二次风旋流强度可调范围的数值模拟研究

利用Ansys12．0软件对实际电站锅炉的炉内流场进行了数值模拟，分别研究了内、外二次风旋流强度对炉内流场的影响．结果表明：随着旋流强度的增加，中心回流区开始远离燃烧器出口轴线位置，回流区长度增加，回流区面积增大，当旋流强度大于某一数值时，将不能形成较好的中心回流区，易发生飞边现象；外二次风旋流强度对回流区的影响较大，但调节范围却较小，而内二次风旋流强度的可调范围较大；内二次风和外二次风旋流强度的可调范围分别为0．58～2．74和0．58～1．00．

Numerical Study on Adjustable Range of Secondary Air Swirl Intensity

Numerical simulation was conducted with software Ansys 12.0 on the flow field of power plant boiler, so as to study the effect of swirl intensity of both the internal and external secondary air on the in- furnace flow field. Results show that with the rise of swirl intensity, the central backflow zone begins to move away from the axis of burner outlet, with an elongated length and an enlarged area; when the swirl intensity rises to a certain value, no ideal central back{low zone would be formed, in which case flash phe- nomenon may occur; the swirl intensity of external secondary air has a higher effect on the backflow zone, with an adjustable range narrower than that of the internal secondary air; the adjustable range of internal and external secondary air is 0.58-2.74 and 0.58-1.00 respectively.