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Showing 1 to 20 of 49 for “"diffusion flames"”.
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Studies on counterflow diffusion flames
Certain aspects of counterflow diffusion flames are addressed in the context of one-step Arrhenius-type global chemical reaction. The general Large-activation-energy asymptotic theory for diffusion flames is first revised and then applied to one dimensional counterflow diffusion flames with finite …
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Soot formation in laminar diffusion flames
Thesis: B.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1958
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On the structure of laminar diffusion flames
The structure of laminar diffusion flames is analyzed in the limiting case of large, although finite, reaction rates. It is shown that the chemical reaction takes place only in a very thin region or "chemical boundary layer" where convection effects may be neglected. Then the temperature and mass …
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Similitude in turbulent free-jet diffusion flames
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1960.
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Soot formation in vitiated-air diffusion flames
… measured using optical techniques in dual mode diffusion flames. A dual mode flame is defined as a diffusion fuel jet that burns in the wake of a premixed flame. The premixed flame combustion products simulate a vitiated-air environment: the air is preheated, rich in radicals, and depleted in …
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Flamelet modelling of soot formation in diffusion flames
… 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 soot formation in …
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Laser diagnostics of soot in hydrocarbon diffusion flames
… to investigate the soot volume fraction in flames. However, the extinction-based technique suffers from relatively high measurement uncertainty due to a low signal-to-noise ratio, as the single-pass attenuation of the laser beam intensity is often insufficient. Multipass techniques can …
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Nitrogen oxide formation in laminar methane-air diffusion flames.
Thesis. 1975. Sc.D. cn--Massachusetts Institute of Technology. Dept. of Chemical Engineering.
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Experimental determination of strain rates in stretched laminar diffusion flames
… velocity components of hydrogen-air counterflow diffusion flames (CFDF). An axisymmetric opposed jet burner (OJB) used seeded air in one cylindrical tube, and a hydrogen-nitrogen mixture in the opposing cylindrical tube. Velocity measurements were made at four different operating flow rates, and …
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Investigation on weakly curved counterflow diffusion flames at infinitely fast chemistry
We investigate the behavior of a counterflow diffusion flame subject to a flow field comprising of a first order potential flow superimposed on a weak second order correction to the potential flow. An Arrhenius one-step irreversible reaction model at infinite Damkohler number and constant density …
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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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Flame Structure and Emissions of Strongly-Pulsed Turbulent Diffusion Flames with Swirl
… emissions of strongly-pulsed, non-premixed flames with co-flow swirl. The fuel injection is controlled by strongly-pulsing the fuel flow by a fast-response solenoid valve such that the fuel flow is completely shut off between pulses. This control strategy allows the fuel injection to be …
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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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Development of Microcombustors and Characterization of Confined Sub-Millimeter Laminar Diffusion Flames
… alpha-alumina surfaces. A laminar diffusion flame structure consisting of a column of cellular edge flames aligned in the direction of flow was discovered and is believed to be novel to the microscale. Characterization of the dynamics of this flame structure showed that the …
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Separation of the Heat Transfer Components for Diffusion Flames Impinging onto Ceilings
… the heat transfer components from a propane diffusion flame impinging onto a ceiling. A 0.3 m square sand burner with propane as the fuel type provided a steady-state fire. In the first series of experiments, measurements of gas temperature and velocity were made at 76 mm vertical intervals …
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A Study of Ion Concentration Fluctuations in Turbulent Diffusion Flames using Correlation Techniques
… equilibrium ion chemical kinetics in a turbulent diffusion flame. In such a system the charged species undergo a chemical reaction concurrently with turbulent mixing. Where the chemical reaction rate is greater than the appropriate mixing rate it has been theoretically predicted that a measurable …
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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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Effect of bromotrifluoromethane and trifluoromethane on laminar jet diffusion flames in normal and microgravity
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1996.
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Flow Visualization Study of Wake-Stabilized Diffusion Flames in a Crossflow: Effects of Crossflow Turbulence
… emissions from non-premixed wake stabilized flames from elevated stacks are investigated. In the current work, two conditions of upstream crossflow are tested to investigate the effects of turbulence on the flame, including the turbulent flow with enhanced freestream turbulence that is …
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