ANALYSIS OF AIRFLOW VELOCITY FIELD CHARACTERISTICS OF AN OAT CLEANER BASED ON PARTICLE IMAGE VELOCIMETRY TECHNOLOGY

To improve the cleaning performance of oat sorting devices with a single-fan three-cylinder screen system, this study investigated the airflow velocity field of a cleaning machine using particle image velocimetry (PIV) technology. Specifically, an optimal cleaning performance can be described as one with no material idling under the optimal operating parameters of the oat cleaning machine, the measured airflow velocity field space is divided into nine representative longitudinal planes that can reflect airflow velocity characteristics in the longitudinal plane. The results showed that a phenomenon of airflow backflow occurred in the radial direction above the medium cylinder screen, the airflow velocity in each longitudinal section of the airflow velocity field was less uniform in the transverse distribution, and a low velocity area appeared on the tail plate surface of the air outlet. The movement of oat extracts in the cleaning room was recorded by a high-speed digital video camera. The phenomenon of oat impurities moving along the airflow backflow direction, and a transverse flow irregularity appearing in the radial direction above the medium cylinder screen were observed. The grain loss rate and impurity rate of the oat cleaner were 1.53% and 1.25%, respectively, under optimal conditions. Therefore, to improve the cleaning performance of the cleaner, it is necessary to theoretically analyze the phenomenon of airflow backflow in the cleaner, which can provide a reference for the follow-up design and optimization of the structure of the cleaner.