Summary

In this work, we used computer simulations and experiments to analyze and characterize the behavior of industrial size CSTRs. The final object of this research endeavour being to find guidelines in order to optimize geometries and operative parameters of industrial CSTRs, in this preliminary part we focused on obtaining power consumption and stirring capability of the different configurations we examined.

In the first place, an experiment was planned to assess the computational fluid dynamics as a reliable tool to investigate on the complex flow field of CSTRs. A laboratory scale vessel equipped with a retreated curved blade impeller $-$ a scaled model of an industrial size reactor $-$ was examined. Numerical simulations gave results in agreement with experimental results.

Second, we considered an industrial size CSTR. In this case the dimensions forbid a thorough experimental analysis and we performed numerical computation of the fully three dimensional, time dependent flow field. The accuracy of the results was verified against literature data $-$ empirical correlations. Comparison of data obtained from the laboratory scale reactor and the full scale reactor made through proper dimensionless parameters indicated that scale-up is possible in the conditions examined.

Finally, in order to examine the characteristics of different flow fields, we considered the same industrial size vessel considered previously equipped with a turbofoil turbine rather than with a retreated curved blade impeller. Results show that this last configuration is more efficient in terms of pumping capability and pumping efficiency.