弯管内气液固三相流中液膜区流场的PIV测量

PIV MEASUREMENT OF LIQUID FILM FLOW FIELD IN GAS-LIQUID-SOLID THREE PHASE FLOW THROUGH A CURVED PIPE

为了深入认识螺旋管内多相流相分离现象,应用粒子图象测速仪(PIV),对组合弯管内气水砂三相流底部水平段和上升段中液膜区的流场进行了测量。研究表明:底部水平段流动主流速度分布比较均匀,颗粒跟随流体运动;二次流十分微弱,颗粒在离心力作用下由内弯侧向外弯侧运动;速度脉动强烈,不利于相分离。上升段中流动受到重力的阻碍,同底部平段相比主流速度降低,离心力作用减弱,颗粒径向时均速度较低;流动的间歇性更强,两相速度脉动更剧烈。

Liquid film flow field in gas-liquid-solid three phase flow through a curved pipe were measured by Particle Image Velocimetry (PIV) for a better understanding of the phase separation phenomena. The results show that the axial velocity is uniform and the secondary flow is negligible in horizontal film. Particles are concentrated to the outer bend of the curved pipe by centrifugal effect. Velocity oscillation plays a negative role in phase separation. While in the upward liquid film, the particle radial motion becomes weaker because axial flow is retarded by gravity and hence centrifugal force is decreased. In addition, the flow intermittency becomes even stronger.