Power consumption in an agitated vessel with an "EGSTAR" agitator, which ha
s been practically used as a bioreactor, was measured under aeration. The p
ower consumption of the "EGSTAR" agitator did not decrease so much with aer
ation, in contrast to the result of a disk turbine impeller. In the turbule
nt flow region of Re-d>300, the power number at a specified gas flow rate t
akes a maximum value. The correlations of the maximum power number Np-g,Np-
R and the rotational speed N-R at which the power number takes the maximum
are derived using both operating conditions and impeller dimensions.
The power number under aeration Np-g in the range of N/N-R>1 in turbulent f
low region is correlated with the rotational speed N, with help of N-R and
Np-g,Np-R, as
Np/Np-g,Np-R=(N/N-R)(-0.30)
The combination of the correlation of Np-g above with the correlations of N
p-g,Np-R and N-R gives rise to the following power correlation of EGSTAR ag
itator under aeration.
Np-g=0.68N(A)(-0.08)Fr(-0.19)(h(d)/d)(0.01)(1-epsilon)Np-0.22,(R)
The power consumption of EGSTAR agitator under aeration is not affected so
much by gas flow rate, in contrast to the result of a disk turbine impeller
.