Study On Gas Combustion Flame Optical Measurement Techniques

The combustion of the fossil fuel provides our majority energy requirement till now. So good understanding of the combustion mechanism is very important to increase the fuel utility efficiency and decrease atmosphere pollution. In there paper some non-intrude optical based techs for premixed gas combustion process character measurement were discussed including light extinction measurement, image tomography, and etc.In order to understand the relationship between the air fuel ratio with the unburned fuel index value, the soot particle's concentration and size distribution have been studied and reconstructed based on multi-wavelength extinction measurement results by the improved genetic algorithm in the first part of this paper. And the particle spatially section concentration in the flame was studied by image filtered back-projection tomography method. The results show these methods have been non-intrude, robust, insensitive and useful for flame measurement.In the second part, the morphology of primal and output soot particles was study by transmission electron microscope. These microscope images figured out the aggregating process the unburned particles.In the third part, high speed CCD camera was used to get high time-resolution (up to 500fps) gas combustion images. From these images, flame flick frequency under different air-fuel ratio was calculated, and the results showed the frequency value was almost linear to the square-root of the nozzle size.At the end of this paper, image correlate algorithm was used to study the flame diffuse effect. The horizontal and vertical diffusion velocity was calculated and the results showed vertical diffusion dominating.This paper also presents the method of integrating flame image signal and computed tomography, a kind of particle concentration diagnosis, based on the construction of flame images. The results of primary experiments are proved that the technology is practical to analyses the particles.