Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Inclination of bubble columns and fluidized beds greatly affects their performance. It can help alleviate segregation problems in slurry bubble columns and fluidized beds. New experimental techniques accurately measured the local volume fraction of the gas, the bubble characteristics, and liquid circulation patterns. They showed that inclination concentrates the gas bubbles, especially the larger ones, not at the high column wall, but near it. A bubble coalescence model, assuming no bubble splitting, predicts the shift in the position of the maximum large bubble concentration towards the high wall in the inclined bubble column and gas-liquid-solid fluidized bed. The most sensitive detection of gas flow patterns in the bubble column and the gas-liquid-solid fluidized bed was provided by the power spectrum of a conductivity probe signal or by the box counting fractal dimension of a bubble probe signal.;The local liquid velocity in both the liquid-solid and gas-liquid-solid fluidized beds was obtained from the local liquid holdup and the particle-liquid heat transfer coefficients. The box counting fractal dimension of the conductivity probe signal was used to detect defluidized zones, the onset of overall fluidization in liquid-solid beds, and the minimum fluidization in gas-liquid-solid beds.;The solid circulation patterns in the liquid-solid fluidized bed were estimated from easily performed liquid mixing measurements. Segregation of a low density particle was avoided at low liquid velocity by inclining the bed, thus reducing power consumption of the pump and particle attrition.



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