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Enhanced Volumetric Ignition and Stabilization of High-Speed Combustion by Free Radicals Injection

通过自由基注入增强体积点火并稳定高速燃烧

基本信息

批准号：
09450090
负责人：
YOSHIKAWA Norihiko
金额：
$ 6.91万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450090/
关键词：
Free Radicals Spectroscopy Ignition Combustion

项目摘要

Injection of free radicals into fresh gas mixtures enhances the ignition mechanism. There are two ways to inject free radicals. One way is to inject hot burned gas into fresh mixture. The other is to generate free radicals using ultra-violet photochemical dissociation of molecules. The present research pursued the fundamental aspects of these ignition phenomena. The main conclusions are summarized below.(1) Simulation of ignition phenomena in ozone-oxygen mixturesReaction mechanism of ozone-oxygen mixtures for the cases of high-temperature and/or O radicals injection are analyzed assuming uniform constant volume conditions. Time evolutions of non-uniform flow fields of initial distributions of temperature and O radical concentrations are also analyzed. The distinguishing conditions between volumetric ignition and point ignition are obtained.(2) Effects of free radicals injection in hydrogen-oxygen mixturesReaction enhancements by injection of O, H, OH radicals are comparatively discussed with heated ignition in the gas mixture. The reaction process is divided into the induction process and the thermal explosion process. The ignition by free radicals injection requires 0.1-1% of the initial enthalpy of the heated gas mixture. This means the free radicals injection method has a great advantage over the conventional point source ignition methods like spark, pilot flame, etc.(3) Laser ignition in hydrogen-oxygen-nitrogen dioxideThe ultra-violet irradiation of 355nm of the 3rd harmonic of Nd : YAG laser is used to induce the photochemical dissociation of nitrogen dioxide to oxygen atom and nitric oxide. Volumetric ignition of the mixture is achieved due to the reaction enhancement. The ignition phenomena are observed by high-speed photography. The experimental results are compared with the computational analysis.

将自由基注入新鲜气体混合物中增强了点火机制。有两种方法可以注射自由基。一种方法是将热的燃烧气体注入新鲜混合物中。另一种是利用分子的紫外光化学解离产生自由基。本研究追求这些点火现象的基本方面。主要结论概述如下。(1)臭氧-氧气混合气体点火现象的模拟在均匀定容条件下，分析了高温和/或注入O自由基情况下臭氧-氧气混合气体的反应机理。分析了温度和氧自由基浓度初始分布的非均匀流场随时间的演化。得到了容积着火与点着火的判别条件。(2)氢氧混合气体中自由基注入的效应本文比较讨论了在混合气体中注入O、H、OH自由基对反应的促进作用和加热点火的影响。反应过程分为诱导过程和热爆炸过程。通过自由基注入的点火需要加热的气体混合物的初始焓的0.1-1%。这意味着自由基注射方法比传统的点源点火方法如火花、引燃火焰等具有很大的优势。(3)氢-氧-二氧化氮中的激光点火利用Nd：YAG激光三次谐波355 nm的紫外光照射，诱导二氧化氮光化学解离为氧原子和一氧化氮。由于反应增强，实现了混合物的体积点火。通过高速摄影观察了点火现象。实验结果与计算分析进行了比较。