Research Papers: Gas Turbines: Turbomachinery

Dual Drive Booster for a Two-Spool Turbofan: Performance Effects and Mechanical Feasibility

[+] Author and Article Information
Trevor H. Speak

Derwent Aviation Consulting Ltd.,
58-60 Wetmore Road,
Burton on Trent DE14 1SN, UK
e-mail: trevor.speak@hotmail.com

Robert J. Sellick

Derwent Aviation Consulting Ltd.,
58-60 Wetmore Road,
Burton on Trent DE14 1SN, UK
e-mail: robertsellick@msn.com

Vadim Kloos

Institute of Jet Propulsion and Turbomachinery,
RWTH Aachen University,
Templergraben 55,
Aachen 52062, Germany
e-mail: kloos@ist.rwth-aachen.de

Peter Jeschke

Institute of Jet Propulsion and Turbomachinery,
RWTH Aachen University,
Templergraben 55,
Aachen 52062, Germany
e-mail: jeschke@ist.rwth-aachen.de

1Corresponding author.

Contributed by the Turbomachinery Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received July 22, 2015; final manuscript received July 29, 2015; published online September 1, 2015. Editor: David Wisler.

J. Eng. Gas Turbines Power 138(2), 022603 (Sep 01, 2015) (9 pages) Paper No: GTP-15-1359; doi: 10.1115/1.4031274 History: Received July 22, 2015

A novel two-spool turbofan engine configuration is described which uses a booster powered by both the low an high pressure spools. Design and off-design performance analysis shows the operating characteristics of the configuration, and a mechanical feasibility study of the gearbox is presented. The trends toward ever higher engine overall pressure ratio and bypass ratio have resulted in a combination of higher pressure ratio and lower blade speed in the booster compressor of conventional two-spool turbofans. This combination gives rise to many stages in the booster and/or lower booster efficiency and also a higher degree of off-design mismatch between the core compressors. The current paper describes an engine architecture which aims to alleviate both these issues by powering the booster compressor from both low and high pressure spools through an epicyclic gear system. We have called this engine architecture the dual drive booster. The concept gives the engine designer greater flexibility to optimize component performance and work split, resulting in the potential for lower cruise specific fuel consumption and higher hot-day takeoff thrust capability than current engine configurations. The gear system is described along with the mathematical derivation of the booster rotational speed in terms of LP- and HP-spool speeds. Both the design point and off-design performance modeling have been conducted and comparison is made between a conventional turbofan and a turbofan fitted with the dual drive booster. The results show a significant enhancement in takeoff thrust due to the better speed match of the booster. The paper also describes the results of a preliminary study into the design and mechanical feasibility of the engine architecture and gear system. The presented concept is an alternative to the conventional turbofan and should be considered during the conceptual design of future aircraft engines.

Copyright © 2016 by ASME
Your Session has timed out. Please sign back in to continue.


Speak, T. , and Sellick, R. , 2014, “ Compressor System,” UK Patent WO 2014/177836 A1.
GasTurb, 2014, “ GasTurb 12,” GasTurb GmbH, Aachen, Germany, www.gasturb.de
Lévai, Z. , 1966, “ Theory of Epicyclic Gears and Epicyclic Change-Speed Gears,” Ph.D. thesis, Department of Motor Vehicles, Technical University of Construction and Transportation, Budapest, Hungary.
Kurzke, J. , 2013, “ GasTurb 12, User Manual,” GasTurb GmbH, Aachen, Germany, www.gasturb.de
Walsh, P. , and Fletcher, P. , 2004, Gas Turbine Performance, 2nd ed., Blackwell Science, Oxford, UK.
Koch, C. , and Smith, L. , 1976, “ Loss Sources and Magnitudes in Axial-Flow Compressors,” ASME J. Eng. Gas Turbines Power, 98(3), pp. 411–424. [CrossRef]
Horlock, J. , 1966, Axial Flow Turbines: Fluid Mechanics and Thermodynamics, Butterworths, London.
Grieb, H. , 2004, Projektierung von Turboflugtriebwerken, Birkhäuser Verlag, Basel, Switzerland.
Gaparovic, N. , 1976, “ Das Zweistromtriebwerk bei optimaler und nicht-optimaler Auslegung,” Forsch. Ingenieurwes. A, 42(5), pp. 157–168. [CrossRef]
Cumpsty, N. , 1989, Compressor Aerodynamics, Longman Scientific & Technical, Harlow, UK.
Traupel, W. , 1988, Thermische Turbomaschinen. 1. Band, 3. neubearbeitete und erweiterte Auflage, Springer-Verlag, Berlin.
MacLeod, J. , Taylor, V. , and Laflamme, J. , 1992, “ Implanted Component Faults and Their Effects on Gas Turbine Engine Performance,” ASME J. Eng. Gas Turbines Power, 114(2), pp. 174–179. [CrossRef]
Hall, D. , Greitzer, E. , and Tan, C. , 2012, “ Performance Limits of Axial Compressor Stages,” ASME Paper No. GT2012-69709.
Riegler, C. , Bauer, M. , and Kurzke, J. , 2001, “ Some Aspects of Modeling Compressor Behavior in Gas Turbine Performance Calculations,” ASME J. Turbomach., 123(2), pp. 372–378. [CrossRef]
Tzannatos, T. , and Elder, R. , 1993, “ The Stability of Split Flow Fans,” Int. J. Turbo Jet Engines, 10(3), pp. 235–251. [CrossRef]
Filton Technical College, 1974, Gear Design Course, Bristol, UK.
van Beek, A. , 2014, “ Bearing Calculator,” Engineering-abc.com, http://www.tribology-abc.com/


Grahic Jump Location
Fig. 1

Diagrammatic arrangement of the dual drive booster

Grahic Jump Location
Fig. 2

Gear pitch circle diagram

Grahic Jump Location
Fig. 3

Graphical determination of the speed relationship

Grahic Jump Location
Fig. 4

Optimal pressure ratios

Grahic Jump Location
Fig. 5

Baseline CTF cross section

Grahic Jump Location
Fig. 7

Effects of gear ratio parameter on off-design performance

Grahic Jump Location
Fig. 6

Effects of gear ratio parameter on engine design

Grahic Jump Location
Fig. 8

Design space for component pressure ratios at constant OPR

Grahic Jump Location
Fig. 9

Booster radius design options for constant pressure ratio

Grahic Jump Location
Fig. 11

Hot-day takeoff thrust

Grahic Jump Location
Fig. 12

Dual drive booster engine cross section

Grahic Jump Location
Fig. 13

Cross section through gear system




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