On capillary-driven flow and phase-change heat transfer in a porous structure heated by a finned surface: measurements and modeling

Abstract Characteristics of capillary-driven flow and phase-change heat transfer in a porous structure heated with a permeable heating source at the top were studied experimentally and theoretically in this paper. The experiments show that for small and moderate heat fluxes, the whole porous structure was fully saturated with liquid except adjacent to the horizontal heated surface where evaporation took place uniformly. For higher heat fluxes, a two-phase zone developed in the upper portion of the porous structure while the lower portion of the porous structure was saturated with subcooled liquid. When the imposed heat flux was further increased, a vapor blanket formed below the heated surface and the corresponding critical heat flux was reached. The heat transfer coefficient was modeled by simultaneously solving the problem of evaporating capillary meniscus in the pore level and the problem of fluid flow through a porous medium. The model is in good agreement with the experimental data, predicting the variations of the heat transfer coefficient with the increasing heating load.

[1]  E. Parmentier,et al.  Two phase natural convection adjacent to a vertical heated surface in a permeable medium , 1979 .

[2]  P. Witherspoon,et al.  Study of two-phase concurrent flow of steam and water in an unconsolidated porous medium , 1985 .

[3]  A. S. Demidov,et al.  Investigation of heat and mass transfer in the evaporation zone of a heat pipe operating by the ‘inverted meniscus’ principle , 1994 .

[4]  Cheng Ping,et al.  The effect of subcooled liquid on film boiling about a vertical heated surface in a porous medium , 1981 .

[5]  E. Kroliczek,et al.  Application of capillary pumped loop heat transport systems to largespacecraft , 1986 .

[6]  Sankaran Sundaresan,et al.  Onset of pulsing in two‐phase cocurrent downflow through a packed bed , 1988 .

[7]  K. Udell,et al.  Heat transfer in porous media heated from above with evaporation, condensation, and capillary effects , 1983 .

[8]  Kenneth E. Torrance,et al.  Boiling in a porous layer heated from below: effects of natural convection and a moving liquid/two-phase interface , 1993, Journal of Fluid Mechanics.

[9]  Amir Faghri,et al.  Heat Pipe Science And Technology , 1995 .

[10]  D. Turcotte,et al.  An experimental study of two‐phase convection in a porous medium with applications to geological problems , 1977 .

[11]  Amir Faghri,et al.  Heat transfer in the inverted meniscus type evaporator at high heat fluxes , 1995 .

[12]  W. Taylor,et al.  Functional and performance tests of two capillary pumped loop engineering models , 1986 .

[13]  P. Wayner,et al.  The interline heat-transfer coefficient of an evaporating wetting film , 1976 .

[14]  Chao-Yang Wang,et al.  Multiphase flow and heat transfer in porous media , 1997 .

[15]  Christoph Beckermann,et al.  A two-phase mixture model of liquid-gas flow and heat transfer in capillary porous media—II. Application to pressure-driven boiling flow adjacent to a vertical heated plate , 1993 .