Study of Particle Size Measurement by the Extinction Method in Flame

Hengsheng Xiang (), Bo Cheng, Chengfei Zhang and Wensheng Qiao
Additional contact information
Hengsheng Xiang: Center for Combustion Energy, Tsinghua University, Beijing 100084, China
Bo Cheng: The Sixth Institute, 601 Branch of China Aeronautical Science and Technology Corporation, Hohhot 010076, China
Chengfei Zhang: The Sixth Institute, 601 Branch of China Aeronautical Science and Technology Corporation, Hohhot 010076, China
Wensheng Qiao: The Sixth Institute, 601 Branch of China Aeronautical Science and Technology Corporation, Hohhot 010076, China

Energies, 2023, vol. 16, issue 12, 1-18

Abstract: The laser extinction method (LEM) is particularly suitable for measuring particle sizes in flames because this method, which is based on the Beer–Lambert law, is non-intrusive and easy to implement. In the LEM, the interpretation of the extinction data is usually developed under the assumption that light extinction due to scattering is a result of the superposition of single scattering by individual particles; however, this could be violated for flames with dense concentrations of particles in which multiple scattering could occur. Quantifying the effect of multiple scattering under general conditions is still a formidable problem. In this work, we carried out a series of careful measurements of the laser extinction using standard particles of various known sizes, number densities and optical path lengths, all under the condition that the acceptance angle of the detector was limited to nearly zero. Combined with a four-flux model, we quantitatively analyzed the effect of multiple scattering on the size measurement using the LEM. The results show that the effect of multiple scattering could be ignored when the optical thickness is less than two under strict restrictions on the detector acceptance angle. Guided by this, the size distribution of an alumina ( Al 2 O 3 ) particle sample was measured by the LEM with dual wavelengths. Parameterized distributions were solved with the help of graph plotting, and the results compared well with the measurement from the Malvern particle size analyzer. The same method was then used to measure the particle size distribution in the plume of a solid rocket motor (SRM). The use of an off-axis parabolic mirror in the experimental setup could suppress the jitter of light passing through the SRM plume, and the particle size in the plume of the measured SRM was in the order of microns.

Keywords: laser extinction method; multiple scattering; particle size distribution; light jitter (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2023
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/1996-1073/16/12/4792/pdf (application/pdf)
https://www.mdpi.com/1996-1073/16/12/4792/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:16:y:2023:i:12:p:4792-:d:1174153

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().