A flat flame burner for the calibration of laser thermometry techniques

Abstract

The design and experimental characterization of a burner is described, which has favourable characteristics for the accurate calibration of a range of optical thermometry techniques. The burner supports stable laminar flames and combines many of the advantages of several widely used burner designs without their disadvantages. It permits the application of point measurement techniques, line-of-sight techniques and planar imaging techniques; trace species, such as metal atoms, can be easily introduced into the flame. The implementation of the burner is described, followed by the presentation of data obtained from coherent anti-Stokes Raman scattering (CARS) measurements and numerical simulations. Spatially resolved measurements were performed over the entire flame profile at three different stoichiometries and factors causing systematic and random errors are described in detail. Measurement errors on mean temperatures were determined to be less than 1%. The shot-to-shot measurement precision was determined to be 3.5-4.0% (FWHM of temperature probability density function). The burner design together with the data presented in this paper can be used for the validation and calibration, respectively, of a variety of combustion thermometry techniques. Complete details of the burner design together with the obtained temperature data will be provided on the World Wide Web. Other researchers intending to validate and calibrate their own laser-based thermometry techniques will be able to cost-effectively reconstruct this burner and adopt the characterization presented here, thus being able to apply it without the need of their own basic validation. The authors are confident that a reconstructed burner, which is applied under the same conditions, will yield the same high level of accuracy and precision as that presented in this paper.

Chemiluminescence Measurements of Laminar Premixed Ethylene/Air Flame at Low Pressure

“…A bendable spark plug extends into one corner of the plate to ignite the premixed gas. The thickness of the burner plate is 20mm, much thicker than 5mm in Hartung et al (20) because of the integrated cooling passage.…”

“…Unlike round flat burner used by other researchers (20), (21) , this paper used a square burner, which is more suitable for light-of-sight technique. And 20~60 kPa is the typical pressure in the inlet of the scramjet combustor, where combustion occurs.…”

Resolution-doubled one-dimensional wavelength modulation spectroscopy tomography for flame flatness validation of a flat-flame burner

“…They are also used as important combustion devices in development and calibration of optical diagnostic techniques [3][4][5][6][7]. Generally, the premixed flame of the flat-flame burner is axisymmetric and assumed to be flat in a radial direction.…”

“…On the other hand, to obtain accurate flame parameters from equilibrium calculations, temperature and mole fractions of chemical species are required to be as constant as possible throughout the core flame. Therefore, the flat-flame burner should be well designed to ensure the flame as flat as possible.To produce a flat flame, the burner plug is always ringed with shrouding nitrogen to isolate core flame from air disturbance [4,8]. However, the effects of heat transfer between the core flame and the cold boundary of air are inevitable, which lead to non-uniform distributions of temperature and mole fractions of chemical species in the radial direction.…”

“…To produce a flat flame, the burner plug is always ringed with shrouding nitrogen to isolate core flame from air disturbance [4,8]. However, the effects of heat transfer between the core flame and the cold boundary of air are inevitable, which lead to non-uniform distributions of temperature and mole fractions of chemical species in the radial direction.…”