Measurements of particle flame temperatures using three-color optical pyrometry
- Northeastern Univ., Boston, MA (United States)
- Factory Mutual, Norwood, MA (United States)
A 3-color near-infrared optical pyrometer was used to monitor the combustion of polymer particles. Individual spherical poly(styrene) particles, 47--355 {micro}m in diameter, burned in air at 1,050--1,400 K gas temperatures, surrounded by sooting, diffusion envelope flames. The pyrometric results were interpreted in view of two models for soot radiation: (a) a conventional model, which assumes that the flame is optically thin and isothermal and thus, the spectral emissivity is inversely proportional to the wavelength; (b) an alterative model, in which the envelope flames are assumed to be again optically thin but nonisothermal in the radial direction. For nonisothermal flames the spectral emissivity was shown to be nearly independent of the wavelength. This model in conjunction with 3-color pyrometry may provide a way of estimating the highest temperature of soot in the flame, as well as the temperature gradient across the flame. Temperatures calculated this way were higher by 200--230 K than those calculated using the conventional model. Experimental results suggest that the agreement among the three individual temperatures obtained from 3-color pyrometry depends on which of the above models for soot radiation is used. Based on the agreement between temperatures, the degree of isothermality of the flame may be determined and thus, indications about the controlling processes during combustion may be obtained.
- OSTI ID:
- 215651
- Journal Information:
- Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 3 Vol. 104; ISSN CBFMAO; ISSN 0010-2180
- Country of Publication:
- United States
- Language:
- English
Similar Records
Two-color pyrometry system to eliminate optical errors for spatially resolved measurements in flames
MONOCHROMATIC RADIATION PYROMETRY OF HOT GASES, PLASMAS, AND DETONATIONS