HYDRAULICS_5

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HYDRAULICS_5

• Design of Irrigation Systems
• by
• László Ormos

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DESIGN OF MANIFOLD

• The manifold is a pipe with multiple outlets to
  the inlets of
• lateral pipes. The size of plot, the flow rate
  and the number
• of shifts in a complete irrigation cycle should
  be taken into
• consideration.
• An orchard is designed for irrigation with a
  solid set system.
• The manifold is laid in the center of the field.
  The whole plot
• is irrigated simultaneously.
• The flow rate of selected sprinklers is
  qs0.11m3/h at a
• pressure hs2bars. The space between the
  sprinklers along
• the laterals is es6m. Space between laterals is
  eL8m.
• What are the diameters of pipes if the local head
  loss in the
• manifold and laterals is 10?

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DESIGN OF MANIFOLD

• The topography of field is the following

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DESIGN OF MANIFOLD

• Design of lateral
• The maximum allowable pressure head variation is
• The number of sprinklers on every laterals is as
  follows
• The length of lateral is
• 4. The total outlet of a lateral is

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DESIGN OF MANIFOLD

• For 16mm PE lateral pipe
• The hydraulic gradient when Q0.88m3/h and
  J1622
• 6. The head loss in the lateral pipe (including
  10 local head loss) and coefficient F60.38, is
• Since hfgt?h the pipe diameter has to be
  increased.
• The hydraulic gradient if diameter is 20mm of PE
  which has
• J206.5 by Q0.88m3/h. is

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DESIGN OF MANIFOLD

• The head loss in the lateral pipe (including 10
  local head loss) and coefficient F80.38, is
• Since hflt?h the pipe diameter is good.
• 9. The inlet pressure in the lateral is
• 10. The water pressure by the last sprinkler on
  the lateral is

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DESIGN OF MANIFOLD

• Design of manifold
• 11. The number of laterals is as follows
• 12. The length of manifold is
• 13. The total flow rate is as follows

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DESIGN OF MANIFOLD

• For 63mm PE manifold pipe
• 14. The hydraulic gradient when Q21.12m3/h and
  J637.2
• 15. The head loss in the manifold (including 10
  local head loss) and coefficient F240.371, is
• 16. The pressure by the manifold inlet is
• 17. The pressure by the inlet of last lateral is

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DESIGN OF MANIFOLD

• 18. The minimum pressure in the entire system at
  the last sprinkler on the last lateral is as
  follows
• 19. The pressure difference between the first and
  last sprinkler is
• Since the pressure difference ?hf-l is lower
  than the allowable pressure head variation ?hmax,
  the system is good.

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References
Azenkot, A.(1998)Design Irrigation System.
Ministry of Agricul- ture Extension Service
(Irrigation Field service), MASHAV Israel Dr.
Avidan, A.(1995)Soil-Water-Plant Relationship.
Ministry of Agriculture Extension Service
(Irrigation Field service), CINADCO, Ministry of
Foreign Affairs, MASHAV, Israel Sapir, E.-Dr. E.
Yagev (1995)Drip Irrigation. Ministry of
Agricul- ture and Rural Development, CINADCO,
Ministry of Foreign Affairs, MASHAV,
Israel Sapir, E.-Dr. E. Yagev (2001)Sprinkler
Irrigation. Ministry of - culture and Rural
Development, CINADCO,Ministry of Foreign
Affairs, MASHAV, Israel Eng. Nathan, R.
(2002)Fertilization Combined with Irrigation
(Fertigation). Ministry of Agriculture and Rural
Development, CINADCO,Ministry of Foreign Affairs,
MASHAV, Israel