Fluid flow and heat transfer in the entrance region of an annulus between independently rotating tubes with a turbulent axial flow
Abstract
Experimental and numerical investigations of turbulent flow and heat transfer have been performed in the entrance region of a concentric annulus between independently rotating tubes. The horizontally mounted test section has an electrically heated outer wall and an adiabatic inner wall. The mean heat transfer rate in the hydrodynamic and thermal entrance region as well as the local Nusselt number at the axial position z/db(sub h) approx. = 60, which is the end of the rotating annular channel, were determined experimentally. Hotwire and thermocouple probes allowed for measurement of velocity and temperature distributions at the end of the annulus. Numerical predictions, applying a k-epsilon eddy viscosity model with a modification by the flux Richardson number, are compared with the experimental results. The comparison shows that general effects of the rotation can be predicted quite well with the aid of a simple turbulence model. Due to stabilizing or destabilizing effects of centrifugal forces in the fluid and due to the additional shear stress, the rotation of the inner and the outer tube influences remarkably fluid flow and heat transfer in the annulus.
- Publication:
-
In AGARD
- Pub Date:
- February 1993
- Bibcode:
- 1993htcg.agarQ....P
- Keywords:
-
- Annular Ducts;
- Axial Flow;
- Flow Distribution;
- Fluid Flow;
- Heat Transfer;
- Rotating Fluids;
- Temperature Distribution;
- Turbulent Flow;
- Centrifugal Force;
- Counter Rotation;
- Eddy Viscosity;
- Flow Velocity;
- K-Epsilon Turbulence Model;
- Nusselt Number;
- Richardson Number;
- Shear Stress;
- Turbulence Models;
- Wall Temperature;
- Fluid Mechanics and Heat Transfer