Optimization of Screen-Hole-Clearing Devices for Mechanized Residual Film–Impurity Separation

The airflow velocity in some nozzles is low, and the clearing of the nozzle is ineffective because of unreasonable airflow pipe arrangements and the distance from the nozzle to the screen surface of screen-hole-clearing devices for trommel-sieve-type residual film–impurity wind separators. In the present study, the main structure and working parameters affecting the screen hole clogging situation were determined through theoretical analysis and computational fluid dynamics simulations. In addition, a three-factor, three-level quadratic regression orthogonal center of rotation combination test was performed. The distance from the nozzle to the screen surface, fan wind speed, and the number of airflow pipes were selected as test factors, and the ratio of impurities in the residual film and the blockage ratio of the screen holes were selected as the evaluation indexes. The results indicated that the ratio of impurities in the residual film was reduced by 2.42% and the blockage ratio of the screen holes was reduced by 1.92% at a nozzle-to-screen distance of 102 mm, a fan wind speed of 24 m/s, and with four air pipes. The resulting impurity ratio in the film was 5.86%, and the blockage ratio of screen pores was 5.41%. The minimum airflow velocity of 15.8 m/s at each nozzle position of the optimized screen-hole-clearing device satisfied the requirements of screen hole clearing and blockage. Furthermore, the ratio of impurities in the residual film and the blockage ratio of the screen holes remained unchanged during the continuous operation of the device. This indicated that the optimized screen-hole-clearing device had a stable working performance. This study may provide a theoretical framework for the future development of screen-hole--clearing devices