Study On The Cleaning Technology Of Double-Channel Airflow In Rapeseed Harvest

As a large agricultural country,China’s current planting area and total output of rapeseed rank first in the world.Because of the large difference in the ripening of rapeseed and the complicated harvesting characteristics,the degree of rapeseed harvest in China is relatively low.In the southern part of China,the hills are mainly dominated by the size and structure.The design of the small combine harvester cleaning device is not perfect,resulting in high machine inclusion rate and high loss rate.The cleaning device is an important factor in determining the rate of inclusion and loss,and is the key part of the harvester.Improving the performance of cleaning is one of the main technical difficulties that need to be solved in mechanized harvesting of rapeseed.In this paper,the design theory and method of the small rapeseed combine harvester cleaning device are studied for the research of rapeseed cleaning.The main contents are as follows:(1)Analyze the existing cleaning technology and the working principle of the cleaning device.In view of the current constraints on the combined harvesting of rapeseed and the problems of small harvesters in hilly areas of China,clarify the superiority of using airflow for grain cleaning and determine the cleaning device.Structure and research technology route.(2)According to the material characteristics of the rapeseed extract,a reasonable cleaning method is selected,and the cleaning is carried out by means of screening and airflow cleaning.Calculate the dimensions and related parameters of key components,complete the design of the inlet,outlet and airflow field diameters of the double duct cleaning cylinder and determine the size and motion parameters of the cleaning screen.(3)For the designed double air duct cleaning device,use ANSYS15.0 to perform the cleaning flow field simulation,mesh the 3D model of the cleaning device,select the Realizable k-ε model,and import it into FLUENT to set the boundary conditions.Iterative calculation.Generate a flow field of speed and pressure with a cloud and vector illustration.Through analysis and judgment,the results of theoretical analysis are verified.(4)The impurity content of the rapeseed extract,the cleaning sieve speed and the centrifugal fan speed were selected as test factors.The test was carried out on the cleaning test bench,and the rules of the inclusion efficiency,the cleaning sieve rotation speed,the centrifugal fan rotation speed,etc.,which affected the cleaning performance,and the better performance interval were obtained.The impurity content is 15%～5%,the cleaning speed is50r/min～80r/min,and the centrifugal fan is 1700r/min～1900r/min.When the impurity ratio is5%,the cleaning speed of the sieve is 60r/min,and the centrifugal fan speed is 1800r/min,the cleaning performance is optimal.The cleaning rate at this time is 98.2%,and the loss rate is4.2%.