Study On The Cylindroconical Fermenters With Different Geometries Configuration Based On Numerical Simulation

The cylindroconical fermenters are used in industrial beer production, and their configuration design are based on the traditional experience, however, the geometrical configuration of fermenter are the important factors affecting temperature distribution and flow condition of the fermentation broth in the subcooling process. So in this study, computational fluid dynamics(CFD) technology was used to simulate the subcooling process of beer fermentation in cylindroconical fermenters with different geometries. By analyzing temperature distributions and velocity distributions of fermentation broth in fermenters, the results provided a theoretical basis for the selection of beer fermentation tank in industrial beer production and provided a reference for temperature control during beer fermentation subcooling process.In this article, the simulation method was verified through the contrast between the actual measurement of temperature change and the simulation of temperature change of the corresponding points, the results showed that CFD method can accurately simulate beer fermentation subcooling process. The simulation results of different fermenters showed that the geometries of fermenters could affect the temperature and convection states of fermentation broth, but on the whole, the temperature in the upper part was higher than the temperature in the lower part, and except there was a large circulation in the H:D=2:1 fermenter, the fermentation broth in others existed in the state of local small vortices. In the comparison of fermenters with different height to diameter ratios, the temperature distribution was more uneven in H:D=4:1 fermenter, and there were temperature faultage phenomenons in H:D=5:1, H:D=6:1, H:D=7:1. In the comparison of fermenters with different effective volumes, the temperature distribution was more uniform in 500 m3 fermenter, and the fermentation broth had a tendency to form whole convection. In the contrast of fermenters with different cooling surfaces, except the temperature distribution was inhomogeneous relatively in the fermenter with 1:1 area ratio of the two cooling surfaces, there were little difference among the temperature distributions in the other fermenters, and the maximum difference of the average temperatures in these fermenters was 0.09 oC, in addition, the fermentation broth in these fermenters all had a tendency to form whole convection, among them, the fermentation broth in the fermenter with 2:1 area ratio of the two cooling surfaces was more turbulent. The simulation results showed that in different fermenters temperature distributions were complex, and convections of the fermention broth were disorder, therefore in the actual production only according to the temperature in several temperature measuring points to develop temperature control strategy is one-sided, and this study has a certain reference value for temperature control in different fermenters.