The aim of this study was to investigate the effects of different working parameters on the cleaning efficiency of a cleaning device during the separation and cleaning process in a flax joint harvesting machine. To achieve this objective, CFD–DEM joint simulation technology was used to construct a CFD model of the cleaning device and a DEM model of the discharged flax material; the simulation results show the flax cleaning process. The Box–Behnken experimental design method was used to establish a mathematical model between the vibrating sieve frequency, vibrating sieve amplitude, fan wind speed, seed impurity rate, and cleaning loss rate to find the optimum combination of cleaning equipment parameters and to conduct a field verification test. The simulation test results show that, when the vibrating sieve frequency is 6 Hz, the vibrating sieve amplitude is 14.42 mm, the fan wind speed is 5.96 m/s, and the machine cleaning effect is the best; the simulation test was measured following a seed impurity rate of 2.97% and cleaning loss rate of 2.17%. The field test verification results show that, after optimizing the working parameters of the cleaning device, the cleaning loss rate is 3.58% and the impurity rate of the grain combine harvester is 3.16%, thus meeting the national and industry requirements. The test results and simulation results are highly consistent with the model, thereby verifying the reliability of the model. The results of the study provide a reference for the design and performance optimization of the flax combine cleaner.

To conduct an in-depth investigation of the impact of various operating parameters on mulching device wear during the operation of full-film dual-row ridging and mulching machine mulching, this paper employed EDEM software to create a 3D discrete element model of how a mulching device interacts with the soil on the seed bed and simulated the dynamic process of the interaction between the mulching device and the soil during the mulching operation. We analyzed the cladding wear process between the cladding device and the cladding sand particles, and two areas of impact wear on the overburden conveyor housing and areas of wear on the chute deflector scratches were detected. A three-factor, three-level Box–Behnken experimental design approach was used, with mathematical modeling of the relationship between the scraper conveyor lifting line speed, seed bed cover, scraper spacing, and wear of the cover device, finding the optimal combination of operating parameters for mulching devices. The results of the simulation test indicated that the mulching device experienced a minimum wear of 0.958 × 10⁻³ mm at a lifting line speed of 0.7 m·s⁻¹ for the scraper conveyor, a mulching volume of 2.55 kg·s⁻¹ for the seed bed, and a scraper spacing of 98 mm. The results of the field trial validation showed that, in a comparison between simulated wear parts and a mulching operation prototype of the same two wear parts, the established discrete element model appeared reasonable concerning the structural parameters, with a feasible abrasion mechanism process of sand particles on the soil-covering devices, demonstrating the model’s reliability and validity. It can serve as a guide for optimizing the design of mechanized full-film dual-furrow seed bed mulching operation.