Chemical Mechanistic Approaches for the Suppression of Soot Formation in the Combustion of High Energy Density Fuels PDF Download
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Author: Publisher: ISBN: Category : Languages : en Pages : 54
Book Description
Significant advantages can be gained by the use of high energy density fuels in volume limited applications. However, excessive soot formation that accompanies the combustion of these fuels presently limits their application. Fuel additive approaches prove attractive as they require minimal modifications to already existing equipment. In the present study, a variety of flame configurations were used to study the additive effects on soot formation. Through tests conducted on laminar diffusion flames carbon disulfide (CS2) and methanol (CH3OH) were found to be the most effective soot suppressants. Chemical interaction by either additive was found to far surpass the physical influences. However, the exact nature of the chemical action could not be established with the current set of experiments. Additionally, both of these additives were found to reduce soot formation in at least one high energy density fuel - quadricyclane (C7H8). To further validate this approach, studies were conducted using droplet flames and high-pressure spray flames.
Author: Publisher: ISBN: Category : Languages : en Pages : 54
Book Description
Significant advantages can be gained by the use of high energy density fuels in volume limited applications. However, excessive soot formation that accompanies the combustion of these fuels presently limits their application. Fuel additive approaches prove attractive as they require minimal modifications to already existing equipment. In the present study, a variety of flame configurations were used to study the additive effects on soot formation. Through tests conducted on laminar diffusion flames carbon disulfide (CS2) and methanol (CH3OH) were found to be the most effective soot suppressants. Chemical interaction by either additive was found to far surpass the physical influences. However, the exact nature of the chemical action could not be established with the current set of experiments. Additionally, both of these additives were found to reduce soot formation in at least one high energy density fuel - quadricyclane (C7H8). To further validate this approach, studies were conducted using droplet flames and high-pressure spray flames.
Author: J. Lahaye Publisher: Springer Science & Business Media ISBN: 1468444638 Category : Science Languages : en Pages : 429
Book Description
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.
Author: Henning Bockhorn Publisher: Springer Science & Business Media ISBN: 3642851673 Category : Science Languages : en Pages : 595
Book Description
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:
Author: Henning Bockhorn Publisher: ISBN: 9783642851681 Category : Languages : en Pages : 612
Book Description
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:
Author: Yuan Xuan Publisher: ISBN: Category : Languages : en Pages :
Book Description
There is interest in mixing ammonia (NH3) with hydrocarbons, as this decreases overall CO2 emissions from the fuel mixture when burned. Co-firing NH3 with hydrocarbons like methane (CH4) also enables stable combustion over a larger set of operating conditions in engines and gas turbines than firing only NH3 permits. When NH3 is co-fired with hydrocarbons, the influence of NH3 on soot formation chemistry becomes relevant. In this work, soot concentrations in laminar nonpremixed co-flow flames of NH3/CH4 and N2/CH4 were analyzed using color-ratio pyrometry. The concentrations of combustion species (CH4, CO2, H2O, O2, C2H2, C6H6, HCN) across the different flames were also determined using on-line electron-impact mass spectrometry. The flames were also interrogated with 2D CFD simulations, which employ a detailed chemical mechanism tailored to capturing fuel-nitrogen chemistry. Addition of NH3 to CH4 flames was found to decrease soot concentrations more significantly than N2-addition (Fig. 1). The NH3/CH4 flames were found to have higher flame temperatures than the N2/CH4 flames, implying the suppression of soot afforded by NH3 is due to a chemical influence of NH3, as opposed to thermal or dilution effects. Based on experimental and simulated soot volume fractions and species concentrations, soot formation pathways affected by NH3 are postulated.
Author: Abhishek Jain Publisher: ISBN: Category : Languages : en Pages :
Book Description
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.
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Author: 
Author: J. Lahaye
Author: Henning Bockhorn
Author: Henning Bockhorn
Author: Henning Bockhorn
Author: Yuan Xuan
Author: J. LaHaye
Author: Ahmet Emre Karatas
Author: Kolja Roth
Author: Abhishek Jain