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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。
The numerical simulation of the airflow characteristics of a tangential fixed vane swirl burner in a pressurized boiler was carried out. The simulation results under normal temperature and pressure conditions were compared with the experimental flow resistance values and the boundary of the central recirculation zone in [11] In contrast, the correctness of the calculation model selected for the study was verified. The analysis of the distribution of backflow zone, velocity distribution and drag coefficient under different inlet wind widths shows that under the condition of supercharging pressure, the inlet wind width and the swirling intensity have a single value corresponding relationship when the geometry is similar and the other structural parameters are not changed ; When the angle of expansion of the tuyere is certain and the swirling intensity is between 1 and 1.35, a central recirculation zone can be formed which is conducive to fuel ignition and stable combustion. As the inlet air width increases, the uniformity of the air flow distribution becomes worse and the center recirculation The maximum axial velocity (absolute value) of the zone becomes smaller and the maximum axial velocity of the main flow zone becomes larger. The axial velocity of each section along the flow direction is distributed as “M”, and the tangential velocity is “N” "Distribution. The coefficient of drag and the swirl intensity show a good positive linear relationship, which is consistent with the conclusion of [15], which further proves the rationality of the selected calculation model.