Investigation of a novel Couette flow with cylindrical baffles

Abstract

The high-precision measure instrument for flow velocity is essential for industrial applications because the high-precision velocity can well reflect the physical characteristic of the flow. A restricted laminar Couette flow with cylindrical baffles, using a synthetic heat conduction liquid, was designed to obtain a steady vortex flow and wider work scope, according to Couette flow and Suspension flow characteristics. The heat transfer mechanism was investigated with a laminar flow model by the Fourier law. The research indicates that the heat transfer enhancement is related to the Temperature Boundary Layer (TBL). The TBL is affected by the Velocity Boundary Layer (VBL). The TBL thickness and Nusselt number (Nu) have a dependent relationship. The Reynolds number (Re) and the gap between the baffle and plate wall (Δh/h) can further affect Nu. The vortex flow generated by Couette flow can significantly enhance the heat transfer performance by a double spiral structure, which can rapidly mix heat fluxes and make the temperature converge to uniform. There is a sensitive and stable relationship between flow velocity and heat transfer. Notably, it is linear when Δh/h or Re is small, which can be used to design a high-precision thermal flow velocity meter.