Abstract:In order to reduce the error-sifting rate of the tea vibrating-sifting machine, the effects of inclination angle, vibration amplitude, and vibration frequency on the motion characteristics of tea particles on the sieve were studied from the perspective of particle dynamics. By combining the discrete element method to numerically simulate the movement of tea particles on the sieve surface, and analyzing the vibrating-sifting process of tea particles, the transport mechanism of tea particles on the sieve during the vibrating-sifting process was clarified. The results showed that tea particles were mainly concentrated in the middle of the sieve, and too high or too low frequency could cause horizontal segregation of tea particles on the sieve. The average velocity and rotational kinetic energy of tea particles on the sieve were gradually increased with the increase of amplitude and frequency. The inclination angle had little effect on the average velocity and rotational kinetic energy of tea particles on the sieve. The velocity of tea particles along the X-axis and Z-axis contributes the most to the average velocity of tea particles on the sieve. The variation amplitude of the migration coefficient was gradually increased with the increase of inclination angle, vibration amplitude, and vibration frequency. The order of influence of different parameters on the particle migration ability of tea vibrating-sifting process was as follows: amplitude, frequency, and inclination angle. When the vibration amplitude was 22.5mm, the inclination angle was 3 °, and the vibration frequency was 4.166Hz, the error-sifting rate of the tea vibrating-sifting test was the smallest. The error between error-sifting rate results of the tea vibrating-sifting test and the simulation test results was within 5 percentages, indicating that the DEM simulation had high accuracy. The research result had important reference value for reducing the error-sifting rate of the tea vibrating-sifting machine.
