Download or read book Theoretical and Experimental Studies on the Hygroscopic Properties of Soot Particles Sampled from a Kerosene Diffusion Flame written by Junteng Wu and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Freshly emitted soot particles from combustion processes are hydrophobic. However, the aging process in the atmosphere can modify their size, morphology and surface chemistry and turn them into efficient cloud condensation (CCN) and ice nuclei (IN) that significantly contribute to the indirect radiative forcing of climate. For spherical and monodisperse aerosols, k-Köhler theory is often used in the literature to quantify the hygroscopic properties of aerosols. In this work, a combined theoretical and experimental approach is proposed to add to the theory the contributions of the particle size distribution and morphology. Hygroscopic properties of the particles are derived by measuring their activated fraction as a function of the water supersaturation using a CCN counter. The model developed in this work is first tested on dry ammonium sulfate particles (quasi spherical and non aggregating). Then, it is applied to soot particles that are complex aggregates of primary particles. Soot particles are generated from a laboratory diffusion jet flame supplied with kerosene, and aged with ozone and sulfur dioxide in controlled conditions of temperature, pressure and relative humidity to simulate their permanence in the atmosphere. The electrical mobility, morphology and chemical composition of fresh and aged soot are measured by scanning mobility particle sizing, electron microscopy and secondary ion mass spectrometry, respectively, before and after the aging and related to the activation process. From the comparison of the experimental activation curves and the model, the values of the hygroscopicity parameter k could be determined for a large variety of operating conditions.

Download or read book Soot in Combustion Systems and Its Toxic Properties written by J. Lahaye and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our interest in Mulhouse for carbon black and soot began some 30 years ago when J.B. Donnet developed the concept of surface chemistry of carbon and its involvement in interactions with gas, liquid and solid phases. In the late sixties, we began to study soot formation in pyrolytic systems and later on in flames. The idea of organ1z1ng a meeting on soot formation originated some four or five years ago, through discussions among Professor J.B. Howard, Dr. A. D'Alessio and ourselves. At that time the scientific community was becoming aware of the necessity to strictly control soot formation and emission. Being involved in the study of surface properties of carbon black as well as of formation of soot, we realized that the combustion community was not always fully aware of the progress made by the physical-chemists on carbon black. Reciprocally, the carbon specialists were often ignoring the research carried out on soot in flames. One objective of this workshop was to stimulate discussions between these two scientific communities. During the preparation of the meeting, and especially during the review process by the Material Science Committee of the Scientific Affairs Division of N.A.T.O. the toxicological aspect emerged as being an important component to be addressed during the workshop. To reflect these preoccupations we invited biologists, physical chemists and engineers, all leaders in their field. The final programme is a compromise of the different aspects of the subject and was divided in five sessions.

Download or read book The Evolution of Soot Morphology in Laminar Co Flow Diffusion Flames of the Surrogates for Jet A 1 and a Synthetic Kerosene written by Mohammad Reza Kholghy and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Soot Particles Size and Concentration Determination from a Kerosene Gaseous Oxygen Rocket Plume written by Silvino Silva and published by . This book was released on 1998-12-01 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation was conducted to measure soot properties and concentration, and infrared signature of the plume of a kerosene/ gaseous oxygen rocket motor. Multiple-wavelength measurements were used to obtain soot parameters. It was found that the multiple-wavelength technique appeared to work well for obtaining soot properties and concentration. The results implied that the soot particulate was very porous for the most fuel-rich conditions and became more compact as the 0/F ratio increased.

Download or read book Soot Formation in Combustion written by Henning Bockhorn and published by Springer Science & Business Media. This book was released on 2013-03-08 with total page 595 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soot Formation in Combustion represents an up-to-date overview. The contributions trace back to the 1991 Heidelberg symposium entitled "Mechanism and Models of Soot Formation" and have all been reedited by Prof. Bockhorn in close contact with the original authors. The book gives an easy introduction to the field for newcomers, and provides detailed treatments for the specialists. The following list of contents illustrates the topics under review:

Download or read book A Fundamental Study of Soot Formation in Diffusion Flames written by Richard L. Axelbaum and published by . This book was released on 1988 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fuel Structure and Pressure Effects on the Formation of Soot Particles in Diffusion Flames written by Robert J. Santoro and published by . This book was released on 1990 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies emphasizing the effects of fuel concentration and operating pressure on the formation of soot particles have been conducted in a series of laminar diffusion flames. These experiments have shown that fuel concentration has a measurable effect on the amount of soot formed in the flame. However, a simple, constant proportionality between the fuel concentration and soot volume fraction has not been found to apply for the range of flow conditions studied. This observation is believed to be a result of flame residence time and diffusion effects which mitigate the consequences of reduced initial fuel concentration. Comparisons with simple laminar diffusion flame models are currently being used to investigate the relationship between initial fuel concentration and local flame concentration fields. Similar studies of soot formation in laminar diffusion flames as a function of operating pressure have also been completed for ethene, ethane and propene fuel species. Keywords: Soot formation, Soot particles, Diffusion flames. (JES).

Download or read book Detailed Studies of Soot Formation in Laminar Diffusion Flames for Application to Modeling Studies written by and published by . This book was released on 1993 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation of soot formation in laminar diffusion flames has shown that soot particle surface growth under laminar diffusion flame conditions ceases because of the depletion of hydrocarbon species, in particular acetylene and benzene, and not due soot particle reactivity loss due to thermal aging of the particles. This results has been obtained through direct species concentration measurements under well controlled conditions while the particle reactivity effects were calculated based on premixed flame results along with particle temperature/time information available from earlier laminar diffusion flame studies. Comparisons with a soot formation model which incorporated detailed chemistry effects showed good agreement in terms of predicted and measured species concentration and soot particle field evolution. In addition, a novel technique for measuring soot volume fraction has been developed based on laser-induced incandescence and applied to similar laminar diffusion flame, studies with good success. This technique represents a major development in terms of its ability to make soot volume fraction measurements in unsteady inhomogeneous combusting flows. Soot formation, Soot particles, Diffusion flames.

Download or read book Soot Growth in Laminar Premixed Flames written by Fang Xu and published by . This book was released on 1999 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental Study of the Processes Involved in the Formation of Soot Particles in Diffusion Flames written by Uri Vandsburger and published by . This book was released on 1986 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental and Numerical Studies on the Soot Formation of Liquid Fuel Relevant Compounds written by Tongfeng Zhang and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the present thesis, fundamental experimental and numerical studies are performed for the soot formation of liquid fuel relevant compounds. The thesis is composed of four research studies. The first develops an improved data analysis approach for the combined laser extinction and two-angle elastic light scattering diagnostics to relate the various measured optical cross sections to soot aggregate properties. Compared to previously reported studies, the proposed approach can be applied to a wider range of soot sources by removing the assumption made to scattering regime or moment ratio of aggregate size distribution. The second study investigates the effects of n-propylbenzene addition to n-dodecane on soot formation and aggregate structure in a laminar coflow diffusion flame using the combined laser extinction and two-angle elastic light scattering method. It is shown that the relative importance of soot inception and surface growth affected by n-propylbenzene addition is different along the flame wing and centerline, with the aromatic fuel chemistry effect being stronger along the centerline. The third study extends the investigation on the same issue using a numerical model. The simulation results show that mixing n-propylbenzene into the liquid fuel mixture accelerates soot inception, and increases soot surface growth per unit surface area by PAH addition, while soot surface growth per unit surface area by HACA is shown to decrease modestly with n-propylbenzene addition. The fourth and final study investigates the soot formation from jet fuel in a laminar coflow diffusion flame using both numerical and experimental methods. The results demonstrate the robustness of the soot model to changes of fuel and also show that the HyChem model (i.e., lumped fuel breakdown approach, Xu et al., 2017) can be used to predict soot formation from real jet fuel combustion in laminar coflow diffusion flames by adding a PAH growth scheme to the model.

Download or read book Surface Reactivity of Combustion Generated Soot Particles written by and published by . This book was released on 1994 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: The focus of this AASERT grant was the development of two novel measurement approaches for soot property characterization: laser-induced incandescence and intrusive probe sampling of soot particles from diffusion flames. Characterization of the laser-induced incandescence technique for soot particle measurements in laminar diffusion flames resulted in the development of a new quantitative measurement technique for soot volume fraction and marked the first use of this technique for quantitative measurements. In particular, the relationship between laser fluence and the temporal character of the laser-induced incandescence signal was carefully examined and documented. Based on the laminar flame work, the technique was extended to soot particle measurements in turbulent diffusion, spray and droplet flames with similar quantitative results. Concurrently, an intrusive probe sampling system to collect soot particles from laminar diffusion flames was developed. This sampling system provided collection sample sizes up to 2 grams of soot. Large soot samples were required to allow for appropriate surface area characterization which was conducted using a BET measurement approach. jg p1.

Download or read book Experimental and Numerical Studies for Soot Formation in Laminar Coflow Diffusion Flames of Jet A 1 and Synthetic Jet Fuels written by Meghdad Saffaripour and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental and Numerical Contributions to Soot Production in Laminar Axisymmetric Diffusion Flames written by Felipe Andrés Escudero Barros and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was performed with the main objective of characterizing soot production for different oxygen indices (OIs) in normal (NDFs) and inverse (IDFs) diffusion flames. Specific absorption-emission based methods were developed, implemented and validated to measure soot volume fraction and temperature. It was found that for IDFs, an increase on the OI produces an enhancement of soot formation but does not affect oxidation processes, leading to an increase on soot volume fraction and radiant fraction. In addition, a scaling analysis based on the smoke point (SP) resulted on a unified behavior for ethylene, propane and butane fueled NDFs in terms of flame height, soot volume fraction and radiant fraction at SP. In a second step, a numerical study was performed with the main objective of evaluating the predictive capabilities of the sectional method (SM) and three methods of moments (MOMs) for the resolution of the population balance equation (PBE) for soot particle size distribution (PSD). For this purpose, the MOMs were added to an existing parallel code for simulating laminar axisymmetric diffusion flames. The SM was able to reproduce the available experimental data whereas the MOMs were not able to predict details of soot morphology with the same level of accuracy. An analysis on the main differences between the SM and MOMs was performed. The main issue identified for the MOMs was the inability to satisfy the assumption of conservation of number density of primary particles and number of primary particles per aggregate during soot surface processes.

Download or read book Combustion Generated Fine Carbonaceous Particles written by Andrea D'Anna and published by KIT Scientific Publishing. This book was released on 2014-08-13 with total page 754 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soot is of importance for its contribution to atmospheric particles with their adverse health impacts and for its contributions to heat transfer in furnaces and combustors, to luminosity from candles, and to smoke that hinders escape from buildings during fires and that impacts global warming or cooling. The different chapters of the book adress comprehensively the different aspects from fundamental approaches to applications in technical combustion devices.

Download or read book Laboratory Investigation of Chemical and Physical Properties of Soot containing Aerosols written by Dan Zhang and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Soot particles released from fossil fuel combustion and biomass burning have a large impact on the regional/global climate by altering the atmospheric radiativeproperties and by serving as cloud condensation nuclei (CCN). However, the exact forcing is affected by the mixing of soot with other aerosol constituents, such as sulfuric acid. In this work, experimental studies have been carried out focusing on three integral parts: (1) heterogeneous uptake of sulfuric acid on soot; (2) hygroscopic growth of H2SO4-coated soot aerosols; (3) effect of H2SO4 coating on scattering and extinction properties of soot particles. A low-pressure laminar-flow reactor, coupled to ion drift chemical ionization mass spectrometry (ID-CIMS) detection, is used to study uptake coefficients of H2SO4 on combustion soot. The results suggest that uptake of H2SO4 takes place efficiently on soot particles, representing an important route to convert hydrophobic soot to hydrophilic aerosols. A tandem differential mobility analyzing (TDMA) system is employed to determine the hygroscopicity of freshly generated soot in the presence of H2SO4 coating. It is found that fresh soot particles are highly hydrophobic, while coating of H2SO4 significantly facilitates water uptake on soot even at sub-saturation relative humidities. The results indicate that aged soot particles in the atmosphere can potentially be an efficient source of CCN. Scattering and extinction coefficient measurements of the soot-H2SO4 mixed particles are conducted using a three wave length Nephelometer and a multi-path extinction cell. Coating of H2SO4 is found to increase the single scattering albedo (SSA) of soot particles which has impact on the aerosol direct radiative effect. Other laboratory techniques such as transmission electron microscopy (TEM) and Fourier transform infrared spectrometry (FTIR) are utilized to examine the morphology and chemical composition of the soot-H2SO4 particles. This work provides critical information concerning the heterogeneous interaction of soot and sulfuric acid, and how their mixing affects the hygroscopic and optical properties of soot. The results will improve our ability to model and assess the soot direct and indirect forcing and hence enhance our understanding of the impact of anthropogenic activities on the climate.

Download or read book Characterization of Soot Particles in Laminar Diffusion by Laser induced Incandescence written by Alexandre Dias Flügel and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: