Numerical analysis of vortex T micromixer with diffuser plates and obstacles

Abstract

The design of passive micromixers is a trade-off among the mixing efficiency, pressure drop, length/time scale and the complexity (or cost) of the mixing channel. The advent of chaotic advection in micromixers has encouraged researchers to explore the untapped potential of disturbance in the flow. Over the past years, the performance of T micromixers has increased significantly, however, the mixing efficiency is still far behind the conventional threshold. In order to enhance the mixing further, non-aligned inlets with rigid diffuser plates (or vortex generators) and cylindrical obstacles are proposed with the present study. The vortex formed at the T-junction is intensified at the leading edge of the diffuser plate and each diffuser plate creates two vortices in opposite directions. These vortices are energized across each pair of the diffuser plate and gets propelled along the mixing chamber. The common flow-up approach with the staggered arrangement is suggested for enhancing the mixing efficiency. For the Reynolds number around 30; mixing efficiency as high as 85% is achieved within the pressure loss of 2300 Pa. The proposed design is simple and similar approach can be used for desired mixing efficiency at specific Reynolds number. Configurations such as in-line & staggered arrangement, flow-up & flow-down arrangement, presence of obstacles etc. are compared and their implementation is proposed accordingly.