Theoretical vs Experimental Equations?

[NedM.]

Hi. I am calculating the pressure loss through straight pipes and pressure loss through pipe fittings. I need to compare the theoretical value with to the actual experimental values. But the thing is, do I use the Darcy equation for both calculations or are there separate equations to calculate these pressure losses?

 

[bigfooted]

The equations are the same, but the friction factors for straight pipes can be found in Moody diagrams whereas the friction factor for fittings are usually given as a constant for the specific geometry, see e.g. Cengel and Turner, Lienhard&Lienhard or other standard engineering textbooks.