对旋流煤粉火焰在两种分级进风的情况下用PIV(particle i mage veloci metry)测量了燃烧室内的速度分布,研究了湍流拟序结构对旋流火焰的燃烧特性及NO排放的影响。燃烧室进口附近,当外二次风率较大时,其拟序结构沿横向的扩散较早,大量...对旋流煤粉火焰在两种分级进风的情况下用PIV(particle i mage veloci metry)测量了燃烧室内的速度分布,研究了湍流拟序结构对旋流火焰的燃烧特性及NO排放的影响。燃烧室进口附近,当外二次风率较大时,其拟序结构沿横向的扩散较早,大量小颗粒被裹入涡结构中参加反应,因此中心区域温度较高;外二次风率较小时,一次风外侧的涡结构使得更多的大颗粒在惯性离心力作用下运动到了近壁区域,因此近壁区温度更高。在本文的实验范围内,保持其他条件不变,增加外二次旋流风,有利于剪切层纵向涡结构的形成,也有利于横向涡的形成,促进了小颗粒煤粒燃烧和大颗粒煤粒挥发分析出,从而促进NO的提前生成以及燃烧中间产物对NO的还原,最终减少NO的生成。展开更多
Large-eddy simulation(LES) is under its rapid development and is recognized as a possible second generation of CFD methods used in engineering.Large-eddy simulation of two-phase flows and combustion is particularly im...Large-eddy simulation(LES) is under its rapid development and is recognized as a possible second generation of CFD methods used in engineering.Large-eddy simulation of two-phase flows and combustion is particularly important for engineering applications.Some investigators,including the present authors,give their review on LES of spray combustion in gas-turbine combustors and internal combustion engines.However,up to now only a few papers are related to the state-of-the-art on LES of gas-particle flows and combustion.In this paper a review of the advances in LES of complex gas-particle flows and coal combustion is presented.Different sub-grid scale(SGS) stress models and combustion models are described,some of the main results are summarized,and some research needs are discussed.展开更多
文摘对旋流煤粉火焰在两种分级进风的情况下用PIV(particle i mage veloci metry)测量了燃烧室内的速度分布,研究了湍流拟序结构对旋流火焰的燃烧特性及NO排放的影响。燃烧室进口附近,当外二次风率较大时,其拟序结构沿横向的扩散较早,大量小颗粒被裹入涡结构中参加反应,因此中心区域温度较高;外二次风率较小时,一次风外侧的涡结构使得更多的大颗粒在惯性离心力作用下运动到了近壁区域,因此近壁区温度更高。在本文的实验范围内,保持其他条件不变,增加外二次旋流风,有利于剪切层纵向涡结构的形成,也有利于横向涡的形成,促进了小颗粒煤粒燃烧和大颗粒煤粒挥发分析出,从而促进NO的提前生成以及燃烧中间产物对NO的还原,最终减少NO的生成。
基金Supported by the National Natural Science Foundation of China (50606026,50736006)the Foundation of State Key Laboratory of Engines,Tianjin University (K-2010-07)
文摘Large-eddy simulation(LES) is under its rapid development and is recognized as a possible second generation of CFD methods used in engineering.Large-eddy simulation of two-phase flows and combustion is particularly important for engineering applications.Some investigators,including the present authors,give their review on LES of spray combustion in gas-turbine combustors and internal combustion engines.However,up to now only a few papers are related to the state-of-the-art on LES of gas-particle flows and combustion.In this paper a review of the advances in LES of complex gas-particle flows and coal combustion is presented.Different sub-grid scale(SGS) stress models and combustion models are described,some of the main results are summarized,and some research needs are discussed.
