Download or read book Effects of Elliptic Co flow on the Structure of a Turbulent Diffusion Flame written by Sayela P. Luna and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Inert Gases and Flow Velocities on the Structure and Stability of Coflow Diffusion Flames written by Daniel Tomio Souza and published by . This book was released on 2021 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: A deeper understanding of flame stabilization and extinguishing mechanisms is necessary in developing the next generation of flame suppressants. In order to understand the effects of inert gases on coflow diffusion flames, a 28-mm diameter cup burner was used to generate methane and propane coflow diffusion flames. The measured minimum extinguishing concentration of N2 added to the coflow air was 28.5 +/- 0.05 % and 34.0 +/- 0.07 % for methane and propane, respectively, and those for CO2 were 17.2 +/- 0.12 % and 22.4 +/- 0.06 %, respectively. Silica-coated, 50-um R-type thermocouples were used to measure temperature in the flames as N2 or CO2 was added to the coflow air. Thin filament pyrometry technique using a 15-um SiC fiber was also applied in an attempt to measure the temperature of the inert gas-added flames. For calibrations of the temperature measurements, a 25.4-mm x 25.4-mm Hencken burner was used to produce a near-adiabatic initially unmixed methane flame. In addition to the thermal flame structure measurements, the stability limits of laminar jet diffusion flames were measured for various fuels (methane, ethane, ethylene, acetylene propane, butane, and 1-butene) to further elaborate the effects of flow velocities on diffusion flame stabilization and extinguishing mechanisms. Through these experimental techniques, the temperature effects of inert gases on coflow diffusion flames were observed and factors leading to instability in laminar jet diffusion flames were identified.

Download or read book Flame Structure and Emissions of Strongly pulsed Turbulent Diffusion Flames with Swirl written by Ying-Hao Liao and published by . This book was released on 2012 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work studies the turbulent flame structure, the reaction-zone structure and the exhaust 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 controlled over a wide range of operating conditions, allowing the flame structure to range from isolated fully-modulated puffs to interacting puffs to steady flames. The swirl level is controlled by varying the ratio of the volumetric flow rate of the tangential air to that of the axial air. For strongly-pulsed flames, both with and without swirl, the flame geometry is strongly impacted by the injection time. Flames appear to exhibit compact, puff-like structures for short injection times, while elongated flames, similar in behaviors to steady flames, occur for long injection times. The flames with swirl are found to be shorter for the same fuel injection conditions. The separation/interaction level between flame puffs in these flames is essentially governed by the jet-off time. The separation between flame puffs decreases as swirl is imposed, consistent with the decrease in flame puff celerity due to swirl. The decreased flame length and flame puff celerity are consistent with an increased rate of air entrainment due to swirl. The highest levels of CO emissions are generally found for compact, isolated flame puffs, consistent with the rapid quenching due to rapid dilution with excess air. The imposition of swirl generally results in a decrease in CO levels, suggesting more rapid and complete fuel/air mixing by imposing swirl in the co-flow stream. The levels of NO emissions for most cases are generally below the steady-flame value. The NO levels become comparable to the steady-flame value for sufficiently short jet-off time. The swirled co-flow air can, in some cases, increase the NO emissions. The elevated NO emissions are due to a longer combustion residence time due to the flow recirculation within the swirl-induced recirculation zone. The reaction zone structure, based on OH planar laser-induced fluorescence (PLIF) is broadly consistent with the observation of luminous flame structure for these types of flames. In many cases, the reaction zone exhibits discontinuities at the instantaneous flame tip in the early period of fuel injection. These discontinuities in the reaction zone likely result from the non-ignition of injected fuel, due to a relatively slower reaction rate in comparison with the mixing rate. The discontinuity in the OH zone is generally seen to diminish with increased swirl level. Statistics generated from the OH PLIF signals show that the reaction zone area generally increases with increased swirl level, consistent with a broader and more convoluted OH-zone structure for flames with swirl. The reaction zone area for swirled flames generally exhibits a higher degree of fluctuation, suggesting a relatively stronger impact of flow turbulence on the flame structure for flames with swirl.

Download or read book The Effect of Pressure and Fuel Structure on the Soot Yield of a Turbulent Diffusion Flame in a Crossflow written by Bruce Tobis and published by . This book was released on 1983 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings of the Engineering Technology Conference on Energy written by and published by . This book was released on 2001 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turbulent Diffusion Flame Structure and Implications for Suppression and Pollutant Formation written by R. W. Bilger and published by . This book was released on 1975* with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of Strain Rate on the Temperature Field Structure in a Turbulent Non premixed Flame Using Planar Rayleigh Scattering written by David Alan Everest and published by . This book was released on 1994 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Pressure on Structure and NOx Formation in CO Air Diffusion Flames written by Howard G. Maahs and published by . This book was released on 1979 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Pressure on Structure and NO Sub X Formation in CO air Diffusion Flames written by and published by . This book was released on 1979 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Nonaxisymmetric Co flow on Diffusion Flames written by Parveen Luna Sayela and published by . This book was released on 2001 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Investigation Into the Relationship Between the Total Soot Yield the Flow Properties and the Structure of a Propane Diffusion Flame in Cross flow written by David W. Turner and published by . This book was released on 1991 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Turbulent Structure and NOx CO Emissions of Strongly pulsed Turbulent Diffusion Flames written by Pei-Ying Tsai and published by . This book was released on 2005 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Joint Meeting of the U S Sections of the Combustion Institute Western States Central States Eastern States written by and published by . This book was released on 1999 with total page 954 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Varied Air Flow on Flame Structure of Laminar Inverse Diffusion Flames written by Mark Alexander Mikofski and published by . This book was released on 2004 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Combined Effects of Dilution and Co flow on the Stability of Lifted Non premixed Gaseous Flames written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This research documents experiments and analysis of turbulent, lifted, non-premixed diffusion flames in co-flow and with dilution with implications for the development and operation of biogas-fueled combustors. Fuels used in this study were methane and ethylene. The diluent used was nitrogen. General trends were observed in the liftoff and reattachment behavior as affected by dilution of the fuel stream. Initial liftoff velocity was observed to decrease linearly with dilution, while initial lift height behavior was bimodal. Reattachment conditions were similar in overall behavior to liftoff conditions. Co-flow effects were not included in liftoff and reattachment studies. Combined effects of dilution and co-flow were also studied. Stabilization height compared to radial stabilization was found to be bimodal, with behavior differing in the potential core region compared with the far-field region. Dilution was found to decrease the radial stabilization distance, and co-flow tended to increase the radial stabilization distance. However, both effects were minor. The major results involve heat release effects. For given stabilization heights, stabilization velocity was found to decrease with dilution faster than laminar burning velocity with dilution. Stabilization height was also found to increase rapidly with dilution beyond a certain diluent concentration. Flames were also found to taper inward and become more cylindrical in shape as dilution increases. Implications for several flame stabilization theories are discussed. Future work for confirming the results of this research are also discussed.

Download or read book Turbulent Jet Flames Into a Vitiated Coflow written by Ricardo Cabra and published by . This book was released on 2003 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt: