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An Experimental Study on Dryout Pattern of Two-Phase Flow in Helically Coiled Tubes  

Chung, Won-Seok (School of Mechanical and Aerospace Engineering, Seoul National University)
Sa, Young-Cheol (School of Mechanical and Aerospace Engineering, Seoul National University)
Lee, Joon-Sik (School of Mechanical and Aerospace Engineering, Seoul National University)
Publication Information
Journal of Mechanical Science and Technology / v.16, no.11, 2002 , pp. 1540-1549 More about this Journal
Abstract
Experimental results are presented for the effects of coil diameter, system pressure and mass flux on dryout pattern of two-phase flow in helically coiled tubes. Two tubes with coil diameters of 215 and 485 mm are used in the present study, Inlet system pressures range from 0.3 to 0.7 MPa, mass flux from 300 to 500 kg/㎡s, and heat flux from 36 to 80 kw/㎡. A partial dryout region exists because of the geometrical characteristics of the helically coiled tube. The length of the partial dryout region increases with coil diameter and system pressure. On the other hand, it decreases with increasing mass flux. The critical quality at the tube top side increases with mass flux, but decreases with increasing system pressure. This tendency is more notable when the coil diameter is larger. When the centrifugal force effect becomes stronger, dryout starts at the top and bottom sides of the tube. However, when the gravity effect becomes stronger, dryout is delayed at the tube bottom side. In some cases when the mass flux is low, dryout occurs earlier at the outer side than at the inner side of the tube because of film inversion.
Keywords
Helically Coiled Tube; Dryout; Critical; Quality;
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  • Reference
1 Banerjee, S., Rhodes E. and Scott D.S., 1967, 'Film Inversion of Cocurrent Two-Phase Flow in Helical Coils,' AIChE Journal, Vol. 13, pp. 189-191   DOI
2 Berthoud, G. and Jayanti, S., 1990, 'Characterization of Dryout in Helical Coils,' Int. J. Heat Mass Transfer, Vol. 33, pp. 1451-1463   DOI   ScienceOn
3 Chen, T.K., Bi, Q.C. and Chen, X.J., 1993, 'Critical Heat Flux and Post CHF Heat Transfer of Steam Water Two Phase Flow in Helical Coil Tubes,' Experimental Heat Transfer, Fluid Mechanics and Thermodynamics, pp. 1283-1290
4 Guo, L., Chen, X., Xu, C. and Lai, K., 1998, 'Forced Convection Boiling Heat Transfer and Dryout Characteristics in Helical Coiled Tubes with Various Axial Angles,' Proc. 11th IHTC, Vol. 2, pp. 261-266
5 Jensen, M.K. and Bergles, A.E., 1981, 'Critical Heat Flux in Helically Coiled Tubes,' J. Heat Transfer, Vol. 103, pp. 660-666   DOI
6 Styrikovich, M.A., Polonsky, V.S. and Reshetov, V.V., 1984, 'Experimental Investigation of the Critical Heat Flux and Post-Dryout Temperature Regime of Helical Coils,' Int. J. Heat Transfer, Vol. 27, pp. 1245-1250   DOI   ScienceOn
7 Collier, J.G. and Thome, J.R., 1994, Convective Boiling and Condensation 3rd Edition, Oxford science publications
8 Kaji, M., Mori, K., Nakanishi, S., Hirabayashi, K. and Ohishi, M., 1995, 'Dryout and Wall-Temperature Fluctuations in Helically Coiled Evaporating Tubes,' Heat Transfer-Japanese Research, Vol. 24, pp. 239-254