Research Papers: Gas Turbines: Aircraft Engine

Performance Investigation of Cycle-Integrated Parallel Hybrid Turboshafts

[+] Author and Article Information
Patrick C. Vratny

Bauhaus Luftfahrt e.V.,
Willy-Messerschmitt-Straße 1,
Taufkirchen 82024, Germany
e-mail: patrick.vratny@bauhaus-luftfahrt.net

Sascha Kaiser

Bauhaus Luftfahrt e.V.,
Willy-Messerschmitt-Straße 1,
Taufkirchen 82024, Germany
e-mail: sascha.kaiser@bauhaus-luftfahrt.net

Arne Seitz

Bauhaus Luftfahrt e.V.,
Willy-Messerschmitt-Straße 1,
Taufkirchen 82024, Germany
e-mail: arne.seitz@bauhaus-luftfahrt.net

Stefan Donnerhack

MTU Aero Engines AG,
Dachauerstrasse 665,
Munich 80995, Germany
e-mail: stefan.donnerhack@mtu.de

Contributed by the Aircraft Engine Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received June 22, 2016; final manuscript received July 18, 2016; published online September 27, 2016. Editor: David Wisler.

J. Eng. Gas Turbines Power 139(3), 031201 (Sep 27, 2016) (9 pages) Paper No: GTP-16-1265; doi: 10.1115/1.4034498 History: Received June 22, 2016; Revised July 18, 2016

Motivated by the long-term target settings for research and innovation in Europe and in North America, initial investigations of parallel hybrid electric power plant systems have indicated significant in-flight fuel reduction potentials for short range air transport. Based on this topology, a special variant, namely the cycle-integrated parallel hybrid (CIPH), has been investigated. In this special configuration, electric motors supplied by batteries are powering an array of compressor stages of a power plant that are mechanically decoupled from the turbine section. The potentials with regard to in-flight fuel reduction and efficiency improvement of this concept are derived for a 12-ton-helicopter accommodating 19 passengers on a 450 nm mission. For the presented CIPH concept, the axial compressor section of a baseline turboshaft (TS) delivering a maximum shaft power of 3300 kW is electrified with the help of linear electric motors (LEMs). The highest potential for this arrangement was identified in part load for moderate degrees of power hybridization—the share between installed electric power and total power—of around 20%. The first assessment has revealed that this additional degrees-of-freedom allows to almost double the overall efficiency, compared to a conventional power with same technology time horizon, and a reduction in power-specific fuel consumption (PSFC) of roughly 45%. The range capability of a hybrid-powered helicopter has been decreased by more than 50%, mainly driven by the battery mass. However, a fuel burn, and thus, in-flight CO2 reduction of more than 40% against the reference at decreased mission range have been found.

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Fig. 1

Common topologies in hybrid electric vehicles with a battery supplied electrical chain: (a) serial hybrid, (b) parallel hybrid, and (c) serial–parallel hybrid

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Fig. 2

Schematic illustration of the possible impact adding electric energy to the engine cycle

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Fig. 3

Simplified sketch of the used electric power architecture (in total, six electric motors per engine)

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Fig. 4

Conceptual example for the integration of a linear electric motor drive on a fan rotor taken from Ref. [17]

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Fig. 5

Schematic configuration of the simulated hybrid electric turboshaft power plant

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Fig. 6

Simplified flow path sketch of the hybrid electric turboshaft with counter rotating axial compressor featuring linear electric motor drive

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Fig. 7

Impact of different off-design degrees of hybridization in part load at ISA, SL on the overall efficiency and power-specific fuel consumption

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Fig. 8

Impact of different off-design hybrid ratios on the electric counter rotating compressor performance. Map based on Ref. [26].

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Fig. 9

Mass comparison of the reference helicopter and the CIPH helicopter at the 220 nm mission



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