Optimization Design And Research Of Unloading Seed Cotton Foreign Fiber Cleaning Machine

Due to the increasing production planting mode of cotton covered with plastic film in Xinjiang,a large number of foreign fibers such as residual film are mixed in the harvesting process,resulting in the content of foreign fibers exceeding the standard seriously.The existing seed cotton foreign fiber cleaning machine has a certain separation effect,but there are some problems,such as low removal rate of residual film,high seed cotton take-out rate,seed cotton blockage in the cleaning machine chamber,etc.In this thesis,the structure of the key components of the unloading seed cotton foreign fiber cleaner is optimized,and the optimal combination of working parameters is obtained through experimental research,so as to improve the residual film removal rate of the cleaner and reduce the take-out ratio of seed cotton.In this thesis,firstly,the structure and working principle of unloading seed cotton foreign fiber cleaning machine are analyzed and introduced,and then the characteristics of seed cotton and residual film materials are discussed by means of investigation and calculation.The main research contents are as follows: average quality of single seed cotton;Suspension speed of single seed cotton;Stress analysis of gravity and suspension force of single seed cotton;Suspension velocity analysis of residual film;Study on unit area density of residual membrane.In this thesis,the motion equation of a single seed cotton in the cleaning machine chamber is established,and its motion trajectory in the cleaning machine chamber at different inlet speeds is analyzed and studied.The stress equation of the residual film when it turns to the outer wall of the net is established.The above research provides a theoretical basis for the optimal design of cleaning machine and the separation of seed cotton residual film.In view of the unreasonable structure of the unloading seed cotton foreign fiber cleaning machine,which leads to the low foreign fiber clearance rate,this thesis puts forward the optimization requirements for the cleaning machine,and optimizes the design of key components such as feed inlet and rotating mesh structure.Finally,the optimized components are verified and analyzed by structural mechanics using workbench software.The analysis results show that the optimized structure can meet the working requirements.When the unloader is blocked or leaked,the flow field in the cleaner chamber is simulated and analyzed,and the unloader is optimized according to the simulation results and the structure and function of the unloader.Rocky software is used to simulate the unloading performance.Discharger speed,discharger radius and output per platform hour are selected as test factors,and discharge rate is taken as evaluation index.The primary and secondary order of influencing discharge rate is discharger radius,output per platform hour and discharger speed.The working parameters are optimized,and the results show that when the speed of the unloader is 76 rpm,the radius of the unloader is 410 mm,and the output per hour is 12t/h,the unloading rate predicted by the model is 98.332%.In order to explore the optimal working parameters of key components,this paper simulates the separation process by using Fluent-Rocky coupling method,and analyzes the movement process of seed cotton residual film inside the cleaner.Combining quadratic orthogonal rotation combination with coupling simulation technology,negative pressure wind speed,rotating speed and inlet wind speed are taken as experimental factors,and the ratio of residual film clearance rate to seed cotton take-out is the evaluation index.According to the coupling simulation test,the order of influence on the performance of the cleaning machine is: inlet wind speed,negative pressure wind speed,and rotating speed of the transfer network.On the basis of the coupling simulation test,taking the ratio of residual film removal rate and seed cotton take-out rate as performance indexes,and taking negative pressure wind speed and inlet wind speed as test factors,the orthogonal test was carried out on the cleaner test device.The results showed that all the influencing factors had significant effects on the residual film clearance rate and the seed cotton take-out ratio.When the rotating speed of the rotating net was fixed at 30r/min,the negative pressure speed was23.5m/s and the inlet wind speed was 2.5m/s,the average residual film clearance rate was 55.20% and the average seed cotton take-out ratio was 1.89%.