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

本研究的目的是研究在内燃机、燃气轮机和燃烧器等燃烧室中测量气体燃料浓度的新技术的可行性。该测量装置对开发节能、低排放、环保的新型燃烧室具有重要意义。设计了一种基于C-H伸缩振动红外光吸收和计算机层析成像技术的气态碳氢化合物分布测量系统。本研究称其为IR-CT方法。利用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。将该系统应用于三个流场中。第一种是带有提升火焰的甲烷流动，它是由葫芦形燃料喷嘴产生的。…通过测量证实了IR-CT方法的可行性。第二种应用是具有扩散火焰的燃烧领域。进行了确定吸收率的标定，并利用相应的温度数据换算出测得的线吸收系数。最后一种情况模拟了内燃机缸内气体流动，气体甲烷在稳定流动状态下被引入进气门。燃气流动模拟了在进气阀处蒸发的气态汽油的行为。由于围墙的存在，内部流动的计算机层析成像测量本质上是困难的。在本实验中，红外激光光束通过红外光纤被引导到平面处。结果表明，燃料在空气-燃料混合气形成过程中起着重要的作用，研制的燃料浓度红外-CT测量系统有助于分析空气-燃料混合气的形成过程和开发新型燃烧室。较少

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