Emissivity Characteristics of Hydrocarbon Flame and Temperature Measurement by Color Image Processing

Abstract

Non-gray radiation should be considered in the temperature and emissivity measurements of hydrocarbon flames. In this paper an improved ratio pyrometry by spectral analysis and color image processing is proposed. A Newton-type iterative method is utilized to analyze the spectrometer signals for the detection of monochromatic emissivity, and then the ratio pyrometry based on color image processing is corrected by the detected monochromatic emissivity without making approximations of the filter profiles of CCD camera. The experiments were conducted on a tubular heating furnace with coal gas and a propane flame. The spectral and spatial distributions of emissivity of hydrocarbon flame were detected, and the temperature measurement results at four conditions coincided with the thermocouple with relative errors less than 8.34%. The soot volume fractions in the turbulent diffusion hydrocarbon flame were approximately estimated from the detected emissivity, and are influenced by the O/C in the combustion. This study will provide a simple and effective method for the detection of non-gray radiation of hydrocarbon flames in the combustion industry.

Flame temperature and alkali emission in combustion of sugarcane bagasse and straw

“…The radiative properties of triatomic gases show strong spectral selectivity, and the characteristics of soot particles are closely related to temperature, wavelength and radiation. Radiation thermometry based on colour image processing has proven to be effective in measuring flame temperature and allows cost savings [2]. Colour CCD cameras were used to investigate the simultaneous measurement of temperature distribution and radiative properties by radiation analysis [3].…”

Online Measurement of the Flame Temperature and Emissivity during Biomass Volatile Combustion Using Spectral Thermometry and Image Thermometry

“…Zheng et al 22 used a polynomial function to model the candle flame emissivity; the results showed that the emissivity of the candle flame decreased with an increasing wavelength. Lin et al 23 used a polynomial function to model the emissivity of a hydrocarbon flame; the relative error between the temperature measurements and the thermocouple results was less than 8.34%. Fu et al 24 used a dual bandpass filter to obtain twocolor radiation images at 643 and 564 nm; the temperature of the blackbody furnace was measured on the basis of the gray model.…”