Continuing with our water distribution network example, we want to show you on this occasion the way in which you can use our water distribution networks design software, AQUEDUCTS, for the evaluation of the system’s operation.
We intend to explain in a simple way how to carry out an affectation analysis, so to speak, of the potable water service under the closure of one or more pipes in the network.
This affectation analysis, as you will see, will tell us in principle how much the water demand is reduced when the pipes are out of service in the network and, additionally, it will allow us to visualize in the software’s drawing area the parcels or sectors that are not being supplied from the water network.
In this way you can easily define or, even better, optimize the location of isolation valves in the network, which is one of the required tasks in all water supply network design.
We also want to make it clear that AQUEDUCTS offers you the option, through the use of demand parcels and demand polygons, to modify the water demand of the nodes of the network model in the event that pipes or nodes are isolated by the effect of the operational closure to which we have referred.
This is something you cannot do in programs like EPANET, among others, unless you manually make the modification yourself.
In our software this is automatic if you wish, allowing you to have a better approach to the real conditions in the hydraulic calculation.
But let’s start with the work…
SHOWING THE SECTORIZATION VALVES SYMBOL IN THE WATER DISTRIBUTION NETWORK DRAWING
The first thing I want you to see is that, for the purpose of representing the isolation valves of the water network, it is possible to change any pipe section to valve as you see here.
If I deactivate this checkbox, it will take the typical representation of a pipe section.
But if it is active, it will insert the valve symbol.
As I have said, this is only at the level of representation in the water distribution network plans and, of course, at the level of definition of the project’s parts list.
At the hydraulic calculation level, it is only important to have defined, if the method of localized head losses calculation is by head loss coefficients, that this pipe section has a valve through the fittings editor inside the pipeline section properties.
Now, suppose that I am in the phase of location of the sectorisation valves within the water distribution network project loaded in the software.
Generally, the codes standards of our countries dictate the guidelines for the location of these components. Usually they establish criteria so that it is not possible to isolate more than two blocks by closing four valves, among others.
Certainly, this is a process of trial and error, but with our software we hope to give you the tools that allow you to make decisions quickly and, of course, hydraulically justified.
Thus, in this process of valves allocation, I decide that I will place a couple of them in these two points.
So that operating these three, these three sections of pipe are isolated.
I quickly go to insert the nodes and change the pipe sections to valves to represent them in the drawing.
Note that, at this level in the Base Scenario, there is no change after performing the calculation.
The demand parcels are assigned to the pipe sections that are not defined as valves, and the nodes demands are redistributed to adjust them to the new topology of the water distribution network.
CREATING THE HYPOTHESIS TO MODEL THE CONDITION OF PIPE CLOSURE IN THE WATER SUPPLY NETWORK
However, what happens when these three valves are closed?
It is clear that the service to these three pipe sections will be annulled along with the supply of the parcels closest to those sections.
But, how do we visualize this in the drawing and numerically?
The answer is by creating a calculation hypothesis that allows us to specify to the software which pipe sections are closed, and thus we achieve a calculation according to the new condition.
We are going to generate a new hypothesis from the Calculation and Design panel.
As always, we assign a name.
A description.
and we make sure we place the appropriate demand factor for the condition we are evaluating.
Here it is important that you know what it means to have this option activated.
When it is checked, you are telling the software to take the pipes and nodes isolated by the closure as if they do not exist for the purposes of water demands calculation. That is, you will be able to more accurately reflect the operating condition generated by the network’s portion shut down.
On the other hand, if you deactivate it, the demands calculation will remain unchanged since it is considered that these pipelines will effectively receive the water necessary to serve the closest parcels.
You decide which one is best suited to your design. For us it will be activated.
I keep the changes, and, at this level, I should go to the pipes tab to tell the hypothesis which pipes will be closed at this time.
But since that is tedious to do from the table, what I will do is go to the drawing area.
I click on each of the pipe sections that I wish to set as closed.
And go to the DRAWING tab and use the Global Editor to modify these pipes only in current hypothesis.
Notice that the pipe sections already appear as selected in the list. We have not had to worry about identifying them in this dialog.
Then I activate the option to apply to the current hypothesis, thus telling the editor that the modification is not made in the network but in the current hypothesis.
And, finally, I activate the Closed property before clicking OK to make the changes.
Verify that the change is made at the level of the hypothesis for these pipes.
Indeed, we have modified them, so we are prepared to see what happens next.
DETERMINING ISOLATED ZONES WHEN VALVES ARE CLOSED
Before performing the hydraulic calculation, I’ll go to the PARCELS tab to show you something.
If I click the button for demands assignation, we can see a change in the results message.
The calculation of demands has been made, but it warns me that there are some parcels, 31 specifically, that have not been assigned.
For sure, you will know that those parcels are located in the influence area of the pipes we have closed.
In addition, when closing this dialog and looking at the summary table, we also see that the average demand has been reduced, because we have 31 parcels without service. Thus, you have a way to estimate the impact or reduction of the service, if you compare it with the total average flow of the network.
You will visually confirm which parcels these are when reviewing the assignment lines in the drawing area.
Note that these parcels do not have the respective assignment lines. Here you have, by calling it in some way, a service affectation plan. Don’t you think?
I’m going to change the color and thickness of the assignment lines from the layers manager to see it better.
Of course, you can now perform the hydraulic calculation with the new demand status.
The warning persists, although the calculation has no errors.
At the annotations level you will see the abbreviation of not available for the hydraulic values because, remember, these pipes do not exist for calculation purposes.
You will also see it at the nodes and pipes tables.
As already mentioned, you can modify this condition of not assigning demands to closed pipes, modifying this property in the properties dialog of the current hypothesis.
Notice that now, when I redo the calculation, the warning message disappears.
Assignment lines reappear for parcels that were previously isolated.
And, of course, the demand of the isolated nodes is kept if, in the hydraulic calculation, it is established that supply is possible.
In this specific case, there are no real changes because the nodes with demand are downstream of the valves or pipes we are closing. But in any case, the function is fulfilled.
And that’s it.
You could continue analyzing the location of the sectorization valves, even without modifying the network creating them. It is just required that you indicate the pipe sections that would be closed due to the valves presence, and then, once you confirm it is the appropriate option, apply the change for the effects of representation in your project plans and generation of a list of materials.
Thanks for staying with us.