Flow Patterns of Liquid in a Cylindrical Mixing Vessel without Baffles

TLDR: In this paper, the velocity distribution of liquid in a cylindrical mixing vessel with flat-plate-baffles like those commonly used was measured by the method similar to the one adopted for the agitator without baffles.

Abstract: The velocity distribution of liquid in a cylindrical mixing vessel with flat-plate-baffles like those commonly used was measured by the method similar to the one adopted for the agitator without baffles.1)Some of the experimental results are shown in Figs. 3, 4, 5, 6, 7, 8 and 9.Variations of the liquid velocity distributions caused by the baffle-plates inserted in the agitated vessel are shown in Fig. 10. Obviously, the insertion of baffle-plates reduces the circulating flow round the impeller axis (the circumferential component υt of liquid velocity) and promotes the circulation flow in the vertical direction (caused by the discharge flow from the tip of the impeller).The discharging performance of various impellers is represented by the ratio NPB/Nq1, which is a dimensionless factor corresponding to the relative power required for a unit quantity discharge. The ratios for various impellers are listed in Table 3 together with those in the non-baffled condition. It is to be noted that, in spite of a considerable increase in Nq1, the circulation efficiency of agitators is lowered by the insertion of baffle-plates.Furthermore, the power consumption in the neighbourhood of the impeller (NPimp) was calculated and compared with that consumed in the outer region of the vessel (ΔNP) as shown in Table 4.It may be concluded from above that the improvement in the circulating capacity can be accomplished to a certain extent by a proper design of baffle-plates.