Title: The thermal boundary layer effects on line-of-sight TDLAS gas concentration measurements
Authors: Qu, Zhechao, Physikalisch-Technische Bundesanstalt (PTB), Fachbereich 3.4, Analytische Chemie der Gasphase
Werhahn, Olav, Physikalisch-Technische Bundesanstalt (PTB), Fachbereich 3.4, Analytische Chemie der Gasphase
Ebert, Volker, Physikalisch-Technische Bundesanstalt (PTB), Fachbereich 3.4, Analytische Chemie der Gasphase
Contributors: HostingInstitution: Physikalisch-Technische Bundesanstalt (PTB), ISNI: 0000 0001 2186 1887
Pages:15
Language:en
DOI:10.7795/EMPIR.16ENV08.JA.20200130
Resource Type: Text / Article
Publisher: Physikalisch-Technische Bundesanstalt (PTB)
Rights: Download for personal/private use only, if your national copyright law allows this kind of use.
Dates: Available: 2020-01-30
File: Download File (application/pdf) 1.06 MB (1109146 Bytes)
MD5 Checksum: cf52b94e0794f49b755c039d2c81789c
SHA256 Checksum: 50cca44fa17b7e6bf6e039add0b478ccdaac49334af490e41a787593e3fc8943
Keywords: TDLAS ; boundary layer ; temperature gradient ; gas concentration ; line-of-sight
Abstract: The effects of thermal boundary layers on TDLAS measurement results must be quantified when using the line-of-sight (LOS) tunable diode laser absorption spectroscopy (TDLAS) under conditions with temperature gradients. In this paper, a new methodology based on spectral simulation is presented quantifying the LOS TDLAS measurement deviation under conditions with thermal boundary layers. The effects of different temperature gradients and thermal boundary layer thickness on spectral collisional widths and gas concentration measurements are quantified. A CO2 TDLAS spectrometer, which has two gas cells to generate the temperature gradients, was employed to validate the simulation results. The measured deviations and collisional widths are in very good agreement with the simulated results for conditions with different temperature gradients. We demonstrate the quantification of the thermal boundary layers thickness with the proposed method by extracting collisional width from the path-integrated spectrum.
Citation: Qu, Zhechao ; Werhahn, Olav ; Ebert, Volker. The thermal boundary layer effects on line-of-sight TDLAS gas concentration measurements , 2020. Physikalisch-Technische Bundesanstalt (PTB). DOI: https://doi.org/10.7795/EMPIR.16ENV08.JA.20200130