The study on heat, mass transfer and stress of porous medium vacuum drying

2009 ◽  
Author(s):  
Zhang Zhijun ◽  
Xu Chenghai ◽  
Zhang Shiwei ◽  
Zhao Lili
Keyword(s):  
Mass Transfer ◽  
Porous Medium ◽  
Heat Mass Transfer ◽  
Vacuum Drying ◽  
Medium Vacuum

scholarly journals Cortex Effect on Vacuum Drying Process of Porous Medium

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Zhijun Zhang ◽  
Shiwei Zhang ◽  
Tianyi Su ◽  
Shuangshuang Zhao
Keyword(s):  
Mass Transfer ◽  
Porous Medium ◽  
Fruits And Vegetables ◽  
Water Saturation ◽  
Coupled Model ◽  
Water Evaporation ◽  
Vacuum Drying ◽  
Vapor Pressures ◽  
Drying Process ◽  
Medium Vacuum

Corns, fruits, and vegetables are usually used as porous medium in drying process. But in fact, it must be considered as the cortex effect on mass transfer because the mass transfer of cortex is very difficult than inner medium. Based on the theory of heat and mass transfer, a coupled model for the porous medium vacuum drying process with cortex effect is constructed. The model is implemented and solved using COMSOL software. The water evaporation rate is determined using a nonequilibrium method with the rate constant parameterKrthat has been studied. The effects of different vapor pressures (1000, 5000, and 9000 Pa), initial moisture contents (0.3, 0.4, and 0.5 water saturation), drying temperatures (323, 333, and 343 K), and intrinsic permeability for cortex part (10−13, 10−14, 10−15 m2) on vacuum drying process were studied. The results facilitate a better understanding of the porous medium vacuum drying process that nearer to the reality.

scholarly journals Nonequilibrium Thermal Dynamic Modeling of Porous Medium Vacuum Drying Process

2012 ◽  
Vol 2012 ◽  
pp. 1-22 ◽  
Author(s):  
Zhijun Zhang ◽  
Ninghua Kong
Keyword(s):  
Mass Transfer ◽  
Porous Medium ◽  
Heat And Mass Transfer ◽  
Water Saturation ◽  
Coupled Model ◽  
Water Evaporation ◽  
Vacuum Drying ◽  
Vapor Pressures ◽  
Drying Process ◽  
Medium Vacuum

Porous medium vacuum drying is a complicated heat and mass transfer process. Based on the theory of heat and mass transfer, a coupled model for the porous medium vacuum drying process is constructed. The model is implemented and solved using COMSOL software. The water evaporation rate is determined using a nonequilibrium method with the rate constant parameterKr.  Krvalues of 1, 10, 1000, and 10000 are simulated. The effects of vapor pressures of 1000, 5000, and 9000 Pa; initial moistures of 0.6, 0.5, and 0.4 water saturation; heat temperatures of 323, 333, and 343 K; and intrinsic permeability of 10−13, 10−14, and 10−15 m2are studied. The results facilitate a better understanding of the porous medium vacuum drying process.

Free Convective Heat and Mass Transfer in a Doubly Stratified Porous Medium Saturated with a Power-Law Fluid

2009 ◽  
Vol 36 (6) ◽  
pp. 524-537 ◽  
Author(s):  
P. A. Lakshmi Narayana ◽  
P. V. S. N. Murthy ◽  
P. V. S. S. S. R. Krishna ◽  
Adrian Postelnicu
Keyword(s):  
Mass Transfer ◽  
Porous Medium ◽  
Heat And Mass Transfer ◽  
Convective Heat ◽  
Power Law ◽  
Power Law Fluid
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