堵塞和煤粉浓缩器对旋流两相流动影响的研究

旋流煤粉燃烧器加进口堵塞和煤粉浓缩器可以影响湍流,燃烧温度以及煤粉浓度的分布,从而影响NO的生成与排放。本文用三维相位多普勒颗粒测速仪(PDPA)测量和双流体模型数值模拟研究了堵塞和煤粉浓缩器对旋流煤粉燃烧器内两相流动的影响。实验结果和数值模拟结果基本符合。实验和模拟结果都表明,无论是进口堵塞还是煤粉浓缩器都会增加旋流燃烧器的进口湍流度,同时增加进口轴线附近的颗粒浓度,后者将有利于降低NO排放。

PDPA STUDIES ON THE EFFECT OF BLOCKINGS AND CONCENTRATORS TO THE TURBULENCE AND PARTICLE CONCENTRATION IN A SWIRL BURNER

Swirl burners are widely used in coal-fired boilers at power stations. To develop low-pollutant burners, the effect of inlet blocking on NO formation is studied. It is recognized that the NO formation is affected by the turbulence, coal concentration and temperature. In this paper, the turbulence and coal concentration in swirl burners with an inlet blocking or a coal concentrator were measured. A DANTEC-made 3-D phase-Doppler particle anemometer (PDPA) installed in the State key Laboratory of Clean Coal Combustion is used to measure the particle velocity and concentration. The measurement results are compared with those obtained by numerical simulation. Both measurement and simulation results indicate that either the blocking or the coal concentrator increases the turbulent kinetic energy at the inlet region and the particle concentration in the near-axis region, which is favorable for reducing the NO emission during coal combustion.