Experimental Study On The Effect Of Tooth Flow Structureon The Hydraulic Performance Of Emitter Drip

The emitter drip is the core part of the drip irrigation system.The drip performance directly affects the operation of the whole drip irrigation system.Therefore,the study on the relationship between the structural parameters and the hydraulic performance of the drip runner is of great significance to optimize the performance of the dripper and improve the water saving effect of drip irrigation system.In this paper,the current application of a wide range of tooth-shaped maze flow throat as the object of study to the channel width,runner depth,tooth angle,tooth spacing,flow channel number and tooth height as the main control parameters,and designed 30 different structures.Then according to the results of single factor analysis,the cross section area,the total length of the flow channel,the width ratio of the flow channel and the curvature of the flow in the flow channel are taken as the controlling factors.The influence of the structural parameters of the flow channel on the hydraulic performance of the dripper was studied by using the computational fluid dynamics software FLUENT15.0 and the hydraulic performance test platform of the dripper.The following conclusions were obtained:(1)FLUENT15.0 provides a number of calculation models for various conditions to choose.In order to more accurately simulate the flow characteristics in the dripper flow path,We used the software provides two-way k-e turbulence model which include the standard k-e turbulence model,the RNG k-e turbulence model and the Realizable k-e turbulence model to numerical simulation,and compare the result with actual test value.Finally,considering the time cost and calculation cost,it is concluded that the standard k-e turbulence model is more closer to actual test value than others,and as the calculation model of this experiment.(2)The relationship between the single factor structural parameters and the hydraulic performance parameters of the drip was analyzed.The results showed that:There were significant correlations between the various factors on the hydraulic performance of the dripper.The flow rate is negatively correlated with the tooth spacing and the number of units,and the flow and tooth spacing do not reach a significant correlation level,and the number of units has achieved a significant correlation;And had a significant correlation with the width of the runner,the depth of the runner,the tooth height and the tooth tip angle,and reached a significant correlation with the depth of the runner,which was significantly correlated with the depth of the runner Of the significant correlation level.The flow parameters of the different structure parameters of the dripper and the drip flow have reached a significant correlation level,with the depth of the runner,the angle of the tooth tip and the number of flow channel units to an excellent correlation level,and the flow channel width,tooth spacing and The teeth were at a significantly correlated level.The correlation between the structural parameters of the different structure of the dripper and the flow index of the dripper is not significant.Only the angle of the tooth tip and the flow path unit and the flow index reach a significant correlation level,the other structural parameters,the flow channel width,Depth,tooth spacing,tooth height and the relationship between the flow index did not reach a significant correlation level.According to the regression results,the order of the drier flow is in the order of runner width,unit number,runner depth,tooth height,tooth spacing and tooth tip angle.(3)From the velocity vector diagram and the pressure distribution map,you can clearly see the micro-flow inside the drip,the flow of internal flow is divided into two areas,namely,the main region and the vortex area.Which mainly occurs in the main region of the tooth tip position,and the vortex area mainly occurs in the tooth low.From the pressure distribution diagram can be seen in the pressure at the entrance of the largest,with the increase in the length of the flow pressure is decreasing.(4)The relationship between the combined factor and the hydraulic performance parameters of the dripper is analyzed.The results show that the flow rate has a significant positive correlation with the area of the irrigation section.The total length of the flow channel is negatively correlated with the drip flow rate.There is a positive correlation between the curvature of the flow and the flow rate of the dripper is similar to that of the flow.The relationship between the flow index and the combination factor is more complicated.In the four factors,only the total flow length has a significant negative correlation with the droplet flow index,and the other three factors are To achieve a significant level.From the results of linear regression,it is found that the factors that affect the maximum flow of the drip are the cross section area,and the order of the drip flow is the order of the total length of the maze flow channel,the width ratio of the flow channel structure and the internal flow curvature.