1986 Volume 12 Issue 4 Pages 459-464
Effects of impeller style (paddle, turbine and pitched-blade turbine types) on the capacity of an agitated vessel with aeration are examined by injecting tracer gas impulsively. Though the paddle-type impeller gives the highest value of final average concentration and also the highest value of mixing rate of gas absorbed, the pitched-blade turbine-type impeller is expected to be the most appropriate one when ease of estimation of the relationship between operational condition and mixing phenomena is also considered. Additionally, it is made clear that each impeller style produces a characteristic inhomogeneity of concentration of gas absorbed in the vessel at even the high-mixedness stage, and it is presumed that the inhomogeneity will affect significantly the capacity of an agitated vessel with aeration in some cases.
