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Development of a trans-rotational temperature diagnostic for vibrationally-excited carbon monoxide using single-photon laser-induced fluorescence

Leiweke, Robert John
http://rave.ohiolink.edu/etdc/view?acc_num=osu1080331250

Abstract Details

2004, Doctor of Philosophy, Ohio State University, Mechanical Engineering.
A new trans-rotational temperature diagnostic with ±50K accuracy has been developed for use in nonequilibrium, low temperature, monatomic gases seeded with carbon monoxide (CO). The scheme utilizes single-photon laser induced fluorescence (LIF) of CO under vibrationally-excited conditions in which single-photon transitions from the CO X1Sig+ ground electronic state to upper electronic A1Pi or D'1Sig+ states become accessible to a tunable, narrowband ArF excimer laser at 193 nm. Two vibrationally excited environments in which the chemistry is well understood were used as a testbed; an optically-pumped 3% CO/Ar plasma at 100 torr and a 4% CO/He d.c. glow discharge at 8 torr. For the optically-pumped CO/Ar plasma, a spatially-averaged temperature of 536±103 K (2sig) was obtained from rotationally resolved X1Sig+(v"=20)-D'1Sig+(v'=2) LIF excitation spectra. Temperature measurements pumping the X1Sig+(v"=7)-A1Pi(v'=1) 4th Positive (528±51 K) were also found to compare well with line-of-sight Fourier Transform-InfraRed (FT-IR) emission measurements (536±10 K). Spatially averaged FT-IR spectroscopy of the CO 1st overtone was used to verify a vibrational population of ~0.1% within the positive column of the CO/He d.c. glow discharge. The A-X (7,1) transition was pumped and subsequent (8,1) emission at 200.8 nm collected. Spectral peaks were assigned and used to determine a spatially averaged rotational temperature of 432±44 K on the discharge centerline. This was found to be in good agreement with FT-IR spectroscopy measurements (395±10 K). As a prelude to Planar-LIF (PLIF) temperature measurements, vibrationally-resolved emission from laser excitation of various rotational lines within the A-X and D'-X bands were used to investigate spectral interferences. This information was used to determine that a simple aqueous organic filter (urea) in the A-X case, or commercial glass filter (UG-11) in the D'-X case, are adequate for rejecting elastically-scattered radiation and extraneous ro-vibrational bands during PLIF imaging. Single-shot and accumulated PLIF images were obtained for the 3% CO/Ar optically pumped plasma. Using a Two-Line ratio method, A-X band Q-branch images were used to spatially resolve the trans-rotational temperature. The single-shot precision was ~±200 K (2s), the accuracy ~±100 K.
Walter Lempert (Advisor)
265 p.
Laser-Induced Fluorescence temperature; Planar Laser-Induced Fluorescence; Argon fluoride excimer laser; Spectroscopic temperature diagnostic; Carbon monoxide fourth positive Bands; Vibrationally-excited carbon monoxide

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Citations

  • Leiweke, R. J. (2004). Development of a trans-rotational temperature diagnostic for vibrationally-excited carbon monoxide using single-photon laser-induced fluorescence [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1080331250

    APA Style (7th edition)

  • Leiweke, Robert. Development of a trans-rotational temperature diagnostic for vibrationally-excited carbon monoxide using single-photon laser-induced fluorescence. 2004. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1080331250.

    MLA Style (8th edition)

  • Leiweke, Robert. "Development of a trans-rotational temperature diagnostic for vibrationally-excited carbon monoxide using single-photon laser-induced fluorescence." Doctoral dissertation, Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1080331250

    Chicago Manual of Style (17th edition)

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This open access ETD is published by The Ohio State University and OhioLINK.