Model And Research On Fertilizer Particle Density In Pipeline Based On Discrete Element Analysis Metho

Due to the rapid development of China’s agriculture at this stage,the demand for chemical fertilizers is high.However,the excessive use of chemical fertilizers will cause a lot of pollution to the environment,and at the same time will damage the soil environment,resulting in soil fertility loss,water pollution and soil compaction,etc.so that the growth environment of local crops is damaged,which is contrary to the national policy of environmental protection and sustainable development.Therefore,it is particularly important to reasonably control the amount of fertilizer in the fertilization process,in which the particle density of granular fertilizer in the drainage pipeline has a direct relationship with the amount of fertilizer.Therefore,this paper uses EDEM to establish a fertilizer drainage model,analyze the motion speed of granular fertilizer in different positions in the drainage pipeline,and analyze the power spectral density of the microwave Doppler sensor echo signal and the velocity information of the position to obtain the particle density of different measurement positions in the drainage pipeline.Therefore,obtaining fertilizer particle density in the drainage pipe is the main purpose of this paper.The main research contents are as follows:(1)The discrete element simulation model of three kinds of granular fertilizers was established by multisphere bonding method,the contact parameters between urea particles,diammonium phosphate and nitrogen-potassium compound fertilizer and PVC plates were calibrated,and the collision recovery coefficients between the three fertilizers and PVC plates were obtained by bouncing collision test of 0.292,0.438 and 0.526,respectively,and the static friction coefficients between the three fertilizers and PVC plates were obtained by inclined slip test of 0.525 and 0.524,respectively.0.599;The rolling friction coefficient and dynamic friction coefficient between the three fertilizers and pvc plates were obtained by means of slope rolling test of 0.158,0.146 and 0.124,and the static friction coefficient and dynamic friction coefficient between the three fertilizers of urea particles,diammonium phosphate and nitrogen and potassium compound fertilizer were calibrated by measuring the angle of rest.The static friction coefficients of the three fertilizers were 0.328,0.26,0.34,and the dynamic friction coefficients were 0.186,0.21 and 0.17.(2)This article uses solidworks to build a discrete meta model of the main components of the outer slot wheel fertilizer conveyor,and save the file as "*.step" format and import it into EDEM.By establishing the simulation model of fertilizer particles and simulating the overall fertilizer drainage process,the average velocity of urea at 100 mm and 500 mm in the pipeline is0.701 m/s and 1.731 m/s,the average velocity of diammonium phosphate at 100 mm and 500 mm is 0.595m/s and 1.505m/s,and the average velocity of nitrogen and potassium compound fertilizer at 100 mm and 500 mm is 0.688m/s and 1.595m/s.The speed of a large number of granular fertilizers was measured,and the falling speed of a large number of granular fertilizers at the same height at different speeds was measured,and the movement speed of granular fertilizers was obtained in direct proportion to the rotational speed.It was measured that at a speed of 70r/min and a height of 100 mm,the particle velocities of urea,diammonium phosphate and nitrogen and potassium compound fertilizer were 0.701 m/s,0.559 m/s and 0.688 m/s,respectively,and the particle velocities of urea,diammonium phosphate and nitrogen and potassium compound fertilizer were 1.731 m/s,1.505 m/s and 1.595 m/s,respectively.(3)The power spectral density of granular fertilizer at 100 mm and 500 mm in the drainage pipe is measured by microwave sensor,and the density of granular fertilizer in the pipeline is estimated by its inverse proportional relationship with the velocity of the granular fertilizer.It was obtained that at 100 mm,the particle density of the three fertilizers in the drainage pipeline was 1.14,1.21,0.89;at 500 mm,the particle density of the three fertilizers in the drainage pipeline was 0.45,0.47,0.37.Through the comparison and verification of mass flow rate and real fertilizer quality,the relative maximum error is 6.41%,which proves that the fertilizer particle density calculation method in the drainage pipeline in this study is feasible.