Effect of Coriolis force on unsteady flow with convective heat transfer through a curved duct in case of negative rotation

摘要

The present study addresses numerical prediction of Dean-Taylor flow through a coiled rectangular duct of curvature 0.1. The spectral method is used as a rudimental tool to solve the system of non-linear partial differential equation of order two. The emerging parameters controlling the flow characteristics are the rotation parameter i.e. Tr, (incorporating Coriolis force), Grashof number (Gr), Prandtl number (Pr=7.0), aspect ratio (a=2), and pressure-driven parameter i.e. Dean number Dn (incorporating centrifugal force). The flow structures are explored for the effects of rotation parameter and pressure-driven parameter. We investigated unsteady flow characteristics for negative rotation of the duct for the Dean numbers Dn = 700 over the Taylor number ranging -500 to -10, and it is found that the unsteady flow undergoes through various flow instabilities, if Tr, is increased in the negative direction. Typical contours of secondary flow patterns and temperature profiles are obtained at several values of Tr, and it is seen that the unsteady flow consists of two-, three-, four-, five-, and six -vortex solutions. Convective heat transfer is also investigated, and it is observed that the chaotic flow enhances heat transfer more significantly than the steady-state or periodic solutions. Axial flow distribution is also calculated that is well matched with the secondary flow patterns.