Numerical Study of Ignition Process in Turbulent Shear-less Methane-air Mixing Layer

EidiAttarZade, Masoud; Tabejamaat, Sadegh; Mani, Mahmoud; Farshchi, Mohammad

doi:10.1007/s10494-017-9818-x

Cited by 6 publications

(1 citation statement)

References 45 publications

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“…15 . During the transition from ( a ) to ( d ), the lift-off axially remains relatively stable due to thermal expansion that opposes to convection by the flow [53] . At the same time, the resulting burnt gases feed high-temperature reservoirs situated in external low-velocity or recirculation regions of the jet.…”

Section: Conceptual Model Of Flame Stabilizationmentioning

confidence: 99%

A conceptual model of the flame stabilization mechanisms for a lifted Diesel-type flame based on direct numerical simulation and experiments

Tagliante

Poinsot

Pickett

et al. 2019

Combustion and Flame

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conceptual model of the flame stabilization mechanisms for a lifted Diesel-type flame based on direct numerical simulation and experiments Official URL:https://doi. ABSTRACT Keywords: ONS Lifr-off length Flame stabilization Auto-ignition Triple flame Diesel combustionThis work presents an analysis of the stabilization of diffusion flames created by the injection of fuel into hot air, as found in Diesel engines. lt is based on experimental observations and uses a dedicated Direct Numerical Simulation ( ONS) approach to construct a numerical setup, which reproduces the igni tion features obtained experimentally. The resulting ONS data are then used to classify and analyze the events that allow the flame to stabilize at a certain Lift-Off Length (LOL) from the fuel injector. Both ONS and experiments reveal that this stabilization is intermittent: flame elements first auto-ignite before being convected downstream until another sudden auto-ignition event occurs closer to the fuel injec tor. The flame topologies associated to such events are discussed in detail using the ONS results, and a conceptual mode( summarizing the observation made is proposed. Results show that the main flame sta bilization mechanism is auto-ignition. However, multiple reaction zone topologies, such as triple flames , are also observed at the periphery of the fuel jet helping the flame to stabilize by filling high-temperature burnt gases reservoirs localized at the periphery, which trigger auto-ignitions.

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Section: Conceptual Model Of Flame Stabilizationmentioning

confidence: 99%

A conceptual model of the flame stabilization mechanisms for a lifted Diesel-type flame based on direct numerical simulation and experiments

Tagliante

Poinsot

Pickett

et al. 2019

Combustion and Flame

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Study of a Flame Kernel Evolution in a Turbulent Mixing Layer Using LES with a Laminar Chemistry Model

Wawrzak

Tyliszczak

2020

Flow Turbulence Combust

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Temporal evolution of an ignition kernel in a spark ignited turbulent hydrogen–air mixing layer is studied using the large eddy simulation approach with an implicit treatment of the reaction source terms. The applied numerical code is based on a high-order compact difference approximation combined with a weighted essentially non-oscillatory scheme, which provide an accurate resolution of the small scale phenomena. The spark is modelled by an energy deposition model coupled with the enthalpy equation. Since the fuel and oxidiser streams move in the opposite directions the flow is dominated by shear stresses and vortical structures. The ignition follows three different scenarios depending on the spark location. An interaction between the developing flame kernel and large turbulent structure is analysed starting from the energy transfer up to a fully reacting state. The size and shape of the flames are correlated with the initial ignition scenario. A 3D visualisation of the transient position of the flame kernel shows its different spatio-temporal behaviour. It is observed that the flame can stay close to the initial position and spread equally in all directions or it can move far from the initial location and follow the evolving flow field. In the latter scenario two separate sub-stages are convincingly identified. Concerning the ignition probability ($$P_{ign}$$ P ign ), when the spark is located in the immediate vicinity of the mixing layer, the $$P_{ign}$$ P ign on the fuel-rich side is higher. On the other hand, when the ignition occurs far from the mixing layer, the $$P_{ign}$$ P ign is significantly larger on the lean side. Unlike the local composition the impact of the strain rate of the velocity field was found to have very limited impact on the $$P_{ign}$$ P ign .

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A spark ignition scenario in a temporally evolving mixing layer

Wawrzak

Tyliszczak

2019

Combustion and Flame

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Numerical Study of Ignition Process in Turbulent Shear-less Methane-air Mixing Layer

Cited by 6 publications

References 45 publications

A conceptual model of the flame stabilization mechanisms for a lifted Diesel-type flame based on direct numerical simulation and experiments

A conceptual model of the flame stabilization mechanisms for a lifted Diesel-type flame based on direct numerical simulation and experiments

Study of a Flame Kernel Evolution in a Turbulent Mixing Layer Using LES with a Laminar Chemistry Model

A spark ignition scenario in a temporally evolving mixing layer

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