Optimal design of periodic-move sprinkler irrigation system considering pump characteristics
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Date
2021-08
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Publisher
G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The ever increasing costs of pressurized irrigation systems has compelled irrigation engineers to minimize the cost of the system over its useful life. In this study optimization models are developed for designing a single and two pipe sizes periodic-move sprinkler lateral for various values of uniform upward and downward slopes. Two layouts are considered; the peripheral main layout (PML) and central main layout (CML). The optimization model has to
maximize the length of the mainline subject to the allowable pressure constraint without throttling the pump at the lateral inlet. The total cost of the system is obtained for the optimal length by using life cycle cost analysis. The step-by-step approach is used for computing the frictional head loss of the pipelines for analyzing the pressure head of sprinklers. The applicability of the optimization models is illustrated by solving standard design problems using LINGO 18.0. The maximum area, pressure variation, pressure head and pump efficiency are obtained as output of the models for the two layouts and their results are compared. The CML was found to cover more area with lesser pressure variation, and better energy efficiency than the PML. Bigger pipe sizes for single and two pipe sizes lateral resulted in the least cost per unit area when compared with smaller pipe sizes. The advantage of using two pipe sizes was also presented in terms of cost savings over single pipe size laterals. The developed optimization models can be used for designing the periodic-move system of sprinkler irrigation for any given field and farmers conditions according to field shape, topography of the land, availability of sprinkler components, pipe sizes and centrifugal pump.