轴向旋流器几何对回流区的影响

采用FLUENT软件对单级轴向旋流器进行冷态流场数值模拟,研究中改变了多种旋流器几何结构参数,获得了回流区尺寸与强度的变化规律,拟合了计算回流区长度的经验公式.通过与实验结果比较发现:所发展的回流区特征参数经验公式能够较准确的估算回流区长度,误差不超过5%;回流区长度随旋流数及扩张比的增大而减小;回流区宽度随扩张比的增大而增大;回流区涡心截面的回流比受旋流器几何参数影响比较复杂;存在临界文氏管扩张角为43°,回流区形态在临界角两侧有很大差异. 

Effects of geometry on characteristics of central toroidal recirculation zone generated by an axial swirler

The non-reaction flow field generated by a single axial swirler was simulated by using FLUENT software. The variation laws of dimensions and strength of central toroidal recirculation zone (CTRZ) with the change of swirler structures were analyzed, and an empirical formula for the length of CTRZ was obtained. The computed results were compared with experiment measurements, and the comparisons of the results indicate that the empirical formula can calculate the length of CTRZ correctly with an error lower than 5%; the length of CTRZ decreases with the increase of swirl number and expansion ratio; the width of CTRZ increases with the increase of expansion ratio; the swirler has a complex impact on backflow ratio of the center plane of vorticity; there is a critical angle of 43° for Venturi; at both sides of the critical angle the CTRZs are quite different.