DESIGN OF WATER NETWORK PIPE SYSTEM OF SPRINKLER IRRIGATION FOR MINIMUM COST

Hassan, A. A.

doi:10.21608/mjae.2017.97466

DESIGN OF WATER NETWORK PIPE SYSTEM OF SPRINKLER IRRIGATION FOR MINIMUM COST

Document Type : Original Article

Author

A. A. Hassan

Senior Researcher at Agric. Rech. Center, Egypt.

10.21608/mjae.2017.97466

Abstract

To optimize the life-cycle cost of pressurized irrigation system, we must find the set of pipe sizes that gives the minimum sum of fixed plus operating costs. If a very small pipe sizes are used, fixed costs will be low, but the operating (power) cost of overcoming friction losses in the pipes will be relatively high. As the pipe diameters increase, the fixed cost will also increase. The optimum pipe sizes are that minimizes the sum of fixed plus the operating costs. A linear programming model was developed for the design of water network of a hand moved sprinkler system of 2 main lines supply 10 fields each contains a submain and two portable hand move sprinkler laterals. The system comprises junctions or nodes and pipe sections between adjacent nodes. The objective function is to minimize total cost subject to three groups of constraints. The first group concerned about pressure head at each node. The second were to limit the water velocity in the pipe sections between 1m/s to 2 m/s. The last, involves the non negativity of the various decision variables. The results showed that the minimum total annual cost to operate the system is 1135 L.E/year. fed. at 1.6 m/s average water velocity in pipes. The head loss gradient was 1.9 m/100m and the total area was 110 feddan, The system operating time 1440 hour/season to add 3400 mm/ season. The sprinkler discharge is 1.4 m³/h operate at 3 bar pressure head spaced 7m by 7 m. Linear programming method results were verified by two other methods, namely, water velocity and unit head loss (head loss gradient). Comparing results of the linear programming method with the other two methods showed faster and more accurate results, especially when applied by Microsoft EXCELL spreadsheet.

Main Subjects

Agricultural Irrigation and Drainage Engineering

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