PDA modle

[chocolate-771]

In EPANET2.2, the critical pressure can only be set to a constant value. How to deal with different critical pressures in the water supply network?

[LRossman]

By "critical pressure" I assume you mean the pressure below which no demand can be delivered under a pressure driven analysis. Additional code would have to be written to allow this value to vary between different network nodes, probably by adding Minimum Pressure and Required Pressure properties to a Node object that would override the global values. The ability to read these values for specific nodes from an input file and from a function call would also be needed.

[chocolate-771]

Thank you for your reply. Do you mean the redevelopment of EPANET2.2? Can I use the toolbox in matlab to achieve this function?

[Mariosmsk]

Hi @chocolate-771, on Matlab you can use the following example:

% Input Arguments:
%   type - Type of demand model
%       'DDA' = Demand driven analysis (in which case the remaining three parameter values are ignored)
%       'PDA' = Pressure driven analysis
%   pmin - Pressure below which there is no demand
%   preq - Pressure required to deliver full demand
%   pexp - Pressure exponent in demand function

type = 'PDA';
pmin = 0;
preq = 0.1;
pexp = 0.5;
d.setDemandModel(type, pmin, preq, pexp);   % Sets the demand model
d.getDemandModel

https://github.com/OpenWaterAnalytics/EPANET-Matlab-Toolkit/blob/dev-2.2-edit/examples/EX21_Pressure_driven_analysis_option.m

[chocolate-771]

@Mariosmsk Thank you for your reply. Year，I know this.When the pressure below which no demand, if the pmin and preq of each node are different, it doesn't work, can this extension program set the pmin and preq of each node in the water supply network?

[LRossman]

@chocolate-771 the EPANET source code would have to be modified to allow pmin and preq to vary among particular nodes. You cannot do this using the current toolkit DLL (or its MatLab interface). If you want to, you could close this issue and submit a new one with an "enhancement" label asking that this feature be added to a future update.

[chocolate-771]

@LRossman
Thank for your reply, I get it.