Irricad

Hi,

just reading through some past forums, and nothing seems to fit my scenario.

I have a golf course with 6 bore-hole pumps, all with different flow rates yet same operating pressure, and all of them supply a common ring-main (or series of ring-mains). As the irrigation demand increases, the 1st pump turns on, then the 2nd, 3rd and so on, and vice-versa as the demand decreases.

What is the best way to analyse the hydraulics of this system, to assist with pipe sizing and pressure losses of the mainline pipework.

Thanks, Damian.

Hi Damian,

The method for a situation such as this is to make system flows to mirror the different flow conditions. One system flow would be where all water supplies and valves are running.
The number of system flows would be determined by the number of flow conditions you wish to check.
Apply each system flow number to the water supplies and valves running at that time.
If valves can run with other valves (i.e. no set group of valves to run together each time) instead of doing all combinations of operations estimate the critical conditions to reduce the number of system flows.

It is a little difficult to give specific advice without knowing the situation more fully. Do the pumps turn on in a particular order? If not, then there will be more flow conditions to analyse.

Here is a simplistic example:-
Sys Flow #1: WS1, WS2, WS3, WS4, WS5, WS6, Zones 1-60 (i.e. all running)
Sys Flow #2: WS1, Zones 1-10 (i.e. a scenario where 1/6 of the valves and water supplies are running)
Sys Flow #3: WS1, WS2, WS3, Z1-10, Z14-19, Z34-43, Z55-60 (i.e. a scenario where 1/2 of the valves and water supplies are running)

Thanks Jo,

your scenario's made perfect sense & covered what I needed, thanks.

One query I had in the process was what the Design Flow and Max Flow actually contributed to the analysis? IrriCAD did not seem to take these figures into account when analyzing the system - can they so the water supply only contributes a set amount of flow into the system?

Thanks again.

The flow demand in a design is based on the outlets running on each system flow. The Flow fields in the Water Supply dialog are simply for your reference, for example, if you have a limit on the water take.
There may be provision in a future version of IRRICAD to use these fields to help with analysing multiple water supply systems. This has been added to the Future Features Request list for consideration.