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Since87 · 05-06-2003, 11:26 PM

Some further torturing of Bill's latest data...

I took a subset of the data ( ID's from 6.1mm to 11.18 mm, and flowrates from 3.783 lpm to 11.35 lpm) and graphed dP vs ID for the four flow rates included.

I used log scale for the dP axis because it can clarify (exaggerate?) patterns in the data.

Then I 'normalized' the four curves by dividing out flowrate^2 for each.

The black line I 'painted' in (actually something a bit less sloppy) is what I was inclined to use as a barb factor.

But I really disliked that 8.89mm ID number, so I just plopped 9.89 mm in instead. I really liked the results with 9.89, but I decided to take a look at the Imperial measurement and saw that it was 0.375". (or 9.525mm)

Here's the second graph redone with 9.525mm in place of 8.89mm.

I'm much happier now.

Too late at night for me to be coming up with an equation though.

Les,

How do you generate those polynomials from a set of data points? Is that something Excel can do?

05-06-2003, 11:26 PM	#102
Since87 Pro/Guru - Uber Mod Join Date: Sep 2002 Location: Indiana Posts: 834	Some further torturing of Bill's latest data... I took a subset of the data ( ID's from 6.1mm to 11.18 mm, and flowrates from 3.783 lpm to 11.35 lpm) and graphed dP vs ID for the four flow rates included. I used log scale for the dP axis because it can clarify (exaggerate?) patterns in the data. Then I 'normalized' the four curves by dividing out flowrate^2 for each. The black line I 'painted' in (actually something a bit less sloppy) is what I was inclined to use as a barb factor. But I really disliked that 8.89mm ID number, so I just plopped 9.89 mm in instead. I really liked the results with 9.89, but I decided to take a look at the Imperial measurement and saw that it was 0.375". (or 9.525mm) Here's the second graph redone with 9.525mm in place of 8.89mm. I'm much happier now. Too late at night for me to be coming up with an equation though. Les, How do you generate those polynomials from a set of data points? Is that something Excel can do?