Fendt P, Brandl M, Peter A, Zigan L, Will S (2021)
Publication Language: English
Publication Type: Journal article
Publication year: 2021
Book Volume: 29
Pages Range: 42184-42207
Journal Issue: 25
DOI: 10.1364/OE.442067
A novel supercontinuum laser absorption spectroscopy (SCLAS) approach combining a planar external Herriott multi-pass cell (HMPC) with fully single-mode fiber (SMF) coupling is presented for broadband multi-scalar combustion measurements in a rapid compression expansion machine (RCEM). For the HMPC, 1-dimensional refractive index gradients occurring in the RCEM combustion chamber are analyzed via ray-tracing with respect to axial and vertical beam steering. The impact of beam steering on the SCLAS signal is compared with the ray-tracing analysis and high-speed flame luminosity images. SCLAS based measurements are presented during compression, auto-ignition and combustion in the RCEM for n-heptane/methane mixtures at varied AFR (air-fuel ratio) and n-heptane/EGR (exhaust gas recirculation) mixtures at temperatures exceeding 1800 K and pressures up to 80 bar. Simultaneous temperature and mole fraction courses of H2O, CH4, and CO2 are inferred from NIR (near-infrared) broadband absorbance spectra detected by a Czerny Turner spectrometer (CTS) in a spectral range of 1374 nm to 1669 nm. The multi-pass approach with SMF coupling, which avoids multi-mode fiber induced noise, allows for high-speed multi-species SCLAS measurements with low standard deviations; for temperature this amounts to about 5 K and partially below at a temporal resolution of 25 μs.
APA:
Fendt, P., Brandl, M., Peter, A., Zigan, L., & Will, S. (2021). Herriott cell enhanced SMF-coupled multi-scalar combustion diagnostics in a rapid compression expansion machine by supercontinuum laser absorption spectroscopy. Optics Express, 29(25), 42184-42207. https://dx.doi.org/10.1364/OE.442067
MLA:
Fendt, Peter, et al. "Herriott cell enhanced SMF-coupled multi-scalar combustion diagnostics in a rapid compression expansion machine by supercontinuum laser absorption spectroscopy." Optics Express 29.25 (2021): 42184-42207.
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