Laser absorption of nitric oxide for thermometry in high-enthalpy air

Abstract

The design and demonstration of a laser absorption sensor for thermometry in high-enthalpy air is presented. The sensor exploits the highly temperature-sensitive and largely pressure-independent concentration of nitric oxide in air at chemical equilibrium. Temperature is thus inferred from an in situ measurement of nascent nitric oxide. The strategy is developed by utilizing a quantum cascade laser source for access to the strong fundamental absorption band in the mid-infrared spectrum of nitric oxide. Room temperature measurements in a high-pressure static cell validate the suitability of the Voigt lineshape model to the nitric oxide spectra at high gas densities. Shock-tube experiments enable calibration of a collision-broadening model for temperatures between 1200–3000 K. Finally, sensor performance is demonstrated in a high-pressure shock tube by measuring temperature behind reflected shock waves for both fixed-chemistry experiments where nitric oxide is seeded, and for experiments involving nitric oxide formation in shock-heated mixtures of N2 and O2. Results show excellent performance of the sensor across a wide range of operating conditions from 1100–2950 K and at pressures up to 140 atm.

Spectroscopic line parameters of NO, NO2, and N2O for the HITEMP database

“…A recent international scandal centered on the under-reporting of diesel engine emissions: the highlighted NO x emissions exceeded legal levels by up to 40 times [7]. The spectroscopy of NO x has been applied to non-invasive thermometry of high-enthalpy environments [8] and in situ measurements of the exhaust gases of coalfired power plants [9] and vehicles [10].…”

Announcing the 2014Measurement Science and Technologyoutstanding paper awards

“…A multifrequency eletromagnetic applicator with an integrated AC magnetometer for magnetic hyperthermia experiments E Garaio 1 , J M Collantes 1 , F Plazaola 1 , J A Garcia 2,3 and I Castellanos-Rubio 4 The 2014 Outstanding Paper Award for Biological, Medical and Life Sciences is given to this paper by Garaio et al [5]. An electromagnetic applicator for magnetic hyperthermia experiments is presented.…”

“…The chairmen would like to thank the authors for choosing to publish their work in Measurement Science and Technology, and hope that other researchers enjoy reading these works and feel encouraged to submit their own best work to the journal. The paper 'Laser absorption of nitric oxide for thermometry in high-enthalpy air' by Raymond Mitchell Spearrin et al [4] was selected as winner in the sensors category. This paper describes the development of a non-intrusive sensing system to measure temperature in air at high pressures (up to 150 atm) and high temperatures (1500-3000 K) in rapidly changing environments.…”

Thermometry and speciation for high-temperature and -pressure methane pyrolysis using shock tubes and dual-comb spectroscopy

“…Sensors using absorption spectroscopy offer a noninvasive method to measure gas properties such as temperature and composition in extreme environments. Many examples of absorption-based thermometry diagnostics are available in the literature [1][2][3][4][5]. However, most existing approaches involve * Author to whom any correspondence should be addressed.…”