aalto1 untyped-item.component.html
Super adiabatic combustion of carbon-free and carbon-containing fuels
Loading...
Access rights
openAccess
CC BY
CC BY
Creative Commons license
Except where otherwised noted, this item's license is described as openAccess
publishedVersion
URL
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This publication is imported from Aalto University research portal.
View publication in the Research portal (opens in new window)
View/Open full text file from the Research portal (opens in new window)
View publication in the Research portal (opens in new window)
View/Open full text file from the Research portal (opens in new window)
Unless otherwise stated, all rights belong to the author. You may download, display and print this publication for Your own personal use. Commercial use is prohibited.
Date
Major/Subject
Mcode
Degree programme
Language
en
Pages
12
Series
Combustion and Flame, Volume 276
Abstract
The present work provides a new perspective on super adiabatic combustion (SAC) of fuel/air mixtures involving methane, ethane, propane, butane, heptane, iso-octane, 1-hexene, toluene, ammonia, and hydrogen. The simulations cover the temperature range of 1200–2000 K, initial pressures of 1–50 atm, and equivalence ratios of 0.5–2.0. The detailed chemical kinetic mechanism C3MechV3.5 has been used for 0D simulations in a constant volume batch reactor with Cantera 2.5.0. It has been found that SAC can be observed in lean, stoichiometric, and rich mixtures. While all hydrocarbon fuels show a strong correlation with each other, hydrogen and ammonia produce a significantly different pattern of SAC compared to carbon-containing fuels. Two reasons for super adiabaticity have been identified: (1) the super-equilibrium of H2O, NO, and/or CO2 due to the time delay between their production and consumption, and (2) the energy intensive dissociation reactions of, e.g., N2, H2O, and CO2. Furthermore, it has been found that a super-equilibrium of H2O always indicates super adiabaticity. For paraffinic hydrocarbons, since SAC is primarily governed by C0-C1 and NOx reactions, the low and intermediate temperature auto-ignition chemistry involving alkyl-peroxyl radical and the poly-aromatic hydrocarbon (PAH) reactions do not influence SAC. Novelty and Significance Statement As of now, super adiabatic combustion (SAC) has been shown mainly for rich premixed hydrocarbon/oxidizer mixtures. In the present work, SAC is reported for a wide range of equivalence ratios covering lean, stoichiometric, and rich mixtures of different classes of hydrocarbons in air. This work also presents a comprehensive analysis of SAC characteristics. Furthermore, the SAC of hydrocarbon fuels is compared with that of carbon-free fuels ammonia and hydrogen. For the first time in the literature, the following key facts about SAC are now reported: (a) there are different trends in SAC of hydrocarbon/air mixtures at different initial pressures and temperatures, (b) ammonia and hydrogen have significantly different trends, and (c) for linear and branched paraffins, SAC can be correlated with the number of carbon atoms in the fuel molecule. In this work, it has been pointed out that there is experimental data in the literature where the super-equilibrium of the water molecule has been observed during auto-ignition, but not linked to SAC. Therefore, the results presented in this work establishes SAC as an important topic in modern combustion chemistry research.
Description
Publisher Copyright: © 2025 The Authors
Other note
Citation
Schurr, J L, Bhattacharya, A, Konnov, A A & Kaario, O 2025, 'Super adiabatic combustion of carbon-free and carbon-containing fuels', Combustion and Flame, vol. 276, 114106. https://doi.org/10.1016/j.combustflame.2025.114106