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TECHNICAL PAPERS: Gas Turbines: Heat Transfer

# Buoyancy-Induced Flow in a Heated Rotating Cavity

[+] Author and Article Information
J. Michael Owen

Department of Mechanical Engineering, University of Bath, Bath, UK

Jonathan Powell

Malvern Instruments Ltd., Malvern, UK

J. Eng. Gas Turbines Power 128(1), 128-134 (Mar 01, 2004) (7 pages) doi:10.1115/1.2032451 History: Received October 01, 2003; Revised March 01, 2004

## Abstract

Experimental measurements were made in a rotating-cavity rig with an axial throughflow of cooling air at the center of the cavity, simulating the conditions that occur between corotating compressor disks of a gas-turbine engine. One of the disks in the rig was heated, and the other rotating surfaces were quasi-adiabatic; the temperature difference between the heated disk and the cooling air was between 40 and 100°C. Tests were conducted for axial Reynolds numbers, $Rez$, of the cooling air between $1.4×103$ and $5×104$, and for rotational Reynolds numbers, $Reϕ$, between $4×105$ and $3.2×106$. Velocity measurements inside the rotating cavity were made using laser Doppler anemometry, and temperatures and heat flux measurements on the heated disk were made using thermocouples and fluxmeters. The velocity measurements were consistent with a three-dimensional, unsteady, buoyancy-induced flow in which there was a multicell structure comprising one, two, or three pairs of cyclonic and anticyclonic vortices. The core of fluid between the boundary layers on the disks rotated at a slower speed than the disks, as found by other experimenters. At the smaller values of $Rez$, the radial distribution and magnitude of the local Nusselt numbers, Nu, were consistent with buoyancy-induced flow. At the larger values of $Rez$, the distribution of Nu changed, and its magnitude increased, suggesting the dominance of the axial throughflow.

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## Figures

Figure 1

Rotating cavity with axial throughflow of cooling air

Figure 2

Schematic diagram of rotating-cavity rig

Figure 3

Figure 4

Transient variation of Vϕ∕Ωr:Reϕ=0.43×106, Rez=0.30×104, x=0.674, z∕s=0.5

Figure 5

Instantaneous and spectral velocity measurements for Reϕ=0.43×106, Rez=0.30×104, x=0.674, z∕s=0.5

Figure 6

Effect of Reϕ on ΔT and Nu for Rez=0.30×104

Figure 7

Effect of Reϕ on ΔT and Nu for Rez=1.3×104 (for legend, see Fig. 6)

Figure 8

Effect of Reϕ on ΔT and Nu for Rez=2.5×104 (for legend, see Fig. 6)

## Errata

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