Nusselt Number Decreasing with increasing Nanoparticle Volume Fraction
 

Hello Good People!

I have calculated Nu no. value in ANSYS fluent for nanofluid passing through a pipe with constant heat flux at the wall. Velocity inlet and pressure outlet condition. But with the increase in nanoparticle volume fraction my Nu is decreasing. This is not expected. Nu needs to be increasing.

I achieved the increase in Nu by changing the Energy value in the Solution Control. As I decrease the Energy value in every simulation (0.60, 0.58, 0.56 etc) the Nu value increases. But this is not the right approach.

Need you guys suggestion, How can I solve this issue?