Delft University of Technology
Discussion: “Beyond Brayton Cycle: It is Time to Change the Paradigm” (S. Can G€ulen,
2018, ASME J. Eng. Gas Turbine Power, 140(11), p. 111702)
Gangoli Rao, Arvind; Colonna, Piero
DOI
10.1115/1.4039832
Publication date
2018
Document Version
Final published version
Published in
Journal of Engineering for Gas Turbines and Power
Citation (APA)
Gangoli Rao, A., & Colonna, P. (2018). Discussion: “Beyond Brayton Cycle: It is Time to Change the
Paradigm” (S. Can G€ulen, 2018, ASME J. Eng. Gas Turbine Power, 140(11), p. 111702). Journal of
Engineering for Gas Turbines and Power, 140(11), [115501-1]. https://doi.org/10.1115/1.4039832
Important note
To cite this publication, please use the final published version (if applicable).
Please check the document version above.
Copyright
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons. Takedown policy
Please contact us and provide details if you believe this document breaches copyrights. We will remove access to the work immediately and investigate your claim.
This work is downloaded from Delft University of Technology.
Green Open Access added to TU Delft Institutional Repository
'You share, we take care!' - Taverne project
https://www.openaccess.nl/en/you-share-we-take-care
Otherwise as indicated in the copyright section: the publisher
is the copyright holder of this work and the author uses the
Dutch legislation to make this work public.
Discussion: “Beyond Brayton Cycle:
It is Time to Change the Paradigm”
(S. Can G€
ulen, 2018, ASME J. Eng. Gas
Turbine Power, 140(11), p. 111703)
Arvind G. Rao
1Propulsion and Power,
Delft University of Technology,
Kluyverweg 1,
Delft 2629HS, The Netherlands
e-mail: A.gangolirao@tudelft.nl
Piero Colonna
Propulsion and Power,
Delft University of Technology,
Kluyverweg 1,
Delft 2629HS, The Netherlands
Discussion
The author makes a compelling argument that the continued effort of increasing the cycle pressure ratio and TIT will hit a wall of diminishing returns, and therefore, new variations to the Brayton Cycle should be looked into, such as intercooling, reheat, and constant volume combustion [1].
The acceptable complexity for any machine is mainly deter-mined by the economic drivers and reliability constraints. In the end, the increase in efficiency achieved by the added complexity should be economically viable. With the global energy scenario
changing more rapidly than ever before due to the increase in renewable energy sources, the role of GT in the power generation business remains uncertain at the moment. Such uncertainties are not conducive to introduce radical changes in the architecture, and that is why OEMs are trying to push the current GT architecture as much as possible. Although intercooler and reheat have been applied to stationary GT in the past, the uncertainty with constant volume combustion is high.
With the arrivals of CMC and the advancements in the cooling technologies, the wall of diminishing returns for the current GT architecture seems to be pushed back. The NOxboundary is
diffi-cult to overcome; nevertheless, there are promising technologies on the horizon which could push the operating boundary even fur-ther. With renewables playing a greater role in the energy sector, parameters like startup times, off-design performance, and fuel flexibility are gaining importance as compared to maximum design efficiency. In this regard, a GT with reheat cycle is attrac-tive. However, the market did not reward the OEM that intro-duced reheat in GT, forcing the OEM to sell its assets.
The aero engine OEMs, on the other hand, have taken signifi-cant steps in their pursuit to decrease fuel consumption by intro-ducing concepts such as geared turbofan and ultra-high bypass turbofan. This drive for change is supported by the market requirements as a decrease in engine fuel consumption has a non-linear effect on the overall aircraft fuel burn. Moreover, aviation is poised to grow at approximately 5%/year for next few decades, thereby providing a stable and a long-term perspective for OEMs to take risks. Unfortunately, industrial gas turbines OEMs are fac-ing unpredictability on their role in the future energy market.
Reference
[1] G€ulen, S. C., 2018, “Beyond Brayton Cycle: It is Time to Change the Paradigm,”
ASME J. Eng. Gas Turbine Power, 140(11), p. 111703.
1
Corresponding author.
Contributed by the Cycle Innovations Committee of ASME for publication in the JOURNAL OFENGINEERING FORGASTURBINES ANDPOWER. Manuscript received February 19, 2017; final manuscript received January 19, 2018; published online October 26, 2018. Editor: David Wisler.
Journal of Engineering for Gas Turbines and Power NOVEMBER 2018, Vol. 140 / 115501-1 CopyrightVC2018 by ASME
