Conclusions

In order to obtain design optimization guidelines for industrial CSTRs, we performed experiments and computer simulations for three different geometrical configurations. The main object was to obtain relationships between agitation and circulation and the power consumption which compare with previous experiments and existing empirical correlations [Nagata, 1975]. These evaluations were expressed through proper dimensionless groups $-$ Reynolds number, Power number, Discharge flow number, Secondary circulation flow number, Pumping efficiency $-$ and can be used as a design tool. This object was obtained performing computational simulations of the fully three dimensional and time dependent flow field in three different CSTRs: i) one laboratory scale CSTR; ii) reactor CE12500, equipped with retreated curved blade impeller; iii) reactor BE12500, equipped with the turbofoil turbine. Further goals were: i) comparison between experimental data collected for the laboratory scale reactor and results of numerical simulations to assess the modeling capability of the computer code used in this work; ii) comparison between results obtained for the laboratory scale and the industrial size vessel CE12500 to identify possible scale-up problems; iii) comparison between CE12500 and BE12500 to investigate on the fluid mechanics, the efficiency and the power consumption of the two different impellers.