Effects of different modification fluids on the flow of rice seed particles during unloading in the silo

Raw materials are usually stored in the form of particles in silos, such as the food, chemical, and pharmaceutical field. The motion of granular materials can vary greatly in the flow of gases and liquids, due to their discrete particle aggregates. It is difficult to accurately explain using traditional theories, such as solid or fluid mechanics, and condensed matter physics. Particularly, the silo can serve as one of the most important carriers to store the particulate matter. It is still lacking in a comprehensive unified theory for the silo subjected to complex forces. Among them, the irregularity of rice seeds has a significant impact on the unloading in the silo, due to the nature of loose particles. Therefore, it is of great significance to clarify the impact of rice seed discharge flow in the silo. Auxiliary devices can also be added to transform the central into the overall flow bin. Simple and effective fluid modification can be used to adjust the structure of silos for the better particle flow. This study aims to explore the impact mechanism of different fluid modifications on the flow of rice seed particles during discharge in the silo. The transformation of the population flow pattern was achieved from the central to the overall flow for better population flow. The discrete element method (DEM) was selected to construct the traditional silo, vertical disturbance, and horizontal disturbance silo models. Rice seed particle models were established for the discharge simulation. The flow pattern was compared with the actual discharge experiment in the silo. A series of experiments was also conducted to verify the accuracy of the discrete element model and numerical simulation. The mass flow index (MFI) and z-axis particle velocity indicated that the particle velocity in the central region of traditional and vertically disturbed silos decreased with the increase of particle stacking height, whereas, the particle velocity increased in the sidewall region. There was a decrease in the particle velocity in the sidewall area of the horizontally disturbed silo, as the particle stacking height increased, whereas, the particle velocity increased in the central area. Traditionally, the conversion heights of the flow pattern were 130, 118, and 130 mm, respectively, in the vertically and horizontally disturbed silos. There was a variation in the vertical, horizontal, and angular velocity in the different areas of the silo. Specifically, the vertical velocity of the population decreased by 34.82% and 83.46%, respectively, compared with the traditional flow area of the silo under the action of the vertical and horizontal fluid. The fluctuation of population horizontal velocity increased, as the height of particle accumulation decreased in the silo population. The standard deviations of particle horizontal velocity were 0.027 3, 0.018 7, and 0.010 3, respectively, in the traditional silos, vertical and horizontal disturbance silos. There were similar changes in the particle angular velocity in the center and sidewall areas of traditional and vertical disturbance silos. The peak angular velocity was smaller in the center area of vertical disturbance silos, compared with the traditional silos. The variation of particle angular velocity was similar to the traditional silo in the flow area of a horizontal disturbance. But there was a small variation of particle angular velocity in a horizontal disturbance silo. The finding can provide the theoretical reference for the fluid design standards, structural and positional parameters, particularly for the high available area of the silo.