Numerical Simulation Of Diaphragm Change Of Pressure Compensated Irrigator Based On Target Flow

Objective: Drip irrigation has the characteristics of saving water and land,saving fertilizer and pesticides,and improving crop yield and quality.It is one of the most important water-saving irrigation technologies currently used in China.It is one of the types of drip irrigation.Improving irrigation efficiency and promoting the development and use of water-saving equipment are of great significance to alleviating the current shortage of water resources,improving the efficiency of water resources utilization,and increasing the output of agricultural products.Therefore,in order to actively respond to the sustainable development of the country,improve the innovation of water-saving equipment,improve the deficiencies of old irrigation methods,and improve the use range of pressure-compensated drip irrigation emitters,it is necessary to irrigate crops based on the principle of water demand under different application conditions.Sexuality issues are further explored.In this study,based on the compensation pri nciple of the pressure-compensated irrigator,the structural parameters of the core component of the diaphragm are orthogonally calculated,and the correlation between the structural parameters of the diaphragm of the pressure-compensated irrigator and the inlet pressure under the target flow rate is obtained,which is: The selection of diaphragm material provides theoretical basis and technical reference.And the common elastic material in the market is used as the diaphragm material to calculate the hydra ulic performance of the pressure compensation irrigation device,which provides the basis for the selection of the optimal material.Methods: In this study,a combination of physical experiments and numerical simulations was adopted.For the two diaphragm structural parameters,48 groups of structural schemes were designed by the orthogonal experimental design method to test the hydraulic performance,and the outflow of different structural schemes under the inlet pressure was measured by the physical test platform.At the same time,the numerical simulation under the same structural scheme is carried out,and the results of the physical test are compared,and the simulation scheme with the flow error range within 10% is selected.According to the simulation scheme,the remaining diaphragm structural parameters are simulated to obtain the outflow flow,and the pressure and flow velocity nephograms of the pressure-compensated emitter under fixed conditions are obtained to verify the influence of the diaphragm change on the outflow flow.Based on the fitting relationship between the diaphragm structure parameters and different inlet pressure and outlet flow,and according to the known physical properties of elastic materials,the pressure-flow relationship is fitted to analyze the hydraulic performance and select the optimal material.Results:(1)The maximum displacement of the diaphragm has a direct influence on the discharge of the pressure compensation emitters.SST K-ω simulation scheme with minimum error between physical test and numerical simulation is selected.When the diaphragm thickness is fixed,the inlet pressure changes more when the discharge rate increases.The maximum displacement of the diaphragm is positively correlated with the change of inlet pressure,and the increasing trend tends to be gentle.The outlet flow within the pressure range provides a certain pressure adjustment space for the selection of target flow and increases the fault tolerance rate of irrigation water.(2)Under multiple diaphragm thickness,the greater the diaphragm thickness,the greater the maximum displacement of the same diaphragm and the outflow flow corresponding to the inlet pressure.The larger the thickness of the diaphragm is,the better the fitting effect of the 3D surface is.The fitting formula under different thickness of the diaphragm is obtained.(3)Based on the existing elastic materials,the elastic material SBS with a diaphragm thickness of 1 mm corresponds to the smallest flow index and the best hydraulic performance.The thickness of the diaphragm is different,and the corresponding optimal material is different.Conclusion: The discharge rate of pressure compensator is affected by the structural parameters of diaphragm,and the maximum displacement of diaphragm can be used to change the size of the cross section area of the water outlet,so as to affect the discharge rate of the emitter.Through the numerical simulation of different structural parameters of the diaphragm,the relationship fitting of the output flow under different working conditions is carried out,which provides theoretical basis and technical specifications for the selection of diaphragm materials.The hydraulic performance of pressure compensation irrigator was studied by using the ex isting elastic material in the market,and the optimal material was obtained under specific working conditions.It is recommended to use the fitting formula under different thickness to provide a basis for selecting diaphragm materials under different discharge rates in practical application.