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Byun, Jung-Hwan;Lee, Sung-Hong
- Transactions of the Korean Society of Mechanical Engineers B
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- v.26 no.11
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- pp.1513-1520
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- 2002
Effect of Convex Surface Curvature on the Onset of Nucleate Boiling of Subcooled Fluid Flow in Vertical Concentric Annuli An experimental study has been carried out to investigate the effect of the transverse convex surface curvature of core tubes on heat transfer in concentric annular tubes. Water is used as the working fluid. Three annuli having a different radius of the inner cores, Ri=3.18mm, 6.35mm, and 12.70mm with a fixed ratio of Ri/Ro=0.5 are used over a range of the Reynolds number between about 40,000 and 80,000. The inner cores are made of smooth stainless steel tubes and heated electrically to provide constant heat fluxes throughout the whole length of each test section. Experimental result shows that heat flux values on the onset of nucleate boiling of the smaller inner diameter model is much higher than that of the larger size test model.
https://doi.org/10.3795/KSME-B.2002.26.11.1513 인용 PDF KSCI

Cha, Sang-Jin;Kim, Nae-Hyun;Ryu, Jin-Sang
- Korean Journal of Air-Conditioning and Refrigeration Engineering
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- v.23 no.9
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- pp.595-603
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- 2011
In this study, an effort has been made to analyze the subcooled boiling heat transfer in a natural circulation vertical evaporator. To verify the analysis, a small-scale model was made and tested. The friction correlation by Ueda, void fraction and quality correlation by Saha and Zuber along with the superposition heat transfer model by Rohsenow yielded a satisfactory agreement with the model test data. The analysis was extended to simulate a 1 ton/day concentration system. Comparison with the test results of 1 ton/day prototype revealed that the data were overpredicted by 13%. The capacity of the prototype was 1.2 ton/day with COP of 5.77.
https://doi.org/10.6110/KJACR.2011.23.9.595 인용 PDF KSCI

Kwon, Yong-Min;Cahng, Soon-Heung
- Proceedings of the Korean Nuclear Society Conference
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- 1998.05a
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- pp.449-456
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- 1998
A theoretical critical heat flux (CLE) model. based on lateral bubble coalescence on the heated wall, is proposed to predict the subcooled flow boiling CHF in a uniformly heated vertical tube. The model is based on the concept that a single layer of bubbles contacted to the heated wall events a bulk liquid from reaching the wall at near CHF condition. Comparisons between the model predictions and experimental data result in satisfactory agreement within less than 9.73 % root-mean-square error by the appropriate choice of the critical void fraction in the bubbly layer. The present model shows comparable performance with the CHF look-up table of Groeneveld et al.
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