N-heptane micro pilot assisted methane combustion in a Rapid Compression Expansion Machine

Schlatter, Stéphanie; Schneider, Bruno; Wright, Yuri M.; Boulouchos, Konstantinos

doi:10.1016/j.fuel.2016.03.006

Cited by 62 publications

(60 citation statements)

References 47 publications

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“…The piston decelerates as the pressure in the combustion chamber builds up and swings back towards the equilibrium position. Within the time interval between -4 ms and 4 ms around TDC the piston motion closely follows the piston stroke of an engine running at 1200 rpm [19]. The RCEM combustion chamber has a cylindrical geometry with a flat cylinder head and virtually flat piston (2.2 mm piston bowl) ( Figure 2).…”

Section: Rapid Compression-expansion Machinementioning

confidence: 90%

“…The camera exposure time was 1 s; the lens was equipped with a 690 nm bandpass filter to suppress the flame luminosity. The aperture sizes of 1 mm and 3 mm were selected to achieve a sufficient contrast of the Schlieren images by an empirical approach, as described in [34], resulting in similar beam-divergence tolerance of the system as in other comparable studies [19,35]. Due to hardware obstructions between the piston and mirror the region closer than 22 mm to the injector orifice is not visibly accessible.…”

Section: Schlierenmentioning

confidence: 99%

“…Various aspects of dual-fuel combustion (Diesel pilot ignited) have been studied up to date in complete engines [5][6][7], single cylinder engines [8][9][10][11][12][13][14][15], optical engines [15][16][17][18] as well as rapid compression machines [19][20][21]. The approach of most of the engine experiments was to substitute part of the Diesel fuel (by reducing the injection duration) with premixed methane while monitoring the exhaust emissions and heat release rate.…”

Section: Introductionmentioning

confidence: 99%

“…Dual-fuel combustion experimental research in optically accessible test rigs mostly focused on the influence of methane on ignition Page 2 of 17 03/02/2018 delay [19][20][21], flame spreading rate [17,[19][20][21]23] and shape of the combustion front [17]. Only a few optical studies investigating incylinder dual-fuel combustion sooting propensity have been published up to date with the available data mostly limited to natural luminosity imaging [15,23] and two-color pyrometry [24].…”

Section: Introductionmentioning

confidence: 99%

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Optical Investigation of Sooting Propensity of n-Dodecane Pilot/Lean-Premixed Methane Dual-Fuel Combustion in a Rapid Compression-Expansion Machine

Srna¹,

Bruneaux²,

Rotz³

et al. 2018

SAE Int. J. Engines

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The sooting propensity of dual-fuel combustion with n-dodecane pilot injection in a lean-premixed methane-air charge has been investigated using an optically accessible Rapid Compression-Expansion Machine to achieve engine relevant pressure and temperature conditions at start of pilot injection. A Diesel injector with a 100 µm single-hole coaxial nozzle, mounted at the cylinder periphery, has been employed to admit the pilot fuel.The aim of this study was to enhance the fundamental understanding of soot formation and oxidation processes of n-dodecane in presence of methane in the air charge by parametric variation of methane equivalence ratio, charge temperature and pilot fuel injection duration. The influence of methane on ignition delay and flame extent of the pilot fuel jet has been determined by simultaneous OH* chemiluminescence and Schlieren imaging. The sooting behavior of the flame has been characterized using the 2D-DBI imaging methodology. The apparent soot black-body temperature has been measured 1D-resolved along the injector axis by applying an imaging spectrograph.Addition of methane into the air charge considerably prolongs the ignition delay with an increasing effect under less reactive conditions and with higher methane equivalence ratios. Therefore, the influence of methane on the formation of soot is two-fold: in case of short pilot injection, the presence of methane was found to decrease the soot formation due to the leaner pilot fuel mixture at time of ignition. For longer pilot fuel injections, methane enhances the soot production by decreasing oxygen availability and introducing additional carbon. In all cases, methane strongly defers the oxidation of soot due to the lower availability of oxygen.

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Section: Rapid Compression-expansion Machinementioning

confidence: 90%

Section: Schlierenmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Optical Investigation of Sooting Propensity of n-Dodecane Pilot/Lean-Premixed Methane Dual-Fuel Combustion in a Rapid Compression-Expansion Machine

Srna¹,

Bruneaux²,

Rotz³

et al. 2018

SAE Int. J. Engines

Self Cite

View full text Add to dashboard Cite

show abstract

“…Previous studies have mostly focused on global quantities, such as engine power output and emission levels [5][6][7]. Recently, several fundamental experiments have been conducted to investigate dual-fuel flame structures [8,9]. Despite these efforts, the ignition and flame development processes occurring in such a dual-fuel mixture have not been studied in sufficient details from a fundamental perspective.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of triple-flames in ignition of turbulent dual fuel mixture: A direct numerical simulation study

Jin

Luo

Wang

et al. 2019

Proceedings of the Combustion Institute

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Pilot-ignited dual fuel combustion involves a complex transition between the pilot fuel autoignition and the premixed-like phase of combustion, which is challenging for experimental measurement and numerical modelling, and not sufficiently explored. To further understand the fundamentals of the dual fuel ignition processes, the transient ignition and subsequent flame development in a turbulent dimethyl ether (DME)/methane-air mixing layer under diesel enginerelevant conditions are studied by direct numerical simulations (DNS). Results indicate that combustion is initiated by a two-stage autoignition that involves both low-temperature and hightemperature chemistry. The first stage autoignition is initiated at the stoichiometric mixture, and then the ignition front propagates against the mixture fraction gradient into rich mixtures and eventually forms a diffusively-supported cool flame. The second stage ignition kernels are spatially distributed around the most reactive mixture fraction with a low scalar dissipation rate. Multiple triple flames are established and propagate along the stoichiometric mixture, which is proven to play an essential role in the flame developing process. The edge flames gradually get close to each other with their branches eventually connected. It is the leading lean premixed branch that initiates the steady propagating methane-air flame. The time required for steady flame propagation is substantially shorter than the autoignition delay time of the methane-air mixture under the same thermochemical condition.Temporal evolution of the displacement speed at the flame front is also investigated to clarify the propagation characteristics of the combustion waves. Cool flame and propagation of triple flames are also identified in this study, which are novel features of the pilot-ignited dual fuel combustion.

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Understanding Combustion in CI Engines for Adoption of Renewable Fuels

Jena

Ágarwal

2023

Energy, Environment, and Sustainability

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N-heptane micro pilot assisted methane combustion in a Rapid Compression Expansion Machine

Cited by 62 publications

References 47 publications

Optical Investigation of Sooting Propensity of n-Dodecane Pilot/Lean-Premixed Methane Dual-Fuel Combustion in a Rapid Compression-Expansion Machine

Optical Investigation of Sooting Propensity of n-Dodecane Pilot/Lean-Premixed Methane Dual-Fuel Combustion in a Rapid Compression-Expansion Machine

Dynamics of triple-flames in ignition of turbulent dual fuel mixture: A direct numerical simulation study

Understanding Combustion in CI Engines for Adoption of Renewable Fuels

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