燃煤锅炉微油点火燃烧器的数值计算分析

NUMERICAL SIMULATION OF THE TINY-OIL IGNITION BURNER IN THE COAL FIRED BOILER

结合煤粉锅炉微油点火燃烧器的结构特点,用数值仿真软件对圆形截面燃烧器的内部燃烧特性进行了三维流动数值模拟,计算了从燃烧器入口到炉膛的燃烧特性。分析了一次、二次燃烧室两个方向上的温度、速度分布.模拟结果表明:燃烧器一次风速度的提高对煤粉气流的着火不利,太低又会引起堵粉,同时使一次燃烧室结焦的可能性增大;微油点火燃烧器在喷口处形成了风包火的着火工况,降低了燃烧器喷口边缘温度,改善了燃烧器的工作环境.

Regarding the structure characteristic of the tiny-oil ignition burner with the round cross section in the coal fired boiler, the interior burning characteristics were simulated in three dimensional flow by using the numerical software. The distributings of temperature and speed in two directions in the primary and secondary combustion chamber were analyzed. The simulation results show that the increasement of the speed of the primary air in the combustion chamber is negative to the pulverized coal flow＇s ignition, meanwhile, low speed of the primary air may result in the pulverized coal blocking and the possibility of the primary combustion chamber coking. It is also indicated that the fire is wrapped by the wind in the location of the tiny-oil ignition burner spout, so the temperature of the verge of the burner spout is reduced and the working condition of the burner is improved.