# Natural Convection in an enclosure

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 January 24, 2017, 09:18 Natural Convection in an enclosure #1 New Member   Asiyanbi Naim Abiodun Join Date: Jan 2017 Posts: 1 Rep Power: 0 Am running an analysis on natural convection in an enclosure with FLUENT 14 using standard boussinesq air properties ,what is the yardstick for choosing the operating temperature? How do i define the Rayleigh number since it is not available as input parameter in fluent? Do i have to read the fluid properties at the chosen operating temperature?

 January 24, 2017, 23:39 #2 Member   Vignesh Lakshmanan Join Date: Nov 2016 Location: India Posts: 65 Rep Power: 5 I think you have to specify the fluid props in the materials panel to input the Rayleigh number. Regarding Operating temperature, I cant be of much help because I too have the same question Regards Vicky

 January 24, 2017, 23:51 NAtural Convection in a closed ENclosure #3 Member   Vignesh Lakshmanan Join Date: Nov 2016 Location: India Posts: 65 Rep Power: 5 Hi All, I am trying to simulate using Fluent natural convection inside a deep freezer geometry, whose walls are maintained at 253 K and the air inside is at 316 K. My aim is to simulate the time required for cooling of air from 316 to 255 K . My questions are: 1) What should be the temperature at which I can define material properties of air ? ( Is it the wall temperature or air temperature?) 2) What should be the operating temperature in my case? 3) Also should the operating temperature and the input density be given as reference values also?? I am planning to use the Boussinessq approximation and run a transcient simulation but the material properties are confusing me Thanks and Regards Vicky

April 11, 2017, 10:22
#4
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alireza keyhani
Join Date: Feb 2017
Posts: 4
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Quote:
 Originally Posted by Ifenaim Am running an analysis on natural convection in an enclosure with FLUENT 14 using standard boussinesq air properties ,what is the yardstick for choosing the operating temperature? How do i define the Rayleigh number since it is not available as input parameter in fluent? Do i have to read the fluid properties at the chosen operating temperature?

hi
how are the walls of your enclosure ?
regards