Perimental Study On Hydraulic Properties Of Porous Membrane Bag

The porous membrane bag is a kind of the new water-saving irrigation equipment with agricultural plastic film material,having water and energy conservation,irrigation uniformity and high ecological and environmental efficiency advantages.It also can be based on production needs,adjusting irrigation quota with more substantial,it's a controlled irrigation techniques.The porous membrane bag not only to achieve the purpose of the fine irrigation,but also expand the space for development of new water-saving irrigation techniques.Compared with the surface irrigation,it can reduce evaporation and deep percolation,adjust the field microclimate,improve the soil environment of the crop root zone,prevent soil secondary salinization,be operated easily,not be blocked easily.It is suitable for the dry field crops to growth and development.This paper focuses on the hydraulic characteristics of porous membrane bag,using a combination of methods with experimental and mathematical analysis,researching the pressure distribution,traffic distribution,irrigation uniformity variation of the porous membrane bag,provide a theoretical basis for the design and the field construction of porous membrane bag.The main findings are as follows:(1)Researching the pressure distribution of the porous membrane bag at different inlet head,opening ratio,aspect ratio and laying slope.Establishing the variable mass momentum equation of porous membrane bag according to the conservation of energy,deriving the head loss formula and pressure head formula at any point of porous membrane bag,deriving the maximum laying length of porous membrane bag with the head loss formula.(2)Researching the total flow,single-hole flow,average single-hole flow of the porous membrane bag at different inlet head,laying length,laying slope,hole distanceand aperture.Researching the relationship between pressure and flow of different types of porous membrane bag,determine each related coefficient of regression equation.(3)Researching the irrigation uniformity of the porous membrane bag at different inlet head,laying length,laying slope,hole distance and aperture,and proposing the specific measure for improving the irrigation uniformity of porous membrane bag.