天然气部分预混燃烧一次空气系数与燃烧器头部温度关系的模拟仿真与实验研究

Simulation and experiment research on the relationship between primary air ratio and burner head temperature of partially premixed combustion burning natural gas

关键词:  部分预混燃烧  一次空气系数  头部温度  沃泊指数  温度修正 

Key words:  partially premixed combustion  primary air ratio  burner head temperature  Wobbe index  temperature correction

摘要:

针对部分预混燃烧过程一次空气系数变化的研究,很少涉及燃烧器头部温度变化的影响,利用ICEM CFD对部分预混燃烧器进行建模,通过模拟仿真计算不同天然气组分在不同燃烧器温度情况对引射一次空气系数的影响,并结合实验测试,对比模拟仿真结果和实验测试结果,明确燃烧器头部温度与部分预混引射一次空气系数之间的变化关系。模拟结果符合随着天然气沃泊指数的增加大气式燃烧器引射一次空气系数降低的变化规律,一次空气系数实验测试值与模拟值偏差在±0.02之内。当燃气发生置换时,一次空气系数的变化不仅与沃泊指数成反比,同时也受燃烧器头部温度的影响,应在现有一次空气系数计算公式基础上对其进行温度修正。当贫气置换富气时,建议对一次空气系数变化的温度修正系数k取值1.1；反之,当富气置换贫气时,建议温度修正系数k取值0.9；气质相近的两两置换,无需进行温度修正。 

Abstract:

There are rarely studies on the influence of gas burner head temperature caused by gas components change or combustion process variation with primary air ratio. In this paper, it simulated the relationship between primary air ratio and gas burner head temperature of partially premixed combustion by using ICEM CFD, and compared with the experiment results, it confirmed the temperature correction coefficient to calculate the specify value of primary air ratio when gas was substituted. The simulation results conform to the characteristic of primary air ratio decreasing with Wobbe Index increasing, the deviation of simulation value and experiment value is within ±0.02. When gas was interchanged, the primary air ratio of partially premixed combustion is not only inversed with Wobbe Index, but also affected by gas burner head temperature. From the experiment results, when rich gas is substituted by poor gas, the suggestion temperature correction coefficient k is 1.1; and when poor gas is substituted by rich gas, the suggestion temperature correction coefficient k is 0.9; but when the properties of interchange gases are similar, it is not necessary to make temperature correction.