【摘要】 针对增压锅炉切向固定叶片式旋流燃烧器的气流特性进行了深入的数值模拟,并将常温常压工况下的模拟结果与试验流动阻力值及文献[11]的中心回流区边界进行对比,验证了研究时所选计算模型的正确性。分析不同进风宽度下的回流区分布、速度分布及阻力系数在增压工况下的计算结果得出:几何相似且其它结构参数不变时,进风宽度与旋流强度呈单值对应关系;当风口扩角一定且旋流强度在1~1.35之间时,可形成有利于燃料着火与稳定燃烧的中心回流区;随着进风宽度的增加,气流分布的均匀性变差,中心回流区的最大轴向回流速度(绝对值)变小,主流区最大轴向速度变大,沿流动方向各截面的轴向速度均呈"M"型分布,切向速度均呈"N"型分布;阻力系数与旋流强度呈良好的正比例线性关系,这与文献[15]的结论一致,进一步证明了所选计算模型的合理性。更多还原

【Abstract】 A numerical simulation study was performed in detail of the flow characteristics of the tangentially fixed blade type swirling burners in a supercharged boiler and the simulation results under the normal temperature and pressure condition were compared with the flow resistance value in the test and the boundary of the central return flow zone provided in the literature No. 11,thus it is verified that the calculation model chosen by the authors is correct. It has been found by analyzing the calculation results of the return flow zone distribution at various air inlet widths,velocity distribution and resistance coefficient under the pressure boosting condition that when the geometrical dimensions are similar and other structural parameters are kept unchanged,the air inlet width will assume a single-value corresponding relationship. When the diffusion angle at the air outlet is constant and the swirling intensity is between 1 and 1. 35,a central return flow zone will be formed and favorable to the ignition of the fuel and the stability of the combustion. With an increase of the air inlet width,the uniformity of the air distribution will get worse,the maximum axial return flow speed( absolute value) in the central return flow zone will become smaller,the maximum axial speed in the main flow zone will become bigger,the axial speeds in various sections along the flow direction will totally assume a " M"-shaped distribution,the tangential speeds will all take on a "N"-shaped distribution,the resistance coefficient will exhibit a good positive proportional relationship with the swirling flow intensity. The foregoing is identical to those given by the literature No. 15,further proving that the calculation model chosen by the authors is rational. Key words: air inlet width,flow characteristics,numerical simulation,swirling burner更多还原