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Phase change and combustion of iron particles in premixed CH4/O2/N2 flames

Xu, Shijie LU orcid ; Qiu, Yue LU ; Xu, Leilei LU ; Huang, Jianqing LU ; Li, Shen LU ; Nilsson, Elna J.K. LU orcid ; Li, Zhongshan LU ; Cai, Weiwei ; Aldén, Marcus LU and Bai, Xue Song LU (2024) In Combustion and Flame 259.
Abstract

Metal powder is a promising carbon-free and recyclable energy carrier. Direct combustion of the micron-sized iron particles involves complex physical and chemical processes, such as heat transfer, surface reaction, and phase change. In this work, computational modelling of these processes is investigated and validated against experiments. A single iron particle combustion and phase change model is proposed in an Eulerian–Lagrangian framework. The new phenomenological model considers five stages, i.e., solid phase oxidation, melting of iron oxides and raw iron, liquid phase oxidation, cooling of liquid iron oxides, and solidification of super-cooled liquid iron oxides. The proposed model is first validated and then adopted in simulations... (More)

Metal powder is a promising carbon-free and recyclable energy carrier. Direct combustion of the micron-sized iron particles involves complex physical and chemical processes, such as heat transfer, surface reaction, and phase change. In this work, computational modelling of these processes is investigated and validated against experiments. A single iron particle combustion and phase change model is proposed in an Eulerian–Lagrangian framework. The new phenomenological model considers five stages, i.e., solid phase oxidation, melting of iron oxides and raw iron, liquid phase oxidation, cooling of liquid iron oxides, and solidification of super-cooled liquid iron oxides. The proposed model is first validated and then adopted in simulations of micron-sized iron particle combustion in premixed CH4/O2/N2 flames to study the effects of ambient temperature and oxygen concentration on single iron combustion. Results show that the new model is capable of replicating the melting, heterogeneous surface reaction, cooling, and solidification processes. Two-stage solidification is observed in experiments and modelled in simulations. This two-stage solidification includes a fast solidification with a significant temperature rise (∼150–200 K) and a thermal equilibrium solidification featuring a constant temperature and a slight particle radiant intensity decrease. In addition, a diffusion-controlled mechanism is identified during the melting process, in which the oxygen concentration dominates the melting time and the subsequent burning time. Furthermore, it is found that the reaction between iron and CH4/O2/N2 flame products, such as CO2 and H2O, plays a non-negligible role in the iron combustion process.

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author
; ; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Carbon neutral fuels, Ignition and combustion, Micron-sized metal particles, Phase change, Two-phase flow
in
Combustion and Flame
volume
259
article number
113171
publisher
Elsevier
external identifiers
  • scopus:85181676314
ISSN
0010-2180
DOI
10.1016/j.combustflame.2023.113171
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2023 The Author(s)
id
a83e790c-1b49-4914-996d-48d5d5ce2d33
date added to LUP
2024-01-28 18:09:07
date last changed
2024-01-31 10:26:04
@article{a83e790c-1b49-4914-996d-48d5d5ce2d33,
  abstract     = {{<p>Metal powder is a promising carbon-free and recyclable energy carrier. Direct combustion of the micron-sized iron particles involves complex physical and chemical processes, such as heat transfer, surface reaction, and phase change. In this work, computational modelling of these processes is investigated and validated against experiments. A single iron particle combustion and phase change model is proposed in an Eulerian–Lagrangian framework. The new phenomenological model considers five stages, i.e., solid phase oxidation, melting of iron oxides and raw iron, liquid phase oxidation, cooling of liquid iron oxides, and solidification of super-cooled liquid iron oxides. The proposed model is first validated and then adopted in simulations of micron-sized iron particle combustion in premixed CH<sub>4</sub>/O<sub>2</sub>/N<sub>2</sub> flames to study the effects of ambient temperature and oxygen concentration on single iron combustion. Results show that the new model is capable of replicating the melting, heterogeneous surface reaction, cooling, and solidification processes. Two-stage solidification is observed in experiments and modelled in simulations. This two-stage solidification includes a fast solidification with a significant temperature rise (∼150–200 K) and a thermal equilibrium solidification featuring a constant temperature and a slight particle radiant intensity decrease. In addition, a diffusion-controlled mechanism is identified during the melting process, in which the oxygen concentration dominates the melting time and the subsequent burning time. Furthermore, it is found that the reaction between iron and CH<sub>4</sub>/O<sub>2</sub>/N<sub>2</sub> flame products, such as CO<sub>2</sub> and H<sub>2</sub>O, plays a non-negligible role in the iron combustion process.</p>}},
  author       = {{Xu, Shijie and Qiu, Yue and Xu, Leilei and Huang, Jianqing and Li, Shen and Nilsson, Elna J.K. and Li, Zhongshan and Cai, Weiwei and Aldén, Marcus and Bai, Xue Song}},
  issn         = {{0010-2180}},
  keywords     = {{Carbon neutral fuels; Ignition and combustion; Micron-sized metal particles; Phase change; Two-phase flow}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Combustion and Flame}},
  title        = {{Phase change and combustion of iron particles in premixed CH<sub>4</sub>/O<sub>2</sub>/N<sub>2</sub> flames}},
  url          = {{http://dx.doi.org/10.1016/j.combustflame.2023.113171}},
  doi          = {{10.1016/j.combustflame.2023.113171}},
  volume       = {{259}},
  year         = {{2024}},
}