application of new inflection point method for hydrodynamics study in slurry bubble column reactors

bubble column reactors are used in a wide variety of applications such as multiphase bioreactors, catalytic slurry reactors, and absorption processes. the superficial gas velocity-gas holdup relationship and transition point are two important parameters for characterizing the hydrodynamics of a bubble column reactor. in this study, systematic investigation of a nitrogen - water - glass beads bubble column was conducted using the taguchi experimental design method. the l16 (45) orthogonal array was selected for experiments design. results showed that the order of importance of parameters is as follows: bed porosity, the ratio of height to diameter, and superficial gas velocity. a novel mathematical model was developed using the experimental data and based on 4th order polynomial. this model was successfully used to obtain the transition point with a high accuracy. the results of the mathematical method were in close agreement with those of the drift flux method. for liquid level of h=12d and slurry content of 13 vol%, transition velocity of  2.98 cm/s was calculated using the presented method, while a velocity of 3.14 cm/s  was obtained from the drift flux method.