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

本研究的目的是研究一种新的气体燃料浓度测量技术在内燃机、燃气涡轮机和燃烧器等燃烧室中的可行性。该测量装置的研制将对开发节能、低排放的新型燃烧器起到重要作用。设计了一套基于C-H伸缩振动模式红外吸收和计算机层析成像技术的气相碳氢分布测量系统。本研究中称之为IR-CT法。通过第二红外光探测器监测光源光强，减小了激光功率波动的影响。对甲烷燃料进行了标定试验，将线吸收系数的空间数据转换为定量的甲烷浓度。该系统应用于三个流场。第一种是甲烷流，火焰由一个弧形燃料喷嘴产生。 ...更多信息 通过测量证实了IR-CT方法的可行性。第二个应用是扩散火焰燃烧场。对吸收率进行了标定，并利用相应的温度数据将测得的线吸收系数转换为空间燃油浓度。最后一种情况是在内燃机缸内气体流动中模拟的，其中气态甲烷以稳定流动状态被引导到进气门。燃料气体流模拟在进气阀郁金香形件处蒸发的气态汽油的行为。由于壁面的存在，使得用CT测量内流有本质上的困难。实验中，红外激光束通过红外光纤被引导到平面部分。结果表明，气流对燃料的对流换热是形成混合气的重要因素，所开发的红外-CT测量系统对分析混合气形成过程和开发新型燃烧室具有重要意义。少

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