Discussion of laser interferometric vibrometry for the determination of heat release fluctuations in an unconfined swirl-stabilized flame

Felix Greiffenhagen, Johannes Peterleithner, Jakob Woisetschläger, Andreas Fischer, Johannes Gürtler, Jürgen Czarske

Research output: Contribution to journalArticlepeer-review

Abstract

Fluctuations in heat release, hot and cold spots convected by the flow and sound waves are all related to density fluctuations, a number easily detected by interferometry. Same as chemiluminescence, interferometry is a line-of-sight method and therefore needs optical access and tomographic reconstruction of density fields. In this work we discuss the use of Laser Interferometric Vibrometry (LIV) as an alternative or extension to chemiluminescence when detecting heat release fluctuations in the flame, convection of hot and cold spots in the non-reacting flow field and sound waves emitted from a 3.4 kW turbulent, unconfined swirl-stabilized methane/air flame under perfectly premixed conditions. For this discussion local temperatures, local ratios of heat release and local Gladstone-Dale constants are determined and their influence on the result discussed. Global and local fluctuations in heat release rate recorded by LIV and chemiluminescence are compared, resulting in the same global values if local temperature fields and local equivalence ratios are used for LIV data evaluation. In contrast, local fluctuations in OH* chemiluminescence emission are influenced by turbulence and strain in this type of flame.

Original languageEnglish
Pages (from-to)315-327
Number of pages13
JournalCombustion and Flame
Volume201
DOIs
Publication statusPublished - 2019

Keywords

  • Chemiluminescence
  • Heat release fluctuations
  • Laser interferometric vibrometry
  • Optical diagnostics
  • Swirl-stabilized flames
  • Uncertainty analysis

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Fuel Technology

Fields of Expertise

  • Mobility & Production

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