Pumping stations and water transport. Practical applications: distribution networks ct5550

Transcription

1 Pumping stations and water transport Practical applications: distribution networks ct5550

2 Introduction Distribution networks represent the majority of pipe line length Design criteria are historically dominated by fire flows and needs for loops Recent developments demand for new starting points for design and operation.

3 Traditional distribution networks Continuity supply looped networks Conventional fire fighting demand Hydrants on Ø110 mm This principal is applied for more than 150 years.

4 Conventional lay out Storage building Hydrant dwelling FP 350 kpa Storage building Hospital FP 350 kpa

5 Characteristics conventional design Conventional fire fighting capacity prescribes diameter and consequently Low velocities Shuttling water Long retention times Accumulation sedimentary deposits Water quality problems because: deposits cause discolouration deposits are breeding ground for bacteria Design is connecting fire hydrants

6 Alternative distribution network Design networks on: The actual drinking water demand Once a day a velocity of 0.4 m/s Branched structure (unidirectional flow)

7 Design distribution network Determine drinking water demand Arrange sections Design main structure Design sections check pressure drops Fitting fire fighting demand check pressure drops Drinking ing water Fire fighting

8 Household demand tap liter pppd Bath 3.5 Brtap 4.0 Dw 1.6 Ktap 14.8 Ostap 5.9 Shower 45.9 Wc 36.6 Wm 14.2 sum Shower: 36% Bath: 3% Dish washer: 1% Wash basin: 3% Outdoor: 5% Wc: 29% Washing machine: 11% Kitchen tap: 12%

9 Drinking water demand (up to proximally 1000 dwellings) q n method: Q Q max n TU = n TU max 0,083 dweling TU varies : maximum demand n dwellings [l/s] : # of dwellings : # of TU per dwelling : Capacity 1 TU (300 l/h)

10 q n method Tap points Toilet cistern Toilet washbasin Kitchen sink Dish washer Bath/shower mixer tap Washbasin tap Washing machine tap Total average house # tap units

11 Maximum flow with several dwelling types Flow [m3/h] # dwellings TU 24 TU 35 TU

12 Design distribution network Determine drinking water demand Arrange sections Design main structure Design sections check pressure drops Fitting fire fighting demand check pressure drops Drinking ing water Fire fighting

13 Arrange sections Determine size section Identify special connections/buildings (large fire fighting capacity) Cluster dwellings to sections Limit pipe length by branching

14 Design distribution network Determine drinking water demand Arrange sections Design main structure Design sections check pressure drops Fitting fire fighting demand check pressure drops Drinking ing water Fire fighting

15 Design main structure (1) Identify main structure Connect section to main structure Determine volume flows

16 Design main structure (2) Determine paths main structure Connect sections Calculate volume flows (n q)

17 Design main structure (3) Determine diameters Ø110 Ø63 Ø63 Ø110 Ø110 Ø110 Calculate pressure loss at maximum demand Calculate pressure loss at fire flows

18 Design distribution network Determine drinking water demand Arrange sections Design main structure Design sections check pressure drops Fitting fire fighting demand check pressure drops Drinking ing water Fire fighting

19 Design sections (1) Pressure at beginning Pressure trunk main minus friction losses in main structure Flow direction in branched structure

20 Design sections (2) Design section based on available diameters, # connections and velocities (0,4 1,5 m/s) Check pressure losses with Darcy Weissbach Redesign if necessary

21 Design distribution network Determine drinking water demand Arrange sections Design main structure Design sections check pressure drops Fitting fire fighting demand check pressure drops Drinking ing water Fire fighting

22 Fire demand + last checks Determine locations hydrants (last one on Ø63) Check distance to buildings Check pressure drops with maximum fire flows (pressure may drop to almost zero) Redesign is necessary

23 Restrictions on design Number of tap units per dwelling Maximum number of connections per section Diameter range pipes (e.g.pvc, Ø 110, Ø 63, Ø40) Minimum velocity 0.4 m/s Maximum velocity 1.5 m/s Fire fighting demand 30 m 3 /h at modern buildings More at special buildings Max 50 m distance to buildings

24 Pipe table 1 2 v π D n = 4 3 0, TUhouse Diameter pipe # houses (TU=22) n = 1 v 4 0, v max = 1.5 m/s v min = 0.4 m/s π 3 D 2 TU house

25 Exercise VP 350 kpa m 3 /h Hospital VP 350 kpa

26 VP 350 kpa m 3 /h Hospital VP 350 kpa

27 VP 350 kpa m 3 /h Hospital VP 350 kpa

28 VP 350 kpa m 3 /h Hospital VP 350 kpa

29 VP 350 kpa Extra pipes for fire hydrants 60 m 3 /h Hospital VP 350 kpa

30 Network composition Materiaal leidingnet cumulatief Leidinglengte [km] overige PE PVC asbestcement nod gij gietijzer 30

31 Classification newly laid pipes in the Netherlands Classification of newly laid pipes % percentage of length 50% 40% 30% 20% 10% %

32 Proving the concept of self cleaning networks 32

33 Measurement locations area 1 Branched PLUS network, 2 nd generation small diameters Internal diameter (mm) ZPE 40 35,2 1 ZPE 50 44,0 4 U-PVC 63 58,2 12 U-PVC 90 83,0 46 U-PVC ,6 100 U-PVC ,6 250 Based on: Q = N v design = 0.4 m/s Minimum # of houses Q-measurement Particle counters Flushing point 33

34 Measurement locations area 2 4 Branched network, 1 st generation, larger diameters X Q-measurement 1 8 Particle counters Flushing point

35 Measurement locations area 3 Looped network Particle counters Flushing point 1 35

36 Measurement results flows flow (l/min) gemeten do 15/06 gesimuleerd Q measured in area 1 and 2 Q simulated with demand model SIMDEUM time (hr) daily volume PS maximum temperature 35 Extreme temperatures, extreme water uses daily volume (m3) temperature (ºC) branched branched PLUS conventional looped

37 Measurement results particle counters volume (μm 3 ) Area 1 branched PLUS loc 1 loc 2 loc 3 loc 4 pc 234 = pc Jun 14-Jun 16-Jun 18-Jun 20-Jun 22-Jun volume (μm 3 ) Area 2 - branched loc 1 loc 2 loc 3 loc 4 pc 234 >= pc Jun 04-Jun 06-Jun 08-Jun 10-Jun 12-Jun 10 4 volume (μm 3 ) 10 3 Area 3 - looped loc 1 loc 2 loc 3 loc 4 pc 234 > pc Jun 24-Jun 26-Jun 28-Jun 30-Jun 02-Jul 04-Jul 06-Jul 37

38 Relation velocity - turbidity turbidity (FTU) - flushing samples branched PLUS - 63/50/40 mm branched - 110/63 mm looped v max (m/s) - SIMDEUM 38

39 Pumping stations and water transport Practical applications: distribution networks ct5550