空气温度对甲醇燃烧影响的数值模拟研究

Numerical Simulation on the Effects of Air Temperature on the Methanol's Combustion

甲醇是一种清洁燃料,在燃烧污染物排放方面比天然气还有优势。但是由于缺少专用的燃烧设备,限制了甲醇在工业领域的大规模推广应用。甲醇的一个重要特性就是汽化潜热大,单位质量的汽化潜热约为汽油的3.7倍,约占到其低位热值的6%。如果采用压力雾化方式燃烧,甲醇在汽化过程中从周围环境吸收大量热量,会造成局部区域温度降低,给燃烧的稳定性造成一定的影响。采用高温空气燃烧可以加速甲醇的蒸发,提高局部区域的温度,改善燃烧稳定性。通过数值模拟方法分析了空气温度对甲醇燃烧过程的影响,为高温空气甲醇燃烧机的设计提供参考。数值模拟结果表明:(1)提高空气温度可以有效提高甲醇的蒸发速率和燃烧效率,有利于提高燃料的利用率;(2)空气温度的升高会导致NO_x排放明显增加。

Methanal is a kind of clean energy,which has emissions advantage comparied with to natural gas,but because of lack of special combustion equipments,its wide employ in industry is limied. One of special characteristics of methanol is its very large latent heat of vaporization,which is 3. 7 times of gasoline＇s based on the unit mass and is about 6% of its low heating value. If methanol is burned by means of pressure atomization,along with methanol＇s evaporation,it will absort a large amount of heat from aroud gas and make a local low temperature rigion. This will lead to combustion instability and low combustion efficiency. High temperature air combustion can accelerate methanol＇ s evaporation and increase local region＇s temperature and combustion stability. The effects of air temperature on methanol＇s combustion is researched with numerical method,and its conclusion can be used to design a methanol burner with high temperature air.