heat transfer distribution
 

I have simulated problem , the base of channel is a heat transfer source ( constant ) , when i plot the total surface heat transfer flux at this section ( the base of the channel ) , its appear as a constant line exept at the end and beginning of the channel ?! i need sombody help me why this happen ??

http://www.cfd-online.com/Forums/att...on-vbvbvbv.jpg

can somebody get me some help ??

Hi,

What is the type of BC you gave to the base of the channel, is it heat flux or temperature?

Hi
Is your geometry 2D or 3D

Thanks for reply ......

my geometry is 3D

thanks for reply .......

heat flux

As the BC is heat flux, fluent will give you this result(constant heat flux), and if you want to check how the heat flux is changing along the channel base you have to use temperature as BC for the channel base.

but why there is jump in the end and the bedninig ??

I dont know why fluent give this jump, but have you checked the temperature variation along the channel base, and the heat transfer coefficient. If there isnt any thing wrong so it maybe something related to the nature of the mesh you are using.

the Tem distribution is ok but the Nu number dont go to standard ( 4.3 ) , Nu go to zero ??

could you put a picture of temperature and Nu plots.

i attached the pictures

The temperature of the channel base is decreasing, so Nu number must be increasing along the channel base, but Nu plot doesnt give you this result because of the jump of Nu number at the end of channel, so try to decrease the range of the Y-axis of the plot to see what is the real distribution of Nu number.

thanks for reply ...
what about Nu no didnt go to 4.32

Have you checked the reference values you are using like length and temperature.

yes i have checked it ...also i try to change it but still no way ..

Malay, did you solve your problem with the heat transfer spikes at each end? I am having similar issues. Could it be a problem in the mesh?

not yet ... do you have any idea ?

Success!
 

Malay,

Do you have a constant temperature value set for your inlet total temperature? If so, this may be a problem. For my inlet conditions, I imported a total temperature profile simulating a thermal boundary layer and this fixed the heat transfer spike at the inlet.

Best of luck!

Try to untick the "node values" option for your plot.