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Show filters. This procedure gives two interferograms for different wave lengths recorded at the same time. Recent development of signal processing devices leads us to apply the methods based on spectroscopy to the visualization of combustion phenomena. A distribution of the intensity of emission or absorption caused by a species can be visualized. Based on the intensi ty distribution, the temperature or species concentration distribution can be inferred. For these methods, a monochromator, sensors, signal processors, and recorders are indispensable. For the method based on absorption spectrometry, a light source is also needed. The reliability of results depends largely on the qualities of these equipments. The methods based on the Rayleigh scattering, Raman scattering, and Laser Induced Fluorescence have been developed and tried to apply for visualization of simple combustion phenomena. Figure 2 shows a typical example of such a system[10]. For these methods, in general, needed are equipments such as a high-power laser, an optical system, signal processors, and recorders. The system composed of those equipments is so expensive that it is not easy to get it for individual researchers. YAG EXCITED SHG TRIG. POWER SUPPLY BEAM SAMPLER CYLINDRICAL LENS FLAME ~~~ 1==~I~--U·--~~---H,rH-lASER SHEET SYNC. OUT DELAY TEKT~X 7934 PULSER TRIG. IMAGE INTENSIFIER TRIG. TRIGGER MONITOR EW.S. PULSER ceo CAMERA Figure 2 Block diagram of two dimensional Rayleigh thermometry[1 0] . Tracers, such as smokes, small particles, gas streams, an bubbles have been used to visualize combustion phenomena. A system using tracers is in general composed of a light source, an optical system , and a recording equipment as well as a tracer generator. Figure 3 shows a system to illuminate small particles as tracers [11 ] . The light beam from a high-pressure mercury vapor lamp of 500 watt passes through a slit and is interrupted by a rotating disc with 18 rectangular cuts at its periphery. Then, the beam is reflected by two concave mirrors and a sheetlike light beam of 5 mm in width is focused by a lens in the combustion chamber. 4 |