Numerical Simulation And Experimental Research On Curved Shaped Parameter Optimization Of Sprinkler

Sprinkler irrigation is one of the world-wide used techniques in water-saving irrigation,for their advantages such as water saving,increasing production,great adaptation,and easy to be mechanized,etc.The turbulence degree of water-flow inside the nozzle is effected by nozzle’s performance,when water flow through the nozzle elbow,it will change its linear-motion direction into circular motion,will destruct the continuity and stability of its flowing field,then generates eddy current and transverse circulation,and energy loss increases,lead to the uneven velocity disturbed water-flow could be transformed into a smooth one,and as it enter the nozzle it is almost in the form of an uniform cross-sectional rate,then we will gets an optimized nozzle hydraulic performance.The main research results as bellows:(1)Take Rain Bird 30PSH sprinkler as an example,after dismantled the rocker arm and other parts in WEDM,cut its flowing channel,then we will get the size of its inner flowing channel and external.Basing on the measured data,we can get a three-dimensional modeling with Pro/E,design three bending curve type called as Circular arcs,Archimedes spiral and Parabola,and change the size of nozzle junction and each curve gradient line into expanded,moderate or reduced one,(2)Took the advantage of fluid dynamics simulation software,which called FLUENT,took RNG-epsilon model,and the still wall as a reference substance,then connecting with standard wall function approach and SIMPLE algorithm pressure and velocity coupling solution,drawn in the same inlet pressure,strain rate,the trend of the wall static pressure,turbulent kinetic energy,the main and auxiliary nozzle exit velocity,main nozzle flow,we can get:parabolic curve gradient line expanded to handle more desirable than other programs.Using multiphase flow model(VOF)to analyze water flow in the external flow field.(3)Select the inlet pressure of 200KPa-500KPa to simulate optimum composition obtained when the pressure increases,the exit velocity of main nozzles and sub-nozzle of the nozzle and the inlet velocity increases with increasing pressure,but the inlet velocity increases trend is more gentle.For the same kind of curve,the gradient line approach is different,the flow field in turbulent kinetic energy is somewhat different,to expand processing curve turbulent kinetic energy increase with the increase of the inlet pressure is more obvious,and moderate processing curve trends more gentle.(4)Using rapid prototyping to get three-dimensional modeling with different bending curve structure combination,then a product will be finished.Experimental research on the nozzle we can obtained that:the simulation inlet flow and experimental inlet flow relative error of maximum relative error is 4.720%,the minimum error is 0.160%.The relative error of the flow rate of experimental sub-nozzle flow and the analog sub-nozzle is also smaller,a maximum of 6.072%,0.130%Min.Experimental sub-nozzle flow rate of the nozzle flow ratio of 10%-11%,the simulation results of the sub-nozzle flow attributable to the nozzle flow ratio of 9.9-10.5%.So the experimental results are very close to the simulation results.