Partikkelien liike ja sekoittuminen kolmefaasi kaasu-neste-kiinteä -fluidisaatiossa

摘要

The objective of this thesis is to study the movement and the mixing of the particles in the liquid-solid and the gas-liquid-solid fluidization as well as to provide validation data of the fluidized bed behavior. The results are used for validation in CFD (computational fluid dynamics) models at a concurrent PhD thesis.The experiments were made in a rectangular 10 cm by 10 cm column. The used liquid and gas phases in the experiments were tap water and compressed air, respectively. The solid particles in the fluidized bed were 2.3 mm diameter glass beads. The experiments were carried out varying the flow rates of the gas and liquid entering the column. The bed height, the pressure difference in the bed, the superficial flow velocities of the gas and the liquid, and the particle movement patterns were observed and measured during the experiments. The particle movement and the bubble flow regimes were analyzed from video recording.In the experiments the minimum fluidization points at the different superficial gas velocities were measured. In addition, the solid and the gas-hold-up as well as the bed expansion were calculated from the measurements for different superficial gas and liquid flow velocities. It was found out that superficial liquid velocity at minimum fluidization point is higher with zero or diminutive gas flow than when the gas flow is larger. In addition, when superficial gas flow is larger the superficial liquid velocity at minimum fluidization point is independent on gas flow rate. It was found that the bed expansion is rather independent on superficial gas flow velocities when superficial liquid flow is smaller. However when superficial liquid flow is larger the increase in superficial gas flow decreases the bed expansion. With this column and particle settings the bubble coalescence was vigorous. With all superficial gas and liquid used in the experiments the bubble flow regime was either in coalesced bubble flow or slug flow regime.