Research on Flow Field in Elliptic Bottom Stirred Tank with Cruciform Baffles

The effect of flow pattern,impeller diameter,the height above the bottom,cruciform baffles,the height and the length of the cruciform baffle on flow field are numerical analyzed in the elliptic header stirred tank with cruciform baffles using the software Fluent.The turbulence model of k-e is employed to simulate the flow filed of water.The experiment of agitator shaft torque is investigated,and it is compared with numerical value.The results show that the radial flow impeller is more suitable for flow field research on the elliptic header stirred tank with cruciform baffles.Compared to six straight blade disc turbine stirring paddle,six straight blade on turbine stirring paddle is more advantageous to mixing and suspension of material.The height above the bottom as 0.7 times of liquid level is more suitable than 0.6 times.When the impeller diameter is much bigger,the axial velocity is more fast,the logarithmic spiral upward axial flow in the central of the stirred tank is more and more obviously.If the height or the length of the cruciform baffle on the flow field is constant,the axial velocity in the center of stirred tank bottom will more larger than other parts,and a loop will be formed in the stirred tank.The torque turn to larger as the rotary speed increasing under the same conditions.The relative error of agitator shaft torque is about 10 % between simulation value and experimental value.Both of simulation value and experimental value of agitator shaft torque have a good consistency.