3.3 EPANET (Examples 3-5) using the Toolkit
Contents
3.3 EPANET (Examples 3-5) using the Toolkit#
Purpose#
This section continues the demonstration of the various previous examples using the Toolkit to run the example and make changes to inputs and rerun the examples. The main concept is that the Toolkit allows manipulation of models independent of a GUI which when combined with either Toolkit supplied control rules, or external “control” lets one model and interpret (assuming IF-THEN interpretation is amenable) many changes automatically.
Installation Notes#
The examples herein are run on the developmental computer (a Raspberry Pi). The scripts should work fine on another computer with the toolkit installed (Windows probably takes a bit more fussing to get the Linux subsystem to call to the Toolkit).
Example 3 : Three-Reservoir-Problem#
This example is a the classic hydraulics problem, that appears in some form in most if not all hydraulics textbooks; here we will use the already built input file - and note we wont use any of the basemap capabilities, as the Toolkit is not really intended for such direct graphics.
Recall the problem statement:
Reservoirs A, B, and C are connected as shown. The water elevations in reservoirs A, B, and C are 100 m, 80 m, and 60 m. The three pipes connecting the reservoirs meet at junction J, with pipe AJ being 900 m long, BJ being 800 m long, and CJ being 700 m long. The diameters of all the pipes are 850 mm. If all the pipes are ductile iron, and the water temperature is 293\(^o\)K, find the direction and magnitude of flow in each pipe.
The input file from earlier is copiec to our work directory; let’s list it
! cat ./ex3-tk/EX3.inp
[TITLE]
[JUNCTIONS]
;ID Elev Demand Pattern
NodeA 0 0 ;
NodeB 0 0 ;
NodeC 0 0 ;
J 110 0 ;
[RESERVOIRS]
;ID Head Pattern
A 100 ;
B 80 ;
C 60 ;
[TANKS]
;ID Elevation InitLevel MinLevel MaxLevel Diameter MinVol VolCurve Overflow
[PIPES]
;ID Node1 Node2 Length Diameter Roughness MinorLoss Status
PAJ NodeA J 900 850 0.1 0 Open ;
PBJ NodeB J 800 850 0.1 0 Open ;
PJC J NodeC 700 850 0.1 0 Open ;
4 A NodeA 10 2400 0.1 0 Open ;
5 B NodeB 10 2400 0.1 0 Open ;
6 C NodeC 10 2400 0.1 0 Open ;
[PUMPS]
;ID Node1 Node2 Parameters
[VALVES]
;ID Node1 Node2 Diameter Type Setting MinorLoss
[TAGS]
[DEMANDS]
;Junction Demand Pattern Category
[STATUS]
;ID Status/Setting
[PATTERNS]
;ID Multipliers
[CURVES]
;ID X-Value Y-Value
[CONTROLS]
[RULES]
[ENERGY]
Global Efficiency 75
Global Price 0
Demand Charge 0
[EMITTERS]
;Junction Coefficient
[QUALITY]
;Node InitQual
[SOURCES]
;Node Type Quality Pattern
[REACTIONS]
;Type Pipe/Tank Coefficient
[REACTIONS]
Order Bulk 1
Order Tank 1
Order Wall 1
Global Bulk 0
Global Wall 0
Limiting Potential 0
Roughness Correlation 0
[MIXING]
;Tank Model
[TIMES]
Duration 0
Hydraulic Timestep 1:00
Quality Timestep 0:05
Pattern Timestep 1:00
Pattern Start 0:00
Report Timestep 1:00
Report Start 0:00
Start ClockTime 12 am
Statistic None
[REPORT]
Status No
Summary No
Page 0
[OPTIONS]
Units LPS
Headloss H-W
Specific Gravity 1
Viscosity 1
Trials 40
Accuracy 0.001
CHECKFREQ 2
MAXCHECK 10
DAMPLIMIT 0
Unbalanced Continue 10
Pattern 1
Demand Multiplier 1.0
Emitter Exponent 0.5
Quality None mg/L
Diffusivity 1
Tolerance 0.01
[COORDINATES]
;Node X-Coord Y-Coord
NodeA 1177.043 8793.774
NodeB 5340.467 7782.101
NodeC 8200.389 5719.844
J 4659.533 6186.770
A 457.198 9046.693
B 4659.533 8093.385
C 8375.486 6089.494
[VERTICES]
;Link X-Coord Y-Coord
PAJ 1643.969 8618.677
PAJ 2149.805 8307.393
PAJ 2519.455 7762.646
PAJ 2947.471 7198.444
PAJ 3161.479 6809.339
PAJ 3492.218 6536.965
PAJ 3822.957 6361.868
PAJ 4309.339 6206.226
PBJ 5749.027 7762.646
PBJ 6060.311 7723.735
PBJ 6215.953 7607.004
PBJ 6196.498 7431.907
PBJ 5787.938 7062.257
PBJ 5301.556 6673.152
PJC 5340.467 6167.315
PJC 6118.677 6050.584
PJC 6702.335 5856.031
PJC 7227.626 5700.389
PJC 7636.187 5680.934
[LABELS]
;X-Coord Y-Coord Label & Anchor Node
[BACKDROP]
DIMENSIONS 0.000 0.000 10000.000 10000.000
UNITS None
FILE
OFFSET 0.00 0.00
[END]
Now we will run it as supplied, then modify using the Toolkit for more useful purposes.
import epamodule as em # import the package
#Open the EPANET toolkit & hydraulics solver
em.ENopen("./ex3-tk/EX3.inp", "./ex3-tk/EX3-tk.rpt")
# build report command strings Keyword Action see user manual
#command0 = "Status Yes"
command1 = "Summary Yes"
command2 = "Nodes ALL"
command3 = "Links ALL"
em.ENsetstatusreport(2) # full status report
#em.ENsetreport(command0)
em.ENsetreport(command1)
em.ENsetreport(command2)
em.ENsetreport(command3)
em.ENsaveinpfile("./ex3-tk/EX3-tk.inp") #overwrite the input file
em.ENclose()
# now run from the new file
em.ENopen("./ex3-tk/EX3-tk.inp", "./ex3-tk/EX3-tk.rpt")
em.ENopenH()
em.ENsolveH()
em.ENsaveH() # need to save to a binary file before write
em.ENcloseH()
em.ENopenQ()
em.ENsolveQ()
em.ENreport() # now write report
# Close hydraulics solver & toolkit */
em.ENclose()
---------------------------------------------------------------------------
OSError Traceback (most recent call last)
/tmp/ipykernel_219785/2226040250.py in <module>
----> 1 import epamodule as em # import the package
2 #Open the EPANET toolkit & hydraulics solver
3 em.ENopen("./ex3-tk/EX3.inp", "./ex3-tk/EX3-tk.rpt")
4 # build report command strings Keyword Action see user manual
5 #command0 = "Status Yes"
~/ects-epanet/ects-epanet-notes/lessons/lesson03/epamodule.py in <module>
10 _plat= platform.system()
11 if _plat=='Linux':
---> 12 _lib = ctypes.CDLL("./libepanet2.so") # For My Raspberry Pi
13 ## _lib = ctypes.CDLL("./en2tools.so.1.5.0")
14 ## _lib = ctypes.CDLL("./epanet2toolkit.so")
/usr/lib/python3.8/ctypes/__init__.py in __init__(self, name, mode, handle, use_errno, use_last_error, winmode)
371
372 if handle is None:
--> 373 self._handle = _dlopen(self._name, mode)
374 else:
375 self._handle = handle
OSError: ./libepanet2.so: cannot open shared object file: No such file or directory
# Check the output
! cat ./ex3-tk/EX3-tk.rpt
Page 1 Sat Jul 29 08:57:04 2023
******************************************************************
* E P A N E T *
* Hydraulic and Water Quality *
* Analysis for Pipe Networks *
* Version 2.2 *
******************************************************************
Input Data File ................... ./ex3-tk/EX3-tk.inp
Number of Junctions................ 4
Number of Reservoirs............... 3
Number of Tanks ................... 0
Number of Pipes ................... 6
Number of Pumps ................... 0
Number of Valves .................. 0
Headloss Formula .................. Hazen-Williams
Nodal Demand Model ................ DDA
Hydraulic Timestep ................ 1.00 hrs
Hydraulic Accuracy ................ 0.001000
Status Check Frequency ............ 2
Maximum Trials Checked ............ 10
Damping Limit Threshold ........... 0.000000
Maximum Trials .................... 40
Quality Analysis .................. None
Specific Gravity .................. 1.00
Relative Kinematic Viscosity ...... 1.00
Relative Chemical Diffusivity ..... 1.00
Demand Multiplier ................. 1.00
Total Duration .................... 0.00 hrs
Reporting Criteria:
All Nodes
All Links
Analysis begun Sat Jul 29 08:57:04 2023
Hydraulic Status:
-----------------------------------------------------------------------
0:00:00: Balancing the network:
Trial 1: relative flow change = 10.124589
Trial 2: relative flow change = 1.170853
Trial 3: relative flow change = 1.161766
Trial 4: relative flow change = 1.124854
Trial 5: relative flow change = 0.990238
Trial 6: relative flow change = 0.644312
Trial 7: relative flow change = 0.226544
Trial 8: relative flow change = 0.048396
Trial 9: relative flow change = 0.002497
Trial 10: relative flow change = 0.000007
maximum flow change = 0.0000 for Link PBJ
maximum head error = 0.0000 for Link PBJ
0:00:00: Balanced after 10 trials
0:00:00: Reservoir A is emptying
0:00:00: Reservoir B is emptying
0:00:00: Reservoir C is filling
Node Results:
----------------------------------------------
Demand Head Pressure
Node L/s m m
----------------------------------------------
NodeA 0.00 100.00 100.00
NodeB 0.00 80.00 80.00
NodeC 0.00 60.00 60.00
J 0.00 79.63 -30.37
A -2.35 100.00 -0.00 Reservoir
B -0.29 80.00 0.00 Reservoir
C 2.64 60.00 -0.00 Reservoir
Link Results:
----------------------------------------------
Flow Velocity Headloss
Link L/s m/s /1000m
----------------------------------------------
PAJ 2.35 0.00 22.63
PBJ 0.29 0.00 0.46
PJC 2.64 0.00 28.04
4 2.35 0.00 0.14
5 0.29 0.00 0.00
6 -2.64 0.00 0.18
Analysis ended Sat Jul 29 08:57:04 2023
Nice! Seems like we have kind of got the hang of the Toolkit.
Note
In class we will draw the actual network simulated above - notice the three extra links, we put these there intentionally (check the video), to be able to interpret pressures at Nodes A,B,C, and J. In the above example, Nodes A,B, and C are all at zero elevation. Node J is at 110 - so any flow towards J must be uphill. Lets use the toolbox to help us find the elevation Node J would need to be, to have a pressure of +1 meters.
First lets manipulate Node J elevation to produce a pressure of 0.
import epamodule as em # import the package
#Open the EPANET toolkit & hydraulics solver
em.ENopen("./ex3-tk/EX3-tk.inp", "./ex3-tk/EX3-tk.rpt") # The modified file
# build report command strings Keyword Action see user manual
#command0 = "Status Yes"
#command1 = "Summary Yes"
#command2 = "Nodes ALL"
#command3 = "Links ALL"
#em.ENsetstatusreport(2) # full status report
#em.ENsetreport(command0)
#em.ENsetreport(command1)
#em.ENsetreport(command2)
#em.ENsetreport(command3)
#em.ENsaveinpfile("./ex3-tk/EX3-tk.inp") #overwrite the input file
#em.ENclose()
# now run from the new file
#em.ENopen("./ex3-tk/EX3-tk.inp", "./ex3-tk/EX3-tk.rpt")
em.ENopenH()
nodej = em.ENgetnodeindex("J") # Get the index of Node J in the internal database
elevj = em.ENgetnodevalue(nodej,0)
# wrap this into a little search loop
em.ENsetnodevalue(nodej, 0, elevj) # set nodej to elevation (code 0) of 100.0
em.ENsolveH()
presj = em.ENgetnodevalue(nodej,11)
print("Initial Values")
print("Elevation J: " + str(round(elevj,3)) + " Pressure J: " + str(round(presj,3)) )
# Lets do a crude search
tol = 1e-3
for iter in range(100):
if abs(presj) <= tol:
print("tolerance met",iter)
break
if presj < 0.0 :
elevj = elevj*0.99
if presj > 0.0 :
elevj = elevj*1.01
em.ENsetnodevalue(nodej, 0, elevj) # set nodej to elevation (code 0) of 100.0
em.ENsolveH()
presj = em.ENgetnodevalue(nodej,11)
print("Elevation J: " + str(round(elevj,3)) + " Pressure J: " + str(round(presj,3)) )
# end search
em.ENsaveH() # need to save to a binary file before write
em.ENcloseH()
em.ENopenQ()
em.ENsolveQ()
em.ENreport() # now write report
# Close hydraulics solver & toolkit */
em.ENclose()
Initial Values
Elevation J: 110.0 Pressure J: -30.371
tolerance met 62
Elevation J: 79.628 Pressure J: 0.0
Now we modify for the target pressure, supplied as a variable - obviously searching as illustrated is terribly inefficient, but does illustrate the utility of the toolkit. We are using the computer to make adjustments and test outputs rather than doing it ourselves using the GUI; for a complex problem, its far faster to do such exercises programmatically rather then trial-and-error in a GUI.
import epamodule as em # import the package
#Open the EPANET toolkit & hydraulics solver
em.ENopen("./ex3-tk/EX3-tk.inp", "./ex3-tk/EX3-tk.rpt") # The modified file
em.ENopenH()
nodej = em.ENgetnodeindex("J") # Get the index of Node J in the internal database
elevj = em.ENgetnodevalue(nodej,0)
# wrap this into a little search loop
em.ENsetnodevalue(nodej, 0, elevj) # set nodej to elevation (code 0) of 100.0
em.ENsolveH()
presj = em.ENgetnodevalue(nodej,11)
print("Initial Values")
print("Elevation J: " + str(round(elevj,3)) + " Pressure J: " + str(round(presj,3)) )
# Lets do a crude search
tol = 1e-3
targetp = 1.0
for iter in range(1000):
if abs(presj-targetp) <= tol:
print("tolerance met",iter)
break
if presj < targetp :
elevj = elevj*0.99
if presj > targetp :
elevj = elevj*1.11
em.ENsetnodevalue(nodej, 0, elevj) # set nodej to elevation (code 0) of 100.0
em.ENsolveH()
presj = em.ENgetnodevalue(nodej,11)
print(str(iter) + " Elevation J: " + str(round(elevj,3)) + " Pressure J: " + str(round(presj,3)) )
# end search
em.ENsaveH() # need to save to a binary file before write
em.ENcloseH()
em.ENopenQ()
em.ENsolveQ()
em.ENreport() # now write report
# Close hydraulics solver & toolkit */
em.ENclose()
Initial Values
Elevation J: 110.0 Pressure J: -30.371
tolerance met 318
318 Elevation J: 78.628 Pressure J: 1.0
Exercise#
A better way for the example above would be some version of bisection. Modify the script to search for the desired elevation using bisection; select a reasonable tolerance to stop. You may find Chat-GPT 4.0 useful to construct a working script.
A bisection solver could be adapted from Cleveland, T.G. (2022) Hydraulic System Design JupyterBook notes to accompany CE 4353/CE 5360 at TTU; Example 1 in specific energy section
Example 4 - A simple looped network#
Expanding the examples, we will next consider a looped network. As before we will use an exercise as the motivating example.
Problem Statement
The water-supply network shown in Figure 61 has constant-head elevated storage tanks at A and C, with inflow and outflow at B and D.
The network is on flat terrain with node elevations all equal to 50 meters. If all pipes are ductile iron, compute the inflows/outflows to the storage tanks. Assume that flow in all pipes are fully turbulent.
As before we will use the previously prepared input file and modify to explore the Toolkit. By this point its legitimately a lot of cut and paste.
import epamodule as em # import the package
#Open the EPANET toolkit & hydraulics solver
em.ENopen("./ex4-tk/EX4-JB.inp", "./ex4-tk/EX4-tk.rpt")
# build report command strings Keyword Action see user manual
command0 = "Status Yes"
command1 = "Summary Yes"
command2 = "Nodes ALL"
command3 = "Links ALL"
em.ENsetstatusreport(2) # full status report
em.ENsetreport(command0)
em.ENsetreport(command1)
em.ENsetreport(command2)
em.ENsetreport(command3)
em.ENsaveinpfile("./ex4-tk/EX4-tk.inp") #overwrite the input file
em.ENclose()
# now run from the new file
em.ENopen("./ex4-tk/EX4-tk.inp", "./ex4-tk/EX4-tk.rpt")
em.ENopenH()
em.ENsolveH()
em.ENsaveH() # need to save to a binary file before write
em.ENcloseH()
em.ENopenQ()
em.ENsolveQ()
em.ENreport() # now write report
# Close hydraulics solver & toolkit */
em.ENclose()
! cat ./ex4-tk/EX4-tk.rpt
Page 1 Sat Jul 29 10:32:27 2023
******************************************************************
* E P A N E T *
* Hydraulic and Water Quality *
* Analysis for Pipe Networks *
* Version 2.2 *
******************************************************************
Input Data File ................... ./ex4-tk/EX4-tk.inp
Number of Junctions................ 4
Number of Reservoirs............... 2
Number of Tanks ................... 0
Number of Pipes ................... 6
Number of Pumps ................... 0
Number of Valves .................. 0
Headloss Formula .................. Darcy-Weisbach
Nodal Demand Model ................ DDA
Hydraulic Timestep ................ 1.00 hrs
Hydraulic Accuracy ................ 0.001000
Status Check Frequency ............ 2
Maximum Trials Checked ............ 10
Damping Limit Threshold ........... 0.000000
Maximum Trials .................... 40
Quality Analysis .................. None
Specific Gravity .................. 1.00
Relative Kinematic Viscosity ...... 1.00
Relative Chemical Diffusivity ..... 1.00
Demand Multiplier ................. 1.00
Total Duration .................... 0.00 hrs
Reporting Criteria:
All Nodes
All Links
Analysis begun Sat Jul 29 10:32:27 2023
Hydraulic Status:
-----------------------------------------------------------------------
0:00:00: Balanced after 5 trials
0:00:00: Reservoir 1 is emptying
0:00:00: Reservoir 2 is filling
Node Results:
----------------------------------------------
Demand Head Pressure
Node L/s m m
----------------------------------------------
3 0.00 75.00 25.00
4 -200.00 79.97 29.97
5 0.00 70.00 20.00
6 200.00 69.90 19.90
1 -121.21 75.00 -0.00 Reservoir
2 121.21 70.00 0.00 Reservoir
Link Results:
----------------------------------------------
Flow Velocity Headloss
Link L/s m/s /1000m
----------------------------------------------
1 121.21 0.19 0.04
2 -121.21 0.19 0.04
3 -63.45 1.29 7.10
4 136.55 1.93 12.47
5 15.34 0.16 0.09
6 184.66 1.47 5.10
Analysis ended Sat Jul 29 10:32:27 2023
Now lets use some of the tools to get more than one thing. First we will get the count of some objects, then we will change the diameter of one pipe and examine the effect. Notice how we can repeatedly change things and rerun the hydraulic module (as above) almost without effort using the Toolkit.
#ENgetcount(countcode)
import epamodule as em # import the package
#Open the EPANET toolkit & hydraulics solver
em.ENopen("./ex4-tk/EX4-tk.inp", "./ex4-tk/EX4-tk.rpt")
howmanynodes = em.ENgetcount(0) # Code 0 == nodes
howmanylinks = em.ENgetcount(2) # Code 2 == links
howmanyFGN = em.ENgetcount(1) # Code 1 == Tanks/Reservoirs
print(" System Topology is:\n")
print(" Node count: " + str(howmanynodes))
print(" Link count: " + str(howmanylinks))
print(" FGN count : " + str(howmanyFGN))
diameter = [] # create empty list
for ilink in range(howmanylinks):
diameter.append(em.ENgetlinkvalue(ilink+1,0)) # Code 0 == diameter
print("Link :" + str(ilink+1) + " Diameter(mm) : " + str(diameter[ilink]))
em.ENopenH()
em.ENsolveH()
hloss = [] # create empty list
for ilink in range(howmanylinks):
hloss.append(em.ENgetlinkvalue(ilink+1,10)) # Code 10 == head loss
print("Link :" + str(ilink+1) + " Head loss (m/1000m) : " + str(round(hloss[ilink],4)))
print("Change diameter link 4")
em.ENsetlinkvalue(4, 0, 100)
diameter = [] # create empty list
for ilink in range(howmanylinks):
diameter.append(em.ENgetlinkvalue(ilink+1,0)) # Code 0 == diameter
print("Link :" + str(ilink+1) + " Diameter(mm) : " + str(diameter[ilink]))
em.ENsolveH()
nhloss = [] # create empty list
for ilink in range(howmanylinks):
nhloss.append(em.ENgetlinkvalue(ilink+1,10)) # Code 10 == head loss
print("Link :" + str(ilink+1) + " Head loss (m/1000m) : " + str(round(nhloss[ilink],4)))
em.ENsaveH() # need to save to a binary file before write
em.ENcloseH()
em.ENopenQ()
em.ENsolveQ()
em.ENreport() # now write report
# Close hydraulics solver & toolkit */
em.ENclose()
System Topology is:
Node count: 6
Link count: 6
FGN count : 2
Link :1 Diameter(mm) : 900.0
Link :2 Diameter(mm) : 900.0
Link :3 Diameter(mm) : 250.0
Link :4 Diameter(mm) : 300.0
Link :5 Diameter(mm) : 350.0
Link :6 Diameter(mm) : 400.0
Link :1 Head loss (m/1000m) : 0.0004
Link :2 Head loss (m/1000m) : 0.0004
Link :3 Head loss (m/1000m) : 4.973
Link :4 Head loss (m/1000m) : 9.9723
Link :5 Head loss (m/1000m) : 0.1026
Link :6 Head loss (m/1000m) : 5.1018
Change diameter link 4
Link :1 Diameter(mm) : 900.0
Link :2 Diameter(mm) : 900.0
Link :3 Diameter(mm) : 250.0
Link :4 Diameter(mm) : 100.0
Link :5 Diameter(mm) : 350.0
Link :6 Diameter(mm) : 400.0
Link :1 Head loss (m/1000m) : 0.0
Link :2 Head loss (m/1000m) : 0.0
Link :3 Head loss (m/1000m) : 40.4552
Link :4 Head loss (m/1000m) : 45.4552
Link :5 Head loss (m/1000m) : 0.1024
Link :6 Head loss (m/1000m) : 5.1024
Exercise#
Change the parameter code to recover flow instead of head loss and rerun the example, what effect does shrinking pipe 4 have on flow rate?
Example 5 - Simulating a Pump#
This example repeats the same problem as before, but using the Toolkit to load and run the model. A bit of the earlier example is replicated below:
Figure XX is a conceptual model of a pump lifting water through a 100 mm diameter, 100 meter long, ductile iron pipe from a lower elevation reservoir to an upper reservoir.
The suction side of the pump is a 100 mm diameter, 4-meter long ductile iron pipe. The difference in reservoir free-surface elevations is 10 meters.
The pump performance curve is given as $\(hp = 15.0-0.1Q^2 \)$ where the added head is in meters and the flow rate is in liters per second (lps). The analysis goal is to estimate the flow rate in the system.
To use the Toolkit we more or less just repeat from the above examples, here I run the entire simulation as some adjustments are left as exercises.
import epamodule as em # import the package
# Run a complete simulation. input file must already exist
em.ENepanet("./ex5-tk/EX5-tk.inp", "./ex5-tk/EX5-tk.rpt")
# Print the output report (it will be sparse)
!cat ./ex5-tk/EX5-tk.rpt
Page 1 Sun Jul 30 15:32:30 2023
******************************************************************
* E P A N E T *
* Hydraulic and Water Quality *
* Analysis for Pipe Networks *
* Version 2.2 *
******************************************************************
Analysis begun Sun Jul 30 15:32:30 2023
Analysis ended Sun Jul 30 15:32:30 2023
Exercise#
Use the Toolkit to modify the input file (EX5-tk) to produce a more useful output file.
# one possible solution
import epamodule as em # import the package
#Open the EPANET toolkit & hydraulics solver
em.ENopen("./ex5-tk/EX5-tk.inp", "./ex5-tk/EX5-tk.rpt")
# build report command strings Keyword Action see user manual
command0 = "Status Yes"
command1 = "Summary Yes"
command2 = "Nodes ALL"
command3 = "Links ALL"
em.ENsetstatusreport(2) # full status report
em.ENsetreport(command0)
em.ENsetreport(command1)
em.ENsetreport(command2)
em.ENsetreport(command3)
em.ENsaveinpfile("./ex5-tk/EX5-tkmod.inp") #overwrite the input file
em.ENclose()
# now run from the new file
em.ENepanet("./ex5-tk/EX5-tkmod.inp", "./ex5-tk/EX5-tkmod.rpt")
! cat ./ex5-tk/EX5-tkmod.rpt
Exercise#
Modify the upstream pool elevation so it is at 14.999 meters. The pump flowrate should go down a lot (but not to zero).
# one possible solution
import epamodule as em # import the package
#Open the EPANET toolkit & hydraulics solver
em.ENopen("./ex5-tk/EX5-tkmod.inp", "./ex5-tk/EX5-tkmod.rpt")
# The upper reservoir is Node 2 in the input file
nodej = em.ENgetnodeindex("2") # Get the index of Node 2 in the internal database
elevj = em.ENgetnodevalue(nodej,0) # Get the elevation and check
print("Internal Node: ",nodej," Initial Head: ",round(elevj,3))
elevj=24.9999 # Change so thet DeltaH is 14.999
print("Increase Head to ", round(elevj,3))
em.ENsetnodevalue(nodej,0,elevj)
em.ENsaveinpfile("./ex5-tk/EX5-tkmod.inp") #overwrite the input file
em.ENclose()
# now run from the new file
em.ENepanet("./ex5-tk/EX5-tkmod.inp", "./ex5-tk/EX5-tkmod.rpt")
! cat ./ex5-tk/EX5-tkmod.rpt
Exercise#
Now modify the pump curve to approximately recover the flowrate.
Warning
At the time of writing, pump curves are edited outside of the Toolkit - you would search the input file for the section
[CURVES]
;ID X-Value Y-Value
;PUMP:
1 0 15
1 1 14.9
1 10 5
Then edit the indicated curve - for this exercise, manual edits would be OK.
Note
Probably just do this in class and leave the file on the server
Files#
The files used in the above examples are located at: