Heat transfer in oil (or other high Pr fluid) flows
 

Does anyone have experience with computing heat transfer in oil (or other high Pr fluid) flows? What is the ideal near wall spacing to use in such a case?

I'm interested in computing the Nu for both laminar as well as turbulent flow regimes in some tube cross-sections carrying oil and the Pr of the flows. I am looking at Pr values in the range of 100 - 150.