Study On Hydraulic Performance Of Truss Irrigation Machine Based On Jet Pulse

To address the issues of high irrigation intensity,low irrigation uniformity,and inadequate water fragmentation of a truss sprinkler,a water-saving pulse truss sprinkler was designed and optimized using the jet attachment switching technology.The pulse truss sprinkler was applied to the truss sprinkler and a new pulse truss sprinkler was constructed.The pulse sprinkler was subjected to experimental research to investigate its combination mobile irrigation characteristics.The main research and experimental conclusions are as follows:(1)Seven factors that affect the water-saving performance of the pulse truss sprinkler were selected,with each factor having four levels.A factorial experiment was conducted to determine32 different structural parameter settings for the pulse truss sprinkler.The CFX software was used to simulate the water-saving performance parameters of each model.The optimal structural parameters for the pulse truss sprinkler were determined as follows: w is 3.8mm,S is 1.9mm,H is38 mm,r is 2.5mm,β is 8°,k is 7mm,cw is 2.5mm.The pressure cloud map of the optimal structural pulse truss sprinkler was exported from CFX post-processing,and the pressure variation rules of the internal flow field were analyzed.Water-saving performance tests were conducted to verify the optimal structural parameters of the pulse truss sprinkler,and the results showed that the experimental data were closely consistent with the numerical simulation results,with a relative error of approximately 8%.(2)A comparison experiment was conducted to investigate the water-saving performance of the truss sprinkler under conditions of pulse water pressure and constant water pressure.The water flow rate,range of application,and radial water distribution of the sprinkler were compared under the same conditions.The results showed that when the inlet pressure was 100 k Pa,150 k Pa,and200 k Pa,the outlet pressure variation ranges of the prototype were 66～89 k Pa,105～131 k Pa,and143～177 k Pa,respectively;the water flow rate of the pulse truss sprinkler was reduced by 8.2%,8.4%,and 5.3%,respectively,compared to the constant water pressure sprinkler,and the range of application was increased by 4.3%,2.5%,and 4.1%,respectively.The peak irrigation intensity was reduced by 44%.This indicates that pulse irrigation can effectively improve the water distribution of the sprinkler and reduce the irrigation intensity.(3)The pulse truss sprinkler was installed on the truss sprinkler,and mobile irrigation experiments were conducted with sprinkler distances of 3m,3.5m,and 4m.The experiment compared the water-saving performance,range of application,and radial water distribution of the sprinkler under different sprinkler distances and inlet pressures.The results showed that when the inlet pressure was 150 k Pa,the water-saving performance of the pulse truss sprinkler was more stable and the ripple was smaller compared to other conditions.When the inlet pressure was150 k Pa,the peak irrigation intensity was 31.4mm/h,which was lower than that of the constant water pressure sprinkler by 6.5% and 11.6%,respectively.The coefficient of irrigation uniformity CU increased by 1.9% and 2%,respectively,and the coefficient of distribution uniformity DU increased by 5% and 0.5%,respectively.This indicates that pulse irrigation can effectively improve the water distribution of the sprinkler and reduce the irrigation intensity.(4)A test system was constructed to measure the water-saving performance of the sprinkler with a 4m sprinkler distance,and mobile irrigation experiments were conducted under conditions of pulse water pressure and constant water pressure.The experiment compared the water distribution,irrigation intensity,peak irrigation intensity,and irrigation uniformity of the sprinkler to evaluate the water-saving performance of pulse irrigation.When the inlet pressure was 100 k Pa,150 k Pa,and 200 k Pa,the peak irrigation intensity of pulse irrigation was reduced by 13.3%,13.3%,and 16.5%,respectively,compared to constant water pressure irrigation.The coefficient of irrigation uniformity CU increased by 17.1%,12.6%,and 3%,respectively,and the coefficient of distribution uniformity DU increased by 24.2%,11.2%,and 9.5%,respectively.The study showed that pulse irrigation effectively reduced the peak irrigation intensity,improved the water distribution,and increased the irrigation uniformity,significantly improving the water-saving performance and irrigation quality of the truss sprinkler.