Emission/Absorption spectroscopy
Emission/Absorption spectroscopy is used to determine the local particulate and gas species concentrations and temperatures in a turbulent or laminar reacting flow. The basic principle is to measure the radiation emitted by the hot particulate-laden gases within a homogeneous volume. In addition, the attenuation of radiation by the same volume of material is also measured. To restrict the measured radiation/attenuation to homogeneous volumes within a turbulent flame, an intrusive collimating light guide is often used. References: 3, 6 and 8.
Spectral Information
To obtain the temperatures from particulate emission, typically the radiation emitted by the volume at 900 and 1000 nm is measured. Normally, this restricts the lowest resolvable temperature to approximately 800 K. To measure even lower temperatures, it is best to utilize longer wavelengths. In the absence of particulates, temperature can be measured using radiation emitted by one of the stable gas species such as carbon-dioxide or hydrogen. Usually, these measurements are obtained in the infrared wavelengths. In addition, attenuation is usually measured across the same volume. In the absence of scattering, particulate or gas species concentrations measured either by emission or by extinction are identical if the probe volume is homogeneous.
Hardware/Software support
En'Urga Inc. provides custom designed hardware and/or software for emission/absorption spectroscopy. The information needed to custom design your spectroscopic system include the temporal/spatial resolution, description of the flow, species or particulate concentrations of interest, and the level of support.
Systems designed by En'Urga Inc. in operation
(1) Fiber optic based emission/absorption probe at Sandia National Laboratories, Albuquerque, NM for measuring the soot volume fractions and temperatures in a 10 meter diameter pool fire. The probe provides important information for model validation studies.
Systems designed by En'Urga Inc. in operation
(1) Fiber optic based emission/absorption probe at Sandia National Laboratories, Albuquerque, NM for measuring the soot volume fractions and temperatures in a 10 meter diameter pool fire. The probe provides important information for model validation studies.
(3) Multi-wavelength emission/absorption probe at Purdue University for measuring the carbon-dioxide concentrations in laboratory scale hydrocarbon flames.
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