System Curve for a network

[waseem19]

Hi,

I can easily draw a system curve for a single pipeline, but how do you do that when you have a network of pipes?

I know that each route will have a different system curve, should I just draw the system curve for the route that will give me the lowest pressure and match this with a pump curve?

can the system curve be combined from two different routes ?

thanks

 

[katmar]

Waseem,

You cannot generate a system curve in the normal sense because that would imply that for each flowrate there would be a unique pressure (head) required. By running multiple scenarios for your network you could generate a system "envelope" - i.e. an area on the pump curve that shows all the feasible combinations of head and flowrate.

From this you could see what pump would be required to satisfy the most extreme case (on the high flow and high head side of the envelope), plus from the other side of the envelope (low head, low flow) you can determine the turndown required in your control system.

Plotting the data this way will give you a much better "feel" for the problem than generating piles of paper printouts from your network program.

Good luck
Harvey

Katmar Software
Engineering & Risk Analysis Software

http://katmarsoftware.com

 

[stanier]

download Epanet and model your system a as network. With various legs of the network on you will get the duty point for your pump. Vary the pump speed to get an idea of the system curve for a rpticluar route.

Invest in Haestads Advanced Water Distribution System Modelling and Management. Haestads software uses the Epanet engine so many of the features described are available to you.

Geoffrey D Stone FIMechE C.Eng;FIEust CP Eng

http://www.waterhammer.bigblog.com.au

 

[BigInch]

You can draw system curves for "paths".