實驗與模擬結果顯示，不論溢流管的類型如何，當進口壓力越大則整體分離效率會越好，而其中又以3 cm MHC表現最佳。探討其原因發現液體可以從薄膜溢流管壁進入溢流管，所以流體流動範圍較大，使得3 cm MHC在溢流端的軸向速度小於3 cm THC，減少顆粒從溢流端離開的機會，進而使分級效率有所提升，證實薄膜溢流管對於改進水旋風分離器的分離效率有所幫助。 This study uses black powder as experimental particles to realize its classification in a 45 mm diameter hydrocyclone. In the experiment, the effects of variations in inlet pressure and vortex finder material types on particle size distribution and separation efficiency were analyzed. In the simulation, the air core and the flow pattern in hydrocyclone was simulated by VOF model and LES model, and using the discrete phase model to track and predict the particle motion.The simulation and experimental results will be analyzed to discuss how the membrane vortex finder can improve the separation efficiency of the hydrocyclone. The results show that the larger the inlet pressure, the greater the efficiency of hydrocyclone. And, 3 cm MHC has the best performance of all. Explore the reasons, and discovered that the liquid can pass through the membrane wall into the vortex finder, so a larger space of liquid can flow, making the axial velocity of 3 cm MHC at the overflow end is less than 3 cm THC, reducing the opportunity that particles leave from the overflow end, and thus make the efficiency has improved. Confirmed the membrane vortex finder is useful for hydrocyclone.