研究內容包括：首先建立高速膠凝澄清池幾何構造及網格，其次輸入物理條件與相關假設。分別以下列3種模式模擬：一、膠凝池內的流體為純水，不含任何其他物質。二、膠凝池底部鋪一層具有均勻透過率的污泥毯。三、含有單種或多種膠體顆粒之多相流分析。再使用FLUENT軟體模擬板新廠高速膠凝澄清池內之流場，藉以瞭解膠凝澄清池內，各區域的速度分佈。找出局部最大操作速度，以及發生泥毯突穿的範圍，解釋污泥毯變動與流態變化之關係。 本研究結果顯示，進口速度方面，膠凝池原水處理量減少，流速由υX=-0.3 m/s降至υX=-0.1 m/s，污泥毯發生突穿程度隨流速改變而降低。轉速方面，降低轉速可以減緩第二反應室內的迴流效應，在池壁的突穿速度隨轉速降低而減少。具均勻透過率之污泥毯，隨著透過率降低，池壁突穿速度減少且流體通過反應罩下方在分離室形成另一迴流區。藉由改變膠羽密度與粒徑大小，找出何種膠羽較易發生懸浮翻騰。 In this thesis, the geometry of the blanket clarifier was established, the meshes were constructed, and the boundary conditions were set, then the velocity field of the clarifier was calculated. Three models were computed individually: 1. the flow filed of the whole clarifier is pure water; 2. the flow filed contains a homogeneous blanket of permeability k and pure water; 3. multiphase flow of pure water and solid particles with different sizes and densities. The results showed that when the inlet velocity decreased from υx=0.3 m/s to 0.1 m/s, the effect of channel flow or break-through of blanket decreased. And decreasing of the rotation velocity of the impeller could decrease the effect of the reversed flow in the secondary reactor. In the case of a uniform blanket on the bottom of the clarifier, the high permeability of the blanket indicates the similar velocity filed with those of pure water. While the clarifier with a low permeability blanket, the break-through of the blanket is seriously. In the multiphase flow modeling, the effect of density of the solid particle on the distribution of the particles is more obviously than particle size.