Experimental and Numerical Investigation of n-Heptane/Air Counterflow Nonpremixed Flame Structure

Abstract

An experimental and numerical investigation of prevaporized n-heptane nitrogen-diluted nonpremixed flames is reported. The major objective is to provide well-resolved experimental data regarding the structure and emission characteristics of these flames, including profiles of major species (N 2 , O 2 , C 7 H 16 , CO 2 , CO, H 2), hydrocarbon intermediates (CH 4 , C 2 H 4 , C 2 H 2 , C 3 H x), and soot precursors (C 6 H 6). A counterflow flame configuration is employed, because it provides a nearly one-dimensional flat flame that facilitates both the detailed measurements and simulations using comprehensive chemistry and transport models. The measurements are compared with predictions using a detailed n-heptane oxidation mechanism that includes the chemistry of NO x and polycyclic aromatic hydrocarbon formation. The measurements are compared with predictions using a detailed n-heptane oxidation mechanism that includes the chemistry of NO x and polycyclic aromatic hydrocarbon formation. Measurements and predictions exhibit excellent agreement for temperature and major species profiles (N 2 , O 2 , n-C 7 H 16 , CO 2 , CO, and H 2), reasonably good agreement for intermediate species (CH 4 , C 2 H 4 , C 2 H 2 , and C 3 H x), but significant differences with respect to benzene profiles. Consequently, the benzene submechanism was synergistically improved using pathway analysis and measured benzene profiles.

An experimental and numerical investigation of n-heptane/air counterflow partially premixed flames and emission of NOx and PAH species

“…Both measurements and predictions indicate that the benzene concentration decreases as the level of partial premixing and/or strain rate is increased. It is worth mentioning that the predictions are based on the reaction mechanism that was synergistically improved using pathway analysis and measured benzene profiles in our previous investigation [38].…”

“…Xue and Aggarwal [7] characterized the structure of n-heptane counterflow PPFs through a numerical investigation and subsequently investigated the effect of double flame structure on NO x formation in these flames [8]. Berta et al [38] recently reported an experimental and numerical investigation of the structure and emission characteristics of prevaporized n-heptane nonpremixed flames in a counterflow configuration.…”

Emission prediction in conceptual design of the aircraft engines using augmented CRN

“…For modelling the gas turbine combustor using the network of ideal reactors, an appropriate chemical mechanism must be selected. So far, there are lots of combustion mechanisms available for different types of fuel (35)(36)(37)(38)(39)(40)(41)(42)(43) .…”

“…In this paper, three different chemical reaction mechanisms were examined. The first chemical mechanism, made available by Ranzi (40)(41)(42)(43) , was the detailed and lumped mechanism of pyrolysis, partial oxidation, and combustion of hydrocarbon and oxygenated fuels. The second is the Gas Research Institute mechanism (GRImech) version 3.0 that was created at the University of California at Berkeley by a team of researchers led by Smith (37) .…”

Investigations on Soot Formation in Heptane Jet Diffusion Flames by Optical Techniques

“…Thus, the combustion of heptane is of special interest for the understanding and modeling of soot formation in these systems of high technical relevance. A survey on some of the more recent work in this context is given in the paper by Berta et al (2008), who report experimental and numerical results on prevaporized nonpremixed heptaneflames. On the other hand, there have been relatively few investigations on non-buoyant laminar diffusion flames.…”