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Combustion Characteristics of Ammonia in a Modern Spark-Ignition Engine

Vrije Universiteit Brussel-Francesco Contino
Université D'Orléans-Charles Lhuillier, Pierre BREQUIGNY, Christine Rousselle
Published 2019-10-07 by SAE International in United States
Ammonia is now recognized as a very serious asset in the context of the hydrogen energy economy, thanks to its non-carbon nature, competitive energy density and very mature production, storage and transport processes. If produced from renewable sources, its use as a direct combustion fuel could participate to the flexibility in the power sector as well as help mitigating fossil fuel use in certain sectors, such as long-haul shipping. However, ammonia presents unfavorable combustion properties, requiring further investigation of its combustion characteristics in practical systems. In the present study, a modern single-cylinder spark-ignition engine is fueled with gaseous ammonia/air mixtures at various equivalence ratios and intake pressures. The results are compared with methane/air and previous ammonia/hydrogen/air measurements, where hydrogen is used as combustion promoter. In-cylinder pressure and exhaust concentrations of selected species are measured and analyzed. Results show that ammonia is a very suitable fuel for SI engine operation, since high power outputs were achieved with satisfying efficiency by taking advantage of the promoting effects of either hydrogen enrichment or increased intake pressure, or a…
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Performance and Emissions of an Ammonia-Fueled SI Engine with Hydrogen Enrichment

Vrije Universiteit Brussel-Francesco Contino
Universite D'Orleans-Pierre BREQUIGNY, Christine Rousselle
Published 2019-09-09 by SAE International in United States
While the optimization of the internal combustion engine (ICE) remains a very important topic, alternative fuels are also expected to play a significant role in the reduction of CO2 emissions. High energy densities and handling ease are their main advantages amongst other energy carriers. Ammonia (NH3) additionally contains no carbon and has a worldwide existing transport and storage infrastructure. It could be produced directly from renewable electricity, water and air, and is thus currently considered as a smart energy carrier and combustion fuel. However, ammonia presents a low combustion intensity and the risk of elevated nitrogen-based emissions, thus rendering in-depth investigation of its suitability as an ICE fuel necessary.In the present study, a recent single-cylinder spark-ignition engine is fueled with gaseous ammonia/hydrogen/air mixtures at various hydrogen fractions, equivalence ratios and intake pressures. A small hydrogen fraction is used as combustion promoter and might be generated in-situ through NH3 catalytic or heat-assisted dissociation. The in-cylinder pressure and exhaust concentrations of selected species are recorded and analyzed. Results show that ammonia is a very suitable fuel for…
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Prediction of the PIONA and oxygenate composition of unconventional fuels with the Pseudo-Component Property Estimation (PCPE) method. Application to an Automotive Shredder Residues-derived gasoline

Vrije Universiteit Brussel-Francesco Contino
Ghent University-Steffen H. Symoens, Marko R. Djokic, Kevin M. Van Geem
Published 2018-04-03 by SAE International in United States
To check if an unconventional fuel can be burned in an engine, monitoring the stability in terms of composition is mandatory. When the composition of a conventional fuel cannot be measured for practical reason, it can be approximated using the API (American Petroleum Institute) relations (Riazi-Daubert) linking the hydrocarbon group fractions with well-chosen properties. These relations cover only the paraffin (coupling iso and normal), naphthene and aromatic (PNA) groups as they were developed for conventional fuels presenting neglected amounts of olefins and oxygenates. Olefins and oxygenates can be present in unconventional fuels. This paper presents a methodology applicable to any unconventional fuel to build a model to estimate the n-paraffin, iso-paraffin, olefin, naphthene, aromatic and oxygenate (PIONAOx) composition. The current model was demonstrated for an automotive shredder residues (ASR)-derived gasoline-like fuel (GLF). The model was trained using real fractions measured with a comprehensive two-dimensional gas chromatography coupled with flame ionization detector (GC × GC-FID) technique. The lowest cumulated absolute error comparing with the confidence interval of the measured fractions was evaluated to be 12.4%. The model was…
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Ammonia-Hydrogen Blends in Homogeneous-Charge Compression-Ignition Engine

Vrije Universiteit Brussel-Francesco Contino
Université catholique de Louvain-Maxime Pochet, Hervé Jeanmart
Published 2017-09-04 by SAE International in United States
Ammonia and hydrogen can be produced from water, air and excess renewable electricity (Power-to-fuel) and are therefore a promising alternative in the transition from fossil fuel energy to cleaner energy sources. An Homogeneous-Charge Compression-Ignition (HCCI) engine is therefore being studied to use both fuels under a variable blending ratio for Combined Heat and Power (CHP) production. Due to the high auto-ignition resistance of ammonia, hydrogen is required to promote and stabilize the HCCI combustion. Therefore the research objective is to investigate the HCCI combustion of varying hydrogen-ammonia blending ratios in a 16:1 compression ratio engine. A specific focus is put on maximizing the ammonia proportion as well as minimizing the NOx emissions that could arise from the nitrogen contained in the ammonia. A single-cylinder, constant speed, HCCI engine has been used with an intake pressure varied from 1 to 1.5 bar and with intake temperatures ranging from 428 to 473 K. Stable combustion was achieved with up to 70 %vol. ammonia proportion by increasing the intake pressure to 1.5 bar, the intake temperature to 473…
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Preliminary Implementation Study of ACHEON Thrust and Vector Electrical Propulsion on a STOL Light Utility Aircraft

Vrije Universiteit Brussel-Dean Vucinic, Anna Sunol
Nimbus SRL-Francesco Grimaccia
Published 2015-09-15 by SAE International in United States
One of the best airplanes ever realized by the European Aircraft industry was the Dornier Do 28D Skyservant, an extraordinary STOL light utility aircraft with the capability to carry up to 13 passengers. It has been a simple and rugged aircraft capable also of operating under arduous conditions and very easy and simple maintenance.The architecture of this airplane, which has operated actively for more than 20 years, is very interesting analyzing the implementation of a new propulsion system because of the unusual incorporation of two engines, as well as the two main landing gear shock struts of the faired main landing gear attached to short pylons on either side of the forward fuselage. This unconventional design allows an easy implementation of different propulsion units, such as the history of different experimental versions allowed.This paper presents the preliminary definition of an increased performance cogeneration system for optimizing the energy efficiency and maximizing the thrust of ducted fan propeller. It then produces an effective design of the ACHEON nozzle for such an aircraft, the definition of the…
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Multifunctional Unmanned Reconnaissance Aircraft for Low-Speed and STOL Operations

Vrije Universiteit Brussel-Anna Sunol, Dean Vucinic
Nimbus SRL-Alfredo Capuani, Francesco Grimaccia
Published 2015-09-15 by SAE International in United States
This paper presents a novel UAS (Unmanned Aerial System) designed for excellent low speed operations and VTOL performance. This aerial vehicle concept has been designed for maximizing the advantages by of the ACHEON (Aerial Coanda High Efficiency Orienting-jet Nozzle) propulsion system, which has been studied in a European commission under 7th framework programme.This UAS concept has been named MURALS (acronym of Multifunctional Unmanned Reconnaissance Aircraft for Low-speed and STOL operation). It has been studied as a joint activity of the members of the project as an evolution of a former concept, which has been developed during 80s and 90s by Aeritalia and Capuani. It has been adapted to host an ACHEON based propulsion system. In a first embodiment, the aircraft according to the invention has a not conventional shape with a single fuselage and its primary objective is to minimize the variation of the pitching moment allowing low speed operations. The shape with convex wings has been specifically defined to allow a future possibility of enabling stealth operations.Main objective of the design activity has been…
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Experimental Identification of the Detachment Point on the ACHEON Thrust-Vectoring Nozzle

Vrije Universiteit Brussel-Anna Suñol Jiménez, Tao Yang, Dean Vucinic
Published 2015-09-15 by SAE International in United States
Thrust vectoring is an interesting propulsion solution in aeronautic applications due to its fast response, improving aircraft's performance for take-off, landing and flight, and enabling Short/Vertical Take-Off and Landing (S/VTOL). In this context, an attempt to design a radically new concept of thrust vectoring nozzle is in current development. This novel nozzle, called ACHEON, bases the jet deviation control on the interaction of two primary jets of different velocities, where the one with higher velocity entrains the one with lower velocity. Two cylindrical walls are positioned after the two air jets mixing. If the inlet conditions are not symmetric, the Coanda effect on the walls forces the resulting air jet to divert from the symmetry axis.This paper shows the experimental pressure distribution along the Coanda wall for different inlet. Besides the generation of experimental data to be utilized for future CFD simulations validation, the obtained results provides important insights on the nozzle controllability. A first significant conclusion is that, for a certain Reynolds number, the air jet detaches at 3 discrete positions instead of offering…
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Structural Analysis of an Engine Chassis for a Disc-Shaped Airship with Thrust Vector Control

SAE International Journal of Materials and Manufacturing

Vrije Universiteit Brussel-Dean Vucinic
Modena and Reggio Emilia University-Mauro Madonia, Antonio Di Furia, Samantha Bonasia
  • Journal Article
  • 2014-01-9102
Published 2015-01-01 by SAE International in United States
This paper presents a structural analysis of an engine chassis for a disc-shaped airship demonstrator. The objective was to verify such design solutions for application in the European Union's MAAT (Multibody Advanced Airship for Transport) project.In many airship designs, the engines are attached to the airship frame, located inside the balloon, in order to allow for thrust vector control. These airships have aerodynamic control surfaces to improve maneuverability.For the demonstrator, three engines are considered, with a non-rigid internal structure for their attachment. The engines are located on a horizontal plane (the symmetry plane of the balloon), with two lateral engines and one in front of the balloon.The chassis installation allows the engines to be attached either directly to the exterior envelope by using Kevlar connections, or to the central structural pipe. This chassis design has a simple construction, compared to typical structures addressed in the literature.The structures have a kinematic device based on a servomotor, which provides the torque to tilt the engine. The critical condition is defined with the vertical wind that varies the…
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Increasing Aeronautic Electric Propulsion Performances by Cogeneration and Heat Recovery

Vrije Universiteit Brussel-Dean Vucinic
Universita di Modena e Reggio Emilia-Michele Trancossi, Antonio Dumas
Published 2014-09-16 by SAE International in United States
Emissions from aviation have become a focus of increasing interest in recent years. The growth of civil aviation is faster than nearly all other economic sectors. Increased demand has led to a higher growth rate in fossil fuels consumption by the aviation sector. Despite more fuel-efficient and less polluting turbofan and turboprop engines, the growth of air travel contributes to increase pollution attributable to aviation. Aircraft are currently the only human-made in situ generators of emissions in the upper troposphere and in the stratosphere. The depletion of the stratosphere's ozone layer by CFCs and related chemicals has underscored the importance of anticipating other potential insults to the ozone layer. Different possible solutions have been advanced to reduce the environmental impact of aviation, such as electrification of ground operations, optimization of airline timetables and airspace usage, limitation of cruise altitude and increased use of turboprop aircrafts. Those improvements seem very limited answers, which allow only marginal reduction of the environmental footprint of air transport. Breakthrough concepts such as the all-electric aircrafts must be considered. Today state…
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Towards the Use of Eulerian Field PDF Methods for Combustion Modeling in IC Engines

SAE International Journal of Engines

Vrije Universiteit Brussel-Francesco Contino
Lund University of Technology-Mehdi Jangi
  • Journal Article
  • 2014-01-1144
Published 2014-04-01 by SAE International in United States
Detailed chemistry and turbulence-chemistry interaction need to be properly taken into account for a realistic combustion simulation of IC engines where advanced combustion modes, multiple injections and stratified combustion involve a wide range of combustion regimes and require a proper description of several phenomena such as auto-ignition, flame stabilization, diffusive combustion and lean premixed flame propagation. To this end, different approaches are applied and the most used ones rely on the well-stirred reactor or flamelet assumption. However, well-mixed models do not describe correctly flame structure, while unsteady flamelet models cannot easily predict premixed flame propagation and triple flames. A possible alternative for them is represented by transported probability density functions (PDF) methods, which have been applied widely and effectively for modeling turbulent reacting flows under a wide range of combustion regimes. For IC engine simulations, the most promising ones are the Eulerian field PDF methods (SEF) whose formulation was originally proposed by Valiño and Sabel'nikov. Such models can be easily incorporated into CFD codes and are less computationally intensive with respect to Lagrangian approaches. In…
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