Research On Performance Of Clay-based And Sand-based Porous Creamic Irrigation Emitter

The uneven spatial and temporal distribution of water resources has brought serious obstacles to the development of agriculture.As the key equipment of micro irrigation system,the irrigation emitter plays an important role in the irrigation system.In recent years,micro irrigation has been formed with the micro plastic belt,porous infiltration irrigation which are made of plastic.The plastic irrigation device is easy to aging,and its one-time application also brings a series of environmental problems.But using pot to irrigation in arid and semi arid has been widely used,its efficient irrigation effect has attracted more and more people of all ages.With the continuous progress of ceramic preparation process,people study on porous ceramic,in order to improve the traditional pottery,made of porous permeable pipe,overcome some shortcomings,so that it can form a system of irrigation network,better adapt to the development of modern agriculture.In this thesis,the clay based porous ceramic emitters and sand based porous ceramic emitters was taken as as the research object.The porous ceramic emitters was developed by China Northwest Agriculture and Forestry University Institute of water saving agriculture in arid regions Wu pute.The micro morphology of the sintered with the scanning electron microscope,through the emitter after the installation of a series of irrigation experiment in the air,the relevant characteristics of hydraulic performance of microporous ceramic emitters.The hydraulic performance of optimal irrigation in clay,sandy soil and loessial soil,irrigation experiment in low water head,further study on soil type and irrigation time and water pressure on soil infiltration in the porous ceramic emitter flow effect.Through the above experimental research,draw a conclusion:(1)The relationship between pressure and flow of the diatomite porous ceramic emitters is logarithmic function.The flow increases with the increasing of pressure;When the experiment is carried out under tap water,with the increase of irrigation times,it will cause a small decline in the flow,after 24 times of irrigation,the flow decline is no more than 10%;But with the muddy water,the flow is effected by not only irrigation times,but also sediment concentration.Under the same number of irrigation,the flow decreased greatly with the sediment concentration increases;Soaking treatment reduces the initial flow of emitter,and the descend range of flow.The micro morphology showed that the porous ceramic aperture in the 10~80? m,so when using the small particle size and high concentration of sand water to start a intermittent irrigation test,it will produce a sharp drop in traffic,and affect the normal use.(2)Under the same conditions the greater the porosity and infiltration area of micro porous ceramics,the greater the infiltration capacity of the emitter;Infiltration quantity is effected by irrigation time,soil type and pressure head on the infiltration rate of irrigation water in the same time.The infiltration rate decreased and the soil mosture content increased with the increase of irrigation time.Under the condition of no pressure,the emitters have a smaller flow rate in sand than in loessal soil,with the increase of the inlet pressure,Drawing the opposite conclusion;In the same soil,with the increase of the pressure head,the infiltration capacity of the irrigation water is increased,but the time of flow from the unstable into a stable time is shorten.(3)The pressure and flow rate of sand based micro hole ceramic implant are positively related;Under the condition of continuous irrigation,the flow rate of micro ceramic emitter is relatively stable,and the change is not large;According to the micro topography analysis,the flow rate of the sand based porous ceramic emitter is greatly affected by the internal structure of the emitter.(4)The infiltration of sand based micro porous ceramic emitters in soil was affected by soil type,irrigation time and irrigation equipment.With the increase of irrigation time and the increase of water content,the emitter flow rate decreased.