Zhenqiang Yao

Surface Texture Effect on Momentum Transfer Behavior in Ultimate Taylor-Couette Flow

Torque behavior in Taylor-Couette flow has been discussed for decades of years and a series of torque behavior models have been proposed to deepen the understanding of dynamic behavior. In industry fields, the empirical relations based on torque measurement of scaled models in laboratory have been widely used to predict the torque behavior of rotating machinery. However, they fail sometimes, especially in ultimate flow regime. Therefore, a uniform theory based on physical mechanism is needed to model the torque behavior. Under the efforts of many scholars, fortunately, Eckhardt-Grossmann-Lohse theory throws light upon this problem from momentum transfer behavior based on N-S equations. It argues that angular velocity current seems to be constant in the gap, meanwhile, bulk flow theory shows that turbulent bulk and boundary layer play different roles in momentum transfer behavior. Compared with the thickness of boundary layer, surface texture is the same level in dimension. What is the interaction mechanism between the boundary layer and surface texture and how much does surface texture affect torque behavior? In this paper, we mainly focus on how surface texture affects the momentum transfer behavior. To investigate the surface effect on momentum transfer behavior, global torque behavior was measured through rotating multicomponent dynamometer of Kistler and surface texture effect on dynamic behavior of boundary layer was observed through high speed camera of Phantom. To compare the effect of different surface texture, the surface morphology was mapped by stereoscopic microscope of Zeiss. The results indicate that irregular surface texture strengthens the momentum transfer behavior through boundary layer transportation.© 2014 ASME