Thanks for your help Katmar, much appreciated. At least I can make progress to an acceptable solution.
Ione: actually I was just testing the equation for water first before I applied it to my application, so if you refer to Hills article: Designing Piping for Gravity Flow, Chemical Engineering...
Would appreciate some assistance: I've had a look at Art's Fluid Flow spreadsheet and using Hill's flow in a sloped line equation.
I keep getting a negative velocity (and hence a negative flow) as the log part of the equation is always less than one. This is mainly driven by the roughness and...
