getting negative values for Nusselt number and htc?

- May 26, 2019 at 2:36 pm
  
  hamda
  Subscriber
  
  Hi,
  
  I wrote some expressions for Nu and htc and when I drew contours I got negative values for them. Here are my expressions
  
  Myhtc=Wall Heat Flux/(T-780[K])
  Nu=Myhtc*0.06[m]/0.31[W m^-1 K^-1]
  But as it can be seen in the pic. I got negative values for Nu. Is there any problem related to the expressions?
  
  Thanks in advance
- June 4, 2019 at 9:56 am
  
  Rob
  Forum Moderator
  
  Look through the expression and work out how a negative number can be derived. As a hint, plot the temperature on the surface.
- June 19, 2019 at 1:22 pm
  
  hamda
  Subscriber
  
  Dear Rwoolhou,
  
  I did that but I didn't get a negative value for T. Just for Nu this happens.
- June 19, 2019 at 3:22 pm
  
  Rob
  Forum Moderator
  
  So
  
  ( T-780[K] ) > 0 ?
- June 19, 2019 at 3:49 pm
  
  hamda
  Subscriber
  
  So
  
  ( T-780[K] ) > 0 ?
  
  Yes
- June 20, 2019 at 10:05 am
  
  Rob
  Forum Moderator
  
  Can you plot wall heat flux?