Dear Epanet Users…
I’m new to Epanet, i’m working on a small community network, but i have a problem with water velocity in this network … Water velocity should be between 1-2m/s but it is not even if i reduced pipe diameter … Please advice what is the problem.
With best regards
This is the project:
Dear Sir, Can you please assist me!
Very grateful to your assistance…
I can’t identify the problem. On your model, the demand for all nodes is being satisfied, and as consequence pipe flows are low, so are the velocities. Are your sure the flow units used (cubic meter per hour) are the same of your demand data?
I’m appreciating your support,
I may entered wrong data units, my entry pipe diameter is in (mm), length (m), flow in CMH and this may be wrong, as the SI units, it pipe flow shall be in CMD, do you think so?
I think you made everything right but it’s just impossible to get water velocity at that range with the usual pipe diameters (75 mm i.e) in a small town like the one you’re modelling, that recommendation is for bigger places.
Thank you very much for the kind reply … you are 100% right as i have checked the pressure at nodes, Its average is 5.5 bar which is very good and acceptable.
Thank you again.
One last question; what is the limitation when i desgin a network? For example flow velocity in pipe shall be 1-2m/s… pressure @ junctions shall be at least 2.5bar … etc?
There are several books, standards or manuals you can read about water distribution for questions like that, for instance this one of IHE made by Dr. Trifunovic is free to use:
Thank you very much for your valuable assistance Mr. Matias …
the reason is that you have very low demands on your nodes, for example in each reservoir you are extracting 37 CMH which is equal to 10 LPS and considering a 200 mm diameter pipe you have a speed equal to (37/60 * 60) * 4 /(pi*(0.2^2))=0.32 m / s.
Check if your demands on the nodes are correct and if they are in the correct units (CMH is cubic meters per hour).
Remember that the speed should be between 0.3 and 3 m / s
M. Santos-Tellez Rodrigo Ulises
Urban Hydraulics Department
Mexican Institute of Water Technology
Tel. +52 (777) 329 3600 ext (366)