Mesh for heat conduction

Munni

Hi folks:

I am modeling a pipe flow where the pipe thickness is considerable (i dont wanna use thin wall option in fluent). So my question is how many nodes do I have to place inside the solid wall for heat conduction. Lets say my pipe diamater is 100 mm, and wall thickess is 10 mm. So I can use my pipe mesh size 5-7, in that case I will have only 1 node inside the wall. Any idea or comments.

Thank you for you time.

Munni