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TECHNICAL PAPERS: Gas Turbines: Heat Transfer

# Influence of Fluid Dynamics on Heat Transfer in a Preswirl Rotating-Disk System

[+] Author and Article Information
Gary D. Lock, Michael Wilson, J. Michael Owen

Department of Mechanical Engineering,  University of Bath, Bath BA2 7AY, UK

J. Eng. Gas Turbines Power 127(4), 791-797 (Mar 01, 2004) (7 pages) doi:10.1115/1.1924721 History: Received October 01, 2003; Revised March 01, 2004

## Abstract

Modern gas turbines are cooled using air diverted from the compressor. In a “direct-transfer” preswirl system, this cooling air flows axially across the wheel space from stationary preswirl nozzles to receiver holes located in the rotating turbine disk. The distribution of the local Nusselt number Nu on the rotating disk is governed by three nondimensional fluid-dynamic parameters: preswirl ratio $βp$, rotational Reynolds number $Reϕ$, and turbulent flow parameter $λT$. This paper describes heat transfer measurements obtained from a scaled model of a gas turbine rotor-stator cavity, where the flow structure is representative of that found in the engine. The experiments reveal that Nu on the rotating disk is axisymmetric except in the region of the receiver holes, where significant two-dimensional variations have been measured. At the higher coolant flow rates studied, there is a peak in heat transfer at the radius of the preswirl nozzles associated with the impinging jets from the preswirl nozzles. At lower coolant flow rates, the heat transfer is dominated by viscous effects. The Nusselt number is observed to increase as either $Reϕ$ or $λT$ increases.

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## Figures

Figure 4

Video image of TLC on rotating disk. Color photograph available in ASME Paper 2004-GT-53158.

Figure 5

Contour map of heat transfer coefficient (W∕m2K) for viscous dominated flow: Reϕ≈0.8×106, λT≈0.125, βp≈0.5. The disk is rotating counter-clockwise. Color contours available in ASME Paper 2004-GT-53158.

Figure 6

Contour map of heat transfer coefficient (W∕m2K) for inertially dominated flow: λT≈0.36, βp≈1.4, Reϕ≈0.8×106. Counter-clockwise rotation. Color contours available in ASME Paper 2004-GT-53158.

Figure 7

Effect of λT and βp on the radial distribution of Nu: Reϕ≈0.8×106

Figure 8

Effect of λT and βp on the radial distribution of Nu: Reϕ≈1.2×106

Figure 1

Simplified diagram of typical pre-swirl cooling-air system for a gas turbine

Figure 2

Schematic diagram of test-section geometry

Figure 3

Cross-sectional drawing of test rig

Figure 9

Effect of Reϕ on the radial distribution of Nu: λT≈0.125, βp≈0.5

Figure 10

Effect of Reϕ on the radial distribution of Nu: λT≈0.24, βp≈1.0

Figure 11

Effect of Reϕ on radial distribution of Nu: λT≈0.36, βp≈1.2

Figure 12

Effect of βp and N on radial distribution of Nu: Reϕ≈1.0×106, λT≈0.24

Figure 13

Effect of λT and N on radial distribution of Nu: Reϕ≈0.8×106, βp≈1.0

Figure 14

Measured variation of CD with λT,p (corrected version of Fig. 8 of Yan (9))

Figure 15

Measured variation of CD with β∞,b (corrected version of Fig. 8 of Yan (9))

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