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Experimental And Numerical Studies On The Soot Formation Of Liquid Fuel Relevant Compounds
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Book Synopsis Experimental and Numerical Studies on the Soot Formation of Liquid Fuel Relevant Compounds by : Tongfeng Zhang
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.
Book Synopsis Experimental and Numerical Studies for Soot Formation in Laminar Coflow Diffusion Flames of Jet A-1 and Synthetic Jet Fuels by : Meghdad Saffaripour
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:
Book Synopsis Multi-Scale Investigations in Soot Formation and Chemical Vapor Deposition by : Abhishek Jain
Download or read book Multi-Scale Investigations in Soot Formation and Chemical Vapor Deposition written by Abhishek Jain and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress is made in this thesis in understanding the complex multi-scale chemical and physical processes governing the formation of condensed phase material from gaseous species. The formation of soot through combustion and the synthesis of functional nanomaterial through chemical vapor deposition (CVD) are examined. We first attempt to characterize the sooting tendencies of alternative fuels using different techniques. A new numerical model based on modified flamelet equations is used along with a modified chemical mechanism to predict the effect of fuel molecular structure on soot yield in gasoline surrogates. These simulations provide trends on sooting behavior and are one-dimensional calculations that neglect other phenomenon that govern soot yield and distribution. To determine how other factors influence sooting behavior in laminar flames we carry out experimental and numerical studies to understand how the addition of oxygen to the oxidizer changes soot yield and distribution. Finite-rate chemistry based Direct Numerical Simulations (DNS) are carried out for a series of methane/air flames with increasing Oxygen Index (OI) using an extensively validated, semi-detailed chemical kinetic mechanism, along with an aggregate-based soot model and the results are compared with experimental measurements. It is seen that the effect of variable OI is well captured for major flame characteristics including flame heights, soot yield, and distribution by the numerical simulations when compared to the experimental data. This study is however confined to a small fuel that may not represent behavior seen in real fuels or the constituents that make up these gasoline fuels or their surrogates. Thus, we examine the effects of premixing on soot processes in an iso-octane coflow laminar flame at atmospheric pressure. Iso-octane is chosen as a higher molecular weight fuel as it is an important component of gasoline and its surrogates. Flames at different levels of premixing are investigated ranging from jet equivalence ratios of 1 (non-premixed), 24, 12, and 6. Numerical simulations are compared against experimental measurements and good agreement is seen in soot yield and soot spatial distributions with increasing levels of premixing. While the above studies for soot were carried out for laminar flames combustion devices frequently operate at conditions that lead to turbulent flow. Therefore, to understand how soot is affected by turbulence we computationally study the effects large Polycyclic Atromatic Hydrocarbons species (PAH) have on soot yield and distribution in turbulent non-premixed sooting jet flames using ethylene and and jet fuel surrogate (JP-8). The effects of large PAH on soot are highlighted by comparing the PAH profiles, soot nucleation rate, and soot volume fraction distributions obtained from both simulations for each test flame. Comparisons are also made with experiments when available and further analysis is performed to determine the cause of the observed behavior. Finally, a new multi-scale model is proposed for the computational modeling of the synthesis of functional nanomaterials using CVD. The proposed model is applied to a W(CO)6/H2Se system that has been used by researchers at Penn State to perform WSe2 crystal growth. A force-field for W/C/O/H/Se is developed and favorable agreement is seen when compared to QM data. A reaction mechanism leading from W(CO)6 and H2Se to the crystal precursor is then developed and used in a reacting flow simulation of the custom CVD chamber at Penn State. The bulk reacting flow numerical predictions show promising results for the gas-phase and precursor species, while additional work is still being performed to make the method more robust.
Book Synopsis Soot in Combustion Systems and Its Toxic Properties by : J. Lahaye
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 Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Numerical Study of Soot Formation by : Jorge Omar Contreras Rodriguez
Download or read book Numerical Study of Soot Formation written by Jorge Omar Contreras Rodriguez and published by . This book was released on 2015 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microgravity ethylene laminar boundary layer diffusion flames generated by a flat porous burner and characterized by the fuel injection velocities of 3 and 4 mm/s and an oxidizer velocity of 250 mm/s have been simulated by using an accurate radiation model, a comprehensive kinetic mechanism, and a soot model consisting of inception as a result of the collision of two pyrene molecules, heterogeneous surface growth and oxidation following the hydrogen abstraction acetylene addition (HACA) mechanism, soot particle coagulation, and PAH surface condensation. Model predictions are in reasonable agreement with the experimental data in terms of the stand-off distance and soot volume fraction. The stand-off distance and soot production are enhanced as the fuel velocity increases. H and OH radicals, responsible of the de-hydrogenation of sites in the HACA process, and pyrene, of the species for soot inception and PAH condensation processes, are found to be located in a region that follows the stand-off distance. Soot is then produced in this region and is transported inside the boundary layer by convection and thermophoresis. Radiative loss is substantially higher in these flames than in normal gravity diffusion flames owing to much longer residence times. Calculations carried out by neglecting soot radiation and by using the optically-thin approximation (OTA) revealed that soot dominates the radiative heat transfer in these flames and that the use of OTA gives rise to significant discrepancies in temperature and soot volume fraction.
Book Synopsis Experimental and Numerical Contributions to Soot Production in Laminar Axisymmetric Diffusion Flames by : Felipe Andrés Escudero Barros
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.
Book Synopsis Soot Formation in Combustion by : Henning Bockhorn
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:
Book Synopsis Soot Formation in Synthetic-fuel Droplets. First Quarterly Technical Progress Report by :
Download or read book Soot Formation in Synthetic-fuel Droplets. First Quarterly Technical Progress Report written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this project is to provide detailed information on methods of minimizing soot formation during synthetic liquid fuel combustion under conditions which minimize fuel nitrogen conversion to nitric oxide. The program consists of two tasks. The purpose of the first task, Fuel Screening Studies, is to investigate the impact of fuel properties on particulate production, to establish the importance of droplet size and examine atomizer effects, and to develop techniques for surrogate fuels productions. In the second task, Flame Studies, the fundamental details of soot formation from synfuel droplet combustion will be investigated in variable slip velocity configurations. This present report describes technical progress during the first three months of the program effort (October-December 1980). During this initial period, attention has focused on the definition of the different experimental efforts and on the design and construction of the required hardware. Aspects of this work are discussed.
Book Synopsis Soot Formation in Synthetic-fuel Droplets. Second Quarterly Technical Progress Report by :
Download or read book Soot Formation in Synthetic-fuel Droplets. Second Quarterly Technical Progress Report written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The main objective of this program is to provide detailed information on methods of minimizing soot formation during synthetic liquid fuel combustion under conditions which minimize the formation of nitric oxides. The program comprises two main tasks, Fuel Screening Studies, and Flame Studies. The purpose of the first task is to investigate the impact of fuel properties on particulate production, to establish the importance of droplet size and examine atomizer effects, and to develop techniques for surrogate fuels production. In the second task, fundamental details of soot formation from synfuel droplet combustion will be investigated in variable slip velocity configurations. This report describes technical progress during the second three-month period of program effort (January-March 1981). During this period attention has continued to be focussed on the design, construction and commissioning of experimental systems. The Task 1 tunnel furnace modification was completed and made operational, and some preliminary fuel screening studies were carried out. Similarly, construction of the controlled flow droplet reactor was completed and efforts directed towards the design and testing of diagnostic systems. Details of this work are discussed.
Book Synopsis Photographic and Three Dimensional Numerical Studies of Diesel Soot Formation Process by : Kiyomi Nakakita
Download or read book Photographic and Three Dimensional Numerical Studies of Diesel Soot Formation Process written by Kiyomi Nakakita and published by . This book was released on 1990 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Oxygen-Enhanced Combustion by : Charles E. Baukal Jr.
Download or read book Oxygen-Enhanced Combustion written by Charles E. Baukal Jr. and published by CRC Press. This book was released on 2013-03-15 with total page 779 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion technology has traditionally been dominated by air/fuel combustion. However, two developments have increased the significance of oxygen-enhanced combustion-new technologies that produce oxygen less expensively and the increased importance of environmental regulations. Advantages of oxygen-enhanced combustion include less pollutant emissi
Book Synopsis Numerical Investigation of Spray Combustion Towards HITAC Conditions by : Shanglong Zhu
Download or read book Numerical Investigation of Spray Combustion Towards HITAC Conditions written by Shanglong Zhu and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The features of High Temperature Air Combustion (HiTAC), i.e. high-efficiency combustion processes creating a uniform temperature distribution with low NOX and CO emissions, lend itself ideally for the combustion of all sorts of "difficult” fuels, ranging from low-calorific gases such as waste-gases, to heavy fuel-oils. However, to date most of the applications of HiTAC are for gaseous fuels and solid fuels, while little has been investigated on liquid fuel spray combustion in such combustion regimes. The objective of the research presented in this thesis is to identify and specify the important parameters for achieving good model performance and to understand how HiTAC conditions can be achieved for spray combustion. For this purpose numerical investigations have been performed on the NIST (National Institute of Standards and Technology) methanol spray flame under a conventional condition, the DSHC (Delft Spray-in-Hot-Coflow) ethanol spray flames in both cold and hot co-flow conditions, and the heavy fuel oil spray combustion in a 9 MW boiler with flue gas recirculation using Stork Double Register Burner (DRB). The NIST methanol spray flame was numerically studied using an Eulerian- Lagrangian RANS model. With steady laminar flamelet model good agreements between experimental data and numerical results were observed. Then we extended the validated models and methods to the the simulation of DSHC flames, and also extended the limited co-flow conditions of experiment to a series of combinations of temperatures and O2 concentrations for comparative study. The results showed that the low O2 concentration plays a key role in the reduction of peak temperature and thus thermal NOX emissions. The flame profiles and SMD at various elevations showed good agreements with experimental data under the similar conditions. The analysis of spray trajectories has been discussed in order to perform proper model validation. Heavy fuel-oil combustion in a 9MW boiler was numerically investigated with the Euler-Lagrange method as well. For Combustion, Eddy Dissipation model with a two-step global reaction mechanism was used instead. The results showed that a more uniform temperature distribution in the boiler can be achieved by diluting the primary and secondary air flow with flue gas recirculation. In this way the thermal NOX can be effectively reduced, while the remained fuel NOX formation is mainly dependent on the local combustion characteristics and the initial concentration of nitrogen-bound compounds. Besides, soot formation should be included in the simulation since it shows considerable influence on peak temperature and NOX formation. It is also concluded that the realization of HiTAC-like conditions in heavy fuel-oil combustion depends on the possibility to guarantee a sufficiently high level of flue gas recirculation flow into the evaporating spray jet.
Book Synopsis Experimental and Computational Study of Soot Formation Under Diesel Engine Conditions by : Ioannis Kitsopanidis
Download or read book Experimental and Computational Study of Soot Formation Under Diesel Engine Conditions written by Ioannis Kitsopanidis and published by . This book was released on 2004 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) Oxygenates totally suppress soot formation at or above 30% oxygen in fuel by mass. Since soot formation is kinetically limited at lower temperatures and soot precursors are not thermodynamically stable at higher temperatures, soot yield exhibits a bell-shape dependence on temperature with a maximum at approximately 1800-2000K. Thus different surface growth mechanisms prevail across the temperature range; the relative contribution of C2H2 over PAH to soot growth increases with temperature. Even though nucleation is mostly governed by PAH coalescence, it was found that the C2H2 route is not negligible under certain conditions. The kinetics of fuel-rich combustion was found to be sensitive to the fuel+HOO reaction. Suggestions are made for better correlation between model and experiments regarding ignition delay and rate of heat release. While performing this study, insight was gained into RCM operation. Assuming uniform and homogeneous environment at the end of compression, was sufficient to model ignition delays under most conditions (2-10 ms), but not rate of heat release and maximum pressure. CFD analysis predicted non-negligible temperature stratification at the end of compression ( -80% of mass within 50K). A multizone model, taking into account zones of constant mass and allowing heat transfer and flow into the crevice, was developed and improved the agreement significantly.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental Study of Soot Formation in Laminar Premixed Flames of Fuels of Interest for Automobile and Aeronautics by : Christopher Betrancourt
Download or read book Experimental Study of Soot Formation in Laminar Premixed Flames of Fuels of Interest for Automobile and Aeronautics written by Christopher Betrancourt and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Emission of soot formed from incomplete combustion of fossil fuels, biofuels and biomass is a serious concern due to soot's harmful impact on human health, environment and its radiative forcing on climate. Gaining fundamental understanding of soot formation, particularly the nucleation step leading to the formation of the nascent soot particles, is critical to develop reliable predictive soot models and to help the design of more efficient and cleaner combustion devices. This work demonstrates that nascent soot particles in the size range of 2-4 nm are able to emit a black body radiation by combined Laser Induced Incandescence (LII), scanning mobility particle sizer (SMPS) and helium-ion microscopy (HIM). These nascent soot particles are investigated in nucleation premixed flames in which soot particles are essentially formed by nucleation, without growth by soot surface processes and in standard sooting premixed flames in which growth processes occur. This work provides an extensive database for improvement of kinetics modelling of sooting flames with a focus on the soot nucleation in flames. Two kinds of fuels have been selected: n-butane and mixture of n-butane and n-propylbenzene. For each fuels two flames have been studied: a nucleation and a standard sooting flames. The database consist of species profiles obtained by online gas chromatography, temperature profiles measured by Laser induced fluorescence thermometry, soot volume fraction profiles obtained by LII calibrated by cavity ring-down extinction and particles size distributions obtained in n-butane flames by SMPS and HIM. From this database effect of equivalence ratio and fuel composition is analyzed.
Book Synopsis Experimental and Numerical Studies of Fuel Spray by : Daliang Jing
Download or read book Experimental and Numerical Studies of Fuel Spray written by Daliang Jing and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
