Circulation and shear in stirring and mixing are quantitatively defined.Stirring power can be resolved as P = QZSk. Circulation rate and total shear intensity

and space distribution of energy dissipation rate should be matched.It is shown by experiments about the influence of mixing on coupling reaction that the impeller with of a medium circulation to shear ratio well matches the requirement of coupling reaction and its segregation index is minimum.The process is simulated by the modified Lagrange method.It is shown that the circulation experience of an aggregate influences the local segregation index

and the segregation index of coupling reaction can be reduced by enlarging the power dissipation per volume

the circulation to shear ratio

and the ratio of energy dissipation in the circulation zone and impeller zone.