Numerical Simulation And Experimental Study On Forced Inertia Separation Chamber

In combine harvester, the performance of combine harvester was depended on the cleaning performance of cleaning device. The components of grain could be separated in forced inertia separation chamber, which is cleaning device of combine harvester threshing prior to cutting. This paper not only can provide a reference for chamber, but also be helpful to provide new methods for cleaning device by analyzing airflow distribution and exploring the movement of grain in forced inertia separation chamber. Combined with the national natural science foundation of china and Heilongjiang province natural science foundation project, airflow cleaning grain principle of chamber was studied on based on numerical simulation and experimental study, the main works were as follows:1. The structural parametric design of forced inertia separation chamber would be development by using VB based on CATIA software. The structure of chamber could be quickly built by imputing the structural parameters of chamber on interactive interface. Then numerical simulation structure of chamber could be provided by structural parametric design software. The labor time would be saved and work efficiency would be improved.2. The airflow of chamber, which was built by parametric design on CATIA, was numerical simulated by choosing criteria k-ε turbulence based on FLUENT software. Grain could be moved by airflow on bottom of separation-board where airflow velocity was14-18m/s. The components of grain could be separated on the end of board where airflow velocity was2-6m/s. Shot-stalk could escaped from chamber on above board where airflow velocity was7-30m/s. Grain could sink on back of chamber where airflow velocity was about2m/s and grain would escape from chamber by discharge rotor.3. The model of grain was established based on discrete phase model. Grain motion was simulated under different length of separation board of chamber. The results showed that cleaning rate of chamber was best when the length of separation board was720mm. Grain motion was simulated under different inlet airflow velocity and different density grain motion was also simulated in chamber. The results showed that grain cleaning rate of chamber was increased with airflow velocity increasing. Different density grain could sink in chamber to avoid harvest losses.4. In order to verify the results of simulation, experiments were done on threshing prior to cutting test system. Airflow velocity on cross-section was measured and contour map of airflow velocity on cross-section was draw by MATLAB. The grain trajectories were trapped by high-speed technology. The single factor test and orthogonal test results showed that airflow velocity was met conditions of cleaning grain; cleaning rate of grain was increased with increasing of inlet airflow velocity and was decreased with increase of mass of grain fed. The orthogonal test results showed inlet airflow was more important than mass of grain fed in the influence of cleaning rate of grain.In summary, this paper systematically revealed the cleaning grain principle of chamber by developing software rapidly to built model of chamber and simulating airflow and grain motion in chamber and doing test. This paper could provide a reference to study similar cleaning device.