Condensation heat transfer coefficients of binary HFC mixtures on low fin and Turbo-C tubes

Jung, Dongsoo; Chae, Soonam; Bae, Dongsoo; Yoo, Gilsang

doi:10.1016/j.ijrefrig.2004.07.023

Cited by 15 publications

(2 citation statements)

References 8 publications

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“…Jung et al [1][2][3] performed falling film condensation tests using plain, low-fin and enhanced tubes and pure refrigerants R-11, R-12, R-123, R-22, and R-134a, and zeotropic and azeotropic refrigerant mixtures R-407C, R-410A, R-32/R134a, and R-134a/R-123 on a test section comprised of a single tube at a saturation temperature of 39 • C. The finned tubes had 1,024 fins per meter, while the enhanced tube tested was the Turbo-C. Chang et al [4] performed tests on single tubes connected by a U-bend, at a saturation temperature of 39 • C on low-fin and 3D enhanced tubes, using refrigerant R-134a. The finned tubes had 1,024 and 1,574 fins per meter, while the two 3D enhanced tubes had T-and Yshape fins.…”

Section: Previous Heat Transfer Coefficient Studiesmentioning

confidence: 99%

Film Condensation of R-134a and R-236fa, Part 1: Experimental Results and Predictive Correlation for Single-Row Condensation on Enhanced Tubes

Christians

Habert

Thome

2010

Heat Transfer Engineering

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New predictive methods for falling film condensation on vertical arrays of horizontal tubes using different refrigerants are proposed, based on visual observations revealing that condensate is slung off the array of tubes sideways and significantly affects condensate inundation and thus the heat transfer process. For two types of three-dimensional enhanced tubes, advanced versions of the Wolverine Turbo-C and WielandGewa-C tubes, the local heat flux is correlated as a function of condensation temperature difference, the film Reynolds number, the tube spacing, and liquid slinging effect. The proposed methods work best when using R-134a, as these tubes were designed with this refrigerant in mind.

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Section: Previous Heat Transfer Coefficient Studiesmentioning

confidence: 99%

Film Condensation of R-134a and R-236fa, Part 1: Experimental Results and Predictive Correlation for Single-Row Condensation on Enhanced Tubes

Christians

Habert

Thome

2010

Heat Transfer Engineering

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“…Similarly the analysis of alternative refrigerants over smooth, low-fin and Turbo-C tubes is also presented by Jung [38]. It was found that for all refrigerants tested (R22, R407C and R410A) the HTCs for Turbo-C was the highest about 2-8% as compared to that of plain tubes as well as the condensation behavior of R407C is somewhat different than the other two refrigerants used and showed a 50% decrease in condensation HTC as compared to R22.Subsequently in an experimental study carried out by Jung [39] for somewhat different refrigerant mixtures of HFC32/HFC134a and HFC134a/HCFC123 (Non Azeotropic Refrigerant mixtures NARMs) for low-fin and Turbo-C tubes. The study recommended that the HTCs across enhanced tubes are severely affected more showing a decrease up to 96% than ideal values in respect of mixtures, and Turbo-C deteriorated more as compared to low-fin tubes.…”

Section: Experimental Heat Transfer Measurementsmentioning

confidence: 87%

An Overview of Recent Progress in Condensation Heat Transfer Enhancement Across Horizontal Tubes and the Tube Bundle

Bano

2021

Journal of Thermal Engineering

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The present paper presents a review of condensation heat transfer across smooth and enhanced horizontal surfaces due to its significance in refrigeration, air conditioning and heat pump applications. The emphasizes is on the recent understanding of experimental as well as the semi-empirical correlations to investigate the heat transfer phenomena during condensation associated with enhanced geometries. An effort has been made to submit freeconvection condensation effects outside of single tubes and the tube bundle with the influence of tube geometries, condensate retention and gravity on film condensation; however, comparison of forced convection is also presented. Alternative of conventional refrigerants in condensation process by low-global warming potential (GWP) refrigerants is addressed as well due to increase in atmospheric burden affected by hydro-fluoro-carbons (HFCs). Although many researchers have reviewed the condensation impact across enhanced surfaces, a few of them revised its behavior across pin-fin tubes. The effects of geometry, surface wettability, and operating conditions on the location, amount and form of condensate film are discussed. Various theoretical models prediction with the new experimental data across pin-fin tubes is also revealed. This review is distributed into two main sections: the first section focuses on condensation across enhanced tubes, sub dividing the study into integral-fin and pin-fin tubes based on theoretical and experimental investigations. It covers the geometrical effects concerning three dimensional (3D) surfaces, fin density, fin spacing and fin thickness. The later part of the paper concentrates on condensation behavior across the tube bundle incorporating the effects of fin density and refrigerant mixtures highlighting both theoretical and experimental knowledge. Recent research shows an agreement between theoretical and experimental models in the defined area; though, a considerable amount of work on semi-empirical correlation formulation is visible in the literature. The strength of this paper is the latest findings on condensation against different geometrical parameters of extended surfaces specifically across pin-fin tubes and the tube bundle. Finally, theoretical enhancement factors along with many heat transfer correlations are presented and recommendations are suggested for the future work.

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Condensation heat transfer coefficients of HFC245fa on a horizontal plain tube

2010

Self Cite

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In this study, condensation heat transfer coefficients (HTCs) of HCFC22, HCFC123, HFC134a and HFC245fa are measured on a horizontal plain tube 19.0 mm outside diameter. All data are taken at the vapor temperature of 39 with a wall subcooling temperature 3-8 . Test results show the HTCs of newly developed alternative low vapor pressure refrigerant, HFC245fa, on a smooth tube are 9.5% higher than those of HCFC123 while they are 3.3% and 5.6% lower than those of HFC134a and HCFC22 respectively. Nusselt's prediction equation for a smooth tube underpredicts the measured data by 13.7% for all refrigerants while a modified equation yielded 5.9% deviation against all measured data. From the view point of environmental safety and condensation heat transfer, HFC245fa is a long term good candidate to replace HCFC123 used in centrifugal chillers.

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Condensation heat transfer coefficients of binary HFC mixtures on low fin and Turbo-C tubes

Cited by 15 publications

References 8 publications

Film Condensation of R-134a and R-236fa, Part 1: Experimental Results and Predictive Correlation for Single-Row Condensation on Enhanced Tubes

Film Condensation of R-134a and R-236fa, Part 1: Experimental Results and Predictive Correlation for Single-Row Condensation on Enhanced Tubes

An Overview of Recent Progress in Condensation Heat Transfer Enhancement Across Horizontal Tubes and the Tube Bundle

Condensation heat transfer coefficients of HFC245fa on a horizontal plain tube

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