화학공학소재연구정보센터
Journal of Non-Newtonian Fluid Mechanics, Vol.94, No.1, 57-66, 2000
On the shear banding flow of elongated micellar solutions
Under steady shear flow, elongated micellar solutions show shear stress saturation above a critical shear rate due to the formation of shear bands that result in non-homogeneous flow. Long transients and oscillations accompany this stress plateau. When measurements are done with a controlled stress rheometer, frequently a metastable branch is observed. At higher shear rates, a second upturn is observed above a second critical shear rate, which indicates that homogeneous flow is recovered. Here, a model consisting of the codeformational Maxwell constitutive equation coupled to a kinetic equation to account for the breaking and reformation of the micelles is presented to reproduce the features described above in steady shear flow. The model also predicts a second metastable branch and long transients at higher sheer rates and the existence of an inflexion point in stress-shear rate plots above which no shear banding behavior is detected.