Journal of Mechanical Science and Technology

The Korean Society of Mechanical Engineers (대한기계학회)
권호 표지

Coupled Heat and Mass Transfer in Absorption of Water Vapor into LiBr-$H_2O$ Solution Flowing on Finned Inclined Surfaces

  • Seo, Taebeom (Department of Mechanical Engineering, Inha University) ;
  • Cho, Eunjun (Department of Mechanical Engineering, Inha University)
  • Published : 2004.07.01
Download PDF
⟨ Previous Next ⟩

Abstract

The absorption characteristics of water vapor into a LiBr-H$_2$O solution flowing down on finned inclined surfaces are numerically investigated in order to study the absorbing performances of different surface shapes of finned tubes as an absorber element. A three-dimensional numerical model is developed. The momentum, energy, and diffusion equations are solved simultaneously using a finite difference method. In order to obtain the temperature and concentration distributions, the Runge-Kutta and the Successive over relaxation methods are used. The flat, circular, elliptic, and parabolic shapes of the tube surfaces are considered in order to find the optimal surface shapes for absorption. In addition, the effects of the fin intervals and Reynolds numbers are studied. The results show that the absorption mainly happens near the fin tip due to the temperature and concentration gradient, and the absorbing performance of the parabolic surface is better than those of the other surfaces.

Keywords

References

  1. Grossman, G., 1983, 'Simultaneous heat and mass transfer in film absorption under laminar flow,' International Journal of Heat and Moss Transfer, 26, 357 https://doi.org/10.1016/0017-9310(83)90040-6
  2. Habib, H. M. and Wood, B. D., 1990, 'Simultaneous heat and mass transfer for a falling film absorber,' the Proceedings of the 12th annual ASME International Solar Energy Conference, 61
  3. Hijikata, K., Lee, S. K. and Nagasaki, T., 1993, 'Water vapor absorption enhancement in $LiBr-H_2O$ films falling on horizontal tubes,' Journal of the Japan Society of Mechanical Engineers, 58, 243-248
  4. Isshiki, N. and Ogawa, K., 1987, 'New thermodynamic cycles for utilization of low temperature difference energy sources and new heating surface called CCS,' JSME 25th Power-Energy Utilization Symposium, Tokyo, 63
  5. Lee, K. S., Seo, S. C., Kim, Y. I. and Park, D. K., 1988, 'Coupled heat and mass transfer during the absorption of water vapor into $LiBr-H_2O$ liquid solution flowing down the outside of the horizontal cylinder,' Korean Journal of Air-Conditioning and Refrigeration Engineering, 17, 140
  6. Mcneely, L. A., 1985, 'Thermodynamic properties of aqueous solutions of lithium bromide,' ASHRAE Trans, 413
  7. Uddholm, H. and Setterwall, F., 1988, 'Moded for dimensioning a falling film absorber in an absorption heat pump,' International Journal of Refrigeration, 11, 41 https://doi.org/10.1016/0140-7007(88)90010-2
  8. Vikas, P. and Parez-Blanco, H., 1996, 'A study of absorption enhancement by wavy film flows,' International Journal of Heat and Fluid Flow, 17, 71 https://doi.org/10.1016/0142-727X(95)00076-3
  9. Wasden, F. K. and Dukler, A. E., 1990, 'A numerical study of mass transfer in free falling wavy films,' AIChE Journal, 36, 1379 https://doi.org/10.1002/aic.690360911
  10. White, F. M., 1997, Fluid Mechanics, 3rd ed., McGraw Hill international editions, 26
  11. Yang, Ru. and Wood, Byard D., 1991, 'A numerical solution of the wavy motion on a falling liquid film,' The Canadian Journal of Chemical Engineering, 69, 723 https://doi.org/10.1002/cjce.5450690314
  12. Yih, S. M. and Seagrave, R. C., 1980, 'Mass transfer in laminar falling liquid film with accompanying heat and interfacial shear,' International Journal of Heat and Mass Transfer, 23, 749 https://doi.org/10.1016/0017-9310(80)90028-9