Variation of heat and mass transfer coefficients during drying of granular beds

Journal Article · Wed Aug 01 04:00:00 EDT 1990 · Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States)

DOI:https://doi.org/10.1115/1.2910439· OSTI ID:5288324

Rogers, J A; Kaviany, M ^[1]

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1. Univ. of Michigan, Ann Arbor (USA)

During convective drying of initially fully saturated granular beds, the solid matrix is gradually exposed to the ambient air, resulting in heat transfer to both the liquid and solid. In an attempt to examine the heat and mass transfer processes occurring on the surface and to examine the influence of particle size and Bond number on the drying rate, experiments are performed in which granular beds constructed of spherical particles (which range from d = 0.2 mm to d = 25.4 mm) are convectively dried. For beds constructed of very small particles (d = 0.2 mm, Bo = 0.0035) the surface areas of the liquid and solid are difficult to estimate due to the random arrangement of the particles. The experimental results confirm existing knowledge that the evaporation rate is nearly constant during the funicular state of drying. For beds constructed of large particles (d = 25.4 mm, Bo = 21.7) an estimate of the surface areas of the liquid and solid reveals that the surface areas and the evaporation rate are highly dependent on surface saturation, contact angle, and surface tension. The results indicate that heat transfer from the solid to the liquid is significant and that the heat and mass transfer processes are not analogous.

• OSTI ID: 5288324
• Journal Information: Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States), Journal Name: Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States) Vol. 112:3; ISSN 0022-1481; ISSN JHTRA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
COOLING
DRYING
ENERGY TRANSFER
EVAPORATION
EVAPORATIVE COOLING
GRANULAR MATERIALS
HEAT TRANSFER
MASS TRANSFER
MATERIALS
PERMEABILITY
PHASE TRANSFORMATIONS