鼓泡塔内气液两相流的研究

Study on Gas/Liquid Two Phase Flow in Bubble Column

用激光多普勒测速仪和粒子成象测速仪详细测量了气液鼓泡塔内气液并流和气液逆流时的流速分布、湍流度分布和气含率分布，并总结出了湍流度、气含率径向分布关联式。在气含率关联式中，首次考虑了塔高的影响。气泡的存在增强了液相湍动。气液并流时，在升力作用下气泡集聚在塔中心区。气液逆流时，气泡集聚在塔壁面附近。中心速度较大且随着表观气速的增大而增大。塔壁附近出现返混区，零轴向速度和最大湍流度均发生在相对半径ｒ／ Ｒ≈０－７ 左右。

The liquid velocities and turbulent intensities of air/water two-phase cocurrent and countercurrent flows in a bubble column were measured by laser Doppler velocimeter(LDV)and particle image velocimeter(PIV) The correlation formula of turbulent intensity and hold up were obtained,and the influence of axial position on gas hold-up was included in the correlation formula of void fraction The presence of bubbles increases the level of turbulence in the flow For air/water up flow,it is found that the bubbles tend to migrate toward the center of the column The result shows that the liquid begins to reverse at r/R≈0 7 Measurements of liquid velocities in bubble columns of different height and different superficial liquid velocities and gas velocities were made