in many cases, the extent of condensate flooding decreased compared to its value in the quiescent vapor case.

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