Research On Design And Mixing Mode Of Integrative Water And Fertilizer Machine

Water and fertilizer integration technology play an important role in China's agricultural production and are also one of the main directions for agricultural development in the future.At present,the application rate of water and fertilizer integrated fertilization equipment is still at a relatively low level.Traditional large-area flood irrigation or simple water and fertilizer integrated equipment are used for irrigation and fertilization.The degree of automation and intelligence is low,which is not conducive to the development of whole-process mechanization of the facility production.Based on Fluent simulation technology,this paper designed the integrated water and fertilizer application machine for facilities greenhouse.It mainly designed and optimized the raw liquid preparation part and the head hub part,and designed the head hub part for the problem that the irrigation pressure of the fertilizer was not adjustable at the current stage.It is proposed to adjust the irrigation pressure by way of pressure backflow.The numerical analysis method was used to simulate and analyze the process of mixing fertilizers,and the mechanism of fluid kinematics in the process of mixing fertilizers was revealed.An experimental platform for mixing fertilizers was built,and the results of numerical simulation were verified through experimental research methods.The main research contents and conclusions are as follows:(1)Design of adjustable head hub for irrigation pressure.The head hub of irrigation pressure regulation based on pressure relief and reflux was designed by using three-dimensional modeling software,and the head hub was processed and manufactured.After debugging and optimization,the way of pressure relief and recirculation can realize the adjustment of irrigation pressure,which can meet the requirements of fertilization and irrigation in different areas,and the flow uniformity of the drop arrow is good.(2)Numerical simulation and experimental study of reflux mixing model.The characteristics of pressure,velocity vector and streamline in fluid domain are extracted by numerical simulation of backflow mixing process.It is found that the pressure gradient distribution is not obvious in the circumfluence mixing mode and the tangential circumfluence mixing mode,and the velocity vector value in the axial section is small.The pressure gradient is obvious and the velocity vector value in axial cross section increases.The pressure gradient distribution is most obvious in the axial superposition tangential reflux mixing mode,the velocity vector fills the entire axial section,and the streamline fills the entire fluid domain.The experimental results show that the solid powder fertilizer takes longer to mix uniformly under the jet reflux mixing mode and the tangential reflux mixing mode,which is not suitable for fertilizer operation.Solid powder fertilizer was mixed uniformly evenly after 150 s in axial refluxing mixing mode and after 75 s in axial superposition tangential mixing mode.The axial superimposed tangential reflux mixing mode is suitable for mixing fertilizers of liquid fertilizer and solid powder fertilizer.(3)Numerical simulation and experimental study of mixing superposition reflux mode.Numerical simulations of the mixing and refluxing process were conducted,and it was found that the pressure gradient distribution in the axial section was obvious,and a distinct vortex structure was formed.The experimental results show that in the stirring mode,the solid powder fertilizer is uniformly mixed after 65 s,and the solid particle fertilizer is uniformly mixed after 170 s.In the stirring superimposed reflux mixing mode,the solid granular fertilizer is mixed uniformly after 105 s,which saves 65 s compared to the stirring paddle mode.The mixing paddle superposition reflux mixing mode is suitable for the mixing operation of solid granular fertilizer.(4)Prototype production and performance test.The prototype was made according to the three-dimensional model,and the performance test of the whole machine was carried out.The test results show that the fertilizer has good stability and continuity,and the error between the drop arrow flow in the irrigation operation is within 5%.In this paper,the design of the integrated water and fertilizer application machine is reasonable and feasible.The prototype runs stably and reliably,and it can meet the facility greenhouse integrated irrigation requirements.