Experimental Study Of Lateral And Orifice Local Head Loss In Drip Irrigation Pipes

The local head loss of emitters and offices must be taken account into the manufacturingand design process of the drip irrigation system. In this paper, by using Pitot Pipes the localhead losses of single emitter and by analysis about hydraulic results of experiment aboutorifice-type drip local head loss, the impacts of upstream flow velocity and total head on thelocal head loss have been studied. The results are as follows:(1) The flow in experiment about emitter local head loss is turbulent. The emitter localhead loss increases with the increment of velocity and Reynolds Number of upstream. Resultsof experiment about orifice local head loss also have this trend. The flow in experiment aboutorifice local head loss is laminar. The orifice local head loss increases with the increment ofvelocity and Reynolds Number of upstream. Pipes which have different diameters have sameperformance.(2) The emitter local head loss coefficient decreases with the increment of velocity ofupstream. The orifice local head loss coefficient also decreases with the increment of velocityof upstream. At present, in order to get the local head coefficient experiment on drip irrigationlaterals is needed.(3) The emitter local head losses increase with increment of upstream total head. Theemitter local head losses also increase with increment of upstream total head. But thepercentage of orifice local head loss to upstream total head decreases with the increment ofupstream total head.(4) The percentage of emitter local head loss to upstream total head is much bigger thanit of orifice-type irrigation pipes. The local head loss effect of emitter is much more obviousthan it of orifice local head loss. Although the orifice local head loss is small, its existence cannot be ignored.