Boundary condition thermometry using a thermographic-phosphor-coated thin filament

Nathan J. Kempema, Marshall B. Long

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Thermographic phosphors (TPs) exhibit a temperature sensitive emission spectrum when excited with ultraviolet radiation. In this study, 14 μm diameter SiC fibers are coated with ZnO or Dy:YAG using a ceramic binder to a total diameter of 70 ± 9 μm. ZnO and Dy:YAG fibers were used to measure fiber temperatures in the range of 294-450 K and 450-1245 K, respectively. The coated fiber provides higher signal levels compared to TP particle seeding and is no more invasive than the commonly used thermocouple. A calibration is performed to relate fiber temperature to the ratio of luminescent signal collected within two different bands of the fiber emission spectrum. Temperature was measured along the inlet of a series of nitrogen diluted ethylene diffusion flames stabilized on the Yale coflow burner to determine suitable thermal boundary conditions for computational modeling. The boundary condition temperatures were derived from a spline fitting of data acquired from the two fiber types in order to obtain fiber temperature sensitivity from 294 to 1245 K. The peak near-burner temperature was found to be higher than ambient conditions and to increase and shift its location radially outward with increased fuel percentage.

Original languageEnglish (US)
Pages (from-to)4691-4698
Number of pages8
JournalApplied optics
Issue number17
StatePublished - Jun 10 2016

All Science Journal Classification (ASJC) codes

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


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