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Effect Of Emitter Clogging On Irrigation Uniformity In Drip Irrigation System

Posted on:2011-10-16Degree:MasterType:Thesis
Country:ChinaCandidate:P WuFull Text:PDF
GTID:2143360308455105Subject:Soil and Water Conservation and Desertification Control
Abstract/Summary:PDF Full Text Request
The anti-clogging performance of the emitter is one of the important factor that impact system cost and irrigation uniformity, and an important index to evaluate emitter quality. However, it is also a technical problem in the drip irrigation system which cannot be completely resolved at present. This paper studies dental shape labyrinth path emitter through computational fluid dynamics (CFD) numerical simulation software Fluent6.3, and analyzes the effect of different structural parameters on anti-clogging performance. Besides, the influence of the sediment concentration and size in water on the anti-clogging of emitter and drip irrigation uniformity is studied through periodic anti-clogging and field irrigation experiment. By the above mentioned analysis and studies, this paper gets the main results as follows:(1)Solid particles move along with the main channel in front area of dental tip, but circumvolve in the passed area of dental tip; The transitive area is the key position which the solid particles break away from the main channel to whirl area. So it can advance the anti-clogging performance by improving the solid particles movement state in the transitive area.(2)The height of dental is the prominent factor that affects the anti-clogging performance of emitter, and the following factor is the width of dental; The anti-clogging performance of emitter descend with the height of dental increasing. It can be realized to analyze the anti-clogging performance of emitter through the method combining single-phase flow with discrete- phase, which can avoid the occupying more computer memory and the difficulty of convergence caused by the use of Euler - Euler two-phase flow model.(3)When the sediment diameter in the muddy water is less than 0.15mm, sediment concentration is the main factor affecting the anti-clogging performance. When the sediment diameter within a certain range, the order of the factors which affect the anti-clogging performance is: the concentration of sedimentï¹¥the diameter of sedimentï¹¥work press; When the work press is decided, the order of the factors which affect the anti-clogging performance is: the concentration of sedimentï¹¥the diameter of sedimentï¹¥the rating flow rate of emitter.(4) Cu and Us were calculated through the average flow rate of several emitters in different segments of drip tape instead of single emitter flow rate. It can avoid the influence of manufacture deviation on irrigation quality by comprehensively using Cu and Us computed from the average flow rate. The field irrigation uniformity Eu can reflect the clogging complexion in drip irrigation system better than Cu and Us; In drip irrigation system, choosing suitable flow rate emitter and reducing the length of drip tape are advisable. According to the change of the average flow rate along with drip tape, when the rating flow rate is 1.38L/h, the decreased extension of average flow rate before 80m of the drip tape is less than other parts,and it is before 70m of the drip tape when the rating flow rate is 2.0L/h.
Keywords/Search Tags:irrigation, anti-clogging experiment, irrigation uniformity, numerical simulation, sediment
PDF Full Text Request
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