脉动燃烧及其污染物生成的机理研究

Efficient energy use and pollution reduction gain increasing attention. Pulse combustion technology is a effective method to solve above problems. In this project, experiment methods and numerical simulation will be used to analyse the pulse combustion and pollution emission in the Helmholtz type pulse combustor.Transient pulsue combustion flowfield will be measured to understand the flowfield by the use of time-resolved particle image velocimetry. Pressure and its distribution will be measured by pressure sensors. Temperature, pollution emission and noise in the pulse combustor will be measured by the thermocouple, combustion gas analyzer and sound pressure meter to understand the complex relationship among combusion, noise and pollution emission.In three-dimensional body-fitted coordinate system, a computation combustion dynamics software based on the LES method will be designed by use of the sub-grid turbulence model and combustion model, and will be further developed by use of direct noise computation method and hybrid LES/RANS method to research pulse combustion. Numerical models and methods applied in the simulation software will be verified by exeriment data and modified according experiment phenomenon. Reliable models and methods gained in this project will be to used to accurately describe the process of the pulse combustion and to understand the influence of the key inlet condition. Finally, credible numerical simulation program and experiment methods will be use to analyse the mechanism of pulse combustion and pollution emission, which will lay a solid foundation for further use of pulse combustion technology and development of low pollution emission pulse combustor.

能源的高效利用及污染减排日益受到重视，脉动燃烧技术是解决上述问题有效途径之一。本项目拟以数值仿真与实验研究相结合对亥姆霍兹型脉动燃烧器中脉动燃烧及污染物生成机理开展应用基础研究。为此，采用TR-PIV系统测量脉动燃烧过程的瞬态燃烧流动，采用水冷压力传感器测量压力脉动变化，分析多循环燃烧流场变化。再结合温度及组分分布测量，利用声压计测量脉动燃烧装置噪声，探索燃烧、噪声及污染物生成之间内在联系。以大涡模拟为基础，采用LES/RANS混合格式及亚网格湍流与燃烧反应模型，基于直接噪声模拟法，开发三维贴体坐标系脉动燃烧计算软件。与试验结果对比，验证数值模拟的可靠性，改进不足，获得能够准确描述脉动燃烧现象的数学模型与方法，数值研究进口参数变化对脉动燃烧及污染物的影响。最终，将数值模拟与实验相结合，初步揭示脉动燃烧及其污染物生成机理，为进一步利用脉动燃烧技术，发展低污染脉动燃烧器提供技术储备。

本项目对脉动燃烧所涉及的瞬态燃烧流场及工作特性采用实验及数值方法进行分析。研究结果表明，脉动燃烧内的压力、速度及温度等特征参数变化的周期性明显。首次采用实验方法证实了脉动燃烧流场的周期性分布特性，为深入研究脉动燃烧机理奠定了基础。本项目编制的DES燃烧过程数值模拟程序，基于本项目提出的复合NO生成模型，对脉动燃烧过程及氮氧化物生成特性进行了数值模拟，数值模拟结果与试验结果较为相符，说明本项目所采用的数学模型及方法准确，可用于脉动燃烧过程进一步的深入研究，为充分认知脉动燃烧机理奠定了基础。