Analysis of transient-grating signals for reacting-flow applications

Michael S. Brown, Yuanyuan Li, William Roberts, James R. Gord

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Single-shot transient-grating measurements for thermometry in pressurized reacting flows are examined in the context of rapid digital signal processing. Simple approaches are discussed for temperature determination and rejection of unwanted signals in real-time measurement applications. Examples of temperature data in pressurized postflame gases are presented in the form of probability-density functions (PDFs). Three contributions to the PDF half-widths are discussed. Analysis of phase-matching requirements indicates that beam steering as a result of density fluctuations affects the signal amplitude but not the grating period. Therefore, such stochastic beam deviations have little effect on the derived temperatures. Mode noise on the cw probe beam as well as linear light scattering are found to be insignificant in the frequency range of the observed transient-grating acoustic signature. Use of a single-mode laser for the pump beams is shown to enhance the signal intensity.

Original languageEnglish (US)
Pages (from-to)566-578
Number of pages13
JournalApplied Optics
Volume42
Issue number3
DOIs
StatePublished - Jan 20 2003

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Engineering (miscellaneous)
  • Electrical and Electronic Engineering

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