Stereoscopic high-speed imaging of iron microexplosions and nanoparticle-release

Research output: Contribution to journalArticlepeer-review

Abstract

In this work, the combustion behavior of seeded iron particles (d50 = 70 μm) in a laminar diffusion flame was studied in a modified Mckenna flat-flame burner. Two high speed cameras in stereo configuration allowed 3D position and 3D velocity measurements of burning iron particles as well as 3D evaluation of particle microexplosions. Microexplosive processes are important since it can affect both combustion stability and formation of product components. The observed microexplosions happened before particle extinction resulting in change of trajectories, velocities, radiation intensities and fragmentation into smaller particles. It was observed for the first time that fragments of these microexplosions tend to produce planar structures. A frequent release phenomenon was observed during the iron particle combustion using magnified thermal radiation imaging and high-speed shadowgraphy. This release phenomenon was indirectly confirmed with scanning electron microscopy of combust products, revealing multiple cracked particle shells and hollow structures. Black body radiation characteristics was observed indicating the release being in condensed phase and emission spectroscopy identified FeO as intermediate species during combustion. The observed release is believed to mainly consist of iron-oxide nanoparticles formed in the homogenous reaction between vapor iron and oxidizers.

Original languageEnglish
Pages (from-to)34465-34476
Number of pages12
JournalOptics Express
Volume29
Issue number21
DOIs
Publication statusPublished - 2021 Oct 11

Subject classification (UKÄ)

  • Materials Chemistry
  • Energy Engineering
  • Atom and Molecular Physics and Optics

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