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Showing 1 to 20 of 37 for “"flamelet"”.
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Flamelet modelling of soot formation in diffusion flames
In this work the steady and unsteady flamelet models have been applied to soot formation in laminar and turbulent diffusion flames. The aim was to study how different model parameters affect soot formation in diffusion flames. It was shown that certain assumptions are more crucial in laminar …
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Studies of premixed turbulent flames under flamelet assumptions
… enhancement and area enhancement based on flamelet assumptions (’missing area’). The definition of turbulent burning velocities was revisited and re-clarified to avoid systematic error based on the conservation equation of Favre-averaged progress of reaction across the flame brush in …
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Unsteady flamelet progress variable modeling of reacting diesel jets
… first part of this work, an existing unsteady flamelet progress variable (UFPV) model is employed in Reynolds-averaged Navier-Stokes (RANS) simulations and large-eddy simulations (LES) to assess its accuracy. The RANS simulations predict that ignition occurs toward the leading tip of the jet, …
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Scalar dissipation rate based flamelet modelling of turbulent premixed flames
… ability is studied. The model is based on the flamelet concept and employs strained laminar flamelets in reactant--to--product opposed flow configuration. The flamelets are parametrised by scalar dissipation rate of progress variable which is a suitable quantity to describe the flamelet …
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Pyrolysis and Flamelet Model for Polymethyl Methacrylate in Solid Fuel Sc(ramjet) Combustors
… of pressure and high oxidizer temperatures on flamelet dynamics. The focus is on modeling the flow field with accurate chemical heat release and residence time, to better study the effects of heat flux on the solid surface and the resulting coupling. An investigation of solid fuel scramjets was …
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Application of Crossed-Plane Tomography and Stereo Particle Image Velocimetry for Three-Dimensional Analysis of Premixed Turbulent Flames
… methods have been used to measure instantaneous flamelet surface normal vectors in premixed turbulent flames to study the wrinkling of flamelet surfaces and the internal structure of the flamelet. CPLT was applied to measure flamelet orientations of premixed turbulent V-flames with increasing …
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Enabling Efficient Uncertainty Quantification of Turbulent Combustion Simulations via Kinetic Dimension Reduction
… to the entire temperature solution space of a flamelet table and can capture the mixture fraction and strain rate dependent effects of the kinetic uncertainty. The computational savings enabled by this novel framework were demonstrated through a proof-of-concept, flamelet-based application in a …
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Simulation of turbulent flames relevant to spark-ignition engines
… reliable, accurate and robust. In this work, the flamelet approach in the Reynolds-Averaged Navier- Stokes framework, is used to simulate flames relevant to spark-ignition IC engines. A central quantity in the current modelling approach is the scalar dissipation rate, which represents coupling …
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Edge-Flames in Premixed Combustion
… turbulent combustion modeling in the laminar flamelet regime.
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Analyses of Bluff Body and Swirl-Stabilised Flames Using Large Eddy Simulation
… interactions require modelling. Statistical flamelet models are a subgroup of combustion models that are computationally inexpensive, but have proven to be robust in capturing the flame stabilisation mechanisms. In this work, a presumed joint Probability Density Function (PDF) with laminar …
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Physical aspects and modelling of turbulent MILD combustion
… zones are observed. Thin reaction zones having flamelet like characteristics propagate until colliding with other thin reaction zones to produce distributed reaction zones. Also, the effect of such interacting reaction zones on scalar gradient has to be taken into account in flamelet approaches. …
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Modelling of turbulent swirling flows
… veloocities at the central axis. A combined CMC flamelet combustion model is employed alongside the anisotropic dissipation Reynolds stress model to predict the flow field and combustion related properties of the TECFLAM swirl burner. The species mass fractions are conditioned on the mixture …
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CFD modelling and validation of a large 2-stroke marine diesel engine
… Equilibrium, the Non-Premixed Steady Flamelet and the Non-Premixed Unsteady Flamelet Diesel were investigated at four engine loads (25%, 50%, 75% and 100% Maximum Continuous Revolution (MCR)). The obtained in-cylinder pressure traces were compared with the test shop data. It was proven …
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Reduced-Order Models for the Prediction of Unsteady Heat Release in Acoustically Forced Combustion
… turbulent, laminar, and the moderately turbulent flamelet regime. Particular emphasis is placed on simplification of the models to facilitate analytical solutions while still reflecting real phenomenology. Each derivation is treated by beginning with general reacting flow equations, identifying a …
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Large eddy simulation of a fuel-rich turbulent non-premixed reacting flow with radiative heat transfer
… the conserved scalar approach with the laminar flamelet model. A detailed chemical mechanism is taken into account to generate the flamelet. The turbulent combustion inside the chamber takes place under a fuel-rich condition for which the overall equivalence ratio of 1.6 is used, the same …
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Effiziente Simulation komplexer Strömungen auf semi-strukturierten Gittern
… Für die Simulation der Diffusionsflamme wird das Flamelet-Modell implementiert und Ergebnisse für verschiedene Turbulenzmodelle erzeugt. Beim KFZ-Außenspiegel wird der DES Ansatz im Vergleich zu einer URANS Simulation eingeführt. Bei beiden Testfällen wird deutlich, dass die Wiedergabe der …
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Entwicklung eines Reynolds-Spannungs-Modells zur Modellierung turbulenter Sprayflammen
… des Verbrennungsprozesses werden über das Flamelet-Modell für laminare Spraydiffusions-flammen erfasst. Hierbei liefern die Sprayflammenbibliotheken über statistische Verteilungsfunktionen des Mischungsbruchs und der skalaren Dissipationsrate die Gastemperatur und die Gemischzusammensetzung …
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Simulating Extinction and Blow-off in Kerosene Swirl Spray Flames
… Simulations in non-premixed laminar counterflow flamelet configurations are conducted at pressures of 1 atm and 10 atm for stable scalar dissipation value flamelets up to extinction, and during the extinction transient. Species trends in the three HyChem fuels and the Dagaut Jet-A1 surrogate are …
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Thermoacoustic Analysis and Experimental Validation of Statistically-Based Flame Transfer Function Extracted from Computational Fluid Dynamics
… transfer matrix approach. CFD analyses, with the Flamelet Generated Manifold (FGM) combustion model are performed and probability density functions (PDFs) of the convective time delay and local heat release rates are extracted. These are then used as inputs to the 1-D Thermoacoustic model. Results …
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LARGE EDDY SIMULATION OF TURBULENT HYDROGEN FLAMES
… combustion modeling approaches. In particular, flamelet-based models and transported probability density function (PDF) methods based on the Eulerian stochastic fields (ESF) framework are employed to capture the interaction between turbulence and chemistry. The study focuses on both premixed and …
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