Download or read book An Investigation of Structure and Radiation Properties of Turbulent Buoyant Diffusion Flames written by San-Mou Jeng and published by . This book was released on 1984 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Investigation of Axisymmetric Buoyant Turbulent Diffusion Flames written by S-M. Jeng and published by . This book was released on 1984 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Investigation of Axisymmetric Buoyant Turbulent Diffusion Flames written by S-M. Jeng and published by . This book was released on 1982 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: This investigation considered measurements of the structure of axisymmetric, buoyant, turbulent diffusion flames in still air. Profiles of mean temperature, mean velocity, velocity fluctuations and total radiant heat flux were completed for methane flames, including careful characterization of burner exit conditions, in order to provide data for the evaluation of models of the process. Preliminary tests also provided mean temperature profiles for propane flames. Test conditions were chosen so that the flow was turbulent near the burner exit while effects of buoyancy were significant over most of the luminous portion of the flames. Both the present measurements and those of other investigators were compared with predictions of a k-E-g differential model, which included effects of buoyancy in the transport equations for turbulence quantities. The results indicated anisotropic effects in regions where buoyancy dominates flow properties suggesting the eventual desirability of multi-stress models for buoyant flames, although extensive recalibration of model constants from a limited data based would be required if this step were taken. Additional measurements and analysis of methane flames are in progress, in order to investigate the flame radiation properties and provide additional data on turbulence properties needed for model development.

Download or read book Radiation from Turbulent Nonluminous and Luminous Diffusion Flames written by United States. National Bureau of Standards and published by . This book was released on 1987 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: A theoretical and experimental study of the structure and radiation properties of turbulent buoyant diffusion flames is described. The results have application to modeling fires within structures, materials test methods, fire detection, and effects of materials on fire properties. The investigation consists of two phases, as follows: study of effects of turbulence/radiation interactions, considering the properties of nonluminous hydrogen/air diffusion flames; and study of extension of the laminar flamelet concept to soot properties needed to predict radiation from luminous acetylene/air and ethylene/air turbulent diffusion flames. Theory and experiment are considered in both phases of the investigation. Measurements in turbulent hydrogen/air diffusion flames yielded radiation fluctuation intensities of 20-110 percent, providing direct evidence of the importance of turbulence/radiation interactions. A stochastic analysis, based on the laminar flamelet concept, was developed which provided encouraging predictions of mean and fluctuating spectral radiation intensities (average discrepancies between predictions and measurements were roughly 30 percent), as well as temporal power spectral densities of radiation fluctuations. The temporal spectra exhibit energy-containing and inertial regions, very similar to other turbulence properties, although the rate of decay of the spectra with increasing frequency in the inertial region is somewhat greater than observed for scalar fluctuations. Measurements and predictions in the turbulent luminous flames concentrated on scalar properties (particularly soot volume fractions) in the overfire region. Predictions of scalar properties based on the laminar flamelet concept were very encouraging. Direct evaluation of soot volume fraction state relationships for the overfire region was hampered by effects of turbulent fluctuations and experimental uncertainties; nevertheless, within these limitations, soot volume fraction state relationships were nearly universal, and soot generation efficiencies nearly constant, for sufficiently long residence times. However, effects of finite-rate chemistry were noted for short residence time ethylene/air flames, causing spatial variations of soot generation efficiencies in the overfire region. For long residence times, present measurements of soot generation efficiencies were in reasonably good agreement with earlier findings for acetylene/air and ethylene/air diffusion flames.

Download or read book STRUCTURE AND RADIATION PROPERTIES OF TURBULENT DIFFUSION FLAMES FLAMES written by MICHAEL EMMANUEL KOUNALAKIS and published by . This book was released on 1990 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: scales. (Abstract shortened with permission of author.)

Download or read book Structure and Radiation Properties of Turbulent Diffusion Flames written by Y. R. Sivathanu and published by . This book was released on 1990 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: Generalized state-relationship correlations, giving the mass fractions of major gas species as functions of local fuel-equivalence ratios, were developed for hydrocarbon/air diffusion flames. Instantaneous soot volume fractions and temperatures were measured in the fuel-rich (underfire) region of turbulent nonpremixed acetylene, propylene, ethylene and propane flames burning in still air. The continuum radiation properties of the underfire region of luminous acetylene and propylene flames burning in still air were studied.

Download or read book Mixing and Radiation Properties of Buoyant Luminous Flame Environments written by and published by . This book was released on 1996 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: Study investigates the radiation and mixing properties of buoyant turbulent diffusion flames, specifically the optical and radiative properties of soot and the structure and mixing properties of buoyant turbulent plumes.

Download or read book Radiation and Mixing Properties of Buoyant Turbulent Diffusion Flames written by Z. Dai and published by . This book was released on 1993 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two aspects of unwanted fires were considered: (1) the optical properties of soot in the fuel-lean region of buoyant turbulent diffusion flames, and (2) the structure and mixing properties of buoyant turbulent plumes. The scattering, absorption and extinction properties of soot were measured for conditions where soot structure was known from earlier transmission electron microscopy measurements. The measurements were compared with predictions based on the Rayleigh-Debye-Gans (RDG) scattering approximation for polydisperse fractal aggregates.

Download or read book Structure and Radiation Properties of Luminous Turbulent Acetylene air Diffusion Flames written by J. P. Gore and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mixing and Radiation Properties of Buoyant Turbulent Diffusion Flames written by Building and Fire Research Laboratory (U.S.) and published by . This book was released on 1995 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: Present measurements emphasized self-preserving conditions far from the source where effects of source momentum and other source disturbances have been lost. The results show that earlier measurements in the literature were not carried out at sufficient distances from the source to reach self-preserving conditions, and provide measured properties at self-preserving conditions needed to develop and evaluate higher-order models of buoyant turbulent flows. The measurements were used to evaluate a simple k-E-g turbulence model finding good agreement between measured and predicted mean velocities and mixture fractions based on standard turbulence model constants, which is not unusual for a simple classical flow like the self-preserving buoyant turbulent plume.

Download or read book A Theoretical Study of Flow Structure and Radiation for Multiphase Turbulent Diffusion Flames written by Chin Feng Chern and published by . This book was released on 1989 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present technical report summarizes the progress made in considering thermal radiation in the analysis of multiphase turbulent flow structure of a halogen gas jet reacts with a liquid metal. The reaction of a halogen gas jet submerged in an alkali liquid metal fuel forms a complex diffusion flame. The flame is turbulent and multiphase in nature and its temperature is relatively high. The purpose of this study is to account for thermal radiation and the radiation/turbulent interaction in analyzing such a diffusion flame structure. A method is hereby proposed to consider the turbulence-radiation interaction in the analysis of a multiphase diffusion flame. Application is made to study the reaction of a halogen gas jet submerged in a alkali liquid fuel bath. The analysis makes use of a k-epsilon-g turbulence model, a local homogeneous two-phase model, a chemical equilibrium combustion model, a probabilistic approach and a radiation model compatible with mixture fraction fluctuation. The equilibrium state relationships for instantaneous properties, required for mean scalar property predictions and structure analysis of the reacting jet, have been generated. The energy equation containing the radiative source term has been solved simultaneously with the FAvre-averaged transport equations. (jhd).

Download or read book Mixing and Radiation Properties of Buoyant Turbulent Diffusion Flames September 1 1993 August 31 1994 written by and published by . This book was released on 1955 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aviation Fuels with Improved Fire Safety written by National Research Council and published by National Academies Press. This book was released on 1997-09-18 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reduction of the fire hazard of fuel is critical to improving survivability in impact-survivable aircraft accidents. Despite current fire prevention and mitigation approaches, fuel flammability can overwhelm post-crash fire scenarios. The Workshop on Aviation Fuels with Improved Fire Safety was held November 19-20, 1996 to review the current state of development, technological needs, and promising technology for the future development of aviation fuels that are most resistant to ignition during a crash. This book contains a summary of workshop discussions and 11 presented papers in the areas of fuel and additive technologies, aircraft fuel system requirements, and the characterization of fuel fires.

Download or read book Publications of the National Institute of Standards and Technology 1988 Catalog written by Rebecca J. Pardee and published by . This book was released on 1989 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Investigation of the Structure of Turbulent Diffusion Flames written by Jan H. Andersen and published by . This book was released on 1991 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NBS Special Publication written by and published by . This book was released on 1968 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mixing and Radiation Properties of Buoyant Luminous Flame Environments written by Z. Dai and published by . This book was released on 1995 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: In addition, dimensionaless extinction coefficients and the soot fractal dimensions were measured. The structure and mixing properties of buoyant turbulent plumes were investigated by examination of the effects of coflow on earlier measurements and by evaluating various modeling approximations, with an emphasis on self-preserving round buoyant turbulent plumes.