Research on the Influence of Wind Speed Parameter Matching on the Operation Quality of an Upper Suction-Type Rice Mill

The rice bran is mixed with broken rice. In traditional horizontal rice mill working, the upper suction-type rice mill, equipped with air duct, is designed to separate rice bran from broken rice. The upper suction-type rice mill working principle, rice particles movement in the air duct and the air duct structure are analyzed. The upper suction-type rice mill model is established with the CFD-DEM coupling method. The rice particles’ movement behavior in milling is investigated. The separation test of rice bran and broken rice is conducted with prototype. Simulation reliability is verified and optimal working parameters are determined. The simulation results show larger air speed results in stronger airflow. The rice bran movement is obvious, and the mix rate is lower. With increasing air speed, the rice grains distribution turns to be evenly, grains move and roll more frequently in the milling chamber’s vertical direction. The accumulation at the bottom of the milling chamber is alleviated, and the broken rice rate is reduced. The separation test is conducted at the Hubei Wufeng Grain Machinery Co., Ltd. (Wuhan, China). The air speed (vo) is 6–8 m/s and the jet air speed (vp) is 10–20 m/s. The results show that when the air speed is 6 m/s and the jet air speed is 20 m/s, the separation rate is 95.4%, the mix rate is 2.4% and the broken rice rate is 5.4%, indicating that the rice mill operation performance is good. The study can provide a reference basis for optimizing working parameters of upper suction-type rice mills.