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
The scientific meaning and practicality of integration of radiant image processing andnumerical simulation of combustion processes in pulverized-coal-fired furnaces are discussed.Through taking account of radiation em...The scientific meaning and practicality of integration of radiant image processing andnumerical simulation of combustion processes in pulverized-coal-fired furnaces are discussed.Through taking account of radiation emitted from wall surface and the uneven distributionof radiant characteristics of two-phase medium in furnaces, an equation relating 2 - Dmonochromatic radiant images and 3 - D combustion processes in furnaces is improved.Numerical simulation technique will be used to estimate the spacious distribution of theradiative characteristics of the two-phase medium in furnaces, and the measuring methodof 3 - D temperature distribution is improved. Taking the radiant images as a kind of"radiative boundary" for numerical simulation of combustion processes, it will be possible toassess different models of combustion reaction and different calculation methods of radiativeheat transfer. Using two sets of radiant image processing devices with filters of differentcentral wavelengths, different solid and gas temperature distributions could be obtainedsimultaneously. These considerations will be helpful for experimental study and numericalsimulation of combustion processes in pulverized-coal-fired furnaces-展开更多
The work is devoted to numerical simulation of pulverized-coal combustion processes in the vortex furnace which is a prospective design of a boiler unit for thermal power plants. New modification of this design charac...The work is devoted to numerical simulation of pulverized-coal combustion processes in the vortex furnace which is a prospective design of a boiler unit for thermal power plants. New modification of this design characterized by additional tangential-injection nozzle located at the bottom of combustion chamber has been studied. Numerical results for the case of Siberian brown coal combustion in this vortex furnace with dual-port loading are presented, including 3-D aerodynamic structure, the fields of temperatures, radiated heat fluxes, species and dispersed phase concentrations, and NOx emissions.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。
文摘The scientific meaning and practicality of integration of radiant image processing andnumerical simulation of combustion processes in pulverized-coal-fired furnaces are discussed.Through taking account of radiation emitted from wall surface and the uneven distributionof radiant characteristics of two-phase medium in furnaces, an equation relating 2 - Dmonochromatic radiant images and 3 - D combustion processes in furnaces is improved.Numerical simulation technique will be used to estimate the spacious distribution of theradiative characteristics of the two-phase medium in furnaces, and the measuring methodof 3 - D temperature distribution is improved. Taking the radiant images as a kind of"radiative boundary" for numerical simulation of combustion processes, it will be possible toassess different models of combustion reaction and different calculation methods of radiativeheat transfer. Using two sets of radiant image processing devices with filters of differentcentral wavelengths, different solid and gas temperature distributions could be obtainedsimultaneously. These considerations will be helpful for experimental study and numericalsimulation of combustion processes in pulverized-coal-fired furnaces-
文摘The work is devoted to numerical simulation of pulverized-coal combustion processes in the vortex furnace which is a prospective design of a boiler unit for thermal power plants. New modification of this design characterized by additional tangential-injection nozzle located at the bottom of combustion chamber has been studied. Numerical results for the case of Siberian brown coal combustion in this vortex furnace with dual-port loading are presented, including 3-D aerodynamic structure, the fields of temperatures, radiated heat fluxes, species and dispersed phase concentrations, and NOx emissions.
