Taylor–Couette reactors may offer an alternative treatment method for ballast water treatment or for flocculation of small size particles to be removed in water treatment processes due to created high energy dissipation and momentum transfer by Taylor vortices occurred during transitional flow regimes. In this study, the effect of shear-thinning behavior on flow structures and transition thresholds in Taylor–Couette flows for narrow and wide gaps is experimentally investigated using xanthan solutions. The experiments presented in this paper establish the existence of non-axisymmetric flow structures before the Taylor vortex flow regime and an instability threshold to the modified wavy vortex flow from Taylor vortex flow in shear-thinning fluids i.e. altering the instability mechanisms. The critical Reynolds numbers for the first and second instabilities and the structural characteristics of the flow states were identified for Newtonian and shear thinning fluids in comparison. The vortices have varying axial wavelength and also drift along the axis in shear-thinning fluids. The variation of the critical Reynolds number with the shear-thinning index has been shown through three different Reynolds number definitions. It is shown that when the Reynolds number is defined using single preferred value of radially varying viscosity, decreasing shear-thinning index may delay the appearance of Taylor vortices depending on the gap ratio. When the local Reynolds numbers defined based on the local viscosity have been taken into account, shear thinning effect has a monotonic effect on the critical Reynolds number which decreases with decreasing shear-thinning index for both narrow and wide gaps in transition to Taylor vortex flow regime.

泰勒-库埃特反应堆可能为压载水处理或絮凝处理中要去除的小尺寸颗粒提供另一种处理方法，因为在过渡流态期间产生的高能量耗散和泰勒涡流会产生动量传递。在这项研究中，使用黄原溶液实验研究了稀疏行为对泰勒-库埃特流在窄缝和宽缝中流动结构和过渡阈值的影响。本文提出的实验建立了在泰勒涡旋流态之前非轴对称流动结构的存在以及剪切稀化流体中泰勒旋涡流对修改后的波浪涡旋流的不稳定性阈值，即改变了不稳定性机理。比较了牛顿流体和剪切稀化流体的第一和第二不稳定性的临界雷诺数以及流动状态的结构特征。在剪切稀化流体中，涡流具有变化的轴向波长，并且还沿轴向漂移。临界雷诺数随剪切稀化指数的变化已通过三种不同的雷诺数定义得到了证明。结果表明，当使用径向变化粘度的单个优选值定义雷诺数时，减小的剪切稀化指数可能会根据间隙比而延迟泰勒涡旋的出现。考虑到根据局部粘度定义的局部雷诺数后，