Mixedness change with time

Figure 2.13 Mixedness change with time when tracer is injected from 10-region in case of FBDT impeller and 45° PBT impeller in a stirred vessel.

Mixedness change with time when tracer is injected from 10-region in... 

As observed, it becomes possible to quantitatively express the degree of the mixing state based on the spatial distribution of the concentration of tracer in the equipment. Accordingly, the evaluation of the mixing capacity of the operation/equipment becomes possible by using the change in mixedness with time. 

Challenge 2.3. Change in mixedness with time of three typical impellers3... 

This equation means that the change in M with t depends on N further, the difference in the flow state in the vessel that is controlled by the discharge flow rate from the impeller affects the change in mixedness with time. 

Nitrogen gas is fed at a fixed flow rate. After confirming that the flow in the column has a steady state and that the carbonic acid gas in the water is desorbed, the carbonic acid gas as the tracer is fed stepwise at the same flow rate as the fixed flow rate of nitrogen gas by changing the valve. The change in concentration of the tracer with time in each region is measured by making use of the electrode conductivity probe after the tracer gas is fed, and the mixedness M defined by Eq. (2.18) is calculated. 

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