The swirl burner with a prechamber was used in a 14 MW pulverized-coal combustion experiment to investigate the influence of inner and secondary air ratios (ISA/OSA) on the combustion characteristic and flame shape in this work. The temperatures and species concentrations in the prechamber were measured via the flue gas analyzer and thermocouples. The flame shape beyond the prechamber outlet was captured by using a high-speed camera. The results showed that the combustion efficiency was increased and low nitrogen combustion was achieved by adopting the swirl burner with a prechamber. The high temperature corrosion and slagging phenomenon did not occur in the prechamber. The influence of ISA/OSA on temperature and species concentration profiles at different areas in the prechamber was different. The flame shape size exhibited an inflection point with increasing ISA/OSA. Considering, comprehensively, the temperature peak, near wall temperature, oxygen-free zone, CO concentration, flame length, flame diameter, and divergence angle, the case of ISA/OSA =1 : 2 had great processing on combustion efficiency and NOx emission. Thus, ISA/OSA = 1 : 2 was selected as the optimized case under experiment conditions.

中文翻译：

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内外二次风比对带预燃室旋流燃烧器燃烧特性和火焰形状的影响

带预燃室的旋流燃烧器用于 14 MW 煤粉燃烧实验，以研究内部和二次空气比 (ISA/OSA) 对本工作中燃烧特性和火焰形状的影响。通过烟气分析仪和热电偶测量预燃室中的温度和物质浓度。使用高速相机捕捉超出预燃室出口的火焰形状。结果表明，采用带预燃室的旋流燃烧器，提高了燃烧效率，实现了低氮燃烧。预燃室未发生高温腐蚀和结渣现象。ISA/OSA 对预燃室不同区域的温度和物种浓度分布的影响是不同的。随着 ISA/OSA 的增加，火焰形状大小呈现出一个拐点。综合考虑温度峰值、近壁温、无氧区、CO浓度、火焰长度、火焰直径和发散角，ISA/OSA=1:2的情况对燃烧效率和NOx排放有很大的影响。因此，ISA/OSA = 1:2 被选为实验条件下的优化情况。