Research Papers

Development of a Flow Visualization Borescope and a Two-Phase Flow Probe for Aeroengine Transmission Gears

[+] Author and Article Information
Hidenori Arisawa

Kawasaki Heavy Industries, Ltd.,
1-1 Kawasaki-cho,
Akashi, Hyogo 673-8666, Japan
e-mail: arisawa_h@khi.co.jp

Yuji Shinoda

Kawasaki Heavy Industries, Ltd.,
1-1 Kawasaki-cho,
Akashi, Hyogo 673-8666, Japan
e-mail: shinoda_yuuji@khi.co.jp

Yoshiyuki Noguchi

Kawasaki Heavy Industries, Ltd.,
1-1 Kawasaki-cho,
Akashi, Hyogo 673-8666, Japan
e-mail: noguchi_yoshiyuki@khi.co.jp

Tatsuhiko Goi

Kawasaki Heavy Industries, Ltd.,
1-1 Kawasaki-cho,
Akashi, Hyogo 673-8666, Japan
e-mail: goi_t@khi.co.jp

Takahiko Banno

Kawasaki Heavy Industries, Ltd.,
1-1 Kawasaki-cho,
Akashi, Hyogo 673-8666, Japan
e-mail: banno_t@khi.co.jp

Hirofumi Akahori

Kawasaki Heavy Industries, Ltd.,
1-1 Kawasaki-cho,
Akashi, Hyogo 673-8666, Japan
e-mail: akahori_h@khi.co.jp

1Corresponding author.

Manuscript received June 1, 2019; final manuscript received June 2, 2019; published online July 10, 2019. Editor: Jerzy T. Sawicki.

J. Eng. Gas Turbines Power 141(9), 091013 (Jul 10, 2019) (16 pages) Paper No: GTP-19-1265; doi: 10.1115/1.4043993 History: Received June 01, 2019; Revised June 02, 2019

To reduce power losses due to oil flows in aeroengine gearboxes, the oil flows should be visualized and measured. In this study, we develop a flow visualization borescope that qualitatively visualizes oil flows along with a two-phase flow probe that quantitatively measures the oil/air ratio and flow velocity. The flow visualization borescope comprises a 16-mm-diameter pipe. Within the pipe, an air purge passage for removing oil mist and a borescope are integrated with an illumination laser and optical lenses, enabling clear, high-speed photography. The two-phase probe consists of a 5-mm-diameter pipe with a 1-mm-diameter measurement hole and an internal pressure adjustment pipe. The borescope and flow probe were demonstrated using a shrouded spur gear with a peripheral speed of 100 m/s and oil supply of 20 l/min. Flow visualization at 30,000 fps revealed that oil outflow from the shroud opening spreads turbulently over the entire width of the opening. Measurements of the oil/air ratio and flow velocity using the two-phase flow probe revealed a thin oil-rich layer on the shroud wall and showed that the flow speed is lower than the gear peripheral speed. The measurement equipment used herein would be easy to install in a gearbox and is therefore expected to be applied in actual aeroengine gearboxes.

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Fig. 1

Configuration of flow visualization borescope

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Fig. 2

Schematics of the inner structure in the visualization borescope

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Fig. 3

Trial visualization setup

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Fig. 4

Trial visualization of oil jet impingement: (a) 0 s, (b) 0.01 ms, and (c) 0.02 ms

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Fig. 5

Schematics of oil jet impingement

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Fig. 6

Image of isokinetic suction [4]: (a) over-suction, (b) isokinetic-suction, and (c) under-suction

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Fig. 7

Measurement system of two-phase flow probe

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Fig. 8

An installation example of two-phase flow probe: (a) perspective view and (b) section

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Fig. 9

Calibration setup for two-phase flow probe: (a) calibration system setup and (b) air bubble condition for high-speed flow of oil and air

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Fig. 10

An example of the general calibration setup for two-phase flow measurement and a difficulty to apply to high-speed oil and air flows: (a) calibration system setup [8] and (b) air bubble condition when high-speed flow of oil and air is used

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Fig. 11

Air solubility for oil and water [9]

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Fig. 12

Images of air dissolution to oil along a pipe

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Fig. 13

Positions of the measurement hole in the calibration: (a) arrangement of probe and supply pipe and (b) positions of measurement hole at section A-A (observed from supply pipe)

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Fig. 14

Correction curves for oil fraction and mixture velocity: (a) correction curve for oil fraction and (b) correction curve for mixture velocity

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Fig. 15

Measurement accuracy of oil fraction

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Fig. 16

Measurement accuracy of mixture velocity

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Fig. 17

Test apparatus and test gearbox: (a) overall test apparatus and test gearbox and (b) detail of setting with two-phase flow probe for z = 14.5

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Fig. 18

Conventional visualization results (normal-speed video, oil supply = 5 l/min): (a) 0 rpm, (b) 7000 rpm, and (c) 10,000 rpm

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Fig. 19

Oil dynamic loss (measured using a torque meter)

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Fig. 20

Schematics of flow pattern from shroud opening (7000 rpm): (a) radial flow (side view), (b) tangential flow (side view), and (c) top view

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Fig. 21

Schematics of flow pattern

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Fig. 22

Difference in oil flow with rotation speed changes: (a1) side view, tangential flow, 7000 rpm, (b1) side view, tangential flow, 8500 rpm, (c1) side view, tangential flow, 10,000 rpm, (a2) top view, 7000 rpm, (b2) top view, 8500 rpm, and (c2) top view, 10,000 rpm

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Fig. 23

Extraction points for flow direction and speed: (a) 7000 rpm, center, (b) 8500 rpm, center, (c) 8500 rpm, side, and (d) 10,000 rpm, center

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Fig. 24

Time history of flow speed

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Fig. 25

Total pressure on cylinder surface

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Fig. 26

Oil fraction (measured by two-phase probe): (a) linear scale display and (b) log scale display

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Fig. 27

Comparison of exponential approximation curves on oil fraction: (a) exponential approximation curves and (b) comparison of exponents

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Fig. 28

Mixture velocity (measured by two-phase probe)

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Fig. 29

Comparison of oil flow rate

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Fig. 30

Oil layer thickness

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Fig. 31

Density-weighted mean velocity compared with visualized velocity

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Fig. 32

Radial distributions of oil flow rate



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