Page 1 |
Save page Remove page | Previous | 1 of 227 | Next |
|
small (250x250 max)
medium (500x500 max)
large ( > 500x500)
Full Resolution
All (PDF)
|
This page
All
Subset |
FLAME STUDIES OF CONVENTIONAL AND
ALTERNATIVE JET FUELS AND THEIR SURROGATES
by
Chunsheng Ji
A Dissertation Presented to the
FACULTY OF THE USC GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements of the Degree
DOCTOR OF PHILOSOPHY
(MECHANICAL ENGINEERING)
August 2011
Copyright 2011 Chunsheng Ji
Object Description
| Title | Flame studies of conventional and alternative jet fuels and their surrogates |
| Author | Ji, Chunsheng |
| Author email | chunshej@usc.edu;chunsheng.ji@gmail.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Mechanical Engineering |
| School | Viterbi School of Engineering |
| Date defended/completed | 2011-04-22 |
| Date submitted | 2011-07-20 |
| Date approved | 2011-07-20 |
| Restricted until | 2011-07-20 |
| Date published | 2011-07-20 |
| Advisor (committee chair) | Egolfopoulos, Fokion N. |
| Advisor (committee member) |
Wang, Hai Tsotsis, Theodore T. |
| Abstract | Conventional and alternative jet propellant (JP) fuels contain a large number of compounds, which makes the modeling of their combustion a rather daunting task. Fuel surrogates, typically mixtures of a small number of neat hydrocarbon compounds, can be used to mimic the physical and chemical characteristics of realistic fuels. The fuel surrogates must be selected carefully in order to reproduce accurately a variety of combustion characteristics of realistic fuels. ❧ Towards the goal of developing a combustion kinetic model for jet fuel surrogates, archival experimental data on global flame phenomena such as propagation and extinction are essential. The counterflow configuration was used to determine laminar flame speeds and/or extinction strain rates experimentally over a wide range of fuel surrogate candidates including normal alkanes (5 ≤ carbon number ≤ 12), branched alkanes (C₈ isomers), cyclic alkanes (cyclohexane and mono-alkylated cyclohexanes), and aromatics (cyclopentadiene, benzene, and alkylated benzenes). Experiments were conducted for both premixed and non-premixed flames at ambient pressure and elevated unburned reactant temperatures. The experimental data were simulated using detailed description of chemical kinetics and molecular transport. Analysis of the computed flame structures provided insight into the physical and chemical processes that control the overall oxidation process. The effects of two possible transport formulations and the boundary velocity gradients realized in the experiments were investigated numerically. The results indicated that both the type of transport formulation and boundary velocity gradient have little or no influence on the propagation of vigorously burning stretched flames, however, they do affect the computed state of extinction. ❧ Detailed sensitivity and reaction path analyses were performed to illustrate the oxidation chemistry of the fuels components in the present study. Compared to flame propagation, flame extinction is in general more sensitive to chemical kinetics and molecular diffusion, especially under non-premixed conditions. ❧ The high temperature oxidation of normal, branched, and cyclic alkanes was determined to be largely sensitive to H₂/CO and C₁-C₄ small hydrocarbon chemistry, with little or no influence from the fuel-related reactions. The variations of the values of laminar flame speeds and/or extinction strain rates for branched and cyclic alkanes are mainly attributed to differences in the production of C₂-C₄ intermediates. On the other hand, fuel-specific reactions were found to restrict the overall oxidation rates of aromatics compounds. Intermediates directly produced from the initial consumption of aromatics compounds, such as benzyl, and methylbenzyl radicals, are considered to be stable and more likely to recombine with H radical. They can be consumed largely through the reaction with O atoms. ❧ The propagation of flames of fuel blends was then studied and found to be mostly sensitive to the flame temperature through its influence on the main branching reaction H + O₂ → OH + O. The kinetic couplings appear to have minor effect on flame propagation. ❧ Finally, the propagation and extinction and conventional and alternative jet fuels were investigated. |
| Keyword | alternative fuels; flame extinction; flame propagation; fuel surrogate; jet fuels; kinetic model |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m |
| Rights | Ji, Chunsheng |
| Access conditions | The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the author, as the original true and official version of the work, but does not grant the reader permission to use the work if the desired use is covered by copyright. It is the author, as rights holder, who must provide use permission if such use is covered by copyright. The original signature page accompanying the original submission of the work to the USC Libraries is retained by the USC Libraries and a copy of it may be obtained by authorized requesters contacting the repository e-mail address given. |
| Repository name | University of Southern California Digital Library |
| Repository address | USC Digital Library, University of Southern California, University Park Campus MC 7002, 106 University Village, Los Angeles, California 90089-7002, USA |
| Repository email | cisadmin@usc.edu |
| Archival file | uscthesesreloadpub_Volume71/etd-JiChunshen-140.pdf |
Description
| Title | Page 1 |
| Full text | FLAME STUDIES OF CONVENTIONAL AND ALTERNATIVE JET FUELS AND THEIR SURROGATES by Chunsheng Ji A Dissertation Presented to the FACULTY OF THE USC GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements of the Degree DOCTOR OF PHILOSOPHY (MECHANICAL ENGINEERING) August 2011 Copyright 2011 Chunsheng Ji |
Comments
Post a Comment for Page 1
