气流对工业火炬火焰稳定性影响的研究

Research on Effects of Air Flow on Flame Stability of Industry Torch

为了明晰工业火炬头在气流作用下容易烧坏的原因,建立了火炬头湍流燃烧模型,采用DES(detached eddy simulation)方法对直径D=100 mm的火炬头在风速U=20 m/s时的燃烧情况进行模拟。对流项和扩散项均采用二阶迎分格式离散,压力速度耦合采用SIMPLE算法。研究表明:①冷流流场中CH4的混合和输运过程受火炬筒体背风面形成的大涡控制;②燃烧流场中燃烧过程也受火炬筒体背风面形成的大涡控制;③空气绕流火炬筒体在其背风面形成的涡是火炬头容易烧坏的主要原因。

To clarify the reason that industrial torch heads easily burn under air flow, turbulent combustion model of torch heads is presented, and DES method is used to simulate combustion of φ100mm torch head at the wind speed of 20m/s. Convection term and diffusion term are solved with second order upwind scheme, and simple scheme is adopted for pressure-velocity couple. The results show ：① The mixing and transport processes of CH4 in non-reacting flow are controlled by large eddy scales on the leeward side of torch cylinder. ② Combustion process in reacting flow is also controlled by large eddy scales on the leeward side of torch cylinder. ③ The main reason that the torch head is easy to burn out is vortex forming on the leeward side of torch cylinder due to air flow.