Design and Experiment of Secondary Throwing Device of Cotton Straw Crushing and Returning Machine Using Fluent

Abstract: Regarding the agronomic requirements of the combined operation machine of cotton straw crushing and returning to field and residual film recovery, the existing straw crushing and returning machines cannot are still insufficient. In this work, a cotton straw crushing and returning device with the function of secondary backward throwing was designed, striving to realize the crushing and backward uniform throwing of cotton straw and lay the foundation for the residual film recovery operation. The curved surface housing comprises a logarithmic spiral curved front housing, a left side plate, a right side plate, and a back baffle. Fluent simulation showed that the logarithmic spiral shell has better fluidity than the broken line shell, which is more conducive to the flow of cotton straw in the shell. The straw crushing and returning device with the function of secondary backward throwing mainly consists of curved shell, transmission device, crushing device and secondary throwing device, and the secondary throwing shaft is equipped with spiral blades to recycle the straw. One time crushing and backward conveying can improve the backward throwing performance of cotton straw. The field experiment demonstrated that under the working conditions of knife roller rotation speed of 2490.00r/min, forward speed of 4.90km/h and ground clearance of 76.0mm, the cotton stalk crushing rate and cotton stalk dropping rate of the second throwing cotton straw chopping and returning machine were 98.78% and 2.88%, respectively. The relative error between the experimental value and the predicted value was less than 5%. The regression model was reliable, and the machine could well complete the operation of cotton straw chopping and returning.