Assessment of boiling heat transfer correlations in the modelling of fin and tube heat exchangers

2007 ◽  
Vol 30 (6) ◽  
pp. 1004-1017 ◽  
Author(s):  
J.R. García-Cascales ◽  
F. Vera-García ◽  
J.M. Corberán-Salvador ◽  
J. Gonzálvez-Maciá ◽  
David Fuentes-Díaz
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Boiling Heat Transfer ◽  
Heat Transfer Correlations

Visualization of Boiling Heat Transfer on Micro Porous Coated Surface in Confined Space

2013 ◽  
Author(s):  
Chien-Yuh Yang ◽  
Chien-Fu Liu
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Boiling Heat Transfer ◽  
Heat Transfer Performance ◽  
Heating Surface ◽  
Nucleate Boiling ◽  
Confined Space ◽  
Two Phase ◽  
Nucleate Boiling Heat Transfer ◽  
Coated Surface

Numerous researches have been developed for pool boiling on microporous coated surface in the past decade. The nucleate boiling heat transfer was found to be increased by up to 4.5 times than that on uncoated surface. Recently, the two-phase micro heat exchangers have been considered for high flux electronic devices cooling. The enhancement techniques for improving the nucleate boiling heat transfer performance in the micro heat exchangers have gotten more importance. Previous studies of microporous coatings, however, have been restricted to boiling in unconfined space. No studies have been made on the feasibility of using microporous coatings for enhancing boiling in confined spaces. This study provides an experimental observation of the vapor generation and leaving processes on microporous coatings surface in a 1-mm confined space. It would be helpful for understanding the mechanism of boiling heat transfer and improving the design of two-phase micro heat exchangers. Aluminum particles of average diameter 20 μm were mixed with a binder and a carrier to develop a 150 μm thickness boiling enhancement paint on a 3.0 cm by 3.0 cm copper heating surface. The heating surface was covered by a thin glass plate with a 1 mm spacer to form a 1 mm vertical narrow space for the test section. The boiling phenomenon was recorded by a high speed camera. In addition to the three boiling regimes observed by Bonjour and Lallemand [1], i.e., isolated deformed bubbles, coalesced bubbles and partial dryout at low, moderate and high heat fluxes respectively in unconfined space, a suction and blowing process was observed at the highest heat flux condition. Owing to the space confinement, liquid was sucked and vapor was expelled periodically during the bubble generation process. This mechanism significantly enhanced the boiling heat transfer performance in confined space.

Boiling Heat Transfer With Freon 11 (R11) in Brazed Aluminum, Plate-Fin Heat Exchangers

1983 ◽  
Vol 105 (3) ◽  
pp. 605-610 ◽  
Author(s):  
J. M. Robertson ◽  
P. C. Lovegrove
Keyword(s):  
Heat Transfer ◽  
Test Section ◽  
Heat Exchangers ◽  
Boiling Heat Transfer ◽  
Industrial Process ◽  
Heat Fluxes ◽  
Test Fluid ◽  
Transfer Coefficients ◽  
Simple Method ◽  
Wide Range

The results of laboratory experiments with Freon 11 (R11) flowing in an electrically heated, serrated-fin test section to measure local boiling coefficients over a wide range of vapor quality, with mass fluxes up to 150 kg/m2 s, heat fluxes to 4 kW/m2, and pressure from 3–7 bar, are reported. These low mass and heat fluxes reflect the industrial process application of these heat exchangers where exceedingly small temperature differences may exist between streams. Results are compared with the very similar boiling characteristics previously reported elsewhere for the same test section, with liquid nitrogen as a test fluid under comparable flow conditions. A simple method using the Reynolds number of the total flow regarded as a liquid has been used to correlate boiling heat transfer coefficients with quality for both fluids. The use of a liquid-film flow model to produce a nondimensional correlation connecting the Nusselt, Reynolds, and Prandtl numbers of the film is discussed.

Assessment of condensation heat transfer correlations in the modelling of fin and tube heat exchangers

2007 ◽  
Vol 30 (6) ◽  
pp. 1018-1028 ◽  
Author(s):  
F. Vera-García ◽  
J.R. García-Cascales ◽  
J.M. Corberán-Salvador ◽  
J. Gonzálvez-Maciá ◽  
David Fuentes-Díaz
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Condensation Heat Transfer ◽  
Heat Transfer Correlations

A Modified Correlation for Flow Boiling Heat Transfer in Plate Heat Exchangers

2019 ◽  
Author(s):  
Tong Lv ◽  
Boren Zheng ◽  
Wei Li ◽  
Zahid Ayub
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Plate Heat ◽  
Error Band ◽  
Flow Boiling Heat Transfer ◽  
Compact Size ◽  
Wide Range ◽  
Data Points

Abstract Corrugated plate heat exchangers are increasingly used in two-phase flow applications for their flexible and compact size and the efficient heat transfer performance. This paper presents a review of recent studies on the subject and creates a database containing 533 data points from experiment studies. The collected database covers seven working fluids, a wide range of vapor quality (both mean and local) 0.01–0.94, heat flux 0.5–46 kW m−2, mass flux 5.5–137 kg m−2 s−1, chevron angle 30°–70°, and hydraulic diameter 1.7–4.0 mm. Based on the database a brief comparison between several previous correlations are discussed. A new prediction method for flow boiling heat transfer coefficient is generated by multiple regression analysis and modifying an existing correlation. It was observed that the modified correlation shows a better agreement and predicts 74.3% of data points within ±30% error band and 94.9% within ±50% error band.

Comparison of Selected Forced-Convection Supercritical-Water Heat-Transfer Correlations for Vertical Bare Tubes

2010 ◽  
Author(s):  
Amjad Farah ◽  
Krysten King ◽  
Sahil Gupta ◽  
Sarah Mokry ◽  
Wargha Peiman ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Supercritical Water ◽  
Heat Exchangers ◽  
Power Plants ◽  
Heat Fluxes ◽  
Operating Conditions ◽  
Transfer Coefficients ◽  
Heat Transfer Correlations ◽  
Bare Tube

This paper presents an extensive study of heat-transfer correlations applicable to supercritical-water flow in vertical bare tubes. A comprehensive dataset was collected from 33 papers by 27 authors, including more than 125 graphs and wide ranges of parameters. The parameters ranges were as follows: pressures 22.5–34.5 MPa, inlet temperatures 85–350°C, mass fluxes 250–3400 kg/m2s, heat fluxes 75–5,400 kW/m2), tube heated lengths 0.6–27.4 m, and tube inside diameters 2–36 mm. This combined dataset was then investigated and analyzed. Heat Transfer Coefficients (HTCs) and wall temperatures were calculated using various existing correlations and compared to the corresponding experimental results. Three correlations were used in this comparison: Bishop et al., Mokry et al. and modified Swenson et al. The main objective of this study was to select the best supercritical-water bare-tube correlation for HTC calculations in: 1) fuel bundles of SuperCritical Water-cooled Reactors (SCWRs) as a preliminary and conservative approach; 2) heat exchangers in case of indirect-cycle SCW Nuclear Power Plants (NPPs); and 3) heat exchangers in case of hydrogen co-generation at SCW NPPs from SCW side. From the beginning, all these three correlations were compared to the Kirillov et al. vertical bare-tube dataset. However, this dataset has a limited range of operating conditions in terms of a pressure (only one pressure value of 24 MPa) and one inside diameter (only 10 mm). Therefore, these correlations were compared with other datasets, which have a much wider range of operating conditions. The comparison showed that in most cases, the Bishop et al. correlation deviates significantly from the experimental data within the pseudocritical region and actually, underestimates the temperature at most times. On the other hand, the Mokry et al. and modified Swenson et al. correlations showed a relatively better fit within the most operating conditions. In general, the modified Swenson et al. correlation showed slightly better fit with the experimental data than other two correlations.

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