We report the first demonstration of heterodyne phase-sensitive dispersion spectroscopy (HPSDS) for the simultaneous temperature and H2O concentration measurements in combustion environments. Two continuous-wave distributed-feedback quantum cascade lasers (DFB-QCLs) at 5.27 and 10.53 µm were used to exploit the strong H2O transitions (1897.52 and 949.53 cm−1) at high temperatures. The injection current of each QCL was modulated at sub-GHz or GHz to generate the three-tone radiation and the dispersion signal was detected by the radio-frequency down-conversion heterodyning. The peak-to-peak ratio of the two H2O dispersion spectra exhibits a monotonic relationship with temperature over the temperature range of 1000–3000 K, indicating the capability of performing two-line thermometry using laser dispersion spectroscopy. We measured the temperatures of CH4/air flames at different equivalence ratios (Φ = 0.8–1.2), yielding a good agreement with the corresponding thermocouple measurements. In addition, one-dimensional kinetic modeling coupled with a detailed chemical kinetic mechanism (GRI 3.0) was conducted to compare with the measured H2O concentrations using HPSDS. Finally, we demonstrated HPSDS is immune to optical power fluctuations by measuring the dispersion spectra at varied incident laser powers.
Applied Physics B – Springer Journals
Published: May 29, 2018
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.
Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera