新型动态旋流燃烧器的燃烧特性数值研究

Numerical Study of the Combustion Characteristics of New Dynamic Swirl Burner

基于旋流燃烧技术,自行设计了一款动态旋流燃烧器,通过电机带动旋流叶片旋转以获得不同的旋流强度。对燃烧器五组旋流叶片转速(v=600 rad/min、900 rad/min、1200 rad/min、1500 rad/min和1800 rad/min)工况进行了数值模拟。结果表明:当旋流叶片转速v=600 rad/min时,燃烧室内没有形成中心回流区域;随着v的增大,中心回流区域的形成直接影响火焰结构和高温区域面积,高温区面积明显减小,并逐渐向燃烧室前段移动,燃烧室内整体温度均匀性得到很好地改善。燃烧室出口NO排放量先增大后减小,在旋流叶片转速v=900 rad/min时,NO排放量达到峰值。当v从900 rad/min增大至1800rad/min时,燃烧室出口处NO排放量降低了98.71%。较高的旋流叶片转速对于提高燃烧器的燃烧效率和燃烧室的整体工作性能,以及降低污染物排放是一个好的选择。

In this paper,a dynamic swirl burner is designed based on the swirl combustion technology,the rotation of the swirl vanes is driven by the motor to obtain different swirl intensity.Numerical simulations were carried out for five different speeds:v=600,900,1200,1500 and 1800 rad/min.The results show that no central reflux area is formed in the combustion chamber when the v=600 rad/min.As the speed of the swirl vanes increases,the formation of the central reflux zone directly affects the flame structure and the area of the high temperature zone.The area of the high temperature zone is significantly reduced and gradually moves towards the front section of the combustion chamber and the overall temperature uniformity in the combustion chamber is well improved.The NO emissions from the combustion chamber outlet,which firstly increase and then decrease,reaches a peak at the swirl vane speed of v=900 rad/min and decreases by 98.71% as the rotational speed of the swirl vanes increases from 900rad/min to 1800 rad/min.A higher rotational speed of the swirl vanes is a good choice for improving the combustion efficiency of the burner,the overall performance of the combustion chamber,and reducing pollutant emissions.