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 20 of 24 for “"laminar flames"”.
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A study of interactions between laminar flames and walls
… combustor was designed and optimized to support laminar, stable flame propagation at constant ambient pressure. Measurements of flame position and heat transfer during head-on quenching of premixed methane-air flames with varying mixture equivalence ratios at a metallic surface were made using …
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Numerical investigation on the effect of fuel droplets on premixed laminar flames
… applied in industry, with a particular focus on laminar premixed flames containing fuel droplets. Despite their prevalence, these flames have not been extensively studied due to challenges in measuring key parameters and discrepancies in one-dimensional numerical simulations. The present work …
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Laser induced incandescence imaging for the investigation of soot formation in laminar flames
… for calibrating other measurements in different flames.From burner setup it is possible to change the boundary temperature of the flame. It was thought that by changing this temperature it would be possible to change the soot concentration within the flame. However, using LII imaging it was shown …
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Laser diagnostic investigation of the structure of steady and driven hydrogen jet diffusion flames
The structure of hydrogen jet diffusion flames has been investigated using coherent anti-Stokes Raman scattering (CARS) and laser-induced fluorescence (LIF) to obtain temperature and nitric oxide (NO) concentrations in steady laminar flames and during the interaction of induced fuel-side vortices …
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Flamelet modelling of soot formation in diffusion flames
… 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 diffusion flames than in turbulent ones. The …
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Kinetic model reduction using integer and semi-infinite programming
… both, homogeneous combustion systems, and 2-D laminar flames. Good agreement was observed between the reaction trajectories predicted by the full mechanism and the reduced model library. For kinetic mechanisms having many more reactions than species, the computational speedup associated with …
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An Investigation of Blast Waves Generated by Constant Velocity Flames
… of blast waves from constant velocity flames were systematically studied through numerical integrations of the non-steady equations for mass, momentum, and energy. The flow was assumed to be that of an adiabatic inviscid fluid obeying the ideal gas law and the flame was simulated by a …
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DNS of inhomogeneous reactants premixed combustion
… inhomogeneous reactants. Unsteady and unstrained laminar methane-air flames are studied in one- and two-dimensional simulations to investigate the effects of normally and tangentially (to the flame surface) stratified reactants. A three-dimensional DNS of turbulent inhomogeneous reactants premixed …
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Edge-Flames and Combustion at the Microscale
… phenomena relevant to the dynamic behavior of laminar flames in devices whose critical dimensions are at or below classical quenching limits. The behavior of premixed and nonpremixed edge-flames in tune-periodic counterflows is modeled using a constant-density approximation and a single-step …
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Large eddy simulation of premixed combustion using flamelets
… address unsteady phenomena in turbulent premixed flames and to capture turbulence scales and their influence on combustion. Thus, this approach is gaining interest in industry to analyse turbulent reacting flows. In LES, the dynamics of large-scale turbulent eddies down to a cut-off scale are …
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Modelling and simulation of soot generation and transport
… model has also been developed for non-premixed laminar flames. By making use of the characteristics of the beta function, the model has been extended to turbulent flames in the pre-scribed probability density function (PDF) approach with low cost in terms of computational resources. The model …
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Quantitative measurements of temperature using laser-induced thermal grating spectroscopy in reacting and non-reacting flows
… measurements of temperature in high pressure flames using OH and NO as target absorbing species in the burned gas. The signal obtained in LITGS measurements appears in the form of a time-based signal with a characteristic frequency proportional to the value or the sound speed of the local …
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Combustion of fine magnesium particles
… screw feeder. Particles were observed to burn in laminar flames as well as in the flames with turbulence induced by a swirling air flow. Particle emission was well detectable above the flame emission background and emission pulses for individual particles were recorded using an array of three …
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Simulations of Nanoparticle Synthesis in Laminar Stagnation Flames
… solver for studying nanoparticle synthesis in laminar flames is presented. The governing equations are convective-diffusive-reactive partial differential equations that are discretised using the finite volume method. Detailed chemical source terms and transport coefficients are used to close …
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A sensor for combustion thermometry based on blue diode lasers.
… measurements have been carried out in laminar flames both by the two-line atomic fluorescence technique, and also by a novel line-shape thermometry method that requires the use of only a single diode laser. The first part of this work involved the development of blue extended cavity …
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Turbulent flame development in a high-pressure combustion vessel
… investigated, to produce a database. Turbulent flames were centrally ignited in isotropic turbulence in the Leeds fan stirred bomb. Flame progress was monitored using high-speed schlieren photography and pressure measurements. The turbulent burning velocity based on the production of burned …
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Experimental Investigation of Large Scale Aerodynamics on Soot Emissions in Swirling Flows
… (RQL) technology that employs turbulent swirling flames with downstream dilution air. These turbulent flames exhibit spatial and temporal fluctuations not present in laminar flames. This adds a level of complexity to turbulent soot studies that is yet to be fully understood. In this study, a …
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Turbulent partially premixed combustion: DNS analysis and RANS simulation
… processes in turbulent partially premixed flames. DNS data of a laboratory-scale hydrogen turbulent jet lifted flame is analysed in this study. The partially premixed nature of this flame is established by examining the instantaneous and averaged reaction rates and the "Flame Index", which …
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Numerical Modelling of Sooting Laminar Diffusion Flames at Elevated Pressures and Microgravity
Fully understanding soot formation in flames is critical to the development of practical combustion devices, which typically operate at high pressures, and fire suppression systems in space. Flames display significant changes under microgravity and high-pressure conditions as compared to …
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A Study of the Dynamics of Laminar and Turbulent Fully and Partially Premixed Flames
… reduced order models for the dynamics of laminar flat flames, swirl stabilized turbulent flames, and in evaluating the effects of the variation in fuel composition on flame dynamics. The laminar flat flame study was conducted on instrument grade methane, propane, and ethane flames for four …
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