| dc.description.abstract | Since humans often need to store granular materials, storage silos have become
indispensable equipment in modern industry and agriculture, crucial for ensuring effective raw
material management, enhancing production efficiency, and maintaining product quality. The
design and performance of silos play a significant role in ensuring these aspects. The
characteristics of silo walls, such as surface material and wall friction, have been shown to
critically affect fluid behavior and discharge performance.
This study used a quasi-2D silo device, where different parts of the silo walls were replaced
with roller sidewall, and the half-angle of the silo was varied. Fixed-weight cylindrical particles
were filled for discharge during the experiments. To understand the impact of bearing-like walls
on particles of different lengths, ABS plastic cylinders with a diameter of dP = 4mm and lengths
of dL = 4mm, 8mm, and 12mm were used. The basic properties of each particle and the friction
effects between the particles and the walls were measured through repose angle experiments
and friction angle experiments. During the silo discharge experiments, high-speed cameras
were used to capture images, and subsequent image processing was performed using particle
image velocimetry (PIV) and MATLAB. Additionally, by studying the average mass flow rate,
improvement rate phase diagrams, velocity field, and stagnant zones, the impact and
effectiveness of replacing the walls with roller sidewall on overall flowability were understood.
The experimental results show that replacing the silo walls with roller sidewall indeed
affects the overall particle discharge. The improvement in mass flow rate is more significant
when using longer particles (with a larger length-to-diameter ratio R of cylindrical particles to
the outer diameter of the rollers), and the improvement trend is more pronounced with a smaller
hopper half-angle. This study plots the discharge improvement phase diagram for cylindrical
particle discharge in silos with various types of bearing-like wall installations, showing the
relationship between the length-to-diameter ratio and the hopper half-angle. There are three
improvement phases: improvement region, transition region, and deterioration region. The
results indicate that the discharge improvement phase diagram for fully installed roller sidewall
is identical to that for replacing only the hopper section with roller sidewall, suggesting that the
roller sidewall of the hopper section have the greatest impact. Additionally, in the significant
improvement zone, the velocity field is noticeably increased due to the installation of bearinglike walls, the stagnant zone is reduced, and the particle flow within the silo tends more towards
mass flow. | en_US |