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NOx Formation Mechanism in engines of next generation aircraft and Effects of Emission of NOx on Global Atmosphere

下一代飞机发动机NOx形成机制及NOx排放对全球大气的影响

基本信息

批准号：
15360446
负责人：
KONO Michikata
金额：
$ 9.92万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

Numerical analysis of ozone depletions by exhaust plume from stratospheric flight at the altitude of 25 km was conducted. Expanding box method was employed to simulate a diffusion of exhaust plume in the stratosphere. Concentrations of chemical species and normalized sensitivities of ozone concentration for reactions were estimated by fifth-order BDF method. Chemical kinetics include NOx, Hex and Ox chemistry. As results, it takes over two days that ozone concentration within a plume becomes ambient level within 1 ppb. Ozone perturbations were changed by an effect of plume-emission time, and they are bigger in daytime than in nighttime. Distributions of sensitivities of ozone concentrations for reactions are also changed for plume-emission time. Ozone depletion is greater by NOx than HOx in an exhaust plume.An experimental research on combustion of liquid kerosene in a scramjet combustor was conducted in order to investigate combustion modes and ignition limits. Three combustors, which had a backward step, were used, and one of these had a cavity and could inject gaseous hydrogen at the upstream of the step. Kerosene was injected normally into a Mach 2.0 high-enthalpy airflow, and the injection and combustion of kerosene were observed by a CCD camera. Combustion modes were judged from a distribution of static pressure on the top wall of the combustor. As a result, atomization behavior is an important role for the ignition of liquid fuel in a supersonic air flow. The ignition and stable combustion is not observed when the inner diameter of fuel injector is 0.3 mm for any total temperatures of the main flow. The ignition occurs for above 2300K of the total temperature of the main flow when the inner diameter of the fuel injector is 0.5 mm.

对25公里高空平流层飞行的排气羽流造成的臭氧消耗进行了数值分析。采用扩展箱法模拟了排气羽流在平流层的扩散过程。用五阶BDF方法估算了反应的化学组分浓度和臭氧浓度的归一化灵敏度。化学动力学包括NOx、Hex和Ox化学。结果，烟羽中的臭氧浓度需要两天以上才能达到环境水平，低于1 ppb。臭氧扰动受羽流发射时间的影响，白天比夜间大。臭氧浓度的反应灵敏度分布也改变了羽流排放时间。为了研究超燃冲压发动机燃烧室中液体煤油的燃烧模式和着火极限，对超燃冲压发动机燃烧室中液体煤油的燃烧进行了实验研究。三个燃烧室，其中有一个后退的步骤，被使用，其中一个有一个空腔，可以注入气态氢在上游的步骤。将煤油垂直喷入马赫数为2.0的高焓气流中，用CCD摄像机观察煤油的喷入和燃烧过程。燃烧模式的判断是从燃烧室顶壁静压分布。因此，雾化特性对超音速气流中液体燃料的点火起着重要作用。当喷油器内径为0.3mm时，无论主流总温是多少，均不能实现着火和稳定燃烧。当喷油器内径为0.5mm时，在主流总温大于2300K时发生点火。