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.

在25 km的高度上，从平流层飞行中对臭氧耗竭的数值分析。使用扩展的框方法来模拟排气羽流在平流层中的扩散。通过五阶BDF方法估算了化学物种的浓度和臭氧浓度的归一化敏感性。化学动力学包括NOX，十六进制和OX化学。结果，需要两天的时间才能在羽流中浓度在1 ppb之内变成环境水平。通过羽状排放时间的效果改变了臭氧扰动，白天比夜间更大。在羽状发射时间内，臭氧浓度浓度的敏感性的分布也会改变。在排气羽流中，臭氧的耗竭比HOX大。进行了对Scramjet燃烧器中液体煤油燃烧的实验研究，以研究燃烧模式和点火限制。使用了三个具有向后步骤的燃烧器，其中一个具有空腔，可以在步骤的上游注入气态氢。煤油正常注入2.0马赫高触觉气流中，并通过CCD摄像头观察到煤油的注射和燃烧。燃烧模式是根据燃烧器顶壁的静压分布来判断的。结果，雾化行为是超音速空气流中液体燃料点火的重要作用。当燃料注射器的内径为0.3毫米时，主流量的任何总温度为0.3 mm时，就不会观察到点火和稳定的燃烧。当燃料注射器的内径为0.5 mm时，对于主流量总温度的2300k以上的高于2300K。