Research Website
http://www.goldensteingroup.com/
Keywords
tunable diode lasers, absorption spectroscopy, wavelength modulation spectroscopy
Presentation Type
Poster
Research Abstract
Tunable diode-laser absorption spectroscopy (TDLAS) sensors are widely used for measuring gas properties. These sensors offer several advantages including: small footprint, affordability, applicability to harsh environments, rapid time response, and calibration-free operation. As a result, diode-laser sensors can be integrated into control-systems and have previously been used to control gas-turbine combustors. In this study, high-frequency sine waves were generated continuously by a LabVIEW program to simultaneously scan and modulate the wavelength and intensity of a diode laser. The modulated laser light was transmitted 20 cm through the air and measured on a photodetector. Custom-built lock-in software was used to acquire the photodetector signal and extract the corresponding 1st- and 2nd-harmonic wavelength-modulation absorption spectroscopy signals (WMS-1f and -2f) resulting from H2O absorption. The WMS-2f/1f signal was then calculated to enable calibration-free monitoring of gases in real time. During future work, newly developed WMS signal-processing techniques will be used to convert the measured WMS-2f/1f signals into measurements of temperature and H2O concentration, thereby enabling monitoring and control of real combustion systems.
Session Track
Sensing and Control
Recommended Citation
Rahul P. Balla and Christopher S. Goldenstein,
"Development of a Diode-Laser Absorption-Spectroscopy Sensor for Real-Time Control of Combustion Systems"
(August 4, 2016).
The Summer Undergraduate Research Fellowship (SURF) Symposium.
Paper 13.
https://docs.lib.purdue.edu/surf/2016/presentations/13
Included in
Development of a Diode-Laser Absorption-Spectroscopy Sensor for Real-Time Control of Combustion Systems
Tunable diode-laser absorption spectroscopy (TDLAS) sensors are widely used for measuring gas properties. These sensors offer several advantages including: small footprint, affordability, applicability to harsh environments, rapid time response, and calibration-free operation. As a result, diode-laser sensors can be integrated into control-systems and have previously been used to control gas-turbine combustors. In this study, high-frequency sine waves were generated continuously by a LabVIEW program to simultaneously scan and modulate the wavelength and intensity of a diode laser. The modulated laser light was transmitted 20 cm through the air and measured on a photodetector. Custom-built lock-in software was used to acquire the photodetector signal and extract the corresponding 1st- and 2nd-harmonic wavelength-modulation absorption spectroscopy signals (WMS-1f and -2f) resulting from H2O absorption. The WMS-2f/1f signal was then calculated to enable calibration-free monitoring of gases in real time. During future work, newly developed WMS signal-processing techniques will be used to convert the measured WMS-2f/1f signals into measurements of temperature and H2O concentration, thereby enabling monitoring and control of real combustion systems.
https://docs.lib.purdue.edu/surf/2016/presentations/13