Abstract

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.

References

1.
Pratt & Whitney
,
2015
, “
Geared TurbofanTM Engine: Driven by Innovation
,”
Encyclopedia of Aerospace Engineering
,
Wiley
,
Hoboken, NJ
.
2.
Reynolds
,
C. N.
,
1985
, “
Advanced Prop-Fan Engine Technology (APET) Single- and Counter-Rotation Gearbox/Pitch Change Mechanism
,” Cleveland, Ohio, Report No.
NASA CR-168114
.https://ntrs.nasa.gov/search.jsp?R=19870019123
3.
Hartono
,
E. A.
,
Golubev
,
M.
, and
Chernoray
,
V.
,
2013
, “
PIV Study of Fluid Flow Inside a Gearbox
,” PIV13, Delft, The Netherlands, July 1–3.
4.
Yang
,
Y.
, and
Telionis
,
D.
,
2013
, “
Design and Testing of Instrumentation for Multi-Phase Flow Sampling and Local Void Fraction Measurement
,”
WIT Trans. Eng. Sci.
,
79
, pp.
311
322
.
5.
Namie
,
S.
, and
Ueda
,
T.
,
1972
, “
Droplet Transfer in Two-Phase Annular Mist Flow—Part 1: Experiment of Droplet Transfer Rate and Distributions of Droplet Concentration and Velocity
,”
Bull. JSME
,
15
(
90
), pp.
1568
1580
.
6.
Ishikawa
,
A.
,
Imai
,
R.
, and
Tanaka
,
T.
,
2014
, “
Experimental Study on Two-Phase Flow in Horizontal Tube Bundle Using SF6-Water
,”
IHI Tech. Rev.
,
46
(
2
), pp.
26
31
.https://www.ihi.co.jp/ihi/technology/review_library/review_en/2013/46_02.html
7.
Ito
,
D.
,
Kikura
,
H.
, and
Aritomi
,
M.
,
2009
, “
Development of Gas-Liquid Two-Phase Flow Measurement Technique in Narrow Channel (Application of Micro Wire-Mesh Sensor to the Flow Between Parallel Plates)
,”
Prog. Multiphase Flow Res.
,
4
, pp.
45
52
.
8.
Fukushi
,
K.
, and
Iguchi
,
M.
,
2005
, “
The Effects of Wettability on the Flow Pattern and Rising Gas Velocity of Gas-Liquid Two-Phase Flow in Vertical Pipe
,”
Tetsu-to-Hagane
,
91
(
5
), pp.
465
470
.
9.
Totten
,
G. E.
, and
Negri
,
V. J.
, “
Physical Properties and Their Determination
,”
Handbook of Hydraulic Fluid Technology Second Edition
,
CRC Press
,
Boca Raton, FL
, p.
117
.
10.
Furuya
,
K.
,
1938
, “
Experimental Research on the Lubricating Oil (1st Report): Measurement of Contact Angle of Oil Drops
,”
Trans. JSME
,
4
(
14
), pp.
78
83
.
11.
Nabesaka
,
S.
,
Etoh
,
T.
, and
Takehara
,
K.
,
2002
, “
A New Technique to Separately Evaluate the Effects of Surface Tension and Viscosity on Rupture of a Bubble at Water Surface
,”
Proc. JSCE
,
705
, pp.
19
29
.
12.
Dawson
,
P. H.
,
1984
, “
Windage Loss in Larger High-Speed Gears
,”
Proc. Inst. Mech. Eng.
,
198A
(
1
), pp.
51
59
.
13.
Arisawa
,
H.
,
Shinoda
,
Y.
,
Tanaka
,
M.
,
Goi
,
T.
,
Akahori
,
H.
, and
Yoshitomi
,
M.
,
2017
, “
Classification of Fluid Dynamic Loss in Aeroengine Transmission Gears—Experimental Analysis and CFD Validation
,”
ASME
Paper No. GT2017-63208.
14.
Ditect
,
2017
,
Dipp Motion User Manual Ver. 1.1.29
,
Ditect
,
Tokyo, Japan
.
15.
Massini
,
D.
,
Fondelli
,
T.
,
Andreini
,
A.
,
Facchini
,
B.
,
Tarchi
,
L.
, and
Leonardi
,
F.
,
2017
, “
Experimental and Numerical Investigation on Windage Power Loss in High Speed Gears
,”
ASME
Paper No. GT2017-64948.
16.
Okamoto
,
T.
, and
Yagita
,
M.
,
1972
, “
The Experimental Investigation on the Flow of a Circular Cylinder of Finite Length Placed Normal to the Plane Surface in a Uniform Stream
,”
Trans. Jpn. Soc. Mech. Eng.
,
38
(
313
), pp.
2259
2267
.
17.
El Telbany
,
M. M. M.
, and
Reynolds
,
A. J.
,
1980
, “
Velocity Distributions in Plane Turbulent Channel Flows
,”
J. Fluid Mech.
,
100
(
1
), pp.
1
29
.
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