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Showing 1 to 14 of 14 for “"Flame Stretch"”.
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The Influence of Preferential Diffusion On the Blow-Off of Laminar Aerated Burner Flames
The blow-off of a laminar aerated burner flame in which Hydrogen is present cannot be characterised by the flame stretch correlation proposed by Reed. A literature review has indicated that the preferential diffusion of Hydrogen towards the point of stability in the region of maximum primary flame …
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Flames in Straining Flows
… is proposed for flammability limits based on flame stretch that is applicable to upward propagation through lean methane/air mixtures in round tube. Predictions of the model are in good agreement with experiment.
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Thermal Diffusion and Flame Structure in a Laminar Hydrogen Jet Diffusion Flames
The steady, undriven flames were used to evaluate the thermal diffusion model. In addition to showing a premixed area inside the flame zone of the stabilization region, temperature and concentration measurements indicated that jet flame attachment is sensitive to nozzle and flow conditions. The …
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Effects of curvature and strain on a lean premixed methane-hydrogen-air flame
The elemental flame is a subgrid model for turbulent combustion, parameterized by time-varying strain rate and curvature. This thesis develops the unsteady one-dimensional governing equations for the elemental flame incorporating detailed chemical kinetics and transport and a robust and efficient …
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LARGE EDDY SIMULATION OF TURBULENT HYDROGEN FLAMES
… use introduces important challenges related to flame stability, strong differential diffusion effects, and increased nitrogen oxides (NOx) emissions. These issues are particularly critical in lean premixed conditions, which are commonly used to limit emissions but lead to complex …
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Laminar flame propagation in mixtures with compositional stratification at small length scales
The behavior and structure of laminar hydrocarbon flames which propagate parallel to the direction of a periodic gradient of mixture composition was studied both experimentally, using a specially designed burner, and computationally, using a planar numerical model. The variations in local mixture …
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Turbulent partially premixed combustion: DNS analysis and RANS simulation
… difficulties involve, notably issues concerning flame stability and ignitability. A partially premixed system has been introduced to remedy these problems, however, our understanding on this combustion mode needs to be greatly improved to realise its full potential. This thesis aims to further …
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Modified source-type flame model and vorticity generated by the flame and bluff bodies
… is developed to simulate the wrinkled laminar flame sheet flapping in weakly turbulent premixed combustion. The wrinkled laminar flame sheet is represented by a discrete distribution of volume sources called source disks. These source disks are utilized to produce the acceleration of combustion …
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Influences of the Darrieus-Landau instability on premixed turbulent flames
… its inventors. The instability, which prevents flames from being too flat, was thought to lead immediately to turbulent flames. Recent studies, initiated by weakly nonlinear analyses and extended by two-dimensional simulations suggest that this is not the case. It was established that the flame, …
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Fundamental studies of premixed combustion
… a fundamental study of spherical premixed flame propagation,originating at a point under both laminar and turbulent propagation. Schlieren cine photography has been employed to study laminar flame propagation, while planar mie scattering (PMS) has elucidated important aspects of turbulent …
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Experimental and theoretical studies of combustion rates at high pressure
… approaching those in engines, with emphasis on flame instabilities. To encourage the development of such instabilities, mixtures with negative Markstein numbers were employed. Three different methods were used to measure burning velocities in a spherical bomb. The bomb was fitted with windows …
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Mathematical modelling of premixed laminar methane-air flames
… laminar, stationary, axisymmetric methane-air flames, and successfully validated with non-intrusive Coherent Anti-Stokes Raman Spectroscopy (CARS) temperature measurements. With the first model, the heat releaser ate model, volumetric heat release rate was generalised from one-dimensional …
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Dynamics of premixed flames in closed vessels
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-20 without embargo terms