Design And Experiment Of Wind-Delivered Rice Side-Deep Fertilizer Application Device

Scientific fertilization is an important measure to achieve cost savings and efficiency in rice production,rice is one of the important food crops in China.At present,China’s rice fertilizer application is mainly surface spreading of quick-acting fertilizers,fertilizer application amount,low utilization rate,not only waste fertilizer resources,increase production costs,but also damage the quality of arable land,intensify agricultural surface pollution.Fertilizer application technology for rice can reduce fertilizer use and runoff loss,improve fertilizer utilization rate,and reduce environmental pollution.Therefore,this study combines the agronomic requirements of the middle and lower reaches of the Yangtze River and designs a wind-fed rice side-depth fertilizer applicator to address the current problems of easy blockage of the fertilizer discharge opening,low continuous fertilizer discharge and poor uniformity of the side-depth applicator.The fertilizer discharge system of the wind-fed rice side-depth fertilizer applicator consists of a double-gear fertilizer discharger and a spiral fertilizer discharger.The device integrates the advantages of the gear fertilizer discharger and the spiral fertilizer discharger,and combined with the better air distribution performance of the air distribution pipe and the better anti-clogging performance of the furrow opener,it can effectively reduce the fertilizer clogging phenomenon and improve the utilization rate of fertilizer and the continuity and uniformity of fertilizer discharge.The main studies are as shown below:（1）Complete the material property measurement of granular fertilizers.Taking the compound fertilizer produced by Stanley as the sample,the triaxial dimensions of granular fertilizer were measured to be mainly concentrated between 2～3.5 mm,where the average value of length of granular fertilizer was 2.86 mm,the average value of width was 2.72 mm,the average value of thickness was 2.57 mm,and the equivalent diameter was 2.71 mm.the actual density of granular fertilizer was 1.344 g/ml3,the bulk density was The contact friction coefficient of granular fertilizer with stainless steel is 0.493 and the collision recovery coefficient is 0.414,and the contact friction coefficient with ABS resin is 0.457and the collision recovery coefficient is 0.481.The above parameters not only provide the parameter basis for the discrete element performance simulation test,but also lay the foundation for the development of the wind-delivered rice side-depth fertilizer applicator.The above parameters not only provide the parameter basis for the discrete element performance simulation test,but also lay the foundation for the development of the wind-delivered rice side deep fertilizer applicator.（2）Complete the overall structure design of the wind-fed rice side-deep fertilizer applicator.According to the agronomic characteristics of rice side-deep fertilizer application,the fertilizer application mode is determined,i.e.the wind-fed rice side-deep fertilizer applicator is paired with rice transplanter,and fertilizer application is carried out at the same time as the transplanter carries out rice transplanting operation.The main structure of the wind-fed rice side-depth fertilizer applicator includes fertilizer box,furrow opener,two-stage fertilizer discharger,air distribution pipe and fertilizer delivery pipe.（3）Complete the design and performance simulation of the fertilizer discharge system.The fertilizer discharge system was designed using the two-stage fertilizer discharge principle,and its structure consisted of a double-gear fertilizer discharger and a helical fertilizer discharger,and the key parameters of the two-stage fertilizer discharger were determined.The gear modulus of the double-gear fertilizer discharger is m=6,the number of teeth is Z=10,the gear width is l=50 mm,and the top height coefficient is _ah^（9）=1.The spiral fertilizer discharger has a spiral shaft diameter range of 17-26 mm,a pitch range of14-20 mm,and a speed range of 110-210 r/min.The structural parameters of the two-stage fertilizer discharger are optimized through discrete element simulation technology,and the simulation results of the double-gear fertilizer discharger are analyzed The simulation results of the spiral fertilizer discharger show that the coefficient of variation of uniformity decreases and then increases with the increase of pitch and diameter,and then decreases and then increases with the increase of rotational speed;the best combination of parameters for the spiral fertilizer discharger is 21.292 mm of spiral shaft diameter,134.07 r/min of rotational speed and 134.07 r/min of spiral shaft diameter.The best combination of parameters is 21.292 mm for spiral shaft diameter,134.07 r/min for rotational speed and16.437 mm for pitch,at which the coefficient of variation of fertilizer discharge stability is2.5%,which meets the stability design requirements.Combined with the theoretical analysis and simulation test of two-stage fertilizer discharger,it is found that the optimal transmission ratio of two-stage fertilizer discharger is 1:4,and the amount of fertilizer discharged is linearly related to time.（4）Complete the design and performance simulation of the fertilizer delivery system.According to the wind-fed rice side-deep fertilizer applicator with side-mounted fan air path structure,the air splitting duct was designed and the air splitting effect was analyzed by finite element performance simulation test.When the diameter of the main duct is unchanged,the air velocity of the outlet nearer to the air inlet is smaller,and the air velocity of the outlet farther away from the air inlet is larger;as the diameter of the main duct increases,the difference in the size of the air velocity of each outlet decreases,and the coefficient of variation of each outlet air velocity consistency gradually decreases,indicating that the larger the diameter of the main duct is,the better the air separation performance is.When the diameter of the main duct is 160 mm,the coefficient of variation of air velocity consistency is the minimum value of 3.2%,and the performance of air separation is the best at this time.According to the structural characteristics of the air path at the fertilizer mixing duct,four different structures of fertilizer mixing ducts were designed and combined with the finite element simulation technology to analyze the internal airflow and pressure distribution,the results show that the vertical,indented and venturi type fertilizer mixing ducts have positive pressure at the connection and the phenomenon of airflow blowing upward,while the embedded fertilizer mixing duct has negative pressure at the connection and no airflow blowing upward,so the embedded fertilizer mixing duct structure was chosen.Therefore,the structure of mixing tube is embedded.（5）Designing a furrow opener system.According to the agronomic requirements of side-depth fertilization,a boat-shaped furrow opener and a furrow opener system were designed,the boat-shaped furrow opener can effectively prevent mud and water from backing up and blocking the fertilizer discharge port to improve the fertilizer application performance of the fertilizer applicator;the lateral furrow opening range of the furrow opener system is 240～360 mm and the furrow opening depth range is 0～100 mm,so the furrow opener system can be used for side-depth fertilization and positive fertilization,which can improve the applicator’s applicability.（6）Complete the performance test of wind-fed rice side-deep fertilizer applicator.The wind-fed rice side-deep fertilizer applicator was processed according to the design plan,and a prototype comparison test was conducted through the two-stage fertilizer discharger and the spiral fertilizer discharger in the fertilizer applicator.The test results showed that the maximum coefficient of variation of fertilizer discharge consistency was 7.88%,the maximum coefficient of variation of stability was 8.11%,and the maximal homogeneity factor of variation for the spiral fertilizer discharger was 28%.;the maximum coefficient of variation of fertilizer discharge consistency was 5.09%,the maximum coefficient of variation of stability was 6.58%,the spiral fertilizer discharger has a maximum coefficient of variation of 23.54%in fertilizer discharge uniformity.The maximum values of the coefficient of variation of the consistency,stability and uniformity of fertilizer discharge of the two-stage fertilizer discharger were all smaller than those of the spiral fertilizer discharger,indicating that the wind-fed rice side-depth fertilizer applicator composed of the two-stage fertilizer discharger had better fertilizer discharge performance,and all of them were smaller than the values specified in the Technical Specification for Quality Evaluation of Fertilizer Application Machinery,indicating that the design of the wind-fed rice side-depth fertilizer applicator was feasible.Meanwhile,analysis of the test results showed that the coefficient of variation of the consistency and uniformity of fertilizer discharge of the rice side-depth fertilizer applicator was the smallest when the spiral shaft speed was 160r/min,indicating that the wind-fed rice side-depth fertilizer applicator had the best performance of fertilizer discharge at this time.