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