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Research Papers

# Aerothermal Characterization of a Rotating Ribbed Channel at Engine Representative Conditions—Part I: High-Resolution Particle Image Velocimetry Measurements

[+] Author and Article Information
Ignacio Mayo

Turbomachinery and Propulsion Department,
von Karman Institute for Fluid Mechanics,
Rhode-Saint-Genèse B-1640, Belgium
e-mail: ignacio.mayo.yague@vki.ac.be

Gian Luca Gori, Aude Lahalle, Tony Arts

Turbomachinery and Propulsion Department,
von Karman Institute for Fluid Mechanics,
Rhode-Saint-Genèse B-1640, Belgium

1Corresponding author.

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received February 5, 2016; final manuscript received February 26, 2016; published online April 26, 2016. Editor: Kenneth C. Hall.

J. Turbomach 138(10), 101008 (Apr 26, 2016) (9 pages) Paper No: TURBO-16-1034; doi: 10.1115/1.4032926 History: Received February 05, 2016; Revised February 26, 2016

## Abstract

The present work is part of a detailed aerothermal investigation in a model of a rotating internal cooling channel performed in a novel facility setup which allows test conditions at high rotation numbers ($Ro$). The test section is mounted on a rotating frame with all the required instrumentation, resulting in a high spatial resolution and accuracy. The channel has a cross section with an aspect ratio of 0.9 and a ribbed wall with eight ribs perpendicular to the main flow direction. The blockage of the ribs is 10% of the channel cross section, whereas the rib pitch-to-height ratio is 10. In this first part of the paper, the flow over the wall region between the sixth and seventh ribs in the symmetry plane is investigated by means of two-dimensional particle image velocimetry (PIV). Tests were carried out at a Reynolds number ($Re$) of 15,000 in static and rotating conditions, with a maximum $Ro$ of 0.77. Results are in good agreement with the data present in literature at the same Reynolds number and with rotation numbers of 0 (static conditions) and 0.38 in a channel with the same geometry as in the present work. When $Ro$ is increased from 0.38 to 0.77, the main velocity and turbulence fields show important changes. At a rotation number of 0.77, although the extension of the recirculation bubble after the sixth rib on the trailing side does not vary significantly, it covers the full inter-rib area on the leading side in the streamwise direction. The turbulence intensity on the leading side shows a low value with respect to the static case but roughly at the same level as in the lower $Ro$ case. On the trailing side, the maximum value of the turbulence intensity slightly decreases from $Ro$  = 0.38 to $Ro$  = 0.77, the wall shear layer is restabilized along the second half of the pitch due to the high rotation, and the secondary flows are redistributed causing spanwise vortex compression. The observed result is the rapid decay of turbulent fluctuations in the second half of the inter-rib area.

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## Figures

Fig. 1

Flow field in a rotating ribbed channel [18]

Fig. 2

Schematic of the facility

Fig. 3

Facility setup

Fig. 11

Wall-normal nondimensional turbulence: trailing side at Ro = 0.77 (a), trailing side at Ro = 0.38 (b), static case (c), leading side at Ro = −0.38 (d), and leading side at Ro = −0.77(e)

Fig. 10

Streamwise nondimensional turbulence: trailing side at Ro = 0.77 (a), trailing side at Ro = 0.38 (b), static case (c), leading side a Ro = −0.38 (d), and leading side at Ro = −0.77 (e)

Fig. 9

Mean wall-normal nondimensional velocity contours: trailing side at Ro = 0.77 (a), trailing side at Ro = 0.38 (b), static case (c), leading side at Ro = −0.38 (d), and leading side at Ro = −0.77 (e)

Fig. 8

Mean streamwise nondimensional velocity contours: trailing side at Ro = 0.77 (a), trailing side at Ro = 0.38 (b), static case (c), leading side at Ro = −0.38 (d), and leading side at Ro = −0.77 (e)

Fig. 7

In-plane mean stream lines: trailing side at Ro = 0.77 (a), trailing side at Ro = 0.38 (b), static case (c), leading side at Ro = −0.38 (d), and leading side at Ro = −0.77 (e)

Fig. 6

In-plane stream lines and velocity modulus contours: present investigation trailing side at Ro = 0.38 (a), present investigation static case (b), present investigation leading side at Ro = −0.38 (c), trailing side from Ref. [19] at Ro = 0.38 (d), static case from Ref.[19] (e), and leading side from Ref. [19] at Ro = −0.38 (f)

Fig. 5

Comparison of the flow field in static conditions at Re = 15,000: data from Coletti et al. [18] (a), data from Coletti et al. [19] (b), and present investigation (c)

Fig. 4

Measurement planes locations

Fig. 12

Nondimensional turbulent kinetic energy contours: trailing side at Ro = 0.77 (a), trailing side at Ro = 0.38 (b), static case (c), leading side at Ro = −0.38 (d), and leading side at Ro = −0.77 (e)

Fig. 13

Richardson number (Eq. (4)) contours: leading side at Ro = −0.77 (a), leading side at Ro = −0.38 (b), trailing side at Ro = 0.77 (c), and trailing side at Ro = 0.38(d)

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