Mechanization of field experiments is the only way to improve crop breeding and seed propagation effects.In order to further clarify and improve the working performance of tapered threshing device for plot breeding,an...Mechanization of field experiments is the only way to improve crop breeding and seed propagation effects.In order to further clarify and improve the working performance of tapered threshing device for plot breeding,and reduce the remaining seeds in the device,the numerical simulation was carried out on the motion process of materials in the longitudinal-axial tapered cylinder threshing and transmission device of the plot wheat breeding combine harvester based on CFD-DEM method.Simulation results showed that,threshing and transmission of particles and short stalks at axial direction could be realized under the influence of air flow.Meanwhile,the material transference and distribution rule and stream field distribution rule of air flow in the threshing and transmission device were obtained,the variations of velocity and displacement of particles and short stalks with time were obtained;the motion trajectories and forms of particles in different types of retention were also studied.At rotating speed of 1300-1600 r/min for the tapered threshing cylinder in the verification test,the particle retention rate in the enclosure was 0-0.13%,while in the simulation the particle retention rate in the enclosure was 0-0.11%,only a 0.02%difference between them.The results proved a favorable feasibility to simulate the working performance of the tapered threshing and transmission device for plot breeding through gas-solid coupling method.展开更多
In order to further clarify and improve the working performance of separating cleaning device of flax threshing material,and study the motion law and characteristics of components of flax threshing material,in this pa...In order to further clarify and improve the working performance of separating cleaning device of flax threshing material,and study the motion law and characteristics of components of flax threshing material,in this paper,numerical simulation was carried out on the separating cleaning process of flax threshing material based on CFD-DEM method.Simulation results showed that the components of flax threshing material were separated and cleaned under the influence of airflow field,meanwhile,variation curves of quantity and mean velocity of flax seeds in the separating cleaning system were obtained.By referring to streamline distribution of gas-solid coupling,the quantity variation law of components of flax threshing material with time was explored and their motion curves and variation tendency of average velocity were studied.Verification test results showed that the cleaning rate of separating cleaning device for flax threshing material was 92.66%with 1.58%of total separation loss.Compared with simulation results,the test results were 1.34%and 0.93%lower,showing that it is feasible to apply the gas-solid coupling theory and method to simulate the separating and cleaning operation of flax threshing material.展开更多
In order to further reduce the damage rate in threshing seed corn,a seed corn threshing testbed with variable diameter and spacing that can realize dynamic adjustment of parameters,such as feed quantity,rotating speed...In order to further reduce the damage rate in threshing seed corn,a seed corn threshing testbed with variable diameter and spacing that can realize dynamic adjustment of parameters,such as feed quantity,rotating speed of the threshing device,threshing spacing of the threshing units,was designed in this research.The software of finite element analysis ANSYS Workbench was applied to do modal analysis on the threshing axis designed for variable diameter and spacing of seed corn.The first 8 orders of natural frequencies were distributed in 201.12-1640.20 Hz,with corresponding vibration amplitude in 5.86-27.04 mm,showing reasonable structural design of the threshing axis,which could realize effective seed corn threshing and conveying.Discrete element method was applied to do simulation analysis on the seed corn threshing and conveying process with variable diameter and spacing.Under the condition of different feed quantity,different rotating speed of the thresher,the moving speed of corn clusters and contact force among clusters were measured through simulation,and the working characteristics of the threshing testbed for low-damage and dynamic threshing and conveying of seed corn with variable diameter and spacing were revealed.Working performance test results of the testbed of seed corn with variable diameter and spacing showed that,when the rotating speed of the threshing axis was 190-290 r/min,feed quantity was 1.80-3.80 kg/s,the damage rate of seed corn was 0.32%-0.63%,threshing rate was 99.20%-99.82%,and content impurity rate was 4.23%-5.86%,the mass of threshed corn grains first increased and then decreased along the axial direction.The test verification process was in line with the simulation results;thus,the test results could satisfy the requirements in design and actual operation.展开更多
基金The authors acknowledge that this work was financially supported by China Agriculture Research System(CARS-14-1-28)Discipline construction fund project of Gansu Agricultural University(GAU-XKJS-2018-189)National Natural Science Foundation of China(Grant No.51365003).
文摘Mechanization of field experiments is the only way to improve crop breeding and seed propagation effects.In order to further clarify and improve the working performance of tapered threshing device for plot breeding,and reduce the remaining seeds in the device,the numerical simulation was carried out on the motion process of materials in the longitudinal-axial tapered cylinder threshing and transmission device of the plot wheat breeding combine harvester based on CFD-DEM method.Simulation results showed that,threshing and transmission of particles and short stalks at axial direction could be realized under the influence of air flow.Meanwhile,the material transference and distribution rule and stream field distribution rule of air flow in the threshing and transmission device were obtained,the variations of velocity and displacement of particles and short stalks with time were obtained;the motion trajectories and forms of particles in different types of retention were also studied.At rotating speed of 1300-1600 r/min for the tapered threshing cylinder in the verification test,the particle retention rate in the enclosure was 0-0.13%,while in the simulation the particle retention rate in the enclosure was 0-0.11%,only a 0.02%difference between them.The results proved a favorable feasibility to simulate the working performance of the tapered threshing and transmission device for plot breeding through gas-solid coupling method.
基金The authors acknowledge that this work was financially supported by China Agriculture Research System(CARS-14-1-28)Discipline construction fund project of Gansu Agricultural University(GAU-XKJS-2018-189).
文摘In order to further clarify and improve the working performance of separating cleaning device of flax threshing material,and study the motion law and characteristics of components of flax threshing material,in this paper,numerical simulation was carried out on the separating cleaning process of flax threshing material based on CFD-DEM method.Simulation results showed that the components of flax threshing material were separated and cleaned under the influence of airflow field,meanwhile,variation curves of quantity and mean velocity of flax seeds in the separating cleaning system were obtained.By referring to streamline distribution of gas-solid coupling,the quantity variation law of components of flax threshing material with time was explored and their motion curves and variation tendency of average velocity were studied.Verification test results showed that the cleaning rate of separating cleaning device for flax threshing material was 92.66%with 1.58%of total separation loss.Compared with simulation results,the test results were 1.34%and 0.93%lower,showing that it is feasible to apply the gas-solid coupling theory and method to simulate the separating and cleaning operation of flax threshing material.
基金financially supported by Key Science and Technology Project of Gansu Province(Grant No.21ZD10NF003-4-01)Department of Agriculture and Rural Areas of Gansu Province Agricultural Machinery Equipment Remediation Project(Grant No.niyf2022-02)+1 种基金Fuxi Young Talents Fund of Gansu Agricultural University(Grant No.Gaufx-03Y01)Youth Tutor Fund of Gansu Agricultural University(Grant No.GAU-QDFC-2021-08).
文摘In order to further reduce the damage rate in threshing seed corn,a seed corn threshing testbed with variable diameter and spacing that can realize dynamic adjustment of parameters,such as feed quantity,rotating speed of the threshing device,threshing spacing of the threshing units,was designed in this research.The software of finite element analysis ANSYS Workbench was applied to do modal analysis on the threshing axis designed for variable diameter and spacing of seed corn.The first 8 orders of natural frequencies were distributed in 201.12-1640.20 Hz,with corresponding vibration amplitude in 5.86-27.04 mm,showing reasonable structural design of the threshing axis,which could realize effective seed corn threshing and conveying.Discrete element method was applied to do simulation analysis on the seed corn threshing and conveying process with variable diameter and spacing.Under the condition of different feed quantity,different rotating speed of the thresher,the moving speed of corn clusters and contact force among clusters were measured through simulation,and the working characteristics of the threshing testbed for low-damage and dynamic threshing and conveying of seed corn with variable diameter and spacing were revealed.Working performance test results of the testbed of seed corn with variable diameter and spacing showed that,when the rotating speed of the threshing axis was 190-290 r/min,feed quantity was 1.80-3.80 kg/s,the damage rate of seed corn was 0.32%-0.63%,threshing rate was 99.20%-99.82%,and content impurity rate was 4.23%-5.86%,the mass of threshed corn grains first increased and then decreased along the axial direction.The test verification process was in line with the simulation results;thus,the test results could satisfy the requirements in design and actual operation.
