Environmental Engineering Reference
In-Depth Information
The results in Table 7.17 show several combinations of the pipe lengths and diameters for the
total available head loss of 20 mwc and the demand of 250 l/s. In all cases, the pipe diameters
have been minimised to deliver this service, and the correlation of the volumes and flows
achieved in three iterations. The most realistic situation is described in the first segment of
the table where both pipes are of 1000 m and with similar diameters and friction losses. As
soon the length of the pipes is significantly different, the corresponding diameters will also
change and achieving the correlation between the pipe volumes and flows will become more
difficult. Thus, the application of the concept becomes limited to the networks of specific
configuration and topography.
To test further the hypothesis, the correlations between the pipe flows and volumes have been
assessed in ten initial networks against their average loss of demand. The results are shown in
Table 7.18. The diagrams related to the results in Tables 7.15 and 7.18 are shown in Figures
7.21 and 7.22, respectively.The correlation between the volumes and flows, and other
reliability measures is not strong. The best pattern has been with the
PBI
values of the ten
networks that are consistently lower if the correlation between the pipe volumes and flows
improves. This is to lesser extent the case with the values of
NBI
and
ADF
avg
, and certainly
weak in case of
NRT
,
I
r
and
NPI
. The results from the 16 optimised nets show even less
consistency although there as well the best correlation has been achieved with the
PBI
values.
Table 7.18
Correlation between pipe flows and volumes and its relation to loss of demand
No.Name
V
j
Q
j
V
j
Q
j
NPI PBI NRT ADF
avg
NBI
I
n
0.45
0.96
0.45
0.54 0.95 0.18
0.93 0.32 0.18
1 sn73
0.39 0.83
0.39 0.46 0.92 0.21
0.99 0.84 0.04
2 sn80
3 O20sn73
0.91 1.00 0.92
0.55 0.90 0.09
0.91 0.08 0.18
0.93 0.98 0.92
0.59 0.90 0.10
0.95 0.33 0.20
4 O20sn80
0.26 0.85 0.30
0.47 0.95 0.30
0.95 0.48 0.06
5 sn0179
0.39
0.84
0.31
0.47 0.92 0.18
0.98 0.79 0.05
6 sn0199
7 sn0109
0.02
0.90
0.02
0.45 0.97 0.50
0.98 0.76 0.03
-0.20 0.80 -0.27
0.69 0.99
11
0.99 0.83 0.40
8 ngt01-50
-0.10 0.80 -0.19
0.69 1.00
37
1.00 0.91 0.35
9 ngt01-151
10 ngt01-200
-0.11 0.66 -0.10
0.67 1.00
33
1.00 0.96 0.36
1.00
0.80
0.60
0.40
ADFavg
NBI
In
NPI
PBI
corrVjQj
0.20
0.00
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
-0.20
-0.40
-0.60
Figure 7.21
Correlation between pipe flows and volumes and its relation to loss of demand - Table 7.15
Search WWH ::
Custom Search