경사면상의 층류 세류유동 특성

Flow Characteristics of a Laminar Rivulet Down an Inclined Surface

  • 김병주 (홍익대학교 기계 시스템디자인공학과)
  • Kim, Byong-Joo (Department of Mechanical and System Design Engineering, Hongik University)
  • 발행 : 2005.11.01

초록

In the present study, the principle of minimum energy is employed to configure the shape of rivulet flowing down an inclined surface. The profile of laminar rivulet is determined by numerical integration. The maximum center thickness, which corresponds to the minimum thickness of falling film, is found to exist regardless of liquid flow rate and is compared with the analytical and experimental data. At small liquid flow rate the center thickness of rivulet and its width increase almost linearly with flow rate. Once the center thickness of rivulet becomes very close to its maximum value, its growth rate retards abruptly. However the width of rivulet increases proportionally to the liquid flow rate and most part of its free surface is as flat as that of stable film. The growth rate of rivulet thickness with respect to liquid flow rate becomes larger at bigger contact angle. The width of rivulet increases rapidly with its flow rate especially at small contact angle, As the liquid-vapor interfacial shear stress increases, the center thickness of rivulet decreases with its flow rate, which is remarkable at small contact angle. However the effect of interfacial shear stress on the width of rivulet is almost negligible.

키워드

참고문헌

  1. Towell, G. D. and Rothfeld, L. B., 1966, Hydrodynamics of rivulet flow, A.I.Ch.E. Journal, Vol. 12, pp. 972-980 https://doi.org/10.1002/aic.690120524
  2. Bankoff, S. G., 1971, Minimum thickness of a draining film, Int. J. Heat Mass Transfer, Vol. 14, pp.2143-2146 https://doi.org/10.1016/0017-9310(71)90034-2
  3. Mikielewicz, J. and Moszynski, J. R., 1976, Minimum thickness of a liquid film flowing vertically down a solid surface, Int. J. Heat Mass Transfer, Vol. 19, pp.771-776 https://doi.org/10.1016/0017-9310(76)90130-7
  4. Doniec, A., 1988, Flow of a laminar film down a vertical surface, Chem. Engng. Sci., Vol. 43, pp.847-854 https://doi.org/10.1016/0009-2509(88)80080-0
  5. Doniec, A., 1991, Laminar flow of a liquid rivulet down a vertical solid surface, Can. J. Chem. Eng., Vol. 69, pp.198-202
  6. Hughies, D. T. and Bott, T. R., 1998, Minimum thickness of a liquid film flowing down a vertical tube, Int. J. Heat Mass Transfer, Vol. 41, pp.253-260 https://doi.org/10.1016/S0017-9310(97)00151-8
  7. Kim, B. J. and Choi, S. H., 1999, Study on the wetting characteristics of rivulet, '99 Summer Conference of SAREK, pp.936-940
  8. Nusselt, W., 1916, Die Oberflachenkondensation des Wasserdampfes, Z. Ver. Dtsch. Ing., Vol. 60, pp. 541-569
  9. Batchelor, G. K., 1983, An introduction to fluid dynamics, Cambrige University Press, New York, pp.63-70
  10. Hildebrand, F. B., 1965, Methods of Applied Mathematics, 2nd ed., Prentice-Hall
  11. Lance, G. N., 1960, Numerical methods for high speed computer, Iliffe & Sons, pp. 5457
  12. Hartley, D. E. and Murgatroyd, W., 1964, Criteria for the break-up of thin liquid layers flowing isothermally over solid surfaces, Int. J. Heat Mass Transfer, Vol. 77, pp. 1003-1015
  13. Hobler, T. and Czajka, J., 1968, Minimal wetting of flat surface, Chemia Stosow, Vol. 2B, pp. 169-186
  14. Munakata, T., Watanabe, K. and Miyashita, K., 1975, Minimum wetting rate on wetted-wall column, J. Chem. Engng. Japan, Vol. 8, p.440
  15. Ponter, A. B. and Boyes, A. P., 1972, The rupture of isothermal vertical liquid films, J. Chem. Engng. Japan, Vol. 5, p. 80 https://doi.org/10.1252/jcej.5.80