| At present,potato has become one of the important grain dish and concurrently using crops.With planting area increasing year by year,our country has now become the largest potato production country in the world.As high production and fertilizer-loving characteristics of potato,it is more important to raise the level of chemical fertilizer when planting.Granular fertilizer which was rich in variety of nutrients for potato growth was commonly used in our country.The correct and reasonable application of chemical fertilizer not only can improve the yield and quality of potato and the utilization of fertilizer,but reduce the influence of fertilizer on the environment and improve the quality of soil environment.Most of the regions in China are still mainly traditional manual fertilization which not only labor intensity,time-consuming,but also harm to human,therefore,mechanical fertilization has become an necessary way for fertilizer spreading.Centrifugal fertilizing machine,with simple structure and wide spreader,is one of the most widely used fertilizer spreader.Centrifugal distributor has two forms disk which are horizontal disk and conical disk.In order to obtain larger spreader width and achievement of variable Fertilizer,conical disc was often selected.There are some problems on fertilizer machinery in our country,such as poor uniformity,easy clogged and so on.China’s most variable fertilizer manure are disc-type fertilizer spread,and most of it are horizontal disk.The research is less on the structure and related theory of the taper spreader.Aiming at such questions,this paper described a cone disc spreader device.It is suitable for spreading granular which is the most common agricultural fertilizer.The structure and working principle of the device were described in this paper.The main contents are as follows:(1)According to the area of potato planting,required wide of spread fertilizer and characteristics of spreader with cone disc,the key components of a cone-type spreader which was conical disk fertilizer device was designed.Various agencies of the device was reasonable designed,so that it can effectively solve the problem of uneven fertilization of fertilizer.(2)The kinematics and dynamics analysis of fertilizer granules in conical disc and air were carried out with single fertilizer granules.Through the above theoretical analysis,therefore,the motion models of granular fertilizer were established both on the two process mentioned above.Parameters of conical disk and vane were determined.The feasibility and reliability of the device were verified theoretically,which can meet the requirement of wide spread of fertilizer granule and evenness of fertilizer application.(3)The physical properties of fertilizers such as urea,diammonium phosphate and compound fertilizers were tested.And the physical parameters such as size guide number,friction coefficient and density of fertilizer granules were obtained,Which provides the theoretical parameters for the structure design of the fertilizer spreader.(4)The motion model and the process of fertilizer granules was solved by MATLAB software.Whole process trajectory of fertilizer granule from falling to conical disc till to the ground were get.Correctness of the theoretical model were verified and the structure parameters of the cone-type fertilizer device were determine.(5)The static test referred to ISO(international organization for standardization)5690 and ASAE(American society of agricultural engineers)S341.2 in America.The test was carried out in the room,in order to reduce the effects on fertilizer spreading because of the speed of wind,the air humidity and so on.Urea was selected as experiment sample.Test bench of cone-type fertilizer device was designed.Quadratic orthogonal rotary combination tests were carried out for the cone disc spreader device.The experimental factors of bench test included position of fertilizer export,length of vane,area of fertilizer export,pitch angle of vane in horizontal plane,rotational speed of disc.Coefficient of variation was test index.The experimental data was processed and optimized by Design-expert 8.0.6.The regression model between the test index and the factors was obtained.Meanwhile,the response surfaces were established between the coefficient of variation and the test factors in order to obtain the relationship intuitively.Related findings:(1)Fertilizer device with cone disc meet the requirements of the fertilizer operation of the potato.The diameter of cone disc was 400 mm and cone angle was 160°.The device effectively improve the distance of spread.Length of vane can be adjusted so that the fertilizer uniformity would be better.The quality of fertilizer would be improved.The motion of fertilizer granules in cone,vane and air was analyzed theoretically,so that the motion model of fertilizer particles in two processes were obtained.(2)In view of the low adjustment precision of the domestic fertilizer control device,a kind of fertilizer adjustment plate were designed to facilitate the adjustment.The area of the fertilizer export was increased or decreased by the arithmetic sequence.The regulation of the amount of fertilizer fertilizer to achieve the same changes.(3)The particle size,friction coefficient and density of urea sample,diammonium phosphate sample and compound fertilizer sample were measured.And the size guide number of the three fertilizer particles were 2.41 mm,2.43 mm and 2.60 mm,respectively.A line chart was established to obtain the proportion of fertilizer granules under different screen sieves.The density of urea granules was 1265 kg/m3 by drainage method.The density of diammonium phosphate particles was 905 kg/m3.The density of compound fertilizers was 1549 kg/m3.The friction coefficient of three urea granules was 0.47,the friction coefficient of diammonium phosphate was 0.58,respectively.The friction coefficient of compound fertilizers was 0.50.(4)Use the ode function of MATLAB software to solve the equations of motion of fertilizer particles in two processes and the displacement and velocity images of fertilizer particles in motion were drawn.The velocity of urea particles moving to the edge of fertilizer disk was 11.2 m/s.The horizontal displacement of the movement of fertilizer particles,that is,the distance was 6.4 m when it moved into the air after leaving the fertilizer disc.The speed of diammonium phosphate moving to the edge of conical fertilizer plate was 9.9 m/s.The horizontal displacement of the movement of fertilizer particles,that is,the distance was 5.4 m when it moved into the air after leaving the fertilizer disc.The velocity of the compound fertilizer particles moving to the edge of the cone fertilizer was 10.7 m/s.The horizontal displacement of the movement of fertilizer particles,that is,the distance was 6.1 m when it moved into the air after leaving the fertilizer disc.(5)Quadratic orthogonal rotary combination tests were carried out for the cone disc spreader device.The regression model between the test index and the factors was obtained.Meanwhile,the response surfaces were established between the coefficient of variation and the test factors in order to obtain the relationship intuitively.The results showed that the order of factors affecting the coefficient of variation of fertilization was rotational speed of disc,position of fertilizer export,pitch angle of vane in horizontal plane,length of vane and area of fertilizer export.(6)The experimental data was processed and optimized by Design-expert 8.0.6.The regression model between the test index and the factors was obtained.Meanwhile,the response surfaces were established between the coefficient of variation and the test factors in order to obtain the relationship intuitively.Test results showed that when the position of fertilizer export was(70 mm,0,800 mm),length of vane was 150 mm,area of fertilizer export was 2456 mm2,pitch angle of vane in horizontal plane was 1°and rotational speed of disc was 1090 r/min,the coefficient of variation which was test index was 5.215%.At this time,the coefficient of variation was smallest,so that the uniformity of the fertilizer was best to meet the requirements of the application.The research provides a better solution for uneven distribution of fertilizer of currently machinery in China and provides a theoretical reference for design and optimization of the cone disc distributor. |
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