【摘要】 应用三维粒子动态分析仪 (3D PDA)测得了矩形截面三分支联接的三维速度分布。在测量中 ,经过理论分析与对比试验 ,选择了蚊香烟雾作为散射粒子。实验结果表明 ,在只有支管进气的情况下 ,在总管的封闭端和支管下游总管壁面处产生了回流 ;以及气流从支管进入总管后由于截面扩张在总管横截面上所诱发的二次流 ,并且二次流现象只发生在支管下游附近的总管横截面上。更多还原

【Abstract】 The three dimensional velocities of the manifold junction with rectangular section are measured by use of three dimensional Particle Dynamic Analyzer(3D PDA). Mosquito repellent incense smoke is selected as scattering particles in the measurement by means of theoretic analysis and making contrast experiments. The results indicate that the recirculations are caused at the closed end of the main duct and near the lower wall of the main duct in the lower side duct, and the secondary recirculation in the main duct’s cross section, which appears only near the lower side duct, is caused due to section enlargement as gas enters the main duct from the side duct,when gas enters only at the entrance of the side duct.更多还原