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Structure Design And Fertilizer Injection Performance Optimization Of Venturi Injector With Double Throat

Posted on:2024-06-16Degree:MasterType:Thesis
Country:ChinaCandidate:G R HuFull Text:PDF
GTID:2543307112998699Subject:Agricultural Engineering
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Object: Fertilization equipment is one of the most important components of irrigation system,and its performance directly affects the quality of irrigation.Venturi injector is widely used in agricultural irrigation system due to its simple structure,convenient operation and low price.The existing Venturi injector generally has problems such as small fertilizer injection flow and excessive energy loss.Under the same working conditions,the fertilizer injection performance of non-asymmetric Venturi injector is better than that of symmetric Venturi injector.At present,many scholars have compared the asymmetric Venturi injector and non-symmetric Venturi injector,and the structure optimization of non-symmetric Venturi injector has not been carried out.The influence of structural parameters and vortex characteristics on the fertilizer injection performance of non-axisymmetric Venturi ejector is not clear.Therefore,the aim of this study is to explore the influence of structural parameters and vortex characteristics on the fertilizer injection performance of non-axisymmetric venturi injector,and to propose the optimal structural parameters of non-axisymmetric venturi injector.On this basis,the dual-channel coupling optimization research was carried out.The structural form of Venturi injector with double throat was proposed and optimized to further improve the fertilizer injection performance and reduce head loss of Venturi injector.Methods: In this study,the combination of physical test and numerical simulation was used to analyze the fertilizer injection performance and flow field distribution of Venturi injector.Through single factor test and orthogonal test,the influence of contraction angle,diffusion angle,throat diameter and fertilizer injection pipe tilt angle of non-asymmetric Venturi injector on the fertilizer injection flow and fertilizer injection efficiency was analyzed.Taking the maximum fertilizer absorption efficiency as the research goal,the optimal structural parameter combination of non-asymmetric Venturi injector was determined.On this basis,the influence of vortex characteristics on the non-asymmetric Venturi injector is further analyzed.The research idea of dual-channel coupling optimization was proposed.The structure form of the Venturi injector with double throat is designed.The effects of contraction angle,diffusion angle and throat diameter on the fertilizer injection performance of the Venturi injector with double throat were analyzed.Through the test of fertilizer injection performance,the energy loss and critical pressure difference of Venturi injector with double throat were measured.Results:(1)When the inlet and outlet diameter of the non-asymmetric Venturi injector was 25 mm,the optimal structural parameters were as follows: the contraction angle 40°,the diffusion angle 6°,the throat diameter 7 mm,and the fertilizer injection pipe tilt angle 120 °.The optimized non-asymmetric Venturi injector increased the fertilizer injection flow and efficiency by 21.56%—66.76% and 26.84%—79.30%,respectively.(2)The Venturi injector with double throat gradient section was separated and two injection ports were set,which was more conducive to improving its fertilizer injection performance;the optimal structural parameters of the Venturi injector with double throat were the contraction angle 40°,the diffusion angle 6°,and the throat diameter 5 mm.(3)Under the same inlet and outlet pressure difference,compared with symmetrical and non-asymmetrical Venturi injectors,the fertilizer injection flow of Venturi injector with double throat increased by 76.19%—249.69% and 23.62%—138.34% respectively,the critical pressure difference of fertilizer absorption decreased by 6.98%—21.98% and 6.41%—12.08% respectively,and the energy loss ratio decreased by 6.98%—21.95% and 6.41%—12.08% respectively.Conclusion: The vortex characteristics have a significant effect on the fertilizer injector performance of Venturi injector(p<0.05).Reducing the vortex area size and intensity,or increasing the distance from the vortex area boundary to the throat are beneficial to improve the fertilizer injection performance of Venturi injector.The structural design of the double throat is beneficial to reduce the turning angle of the fluid in the contraction section and the diffusion section.Which also can reduce the energy loss caused by multidirectional velocity collision and vortex,make the streamline more stable,and significantly improve the fertilizer injection performance and hydraulic performance of Venturi injector.
Keywords/Search Tags:Venturi injector, Fertilizer injection performance, Vortex, Structural optimization
PDF Full Text Request
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