Abstract: Air exhaust from separator is useful for increasing separation efficiency，but less used in industries. Experimental research and numerical simulation on uniflow type multicyclones were performed with air exhaust from side seam. Air extraction could increase multicyclones efficiency in some low concentration area and higher air extraction flow rate resulted in higher efficiency. But air extraction decreased efficiency when concentration was high，and higher air extraction flow rate led to lower efficiency. Calculation results showed that air exhaust decreased axal velocity in the separation space，increased tangential velocity of free vortex and decreased radial velocity near the wall. All the calculation results could well explain the experimental results. High concentration of water led to more active water film，which reduced separation efficiency.

Key words: uniflow type multicyclones, gas-liquid separation, air exhaust, separation efficiency

摘要： 抽气是一种依靠从排料口抽取少量气体以达到优化分离器性能的手段，但目前工业应用较少。本文通过实验与数值模拟方法，研究了抽气对一种侧缝排液的多管直流式分离器分离性能的影响规律，为工程应用提供了理论基础。实验结果表明：在低浓度区域，抽气能提高分离器的效率，抽气率越大，分离效率越高；在高浓度区域，抽气导致效率下降，且抽气量越大，效率下降越明显；较少的抽气量对分离器压降影响可忽略。数值模拟结果表明：抽气能降低分离空间的轴向速度；增大分离空间自由涡区域的切向速度；降低边壁附近向心的径向速度。数值模拟结果很好地解释了实验结果，指出高浓度导致分离器壁面液膜活跃度增加，活跃液膜容易被夹带而降低分离效率。

关键词: 多管直流式分离器, 气液分离, 抽气, 性能