On the Quantification of Boundary Layer Effects on Flame Temperature Measurements Using Line-of-sight Absorption Spectroscopy
| Autor: | Min Yang, Chaokai Yuan, Wei Ren, Liuhao Ma, Kin-Pang Cheong |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Materials science
Line-of-sight Absorption spectroscopy business.industry 020209 energy General Chemical Engineering General Physics and Astronomy Energy Engineering and Power Technology 02 engineering and technology General Chemistry 01 natural sciences 010305 fluids & plasmas Adiabatic flame temperature Boundary layer Fuel Technology Optics 0103 physical sciences 0202 electrical engineering electronic engineering information engineering Measurement uncertainty business |
| DOI: | 10.6084/m9.figshare.14623850.v1 |
| Popis: | We studied the boundary layer effects on flame temperature measurements using line-of-sight (LOS) absorption spectroscopy. The primary objective is to quantify the measurement uncertainty of the LOS-determined temperature, which is influenced by the thermal and species boundary layers existing in standard laminar premixed flames. The boundary layer thickness (δ), central flame temperature (Tc) and species concentration (Xc) are the major factors investigated in this work. Typical absorption lines of H2O in the wavelength range of 1.4–2.9 μm were examined under different boundary layer conditions (δ/L = 0–50%, L is the optical path length above the flame; Tc = 1400–2200 K; and Xc = 14–20%). As a result, the thermal boundary layer is observed to contribute mainly to the temperature deviation of the LOS measurement, which increases with δ and Tc. In comparison, the variation of Xc between 14% and 20% has a negligible effect on the temperature measurement in the presence of both thermal and species boundary layers. A systematical investigation of all the selected line pairs reveals that a properly selected line pair reduces the temperature deviation by a maximum of 16.8% under typical laminar flame conditions. The particular line pair centered at 4029.52 cm−1 and 4030.73 cm−1, which could be detected by a single tunable semiconductor laser, is recommended for the LOS temperature measurement over a temperature range of 1400–2200 K. Finally, we performed a case study of five representative temperature measurements in laminar flames and successfully corrected the LOS-determined temperature by taking into account the boundary layer effects. |
| Databáze: | OpenAIRE |
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