Studies of aromatic hydrocarbon formation mechanisms in flames: Progress towards closing the fuel gap

Fifty years after the foundation of the Combustion Institute and almost 150 years after Michael Faraday's famous lectures on the combustion of a candle, combustion diagnostics have come a long way from visual inspection of a flame to detailed analysis of a combustion process with a multitude of sophisticated techniques, often using lasers. The extended knowledge on combustion phenomena gained by application of these diagnostic techniques, combined with equally advanced numerical simulation of the process, has been instrumental in designing modern combustion devices with efficient performance and reduced pollutant emission. Also, similar diagnostic techniques are now employed to develop sensors for process control in combustion. This article intends to give a perspective on the potential of combustion diagnostics by highlighting selected application examples and by guiding the reader to recent literature. In particular, techniques are emphasized, which permit measurement of important features of the chemical composition, sometimes in conjunction with flow field parameters. Although a complete image of present research and applications in combustion diagnostics and control is beyond the scope of this article, this overview may be a starting place where ideas may be found to solve specific combustion problems with the aid of diagnostics. (Less)

Combustion at the focus: laser diagnostics and control

Soot formation in laminar counterflow flames

Combustion characteristics and emissions of Fischer–Tropsch diesel fuels in IC engines

The formation mechanism of polycyclic aromatic hydrocarbons (PAH) with three fused aromatic rings starting from naphthalene has been studied using accurate ab initio G3(MP2,CC)//B3LYP/6-311G** calculations followed by the kinetic analysis of various reaction pathways and computations of relative product yields. The results reveal new insights into the classical hydrogen abstraction–C2H2 addition (HACA) scheme of PAH growth. The HACA mechanism has been shown to produce mostly cyclopentafused PAHs instead of PAHs with six-member rings only, in contrast to the generally accepted view on this mechanism. Considering naphthalene as the initial reactant, the HACA-type synthesis of higher PAHs with all six-member rings, anthracene and phenanthrene, accounts only for 3–6% of the total product yield at temperatures relevant to combustion (1000–2000 K), whereas cyclopentafused PAHs, including acenaphthalene (41–48%), 4-ethynylacenaphthalene (∼14%), 3-ethynylacenaphthalene (∼7.5%), 1-methylene-1H-cyclopenta[b]naphtha...

J.F. Roesler

Papers

Investigating the role of methane on the growth of aromatic hydrocarbons and soot in fundamental combustion processes