Open Access

ARTICLE

Thermal Fluid Transport Phenomena in Concentric Annulus with Movement and Rotation of Inner Core

S. Torii¹

1 Department of Mechanical Engineering, Kagoshima University, Kagoshima, 890-0065, JAPAN

Computer Modeling in Engineering & Sciences 2004, 5(3), 257-268. https://doi.org/10.3970/cmes.2004.005.257

Abstract

A numerical study is performed to investigate the thermal fluid-flow transport phenomena in the concentric annulus with a slightly heated rotating inner core moving in the flow direction and a stationary insulated outer cylinder. Emphasis is placed on the effects of the axial rotation and streamwise movement of inner core on the flow structure and heat transfer performance. A k-ε turbulence model is employed to determine the turbulent viscosity and the turbulent kinetic energy. The turbulent heat flux is expressed by Boussinesq approximation in which the eddy diffusivity for heat is determined using two-equation heat transfer model. The governing equations are discretized by means of a control volume finite-difference technique and numerically solved. An inner core rotation causes amplification of the turbulent kinetic energy over the whole cross section, resulting in a substantial enhancement in the Nusselt number. This trend is suppressed due to the inner core movement. The streamwise movement of the inner core causes substantial reductions in the turbulent kinetic energy intensified by the inner core rotation, resulting in the deterioration of heat transfer performance. Heat transfer characteristics in Couette flow in concentric annulus are found to be affected by both the velocity ratio of the moving inner cylinder to the fluid flow and the inner core rotating speed.

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