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Numerical Simulation Of Dental Labyrinth Flow Passage Of Drip Emitter

Posted on:2014-06-29Degree:MasterType:Thesis
Country:ChinaCandidate:Q L XieFull Text:PDF
GTID:2253330401972745Subject:Agricultural Soil and Water Engineering
Abstract/Summary:PDF Full Text Request
Drip emitter is the key component of drip irrigation system. Its performance and qualitywill directly determine the working performance of the whole drip irrigation system. Dentallabyrinth channel emitter is used widly, and is used as the study model in the paper. Fencinginlets is the most common inlets form of dental labyrinth channel emitters. The inlets numberof emitter is set in the range of3to30generally. The traditional experimental method is hardto observe the flow flied for its minimal size and complex internal structure. It is necessary toanalyze the influence of emitter channel structure on the performance of emitter for emitterstructural optimization with the computational fluid dynamics software. The liquid-soil two–phase flow in the emitter is simulated numerically by means of FLUENT6.3. Influence oftooth angle, pitch, and inlets structure on the hydraulic and anti-clog performances of emitteris explored. The main results show that:(1) The discharge coefficient can be correlated to tooth angle and pitch with a positiverelationship; there is a very small range of changes in flow state exponent; influence of toothangle on flow state exponent is more complicated, flow state exponent changes around120°.(2) Emitter channel structure affect the distribution of suspended granule greatly. Thewater flow direction changes gradually smooth with increasing tooth pitch, suspended sandparticle outflow propitious with water, and the anti-clogging performance is improved. Toothangle is an important factor on the emitter anti-clogging performance, but the regularity needto be investigated further.(3) In the case of total area of inlets is greater than the minimum cross-sectional area ofdental labyrinth channels, the structure of inlets has no influence on emitter flow rate, in thecase of total area of inlets is less than the minimum cross-sectional area of dental labyrinthchannels, emitter flow rate decreases with the decrease of total area of inlets.(4)The smaller of inlet flow rate the farther away from the dental labyrinth channels,moreover the flow rate is mainly concentrated in inlets near the dental labyrinth channels. Thedistribution of flow rate and velocity between inlets can be more evenly, by the means ofreducing inlets width, increasing inlets depth and store.(5) To decrease inlets number appropriate, it can improve the distribution of flow rateand velocity between inlets significantly, improve the velocity of inlets flow, improve the flowfield of inlet and neighboring areas, reduce the size of the area of high concentration, and prevent the clogging of inlet and neighboring areas.
Keywords/Search Tags:emitter, numerical simulation, structure parameter, structure of inlet, hydraulic performance, anti-clogging performance
PDF Full Text Request
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