Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 12 of 12 for “"Turbulent flame speed"”.
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Fundamental studies of flame propagation in lean-burn natural gas engines
… characteristic time required for steady premixed flame propagation has three components: time for autoignition to occur, time for peak temperature to be achieved following autoignition, and time for steady flame propagation in the premixed fuel/air mixture to be achieved. The autoignition time …
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Turbulent flame propagation characteristics of high hydrogen content fuels
… tools to better understand the physics of turbulent flame propagation in highly stretch sensitive premixed flames in order to predict their behavior at conditions realistic to the environment of gas turbine combustors. This thesis presents the results of an experimental study into the flame …
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Propagation of large scale premixed turbulent flames
We examine premixed turbulent combustion within the context of a hydrodynamic model derived from physical first principles. This is an asymptotic model that exploits the multi-scale nature of the problem, characterized by two disparate length scales: the diffusion length scale representing the …
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Flame propagation model for the CFR engine under knocking and non-knocking conditions
… octane measurement and is often equated to the turbulent flame speed of the fuel. The objective of this project is to develop a combustion model using the turbulent flame propagation concept that can be used to study the influence of the underlying flame speed behaviour during combustion. The …
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Propagation and topology in turbulent premixed flames
… this work, the phenomenon of self-interaction in turbulent premixed flames is investigated. This refers to the self-intersection of a highly curved flame iso-surface, which leads to local annihilation at the point of intersection as the enveloped mixture is depleted. With a rise in turbulence …
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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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The structure and stability of expanding and converging near-stoichiometric flames
… stability of expanding and converging premixed flames is investigated theoretically. These configurations are inherently unsteady and represent simple examples of positively (expanding) and negatively (converging) stretched flames. A new model is employed in this study that incorporates both …
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Turbulent combustion simulation in realistic gas-turbine combustors
… using the previously proposed models Zimont Turbulent Flame Speed Closure (ZTFSC) and Extended Coherent Flamelet Method (ECFM)) is presented in a first step. Comprehensive chemical reactions containing 244 reactions and 50 species are taken into account using a tabulated detailed chemistry …
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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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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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Scalar dissipation rate based flamelet modelling of turbulent premixed flames
… 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 thesis a …