Visual flame monitoring system based on two-color method

Abstract

Monitoring and control of combustion flames in utility boilers are required in order to optimize combustion conditions. This paper presents an instrumentation system for the concurrent measurement of the temperature distribution and soot concentration of flames developed on the two-color principle. This system consists of an endoscope, an optical assembly with optical filters, a CCD camera, a frame grabber and associated image processing software. Experiments are performed on a methane-air combustor and the temperature fields and the soot concentrations corresponding to the flame images are obtained. The results have demonstrated that the system is capable of performing on-line measurement of flame and temperature distribution, providing temporal and spatial characterization of the combustion process. In addition, the combination of advanced optical sensing and digital image processing technique can help to define the threshold by the analysis of the background noise. Furthermore, the utilization of the filter technique can enhance the image presentation effect to an extent.

Soft Sensors for Monitoring Combustion Quality and Flue Gas Emissions in Power Station Boilers

“…8b and c the entire surface lies near the intensity of 150 and 20 approximately. Image J was used to obtain the histogram and surface plots (Jiang et al, 2009).…”

3-D Reconstruction of Flame Temperature Distribution Using Tomographic and Two-Color Pyrometric Techniques

“…where N is the number of pixel locations, M is the number of images, w( p) is the weighting function that is used to fit the data more near the extreme pixel value, and λ controls the smoothness of g. The first term of (8) ensures the solution satisfies (7), and the second term ensures the function g is smooth. Obviously, this is a typical linear least-square problem that can be solved by such standard methods as singular value decomposition.…”

“…Then, the transient 2-D temperature is determined from the ratio of gray levels of corresponding pixels within the two images based on the two-color principle. Lu et al [5], Han et al [6], and Jiang et al [7] focus on the 2-D reconstruction of not only the temperature but also the soot concentration of diffusion flame, where the optical transmission and filtering assembly provided two optical paths to meet the requirement in the two-color method. Brisley et al [8] address a 3-D reconstruction method to first reconstruct band-limited grayscale representations of the flame and then to determine its temperature distribution.…”

A Refrigerated Web Camera for Photogrammetric Video Measurement inside Biomass Boilers and Combustion Analysis

“…The use of a thermographic camera to produce a temperature map of a combustion chamber is presented in [ 6 ]. Temperature distribution and soot concentration of flames measured by the two-colour principle with an endoscope, an optical assembly with optical filters and a CCD camera is presented in [ 8 ]. Huang et al [ 9 ] present two-dimensional temperature measurements of open flames by dual-spectral image analysis.…”