Improving micro-irrigation efficiency by pressure regulated emission devices [electronic resource].

Includes references.

The main objectives of this study are to define and analyze the factors that affect the flow deviation and the economic impact of applying pressure regulated emission devices (pressure compensating). To fulfill these objectives, an analytical procedure was developed to predict the flow variation due to the pressure distribution by applying the dimensionless energy gradient...concept. Results revealed that lateral slope, manifold slope, emitter flow exponent and design allowable pressure variation were the most effective variables on the discharge variation. The relationship between the discharge variation~ and lateral slope, manifold slope, and emitter flow exponent was. found to. be linear function while power function was observed with the allowable ..pressure variation. The analysis indicated that, applying the pressure--regulated emitters could save water compared with regular emitters at the same operational conditions. For example, the excess water provided by turbulent flow emitter.:(x = 0.5) is about 4.6% of the required water quantity under the economic design rule (20% allowable pressure variation of the emitter operating pressure) for leveled lands. This excess water is due to the pressure variation. To overcome this problem, it is recommended to use pressure regulated emitters (regulated system). The advantage of applying such systems extended to saving in equipment costs also. This was managed. by increasing the regulated system inlet pressure, which causes additional cost of energy but permits using smaller lateral sizes. A comparison between the .added cost for additional pressure and the saving in equipment was done.. to justify the increase of the regulated system inlet pressure. Through a case. Study by applying. micro sprinkler regulated system versus conventional one, the results indicated annual profits ranging between 55 to 313 LE/fed. year according to the system increased inlet pressure. For simplicity, a nomograph was .deve1oped to evaluate the economic feasibility.

Summary in Arabic.

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