DESIGN AND EXPERIMENT OF A BUILT-IN SCREEN-TYPE CYCLONE SEPARATION CLEANING SYSTEM FOR A SMALL-SCALE WHEAT COMBINE HARVESTER

To address the issues of high grain impurity rate and low cleaning efficiency in the cyclone separation cleaning system of small wheat combine harvesters in hilly and mountainous areas, this study proposes an internally screened cyclone separation cleaning system. Using the CFD-DEM coupled simulation method, the effect of the screen structure on the motion trajectory and separation behavior of the threshed material was systematically analyzed. A response surface methodology was applied to analyze the impact of interaction factors on cleaning performance. The optimal working parameters were determined to be: fan speed of 4020 r/min, scraper shaft speed of 340 r/min, clearance between the screen and the chamber wall of 37mm, and mesh size of 29 mm. Under these parameters, the simulation results showed a grain impurity rate of 2.99% and a cleaning loss rate of 1.10%, while the field experiment results were 3.08% and 1.14%, respectively. The field experiment results indicate that the designed cleaning system improved the cleaning performance and operational efficiency of the small combine harvester, providing both theoretical support and engineering guidance for the optimized design of cleaning system in small combine harvesters for hilly regions.