Mixing Characteristics under Gas Injection through Rotary Lance Submerged in Liquid Bath.

The mixing time of a water bath stirred by gas injecton through a rotary lance was measured by an electrical conductivity method.Effects of the gas flow rate, the rotation speed and the bath depth.on the mixing time were examined.Measurement of torque produced during the lance rotation was also carried out.It is found that the effect of the gas flow rate on the mixing time becomessignificant in the deep bath, H, under the low rotation speed.R. In the present experiments, the conditions are H/D>0.625 and R 0.33 s~1 , where D is the vessel diameter.On the other hand, the effect of the lance rotation is appreciable when the bath is shallow.Thetorque increases with increasing the rotation speed, whereasthe bath depth has no effect on the torque.The results are explained in terms of specific powers of the injected gas and the rotary lance.The effects of operati ng variables on the mixi ng time are examinedquantitatively from the mu Itiple regression anal ysis.