The mixing characteristics of liquid was investigated in a continuous flow stirred tank reactor （CFSTR） with a 6-bladed turbine impeller. The inlet and the outlet were located at the bottom center and the top edge of the reactor, respectively.
For the CFSTR, three zones （inlet zone, impeller zone and recirculation flow zone） with different mixing characteristics were assumed and the theoretical conversions based on the assumption were compared with the experimental results obtained from the irreversible second order reaction system.
For the case of the lower inlet flow rate and the lower agitation speed, the experimental results showed that the mixing characteristics of the inlet and the recirculation flow zones were considered to be that of macrofluid. For the higher inlet flow rate as well as the higher agitation speed, however, the inlet zone showed the perfect mixing nature of microfluid with a considerable dilution of the macrofluid of recirculation. Also, the higher agitation speed, the larger was the volume of the impeller zone, in which the microfluid characteristics could be excellently assumed.