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Old   September 10, 2014, 16:22
Default Radiation on the surface
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jhon fredy hincapie
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Good all

I am modeling heat transfer with Natural convection and heat radiation. I have five temperature sensors; these sensors have different surface, Bright and black finish. Emissivity for bright sensors is (0.1) and black is (0.96). I'm not simulating combustion, I'm getting as input for speed burner and heat flux.

Doninio inside it has an entry cone froma with speed and heat flux. There are five temperature sensors (SAQ1, SAQ2, SAQ3, SAQ4, SAQ5). two of these sensors are black (SAQ2, SAQ3) and three diamonds. When I compare with the experimental data of the simulation, the highest temperatures are in bright sensors and lower temperatures in the black sensors. Compares the two types of visualization Hybrid and Conservative, and show very large differences in temperature. (Fig 1)(Fig3)

Hybrid visualization looks as shown in Fig 2
Boundary Data: conservative
-Min 341.165 [K]
-Max 641.306 [K]
Boundary Data: Hybrid
-Min 332.567 [K]
-Max 792.161 [K]
(Show Fig 2, Fig 4)

Radiation analysis is performed in this way
Thermal Radiation -> Monte Carlo /Number of histories -> 4000000 / Transfer model -> Surface to surface/ Spectral model -> Gray


I have no idea why this problem or I can do to fix it. I appreciate any collaboration or suggestion, thanks.
Attached Images
File Type: jpg Fig 1.jpg (67.5 KB, 1 views)
File Type: jpg fig 2.jpg (47.9 KB, 2 views)
File Type: jpg fig3.jpg (36.0 KB, 2 views)
File Type: jpg Fig 4.jpg (29.5 KB, 2 views)
Attached Files
File Type: txt CFX Radiation.txt (58.2 KB, 3 views)
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Old   September 10, 2014, 17:05
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Glenn Horrocks
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Have you read the FAQ on accuracy? http://www.cfd-online.com/Wiki/Ansys..._inaccurate.3F

Also, have you read the CFX documentation about the difference between hybrid and conservative variables?
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