The Water-Enhanced Turbofan as Enabler for Climate-Neutral Aviation

A significant part of the current aviation climate impact is caused by non-carbon-dioxide emissions, mainly nitrogen oxides (NO<sub>x</sub>) and contrails. It is, therefore, important to have a holistic view on climate metrics. Today’s conventional, but already well-developed, aero-engin...

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Main Authors: Sascha Kaiser, Oliver Schmitz, Paul Ziegler, Hermann Klingels
Format: Article
Language:English
Published: MDPI AG 2022-12-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/12/23/12431
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author Sascha Kaiser
Oliver Schmitz
Paul Ziegler
Hermann Klingels
author_facet Sascha Kaiser
Oliver Schmitz
Paul Ziegler
Hermann Klingels
author_sort Sascha Kaiser
collection DOAJ
description A significant part of the current aviation climate impact is caused by non-carbon-dioxide emissions, mainly nitrogen oxides (NO<sub>x</sub>) and contrails. It is, therefore, important to have a holistic view on climate metrics. Today’s conventional, but already well-developed, aero-engines are based on the Joule–Brayton cycle, and leave only limited room for improvement in climate impact. The revolutionary Water-Enhanced Turbofan (WET) concept represents a technical step change addressing all relevant emissions by implementing the Cheng cycle, which combines the gas turbine cycle with a Clausius–Rankine steam cycle. This paper builds upon previous publications regarding the WET concept, and outlines the evolution since then. Promising WET configurations are evaluated according to their ability to reduce global warming potential compared to an evolutionarily advanced turbofan engine. A quantitative approach to estimate reduction of NO<sub>x</sub> emissions through steam injection is presented. The impact on the creation of contrails is considered using the Schmidt-Appleman criterion. In conclusion, all three climate-relevant emissions can be reduced with the WET concept compared to a technologically similar turbofan in terms of CO<sub>2</sub> (up to 10%), NO<sub>x</sub> (more than 90%), and contrails (more than 50%). The resulting in-flight climate impact can be reduced by more than 40% when using fossil kerosene, paving the way to climate-neutral aviation.
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spelling doaj.art-aca303a1e4ea44308112f207432830832023-11-24T10:36:24ZengMDPI AGApplied Sciences2076-34172022-12-0112231243110.3390/app122312431The Water-Enhanced Turbofan as Enabler for Climate-Neutral AviationSascha Kaiser0Oliver Schmitz1Paul Ziegler2Hermann Klingels3MTU Aero Engines AG, Dachauer Str. 665, 80995 Munich, GermanyMTU Aero Engines AG, Dachauer Str. 665, 80995 Munich, GermanyMTU Aero Engines AG, Dachauer Str. 665, 80995 Munich, GermanyMTU Aero Engines AG, Dachauer Str. 665, 80995 Munich, GermanyA significant part of the current aviation climate impact is caused by non-carbon-dioxide emissions, mainly nitrogen oxides (NO<sub>x</sub>) and contrails. It is, therefore, important to have a holistic view on climate metrics. Today’s conventional, but already well-developed, aero-engines are based on the Joule–Brayton cycle, and leave only limited room for improvement in climate impact. The revolutionary Water-Enhanced Turbofan (WET) concept represents a technical step change addressing all relevant emissions by implementing the Cheng cycle, which combines the gas turbine cycle with a Clausius–Rankine steam cycle. This paper builds upon previous publications regarding the WET concept, and outlines the evolution since then. Promising WET configurations are evaluated according to their ability to reduce global warming potential compared to an evolutionarily advanced turbofan engine. A quantitative approach to estimate reduction of NO<sub>x</sub> emissions through steam injection is presented. The impact on the creation of contrails is considered using the Schmidt-Appleman criterion. In conclusion, all three climate-relevant emissions can be reduced with the WET concept compared to a technologically similar turbofan in terms of CO<sub>2</sub> (up to 10%), NO<sub>x</sub> (more than 90%), and contrails (more than 50%). The resulting in-flight climate impact can be reduced by more than 40% when using fossil kerosene, paving the way to climate-neutral aviation.https://www.mdpi.com/2076-3417/12/23/12431climate impactNO<sub>x</sub> emissionscontrailswater-enhanced turbofanemission reductionfuel burn
spellingShingle Sascha Kaiser
Oliver Schmitz
Paul Ziegler
Hermann Klingels
The Water-Enhanced Turbofan as Enabler for Climate-Neutral Aviation
Applied Sciences
climate impact
NO<sub>x</sub> emissions
contrails
water-enhanced turbofan
emission reduction
fuel burn
title The Water-Enhanced Turbofan as Enabler for Climate-Neutral Aviation
title_full The Water-Enhanced Turbofan as Enabler for Climate-Neutral Aviation
title_fullStr The Water-Enhanced Turbofan as Enabler for Climate-Neutral Aviation
title_full_unstemmed The Water-Enhanced Turbofan as Enabler for Climate-Neutral Aviation
title_short The Water-Enhanced Turbofan as Enabler for Climate-Neutral Aviation
title_sort water enhanced turbofan as enabler for climate neutral aviation
topic climate impact
NO<sub>x</sub> emissions
contrails
water-enhanced turbofan
emission reduction
fuel burn
url https://www.mdpi.com/2076-3417/12/23/12431
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