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-   -   energy absorption instead generation (http://www.cfd-online.com/Forums/fluent/67854-energy-absorption-instead-generation.html)

bohis August 28, 2009 06:51

energy absorption instead generation
 
Hello there,

I face ti very interesting thing. My problem is related to viscous dissipation. My job is 2d axisymmetric tube. The non-newtonian fluid is the flowing medium. The inlet temperature is 19C. The tube external wall is cooled by water (temp of 5 C). In the core of flow, where there is almost no velocity gradient, I can clearly see drop temperatures about 2C. In near wall region, there is heat generation, thus temperatures are more than 19C.
Could anybody please explain to me this strange artificial heat absorption. I cannot even mathematically imagine, how it is even possible.
many thanks!!
Honza

bohis August 29, 2009 14:11

viscous heating
 
any idea, please!! ?? come on, guy. I do know..


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