| Water are the necessary resources in survival and development of humansociety. The very scarce of water resources state in China. With the quicklydevelopment of economy and population in our country, The demand for waterin society is more and more big,but the pollution and waste problems is veryserious, The supply and demand of water resource is in state of emergency. Inmany countries, the government is actively promoting water savingmeasures,ease maximize the contradiction between supply and demand of waterresources.Our country is a large agricultural country, agricultural water accounts for alarge proportion. The traditional irrigation techniques have been used in manyareas, resulting in a serious waste of water resources. Now, With theimprovement of consciousness of water-saving among people. China began tovigorously promote water-saving irrigation technology. In many measures ofsaving water, The most of water use efficiency is drip irrigation technology,which was advanced and used widely. the most important equipment of dripirrigation is drip irrigation emitter, Labyrinth Emitter is the best form of dripirrigation emitters, the vortex area of channel affects the energy dissipationcapacity and anti-clogging performance of irrigation emitter.Combined with natural science fund project in Shanxi Province 《The dripirrigation water sand two phase flow research》(2008011054),This article selectsthe most common four vortex exist channel labyrinth emitter as the basic model. According to the simulation of the optimal boundary streamline the limit toeliminate vortex, draw four corresponding without vortex structure model. Thesimulation conditions set3m of8kinds of pressure head, then we can calculatethe relationship of pressure and flow,flow coefficient, flow index and reynoldsnumber, hydraulic loss coefficient, the pressure drop of unit channel length andget the velocity vector graph, velocity chart of specified section, pressuredistribution, pressure distribution of specified section.Therefore,conclusions are as follows:(1) Flow of non-vortex exist channel in the same pressure head more thanvortex exist channel. flow coefficient of non-vortex exist channel more thanvortex exist channel. Flow states coefficient of rectangle, profile, trapezoidnon-vortex exist channel more than vortex exist channel, flow states coefficientof triangle non-vortex exist channel less than vortex exist channel.(2) Compared with four vortex exist channel, flow coefficient of trianglevortex exist channel less than other three labyrinth emitter, flow statescoefficient is biggest. Flow states coefficient rectangle channel is smallest,hydraulic performance is best.(3) Compared with four non-vortex exist channel, flow coefficient and flowstates coefficient less than other three labyrinth emitter, flow states coefficient isdecreased and hydraulic performance is increase,so triangle non-vortex existchannel is chose.(4) Under the same condition of pressure head, eight types of labyrinthemitter in turbulent state, reynolds number is increased. reynolds number of fournon-vortex exist channel more than vortex exist channel, greater than the criticalReynolds number87.5～125.0.(5) Under the same condition of pressure head, the vortex volume ofrectangle vortex exist channel is smaller than other three kinds of vortex. Thevortex range of triangle and Tooth profile vortex exist channel is greater,Thevortex range of rectangle and trapezoid vortex exist channel is less.The vortex range of triangle non-vortex exist channel is more than other three labyrinthemitters.(6) Compared with the velocity distribution of the specified section1~6: thespeed oscillation region of vortex exist channel more than non-vortex existchannel. The speed oscillation region of profile vortex exist channel more thanother three channel. The zero speed exist of triangle non-vortex exist channel ismore than other three labyrinth emitters.(7) Decreasing the pressure distribution along the flow direction of vortexexist and non-vortex exist channel. The pressure drop of non-vortex existchannel more than vortex exist channel. The Pressure regulation ability ofnon-vortex exist channel more than vortex exist channel.(8) Compared with the pressure distribution of channel in the specifiedsection1~6: The pressure oscillation region of profile vortex exist channel isgreater, The pressure oscillation region of triangle and non-vortex exist channelmore than other three channel.(9) Comprehensive consideration, under the same conditions, choice toothis the best in vortex exist channel emitter, choice triangular is the best innon-vortex exist channel emitter.In a word, the hydraulic performance oftriangular non-vortex exist channel emitter is the best theoretically. |
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