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brandonbw (Civil/Environmental) (OP)
4 Oct 11 21:54
I was curious if anyone had a good excel spreadsheet they could share that solves for the Q through circle and rectangular pipes of different sizes (~4"-12") and materials (ABS, PVC and Iron).

B+W Engineering and Design
Los Angeles Civil and Structural Engineering

Helpful Member!  Wicsteve (Mechanical)
5 Oct 11 17:56
Not an excel spreadsheet but a program called 'SF Pressure Drop 7.0' available from Software-Factory.  It is free to try and costs a little over $100 (US.  Program was made by Nobert Schmitz (Germany).  Allows pipe expansions, contractions, etc. Allows elements to be ganged together and estimate flow and pressure drop. It also seems to have a good database for materials.

Can't swear to the accuacy, but I guess it's as good and any other calculator and resonably priced.  
brandonbw (Civil/Environmental) (OP)
5 Oct 11 19:13
Thanks, that's really nice.  Especially since it has a mobile version!

B+W Engineering and Design
Los Angeles Civil and Structural Engineering

brandonbw (Civil/Environmental) (OP)
10 Oct 11 17:06
After looking at that site closer, I was looking for something that is gravity flow through pipes, not forced pressure piping.

B+W Engineering and Design
Los Angeles Civil and Structural Engineering

Helpful Member!  gbam (Civil/Environmental)
10 Oct 11 17:26
Are you looking for full flow discharge?  If so, this equation (Manning's) is easy to code.

Qff = 0.4644/n * D^2.67 * S^0.5

Vff = 0.5913/n * D^0.67 * S^0.5

From FHWA HEC22.

For Partial Flow you can use a lookup routine and code a partial flow nomogragh in table form or actually compute the partial flow using the Manning's equation and the area and perimeter for a partial circle.

I coded this into visual basic for my calculator.  It is pretty straight forward and the excel solver could be used within a spreadsheet. I can upload the partial full pipe geometric equations if you'd like.
gbam (Civil/Environmental)
10 Oct 11 17:27
oops should have noted that the "D" is in feet and Q in cfs
brandonbw (Civil/Environmental) (OP)
10 Oct 11 17:39
Yes Full Flow Discharge is exactly what I am looking for, I should have been more specific.  Putting that into excel would be my goal.  Though putting that on my HP48 would be nice too.  

Any idea how to do this for a rectangle pipe?  Example 3" height x 5" width?  And D=FT and Q=CFS is what I need.

I have been working nonstop on some rush projects that last 2 weeks and can't think straight outside of the designs I am working on.


B+W Engineering and Design
Los Angeles Civil and Structural Engineering

gbam (Civil/Environmental)
11 Oct 11 10:46
Brandonbw - for rectangular shapes just use Manning's equation.  

Q=1.487/n * A * R^(2/3) * S^0.5
Where: A = H x W (ft^2)
       R = A/P (ft)
       S (ft/ft)
       Q (cfs)

Area and perimeter are geometric functions of your shape (rectangular) the coding into excel is straight forward.

You will need to obtain the roughness coefficient for your pipe material but there are many sources for that.  Another equation to use woiuld be the Chezy equation; you can look that up in any hydraulics text.

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