Open AccessSpatially localized, see-through-wall temperature measurements in a flow reactor using radar REMPI
Author(s) -
Yue Wu,
Mark Gragston,
Zhili Zhang,
Joseph D. Miller
Publication year - 2016
Publication title -
optics letters/optics index
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.524
H-Index - 272
eISSN - 1071-2763
pISSN - 0146-9592
DOI - 10.1364/ol.42.000053
Subject(s) - optics , flow (mathematics) , materials science , radar , remote sensing , physics , mechanics , geology , aerospace engineering , engineering
See-through-wall coherent microwave scattering from resonance-enhanced multiphoton ionization (REMPI) for rotational temperature measurements of molecular oxygen has been developed and demonstrated in a flow reactor at atmospheric pressure. Through limited, single-ended optical access, a laser beam was focused to generate local ionization of molecular oxygen in a heated quartz flow reactor enclosed by ceramic heating elements. Coherent microwaves were transmitted, and the subsequent scattering off the laser-induced plasma was received, through the optically opaque ceramic heater walls and used to acquire rotational spectra of molecular oxygen and to determine temperature. Both axial and radial air-temperature profiles were obtained in the flow reactor with an accuracy of ±20 K(±5%). The experimental results show good agreement with a steady-state computational heat transfer model. This technique shows great potential for non-invasive, high-fidelity measurement of spatially localized temperature and radical species concentration in combustion kinetic experiments and confined combustors constructed of advanced ceramic materials in which limited or non-existing optical access hinders usage of conventional optical diagnostic techniques to quantify thermal non-uniformity.