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Simultaneous measurements of fuel concentration and temperature in gas jets by laser induced breakdown spectroscopy
摘要： Laser induced breakdown spectroscopy (LIBS) enables quantitative measurements of the equivalence ratio in flames, spray and gas jets. Although there are always considerable temperature differences between the calibrations and the LIBS measurements in flames and fuel jets, the temperature effects on LIBS were rarely mentioned and not corrected in the previous LIBS measurements. In this study, a novel method to simultaneously measure the equivalence ratio and the gas temperature by LIBS in a single laser shot is proposed. This method can correct the temperature effects based on the linear correlation between the peak intensity ratio (PIR) of atomic lines and the gas temperature. The PIR of H656/N746 and the full width at half maximum (FWHM) of H656 are employed to establish calibration curves with the equivalence ratio and the gas temperature, respectively, and both of calibrations show high coefficients of determination (R2). Then, the measurement accuracy and precision of the proposed method are discussed in detail. The total uncertainties in measurements of equivalence ratio and gas temperature are estimated by 5.6% and 5.8%, respectively. Finally, the simultaneous measurements of equivalence ratios and gas temperatures in methane jets at different positions and at different injection pressures are conducted. The comparison of equivalence ratios before and after correction of the temperature effects indicates that the accuracy of the fuel concentration measurements by LIBS would be remarkably degraded if the temperature variations were neglected.
关键词： Measurement uncertainties,Laser-induced breakdown spectroscopy (LIBS),Equivalence ratio,Gas temperature,Full width at the half maximum (FWHM)
更新于2025-09-12 10:27:22
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Calculation of Voltage Reflection Coefficients of Coaxial Airlines and Evaluation of Their Measurement Uncertainties at SCL
摘要： This paper describes the use of a simple software tool developed by Standards and Calibration Laboratory (SCL) to calculate the voltage reflection coefficients (VRC) of coaxial airlines and evaluate their measurement uncertainties with Monte Carlo method. The results can be used to verify vector network analyzer before using it to take measurement.
关键词： Coaxial airlines,measurement uncertainties,voltage reflection coefficients,Monte Carlo method
更新于2025-09-10 09:29:36