Investigation of Fluid Flow in a Dual Rushton Impeller Stirred Tank Using Particle Image Velocimetry

Abstract

Abstract: The flow fields in a dual Rushton impeller stirred tank with diameter of 0.48 m(T)were measured by using Particle Image Velocimetry(PIV).Three different size impellers were used in the experiments with diameters of D=0.33T,0.40T and 0.50T,respectively.The multi-block and 360°ensemble-averaged approaches were used to measure the radial and axial angle-resolved velocity distributions.Three typical flow patterns,named,merging flow,parallel flow and diverging flow,were obtained by changing the clearance of the bottom impeller above the tank base(C₁)and the spacing between the two impellers(C₂).The results show that while C₁ is equal to D,the parallel flow occurs as C₂≥0.40T,C₂≥0.38T and C₂≥0.32T and the merging flow occurs as C₂≤0.38T, C₂≤0.36T and C₂≤0.27T for the impellers with diameter of D=0.33T,0.40T and 0.50T,respectively.When C₂ is equal to D,the diverging flow occurs in the value of C₁≤0.15T for all three impellers.The flow numbers of these impellers were calculated for the parallel flow.Trailing vortices generated by the lower impeller for the diverging flow were shown by the 10°angleresolved velocity measurements.The peak value of turbulence kinetic energy (k/V_tip²=0.12-0.15 or above)appears along the center of the impeller discharging stream.

Key words: particle image velocimetry, dual Rushton, flow field, flow pattern

摘要： The flow fields in a dual Rushton impeller stirred tank with diameter of 0.48 m(T)were measured by using Particle Image Velocimetry(PIV).Three different size impellers were used in the experiments with diameters of D=0.33T,0.40T and 0.50T,respectively.The multi-block and 360°ensemble-averaged approaches were used to measure the radial and axial angle-resolved velocity distributions.Three typical flow patterns,named,merging flow,parallel flow and diverging flow,were obtained by changing the clearance of the bottom impeller above the tank base(C₁)and the spacing between the two impellers(C₂).The results show that while C₁ is equal to D,the parallel flow occurs as C₂≥0.40T,C₂≥0.38T and C₂≥0.32T and the merging flow occurs as C₂≤0.38T, C₂≤0.36T and C₂≤0.27T for the impellers with diameter of D=0.33T,0.40T and 0.50T,respectively.When C₂ is equal to D,the diverging flow occurs in the value of C₁≤0.15T for all three impellers.The flow numbers of these impellers were calculated for the parallel flow.Trailing vortices generated by the lower impeller for the diverging flow were shown by the 10°angleresolved velocity measurements.The peak value of turbulence kinetic energy (k/V_tip²=0.12-0.15 or above)appears along the center of the impeller discharging stream.

关键词: particle image velocimetry, dual Rushton, flow field, flow pattern

PAN Chunmei, MIN Jian, LIU Xinhong, GAO Zhengming. Investigation of Fluid Flow in a Dual Rushton Impeller Stirred Tank Using Particle Image Velocimetry[J]. , 2008, 16(5): 693-699.

潘春妹, 闵健, 刘心洪, 高正明. Investigation of Fluid Flow in a Dual Rushton Impeller Stirred Tank Using Particle Image Velocimetry[J]. , 2008, 16(5): 693-699.

References

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