Buoyancy-affected flow and heat transfer in asymmetrically heated rotating cavities
- Univ. of Sussex, Brighton (United Kingdom). Thermo-Fluid Mechanics Research Center
Finite-volume predictions are presented for the convective heat transfer rates in a rotating cavity, formed by two co-rotating plane disks and peripheral shroud,and subjected to a radial outflow of cooling air. The heating of the disks is asymmetric, the air entering the cavity through a central hole in the cooler (upstream) disk. The predicted Nusselt number distribution for each disk are compared with unpublished data from the University of Sussex for dimensionless mass-flow rates in the range 2,800 {le} C{sub w} {le} 14,000 and rotational Reynolds numbers, Re{sub {theta}} up to 5.2 {times} 10{sup 6}. A single-grid elliptic procedure was used with turbulent transport represented via a low-Reynolds-number {kappa}-{epsilon} model and the turbulence Prandtl number concept. Under conditions of asymmetric heating, rotationally induced buoyancy forces can exert significant radial outflow. The extent to which the effects of such flow behavior can be captured by the steady, axisymmetric calculation approach used here is questionable, but it is found that the turbulence model (used previously for the prediction of heat transfer in symmetrically heated cavities) still leads to good ({+-}10 percent) predictive accuracy for the heated (downstream) disk. However, the predicted Nusselt numbers for the cooler (upstream) disk generally show little accord with experimental data, often signifying heat flow into the disk instead of vice versa. It is concluded that the modeling of the turbulent heat transport across the core region of the flow is erroneous, especially at high rotational Reynolds numbers: This is attributed to overestimated turbulence energy production in that region due to the action of the radial-circumferential component of shear stress ({ovr vw}). Adoption of an algebraic-stress model for this shear stress is partly successful in removing the discrepancies between prediction and experiment.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 103658
- Report Number(s):
- CONF-930502-; ISSN 0889-504X; TRN: IM9541%%97
- Journal Information:
- Journal of Turbomachinery, Vol. 117, Issue 3; Conference: 38. ASME international gas turbine and aeroengine congress and exhibition, Cincinnati, OH (United States), 24-27 May 1993; Other Information: PBD: Jul 1995
- Country of Publication:
- United States
- Language:
- English
Similar Records
Heat transfer in a cover-plate preswirl rotating-disk system
Heat transfer in an air-cooled rotor-stator system