An Analytic Study on Laminar Film Condensation along the Interior Surface of a Cave-Shaped Cavity of a Flat Plate Heat Pipe

  • Lee, Jin-Sung (Computational science & Engineering (CSE) Center, Samsung Advanced Institute of Tech.) ;
  • Kim, Tae-Gyu (Computational science & Engineering (CSE) Center, Samsung Advanced Institute of Tech.) ;
  • Park, Tae-Sang (Computational science & Engineering (CSE) Center, Samsung Advanced Institute of Tech.) ;
  • Kim, Choong-Sik (Computational science & Engineering (CSE) Center, Samsung Advanced Institute of Tech.)
  • 발행 : 2002.07.01

초록

An analytic approach has been employed to study condensate film thickness distribution inside cave-shaped cavity of a flat plate heat pipe. The results indicate that the condensate film thickness largely depends on mass flow rate and local velocity of condensate. The increasing rate of condensate film for circular region reveals about 50% higher value than that of vertical region. The physical properties of working fluid affect significantly the condensate film thickness, such as the condensate film thickness for the case of FC-40 are 5 times larger than that of water. In comparison with condensation on a vertical wall, the average heat transfer coefficient in the cave-shaped cavity presented 10∼15% lower values due to the fact that the average film thickness formed inside the cave-shaped cavity was larger than that of the vertical wall with an equivalent flow length. A correlation formula which is based on the condensate film analysis for the cave-shaped cavity to predict average heat transfer coefficient is presented. Also, the critical minimum fill charge ratio of working fluid based on condensate film analysis has been predicted, and the minimum fill charge ratios for FC-40 and water are about Ψ$\_$crit/=3∼7%, Ψ$\_$crit/=0.5∼1.3% respectively, in the range of heat flux q"=5∼90kW/㎡.

키워드

참고문헌

  1. Kamel, A. R. and Mauricio, A. Z., 1991, 'Modeling and Analysis of Flat Plate Heat Pipe with Sintered Wick,' Proceedings of the 7th Int. Heat Pipe Conference, pp. 433-440
  2. Krupiczka, R., 1985, 'Effect of Surface Tension on Laminar Film Condensation on a Horizontal Cylinder,' Chem. Eng. Process, Vol. 19, pp. 199-203 https://doi.org/10.1016/0255-2701(84)80022-7
  3. Memory, S. B., Adams, V. H. and Marto, P. J., 1997, 'Free and Forced Convection Laminar Film Condensation on Horizontal Elliptical Tubes,' Int. J. of Heat and Mass Transfer, Vol. 40, pp. 3395-3406 https://doi.org/10.1016/S0017-9310(96)00374-2
  4. Mossad, M., 1999, 'Combined Free and Forced Convection Laminar Film Condensation on an Inclined Circular tube with isothermal surface,' Int. J. of Heat and Mass Transfer, Vol. 42, pp. 4017-4025 https://doi.org/10.1016/S0017-9310(99)00032-0
  5. Mou, Q. and Gamal, M. G., 1997, 'Theoretical and Experimental Investigation of Flat Plate Heat Pipe for Electronic Cooling,' Proceedings of the 10th Int. Heat Pipe Conference
  6. Ooijen, H. V. and Hoogendoorn, C. J., 1979, 'Vapor Flow Calculations in a Flat Plate Heat Pipe,' AIAA Journal, Vol. 17, pp. 1251-1259 https://doi.org/10.2514/3.61306
  7. Tan, B. K., Huang, X. Y., Wong, T. N. and Ooi, K. T., 2000, 'A Study of Multiple Heat Sources on a Plate Heat Pipe Using a Point Source Approach,' Int. J. of Heat and Mass Transfer, Vol. 43, pp. 3755-3764 https://doi.org/10.1016/S0017-9310(00)00016-8
  8. Vafai, K. and Wang, W., 1992, 'Analysis of Flow and Heat Transfer Characteristics of an Asymmetrical Flat Plate Heat Pipe,' Int. J. of Heat and Mass Transfer, Vol. 35, pp. 2087-2099 https://doi.org/10.1016/0017-9310(92)90054-V
  9. Vafai, K., Zhu, N. and Wang, W., 1995, 'Analysis of Asymmetric Disk Shaped and Flat Plate Heat Pipes,' J. of Heat Transfer, Vol. 117, pp. 209-218 https://doi.org/10.1115/1.2822305
  10. Wang, B. X. and Du, X. Z., 2000, 'Study on Laminar Filmwise Condensation for Vapor Flow in an Inclined Small/Mini-Diameter Tube,' Int. J. of Heat and Mass Transfer, Vol. 43, pp. 1859-1868 https://doi.org/10.1016/S0017-9310(99)00256-2
  11. Wang, Y;Vafai, K. An Experimental Investigation of the Thermal Performance of an Asymmetrical Flat Plate Heat Pipe Int. J. of Heat and Mass Transfer https://doi.org/10.1016/S0017-9310(99)00300-2
  12. Yang, S. A. and Hsu, C. H., 1997, 'Free and Forced Convection Film Condensation from a Horizontal Elliptic Tube with a Vertical Platte and Horizontal Tube as Special Cases,' Int. J. of Heat and Fluid Flow, Vol. 18, pp. 567-574 https://doi.org/10.1016/S0142-727X(97)00025-8