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Showing 1 to 12 of 12 for “"Scalar dissipation rate"”.
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Scalar dissipation rate based flamelet modelling of turbulent premixed flames
… view reliable predictions of species formation rates in the flame zone are required while from the point of view of thermo--acoustics the prediction of spatial variation of heat release rate is crucial; both tasks are challenging but imperative in CFD based design of combustion systems. In this …
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Unsteady flamelet progress variable modeling of reacting diesel jets
<p>Accurate modeling of turbulence/chemistry interactions in turbulent reacting diesel jets is critical to the development of predictive computational tools for diesel engines. The models should be able to predict the transient physical and chemical processes in the jets such as ignition and flame …
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Simulating Extinction and Blow-off in Kerosene Swirl Spray Flames
… 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 compared in detail. In comparison with experimental blow-off trends, only C5 …
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Computations of Turbulent Premixed Flames Using Conditional Moment Closure
… associated with the modelling of the conditional scalar dissipation rate (CSDR) of the conditioning scalar, the progress variable. In premixed CMC, this term is an important quantity and represents the rate of mixing at small scales of relevance for combustion. The numerical accuracy of the CMC …
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CFD Simulation of Combustion Using Automatically Reduced Reaction Mechanisms : A Case for Diesel Engine
… intermediate and minor species in order to accurately capture the flame propagation and predict pollutant formation. In current work, using n-heptane as a model Diesel fuel, a one- and two-dimensional ILDM with the CO2 and H2O as the progress variable is created. It is combined with a presumed …
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Bio-butanol fuel atomization and combustion processes
… were achieved within a narrow region of low flow rates and a non-dimensional analysis was performed in order to develop an empirical expression correlating the dimensionless average diameter, flow rate and applied voltage. Butanol non-premixed flames were studied in a counter-flow burner …
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Simulation of turbulent flames relevant to spark-ignition engines
… predict such combustion have to be 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 …
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Physical Insights of Non-Premixed MILD Combustion using DNS
Moderate or Intense Low-oxygen Dilution (MILD) combustion is a combustion technology that can simultaneously improve the energy efficiency and reduce the pollutant emissions of combustion devices. It is characterised by highly preheated reactants and a small temperature rise during combustion due …
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Extinction in turbulent swirling non-premixed flames
… mixture fraction statistics, averaged reactive scalars in both physical and mixture fraction space. The local extinction level from the increased central fuel velocity is reasonably predicted. At the experimental blow-off point, the LES/3D-CMC modelling does not obtain the occurrence of complete …
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Large eddy simulations of premixed turbulent flame dynamics : combustion modeling, validation and analysis
… onset and proposing passive and active control strategies are critical to large-scale implementation. For the numerical study of such systems, large eddy simulation (LES) techniques with appropriate combustion models and reaction mechanisms are highly appropriate. These approaches balance the …
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Predicting Soot Emissions with Advanced Turbulent Reacting Flow Modelling
… reacting flows are required, not only for accurate predictions related to flame characteristics but also to meet increasingly stringent regulations. Over the last decades, advances in the understanding of key processes controlling soot formation and oxidation have led to the development of …
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Measurements of the structure of turbulent premixed and stratified methane/air flames
… independently of the overall fuel/air flow rate. The resulting measurements of scalar and velocity fields provide detailed test cases for existing and emerging turbulent flame models, covering a range of u'/sL from 1 to 10, turbulence intensities from 5% to 60%, and stratification ratios …