对冲燃烧锅炉旋流燃烧器风量分布优化的数值模拟

Numerical Simulation on Air Flow Distribution Optimization of Swirl Burners for Opposed Firing Boilers

针对某发电厂1 000 MW机组对冲燃烧锅炉两侧燃烧器二次风量偏低的问题,提出了一种可优化燃烧器二次风量的风箱结构。采用数值模拟方法,研究了该二次风箱内的流动特性及燃烧器流量分配。结果表明,在不改变燃烧器出口二次风旋流强度及通流面积的前提下,通过设置调节挡板,可使得两侧燃烧器的全压高于中间燃烧器的全压,进而两侧燃烧器风量高于中间燃烧器风量约5%~6%,燃烧器出口速度分布也较为均匀。在机组满负荷运行,二次风叶片角度减小到15°时,送风机全压足以克服二次风道和各燃烧器阻力,确保机组的安全运行。

Given the low secondary airflow of the burners on both sides of opposed firing boiler of a 1 000 MW unit in a power plant, this paper presents a new secondary bellow structure that optimizes secondary airflow for burners. A numerical simulation method is used to investigate the flow characteristics in the secondary bellow and air distribution for the burners. The results show that the total pressure of burners at both sides can be higher than that of the middle burner by damper regulator setting dispensing with swirl strength and throughflow area change of secondary air at burner outlet, by which the airflow of the burner at both sides is 5%~6% higher than that of the middle burner, and velocity distribution at burner outlet is quite even. In the case of full-load operation of unit and the secondary air blade angle decreases to 15°, the total pressure of blowers can overcome the resistance from secondary air duct and burners to ensure operation safety of the units.