0
Research Papers: Gas Turbines: Aircraft Engine

Ejector Application for Scavenging of an Aero Engine Bearing Chamber

[+] Author and Article Information
Michael Flouros

MTU Aero Engines,
Munich 80995, Germany
e-mail: Michael.Flouros@mtu.de

Christina Salpingidou

Laboratory of Fluid Mechanics
& Turbomachinery,
AUTH,
Thessaloniki 54124, Greece
e-mail: csalpingidou@eng.auth.gr

Kyros Yakinthos

Laboratory of Fluid Mechanics
& Turbomachinery,
AUTH,
Thessaloniki 54124, Greece
e-mail: kyak@auth.gr

Markus Hirschmann

MTU Aero Engines,
Munich 80995, Germany
e-mail: Markus.Hirschmann@mtu.de

Francois Cottier

MTU Aero Engines,
Munich 80995, Germany
e-mail: francois.cottier@mtu.de

Contributed by the Aircraft Engine Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received January 17, 2017; final manuscript received March 20, 2017; published online May 16, 2017. Editor: David Wisler.

J. Eng. Gas Turbines Power 139(10), 101202 (May 16, 2017) (11 pages) Paper No: GTP-17-1022; doi: 10.1115/1.4036516 History: Received January 17, 2017; Revised March 20, 2017

Oil system architecture in aero engines has remained almost the same for the last 35 years. At least one mechanically-driven oil feed pump is responsible for distributing pressurized oil into the bearing chambers and several scavenge pumps, also mechanically driven, are responsible for evacuating the bearing chambers from the oil and air mixture. Air is used as the sealing medium in bearing chambers and is the dominant medium in terms of volume occupation and expansion phenomena. In order to simplify the oil system architecture, improve the system's reliability with less mechanical parts, and also decrease weight, an ejector system has been designed for scavenging bearing chambers. In Flouros et al. (2013, “Ejector Scavenging of Bearing Chambers. A Numerical and Experimental Investigation,” ASME J. Eng. Gas Turbines Power, 135(8), p. 081602), an ejector system was presented which used aviation oil (MIL-PRF-23699 Std.) as the primary medium. In the course of further development, the original design was modified leading to a much smaller ejector. This ejector was tested in the rig using alternatively pressurized air or pressurized oil as primary medium. Additionally, three in-house developed primary nozzle (jet) designs were introduced and tested. The design of an ejector for application with compressible or incompressible media was supported through the development of an analysis tool. A momentum-based efficiency function is proposed herein and enables comparisons among different operating cases. Finally, ANSYS cfx (ANSYS, 2014, “ANSYS® CFX, Release 14.0,” ANSYS Inc., Canonsburg, PA) was used to carry out the numerical analysis. Similar to the ejector described in Flouros et al. (2013, “Ejector Scavenging of Bearing Chambers. A Numerical and Experimental Investigation,” ASME J. Eng. Gas Turbines Power, 135(8), p. 081602), the new design was also manufactured out of pure quartz glass to enable optical access. Through suitable instrumentation for pressures, temperatures, and air/oil flows, the performance characteristics of the new ejector were assessed and were compared to the analytic and numerical results. This work was partly funded by the German government within the research program Lufo4 (Luftfahrtforschungsprogramm 4/Aeronautical Research Program 4).

Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.

References

Flouros, M. , Cottier, F. , Hirschmann, M. , Kutz, J. , and Jocher, A. , 2013, “ Ejector Scavenging of Bearing Chambers. A Numerical and Experimental Investigation,” ASME J. Eng. Gas Turbines Power, 135(8), p. 081602. [CrossRef]
Engineering Science Data Unit (ESDU), 1985, “ Ejectors and jet Pumps—Design and Performance for Incompressible Liquid Flows,” ESDU International PLC, London, Item No. 85032.
Rotta, J. , 1957, “ Ejektorpumpen mit Extrem Hohem Durchsatzverhältnis,” Forsch. Geb. Ingenieurwes., 23(4), pp. 157–167. [CrossRef]
Engineering Science Data Unit (ESDU), 1984, “ Ejectors and Jet Pumps, Design and Performance for Compressible Air Flow,” ESDU International PLC, London, Item No. 84029.
Flügel, G. , 1939, Berechnung von Strahlapparaten (VDI-Forschungsheft 395, Beilage zu “Forschung auf dem Gebiete des Ingenieurwesens”), Ausgabe B, Bd. 10, Hannover, Germany.
Levy, S. , 1999, Two-Phase Flow in Complex Systems, Wiley, Toronto, ON, pp. 90–107.
Storek, H. , and Brauer, H. , 1980, Reibungsdruckverlust der Adiabaten Gas/Fluessigkeitstroemung in Horizontalen und Vertikalen Rohren (VDI Forschungsheft, Vol. 599), VDI Verlag, Duesseldorf, Germany, pp. 8–9.
Collier, J. G. , and Thome, J. R. , 2001, Convective Boiling and Condensation, 3rd ed., Oxford University Press, Oxford, UK, p. 44.
Tye, R. P. , 1969, Thermal Conductivity, Vol. 1, Academic Press, New York, p. 319.
Taitel, Y. , and Dukler, A. E. , 1976, “ A Model for Predicting Flow Regime Transitions in Horizontal and Near Horizontal Gas-Liquid Flow,” AIChE J., 22(1), pp. 47–55. [CrossRef]
ANSYS, 2014, “ ANSYS® CFX, Release 14.0,” ANSYS Inc., Canonsburg, PA.
ANSYS, 2014, “ ANSYS® ICEM CFD Mesh Editor, Release 13.0,” ANSYS Inc., Canonsburg, PA.
Jocher, A. , 2011, “ Auslegung und Fluidmechanische Untersuchung Eines Zwei- Phasen-Ejektors Fuer Flugtriebwerke” Diploma Thesis (Design and Fluid Mechanical Investigation of a Two-Phase Flow Ejector for Aero Engines), Lehrstuhl Fuer Thermodynamik (Department of Thermo-Dynamics), Munich Technical University, Munich, Germany.
Menter, F. R. , 1994, “ Two-Equation Eddy-Viscosity Turbulence Models for Engineering Applications,” AIAA J., 32(8), pp. 1598–1605. [CrossRef]
Schiller, L. , and Naumann, Z. , 1935, “ A Drag Coefficient Correlation,” Z. Ver. Dtsch. Ing., 77, pp. 318–320.
Sato, Y. , 1975, “ Liquid Velocity Distribution in Two-Phase Bubble Flow,” Int. J. Multiphase Flow, 2(1), pp. 79–95. [CrossRef]
Flouros, M. , Iatrou, G. , Yakinthos, K. , Cottier, F. , and Hirschmann, M. , 2015, “ Two Phase Flow Heat Transfer and Pressure Drop in Horizontal Scavenge Pipes in an Aero Engine,” ASME J. Eng. Gas Turbines Power, 137(8), p. 081901. [CrossRef]
Engineering Science Data Unit (ESDU), 1973, “ Performance of Conical Diffusers in Incompressible Flow,” ESDU International PLC, London, Item No. 73024.

Figures

Grahic Jump Location
Fig. 1

Bearing chamber using ejector scavenging. The primary jet fluid can be either air or oil.

Grahic Jump Location
Fig. 2

The MTU rig facility with bearing chamber, oil reservoir, and ejector

Grahic Jump Location
Fig. 3

The quartz glass ejector in operation with inlet, diffuser, and primary nozzle

Grahic Jump Location
Fig. 4

Ejector schematic with instrumentation (pressure taps)

Grahic Jump Location
Fig. 5

Spray pattern of the Delavan BIM 11 nozzle

Grahic Jump Location
Fig. 6

The four different types of nozzles for the ejector's primary nozzle

Grahic Jump Location
Fig. 7

The operational domain for the primary nozzle as a function of the flow ratio

Grahic Jump Location
Fig. 8

Total pressure of the secondary flow at ejector inlet as a function of the secondary mass at a constant diffuser pressure of 102 kPa

Grahic Jump Location
Fig. 9

The planes in the ejector which are considered for efficiency calculations

Grahic Jump Location
Fig. 10

The hexahedral mesh of the ejector on the top. On the bottom left, the triple triangular jet and on the right the converging–diverging nozzle.

Grahic Jump Location
Fig. 11

High-speed camera snapshot of the slug flow in the horizontal part of the scavenge line

Grahic Jump Location
Fig. 12

Oil flow pattern comparison between test and ANSYS cfx showing very good compliance (volume fraction = 1: pure oil, = 0: lean air) using the convergent divergent primary nozzle with air

Grahic Jump Location
Fig. 13

The comparison between CFD and measurement results for locations 1–5 at a bearing chamber pressure of 1.03 bar and air as the primary flow at 4.2 barg

Grahic Jump Location
Fig. 14

The comparison between CFD and measurement results for locations 1–5 at a bearing chamber pressure of 1.21 bar and air as the primary flow at 4.2 barg

Grahic Jump Location
Fig. 15

Efficiency of the ejector as a function of the pressure in the bearing chamber for two different primary media. The secondary flow was at 400 L/h oil and 5–30 kg/h air. The primary nozzle was of converging–diverging type.

Grahic Jump Location
Fig. 16

Efficiency of the ejector as a function of the primary pressure using a converging–diverging nozzle. The oil flow is at 400 L/h and the secondary air flow is about 5 kg/h resulting in a bearing chamber pressure of 1.05 bar abs.

Grahic Jump Location
Fig. 17

The variation of the efficiency as a function of the primary oil flow at a bearing chamber pressure of 1.05 bar using a converging–diverging nozzle

Grahic Jump Location
Fig. 18

Efficiency of the ejector as a function of the pressure in the bearing chamber for two different primary media. The secondary flow was at 400 L/h oil and 5–30 kg/h air. The primary nozzle was of single jet type.

Grahic Jump Location
Fig. 19

Efficiency of the ejector as a function of the pressure in the bearing chamber for two different primary media. The secondary flow was 400 L/h oil and 5–30 kg/h air. The primary nozzle was of triple linear jet type.

Grahic Jump Location
Fig. 20

Efficiency of the ejector as a function of the pressure in the bearing chamber for two different primary media. The secondary flow was 400 L/h oil and 5–30 kg/h air. The primary nozzle was of triple triangular jet type.

Grahic Jump Location
Fig. 21

Streamlines of the primary medium flow for the four nozzles used during the test campaign (a) converging-diverging, (b) single jet, (c) triangular linear, and (d) triple triangular. Type D produces the highest dispersion.

Grahic Jump Location
Fig. 22

Diffuser geometry with an initial angle Φ of 4 deg

Grahic Jump Location
Fig. 23

Ejector diffuser schematic

Grahic Jump Location
Fig. 24

Diffuser angle variation at a primary jet pressure of pressure of 4.2 barg

Grahic Jump Location
Fig. 25

Ejector efficiency comparison between the nominal ejector (Φ = 4 deg) and an ejector without diffuser (tail pipe). The primary nozzle is of converging–diverging type and the primary medium is air at 4.2 barg.

Grahic Jump Location
Fig. 26

Ejector efficiency as a function of the relative mixing length. For the nominal geometry, the relative mixing length is1.

Grahic Jump Location
Fig. 27

An example of an engine attitude envelope indicating the operational limits during flight. Within the boundaries of the inner hexahedron, the operation of the engine should be capable to operate unrestrictedly.

Grahic Jump Location
Fig. 28

The oil distribution in the ejector at 60 deg nose up, 4.2 barg primary air pressure and a bearing chamber pressure at 105 kPa. No oil recirculation zones were detected.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In