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laminr vs turbelent
Posted Aug 15, 2016, 12:21 a.m. EDT Fluid & Heat, Computational Fluid Dynamics (CFD), Mesh Version 5.1 3 Replies
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hello !
my model is PV cell with duct embedded below in order to cool it down . I used laminar conjugate heat transfer ,so the result show good .But depend on Reylond number the flow is turbulent so I try to solve it using k_epsilon turbulent but the result give unexpected high temperature for PV panel reaches to 90 c.As I know the turbelent flow rises the heat exchange coefficient .
my model is PV cell with duct embedded below in order to cool it down . I used laminar conjugate heat transfer ,so the result show good .But depend on Reylond number the flow is turbulent so I try to solve it using k_epsilon turbulent but the result give unexpected high temperature for PV panel reaches to 90 c.As I know the turbelent flow rises the heat exchange coefficient .
3 Replies Last Post Aug 15, 2016, 9:23 p.m. EDT
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Posted:
8 years ago
Dear Hussein,
In your model, check the wall lift off in length units. If the values are relatively large, you might want to switch to a low-reynolds k-eps model, spallart-Allmaras, or one of our algebraic models (L-VEL / algebraic Yplus), these do not use wall functions which can improve the accuracy in these type of thermal computations.
In your model I suspect that the wall lift off is relatively big, which isolated the panels.
Best regards,
Frank
In your model, check the wall lift off in length units. If the values are relatively large, you might want to switch to a low-reynolds k-eps model, spallart-Allmaras, or one of our algebraic models (L-VEL / algebraic Yplus), these do not use wall functions which can improve the accuracy in these type of thermal computations.
In your model I suspect that the wall lift off is relatively big, which isolated the panels.
Best regards,
Frank
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Posted:
8 years ago
Dear Frank ,
Thank you to quick reply !!
I use turbulent _epsilon with low-reynolds number as you advised me,but still have problem in solving ,as you can see from attached picture " time consuming with out finish ".
best regards,
hussein
Thank you to quick reply !!
I use turbulent _epsilon with low-reynolds number as you advised me,but still have problem in solving ,as you can see from attached picture " time consuming with out finish ".
best regards,
hussein
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Posted:
8 years ago
hello !!
dear Frank ,
1_spalart _Allmaras and y_ plus also give unexpected temperture !!!
2_L-vel give the same result with laminar flow !!
3_ How can I check the wall lift off in length units
4_did you expect that I have problem in mesh??
thanck you again
best regard,
hussein
dear Frank ,
1_spalart _Allmaras and y_ plus also give unexpected temperture !!!
2_L-vel give the same result with laminar flow !!
3_ How can I check the wall lift off in length units
4_did you expect that I have problem in mesh??
thanck you again
best regard,
hussein