Hydraulic Characteristic Experimental Research Of Orifice Outlet Drip Irrigation Laterals Under Low Pressure Condition

With consciousness enhancement of energy and water saving, low pressure drip irrigation system which is low energy consumption, maintains simply, easy to use and other merits and becomes one of drip irrigation important development directions. This article uses the method which in integrate the experiment with the mathematical analysis, base on the influence factor to outflow rule and head losses of the orifice outlet drip irrigation laterals under low pressure condition, do research on outflow and head losses rule of the orifice outlet laterals under low pressure condition, provided the theory basis for the low pressure drip irrigation design and the operating management. Obtained following conclusion through the experiment and the analysis:1) For orifice outlet drip irrigation laterals, manufacture coefficient C v is maximal when 0.6mm aperture, midst when 1.2mm aperture, minimal when 0.9mm aperture. When pitch is const, the scale of which C vchange with pitch inφ16 laterals is larger than that inφ12 laterals.2) The change rule of orifice discharge along with the aperture is similar in same diameter laterals, orifice discharge increases along with aperture increases, this amplitude increases along with the laterals'diameter increases; Except that 0.6mm aperture under same working head, orifice discharge of pitch in 33cm is larger than discharge of pitch in 100cm, change rule of orifice discharge along with the aperture performance in other two kind of aperture laterals is: Orifice discharge of 100cm pitch laterals is larger than that in 33cm pitch laterals, the orifice discharge of 50cm pitch laterals is smallest.3) Discharge coefficient k increases along with aperture d increases, curve of k and d almost parallel in laterals which pitch in 33cm,50cm , k change with the d change in laterals which pitch in 100cm are obviously larger than that in other two kind of pitch's laterals. Flow regime exponent x increases first and then reduces after the d increases inφ16laterals, inφ12 laterals x reduces first and then increases after the d increases.4) There are three flow regime of current in laterals under experimental condition: laminar only, laminar together with turbulent, turbulent only. The change rule of irrigation uniformity Cu and working head h is different under different flow regime and emitter discharge exponent x condition, under low pressure condition: Under laminar condition, the Cu increases along with the h increases and they are independent of x. Under laminar together with turbulence condition, Cu increases along with h increases when 0.5