CFD simulation of fixed bed dryer by using porous media concepts: Unpeeled longan case
Keywords:
deep-bed dryer, longan, velocity and temperature distribution, Computational Fluid Dynamic (CFD), ANSYSAbstract
Quality of dried product depends on the temperature and velocity at each position in the dryer. Simultaneous microscopic and macroscopic simulation on Computational Fluid Dynamic (CFD) is a general problem of fixed bed dryer consisting of water transportation in porous media and dynamic flow of hot air in the dryer. Simplifying the dryer by assuming the packed bed as porous volume, viscous and inertial resistances (1/? and C2) are necessary for calculating the pressure drop and velocity change in the bulk. Comparing the ?P/L of the standard packing with experimental results, the porosity and resistance parameters can be estimated. Simulation of unmodified, adding false floor and invest mesh, and insulating the dryer wall are used for validation with previous results. Adding the round holed sieve as false floor and invert mesh can produce better profile but cannot obtain uniform distribution. Air velocity distribution shows similar but the calculating temperature is higher than that from the experiment. By analysis of thermal efficiency of dryer without insulator, the heat loss rates with flue gas and heat flux at wall are in the range 14%-17% and 5.5%-7.3%. Integrating with single fruit or thin layer drying kinetic in the future, the CFD simulation can be used for optimal design of fixed bed dryer.References
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[8] Azc
[2] Xia B, Sun D W. Applications of computational fluid dynamics (CFD) in the food industry: A review. Computers and Electronics in Agriculture, 2002; 34(1-3): 5-24.
[3] Lawrence J, Maier D E. Three-dimensional airflow distribution in a maize silo with peaked, levelled and cored grain mass configurations. Biosystems Engineering, 2011; 110(3): 321-329.
[4] Molenda M, Montross M D, McNeill S G, Horabik J. Airflow resistance of seeds at diferent bulk density using Ergun's equation. Transactions of the ASAE, 2005; 48(3): 1137-1145.
[5] McCabe W L, Smith J C, Harriott P. Unit Operations of Chemical Engineering. 6th Ed. New York: McGraw-Hill Higher Education; 2001.
[6] Phaphuangwittayakul W, Alikhani Z, limpiti S. A batch dryer for un-peeled longan drying. Agricultural Mechanization in Asia, Africa and Latin America, 2004; 35(1): 41-44.
[7] Henz L C. Thermal efficiency investigation of a longan dryer in Chiang Mai, Thailand. Project report, Stuttgart, Germany: University of Hohenheim; 2005.
[8] Azc
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Published
2013-03-19
How to Cite
Prukwarun, W., Khumchoo, W., Seancotr, W., & Phupaichitkun, S. (2013). CFD simulation of fixed bed dryer by using porous media concepts: Unpeeled longan case. International Journal of Agricultural and Biological Engineering, 6(1), 100–110. Retrieved from https://ijabe.migration.pkpps03.publicknowledgeproject.org/index.php/ijabe/article/view/677
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Agro-product and Food Processing Systems
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