| The pressure compensating emitters have the advantages of constant flow under thechange of pressure anti-clogging and self-cleaning performance. It was mainly usingexperimental methods to study the hydraulic and anti-clogging characteristics because of itssmall channel size. It was lack of deeply understanding of the relationship betweendistribution of flow field and performance of work. The working principle of pressurecompensating emitter is the result of pressure flow coupling with structure deformation. Toreflect its distribution of flow field accurately, it need using Fluid-Structural Interactionmethods. In this paper, Fluid-Structural Interaction simulation and experiments wereconducted to study the relationship of channel structure and elastic diaphragm deformationwith hydraulic characteristics of pressure compensating emitters. Follow are the mainconclusions:(1)Experiments were conducted to study the hydraulic and anti-clogging characteristicsof different structural emitter. After analysising the pressure-flow relationship, average flowand clogging rate, we found that, as the inlet pressure increase, the flow rate of pressurecompensating emitter is more uniform than that of non-pressure compensating emitter. Thepressure compensating emitter has the smaller fluid index. When the flow rate increases, theemitter anti-clogging characteristic is not improve absolutely.(2)Pressure compensation emitter shell model was established by a modeling softwarePro/E. The channel model, which was used to simulate the flow field within emitter, wasestablished by GAMBIT and calculated Fluid-Structural Interaction by the commercialsoftware. The results were compared with traditional emitter’s hydraulic performance tests. Itshows that simulating flow mostly were bigger than fact flow, but the windage was under10%, indicating that the method is a feasible way to study the hydraulic characteristic ofpressure compensating emitter. The volume deformation of elastic diaphragm and thedistribution of inter-liquid field under the certain pressure were obtained. Numerical visualization can be easier to understanding work principle and performance of pressurecompensating emitter. It is also realize low cost and high efficiency development of highquality emitter.(3)Based on fluid-structure interaction and two phase flow theory, the granuledistribution in the pressure compensating emitter was simulated. The results indicate thatnumerical simulation is a new and strong feasibility method to study and improve emitterperformance. The paper analyzed flow rate, the velocity distribution of water and granulevolume fraction under different granule diameters and initial volume fraction in a pressurecompensating emitter. We can conclude that the flow rate was reducing with the increase ofgranule diameter or initial volume fraction. Water velocity is a little larger than granule’s insame position. The granule volume fraction increases in the local channel where is easier tobe clog by sedimentary granule. To improve the anti-clogging of drip irrigation system, weneed not only to improve the structure of emitter to enhance its dynamic ability, but also toimprove filter facilities to reduce granule diameters and volume fraction in channel of pipe. |
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