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微尺度下氢气-空气表面催化燃烧过程数值模拟

发表时间:2015-11-30  浏览量:1416  下载量:467
全部作者: 李擎擎,李君,陈金星
作者单位: 天津大学机械工程学院
摘 要: 根据空间气相和表面催化反应机理,应用计算流体力学软件FLUENT,对涂有Pt 催化剂的平板式微型 燃烧器内氢气和空气预混火焰进行数值模拟。构建3 种反应模式(空间气相反应、表面催化反应以及空间气 相与表面催化的耦合反应),讨论不同反应模式的燃烧特性,以及入口流速和当量比对空间气相与表面催化的 耦合反应的燃烧特性的影响。同时,通过对比考虑催化燃烧和不考虑催化燃烧的微燃烧器内燃烧特性的差异, 分析表面催化反应对微通道内燃烧特性的影响。结果表明:入口流速和当量比的增加均会使气相-催化耦合反 应的轴线温度和壁面温度升高;入口流速增大时火焰位置向下游移动,当量比的影响与之相反;入口流速和 当量比的增大均导致火焰速度增大;气相-催化耦合反应与单纯的空间气相反应相比,火焰位置更靠近下游, 同时火焰速度更小。计算结果为微尺度条件下表面催化燃烧的应用提供了理论依据。
关 键 词: 工程热物理;催化燃烧;微尺度;火焰位置;火焰速度
Title: Numerical simulation on catalytic combustion of premixed hydrogen and air in the micro-scale
Author: LI Qingqing, LI Jun, CHEN Jinxing
Organization: School of Mechanical Engineering, Tianjin University
Abstract: Catalytic combustion of premixed hydrogen and oxygen in a planar micro combustor with Pt catalyst was numerical simulated by using the computational fluid dynamics software FLUENT and detailed gas phase and catalytic reaction mechanism. We constructed three kinds of reaction mode, i.e. space gas phase reaction, surface catalytic reaction and space gas phase coupled with surface catalytic reaction. Then, We discussed the combustion characteristic of different reaction models and the influence of inlet flow velocity and equivalent ratio on both homogeneous and heterogeneous reaction of premixed hydrogen and air. The influence of surface catalytic reactions on hydrogen-air premixed flames was investigated by comparing differences of flame structures with surface reactions. The calculation results indicate that the axis temperature and wall temperature of both homogeneous and heterogeneous reactions increase when inlet flow velocity or equivalent ratio increases. The flame location moves downstream as the inlet flow velocity increases, and the influence of the equivalent ratio is on the contrary. The increase of inlet velocity and equivalent ratio leads to larger flame speed. Both homogeneous and heterogeneous reaction gets downstream flame position and smaller flame speed compared with free flame. The calculation results provide a theoretical basis for the application of catalytic combustion in the micro-scale.
Key words: engineering thermophysics; catalytic combustion; micro-scale; flame location; flame speed
发表期数: 2015年11月第22期
引用格式: 李擎擎,李君,陈金星. 微尺度下氢气-空气表面催化燃烧过程数值模拟[J]. 中国科技论文在线精品论文,2015,8(22):2393-2401.
 
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