儲槽在工業界上是廣泛被應用的，而在儲槽研究裡，微小顆粒體( <500 μm)的運動是相當值得探討的，微小顆粒體的流動現象與粗顆粒體( >600 μm)的流動完全不一樣，因為空氣會對粉顆粒體的流動造成影響，仍是一種固態與氣態的二相流動現象，在非開放系統的儲槽裡，還會發生氣泡流動的現象，導致儲槽的流動不穩定，造成排放的質量流率下降。 本研究將以兩種系統作為探討的方向，一為開放系統，另一為非開放系統，藉由兩系統的差別來進行各種現象的比較。實驗顆粒以數組不同且均小於500 μm的尺度顆粒，再加上三組尺寸大於500 μm的顆粒尺度來做比較，並藉由著改變儲槽開口的大小，來進行質量流率、壓力降、衝擊力、氣泡流動等物理現象之探討。 In numerous industrial processing operations involving powders, bulk solids and granules, silos and bins are used to store particulate solids. It is imperative to control the flow rate during discharge of these solids from such equipment. It is considerable to study gravity discharge of fine particles. Most theoretical and empirical equations for calculation of flow rate of fine particles overestimate flow rates when particles smaller than about 500 μm are discharged. An air stream flows through silo from outlet to the top and flow rate is unstable and decreases with time. Two systems, one is cover system (Closed-top silo), the other is no-cover system (Open-top silo) are experimentally studied in this Thesis. The flow rate, impact forces, pressure drop, velocities of particles and bubble areas are measured in vertical rectangular silo with transparent walls and outlet gap in flat-bottom. Particle size and area of gap are variables in experiments with fine particles of silica sand.
