PIV experimental characterization of fluid dynamics generated by rotating inner cylinders with and without rough wall in a taylor-couette reactor

The vortex flow in a Taylor-Couette reactor (radius ratio ?=0.8, aspect ratio of 10) was experimentally studied with the help of a two-dimensional particle image velocimetry for a range of Reynolds numbers Re varying from 2498 to 4164, corresponding to turbulent vortex flow regime. The effect of the rough surface of rotating inner cylinder on the velocity field and turbulence in the Taylor-Couette reactor has been investigated. The rough wall of inner cylinder is achieved by wrapping on the smooth wall inner cylinder a perforated wire mesh with square holes, which is characterized by a mesh number of 20 and a wire diameter of 1mm. The velocity field and the turbulent field were obtained from the PIV measurement. The experimental results acquired in the TC reactors adopting a rotating inner cylinder with rough surface were compared with that in a TC reactor using a smooth rotating inner cylinder of the same diameter. It is found the Taylor-vortex was obviously deformed by using the inner cylinder with a rough surface. The highest turbulent kinetic energy was found to occur at the position of outflow boundary of Taylor vortices for both TC reactors using inner cylinder with rough surface and inner cylinder with smooth surface. However, the overall turbulent kinetic energy of flow field generated by rough surface inner cylinder is significantly increased by almost 300% in comparison with that produced by smooth inner cylinder when Reynolds number is 4164. In terms of turbulent energy dissipation rates, the results show that the maximum turbulent dissipation rate is also observed at the outflow boundaries of Tylor vortices, the overall turbulent dissipation rate of the fluid field generated by the smooth surface inner cylinder is greatly smaller than that of inner cylinder with rough surface.