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Annual Reviews of Heat Transfer

ISSN 1049-0787

Individual price:

$175.00 (Must be sent to your home address)

You can order single issue or individual article. To purchase a single issue or an individual article as well as to view tables of contents and abstracts click on issue number.

Institutional price:

$349.00

Volumes per year:

various

Year 1998

464 pages

Volume price - $141.00

ADVANCES IN TURBULENT TRANSPORT PHENOMENA IN TWO-DIMENSIONAL ANNULAR FLOW SYSTEMS

Shuichi Torii
Department of Mechanical Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima, 890-0065; and Department of Mechanical Engineering and Materials Science, Kumamoto University 2-39-1, Kurokami, Kumamoto, 860-8555, JAPAN

Wen-Jei Yang
Department of Mechanical Engineering and Applied Mechanics, University of Michigan, Ann Arbor, Michigan 48109, U.S.A.

ABSTRACT

A numerical study is performed to investigate turbulent fluid flow and heat transfer in hydrodynamically-and-thermally developing and fully-developed regions of a concentric annulus, consisting of a heated inner cylinder either moving in the flow direction (parallel Couette flow) or rotating around the axis (circular Couette flow) and an insulated stationary outer cylinder. Three different turbulence models are employed to determine the Reynolds stress in the momentum equation and the turbulent heat flux in the energy equation. The governing boundary-layer equations are discretized by means of a control volume finite-difference technique and numerically solved using the marching procedure. Results are obtained to determine the effects of streamwise movement and axial rotation of the inner core on Nusselt number, friction coefficient and turbulent transport mechanism of fluid flow and heat transfer. It is disclosed that in the entrance region, the streamwise movement of the inner cylinder suppresses the development of thermal boundary layer, resulting in a decrease in both the Nusselt number and turbulent kinetic energy in the inner cylinder wall region. This feature is in sharp contrast to that in the circular Couette flow, where inner cylinder rotation promotes the development of thermal entrance region, resulting in an enhancement in both the Nusselt number and turbulent kinetic energy in the vicinity of the inner cylinder wall. In the fully-developed region, however, an increase in the ratio of inner core moving velocity to fluid flow velocity causes an attenuation in both turbulence intensity and turbulence variance, resulting in a substantial deterioration in heat transfer performance. In contrast, an increase in the Taylor number, i.e. the inner core rotational velocity, causes an amplification of turbulent kinetic energy over the whole flow cross section, resulting in a substantial enhancement in the Nusselt number.