轴对称射流火焰的数值模拟及稳定性分析  

Direct Numerical Simulation and Stability Analysis of an Axisymmetric Jet Flame

作　　者：陈阳[1] 罗开红[1,2] 

机构地区：[1]清华大学燃烧能源中心和热科学与动力工程教育部重点实验室,北京100084 [2]南安普顿大学

出　　处：《工程热物理学报》2013年第10期1973-1977,共5页Journal of Engineering Thermophysics

基　　金：清华大学燃烧能源中心启动基金

摘　　要：燃烧过程是能源利用过程中不可缺少的环节,而燃烧不稳定现象则是燃烧过程优化应用中潜在的威胁,其导致的热释放率和压力波动会对燃烧器造成极大危害.燃烧不稳定性的产生机理研究和有效控制具有十分重要的意义。近年来很多学者围绕燃烧不稳定性做了大量的理论和实验研究,但绝大部分研究针对预混火焰而不是扩散火焰.人们认为热声的耦合作用是燃烧不稳定性产生的根本原因,瑞利(Rayleigh)准则提供了判断燃烧不稳定性的一个重要判据。本文通过轴对称射流火焰的直接数值模拟(DNS)探究了压力扰动和速度扰动对燃烧不稳定性的影响,并且利用Rayleigh准则对结果进行了分析。结果表明,通过适当地改变射流入口压力和速度脉动,能够使声能的增长受到抑制,从而为控制燃烧不稳定性提供有效的途径。Combustion is an indispensable component of energy utilization, but combustion insta- bility is a potential threat to the optimal harness of the combustion process. The heat release rate fluctuations and pressure fluctuations caused by combustion instability will do great harm to burners. The study of combustion instability mechanism and its effective control are of great significance. In recent years, many scholars have made many theoretical and experimental studies in the field, but most of those studies are targeted at premixed flames rather than diffusion flames. Thermal-acoustic coupling is the root cause of combustion instability, and Rayleigh criteria provide an important mathematical and physical foundation to measure the onset of combustion instability. This paper studied the influence of pressure, velocity and temperature perturbations, respectively, on combustion instability by direct numerical simulation （DNS） of an axisymmetric jet flame, and analyzed the results with the Rayleigh criteria. The results showed that imposing suitable pressure and velocity disturbances at the inlet would significantly suppress the growth of acoustic energy in the combustion process, thus providing an effective way to control combustion instability.

关 键 词：燃烧稳定性 直接数值模拟（DNS） 瑞利准则 

分 类 号：TK16[动力工程及工程热物理—热能工程]