Spatial Distribution Analysis of Hydrocarbon Fuel by Infrared Light Absoption Computed Tomography

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The objectives of the research are to study feasibility of a new measurement technique for gaseous fuel concentration in such a combustor as an internal combustion engine, gas turbine engine and a burnner. This measuring device will play a vital role in developping a new combustor which will save fuel energy and emit low exhaust gas to protect the environment.A system to measure gaseous hydrocarbon distributions was devised, which is based on infrared light absorption by C-H stretch mode of vibration and computed tomography method. It is called IR-CT method in the research. Affection of laser light power fluctuation was diminished by monitoring source light intensity by the second infrared light detector. Calibration test for methane fuel was carried out to convert spatial data of line absorption coefficient into quantitative methane concentration. This system was applied to three flow fields. The first is methane flow with lifted flame which is generated by a gourd-shaped fuel nozzle. … More Feasibility of the IR-CT method was confirmed through the measurement. The second application is combustion field with diffusion flame. Caliblation to determine absorptivity was undertaken, and measured line absorption coefficient was converted spatial fuel concentration using corresponding temperature data. The last case is modeled incylinder gas flow of internal combustion engine, where gaseous methane was led to the intake valve in steady flow state. The fuel gas flow simulates behavior of gaseous gasoline which is evaporated at intake valve tulip. Computed tomography measurement of inner flow is essentially difficult because of existence of surrounding wall. In this experiment, infrared laser beam was led to planed portion by infrared light fiber. It is found that fuel convection by airflow takes great part in air-fuel mixture formation and the developped IR-CT system to measure fuel concentration is useful to analyze air-fuel mixture formation process and to develop new combustors. Less