唇形密封元件常為工業界廣泛使用於旋轉軸相關機械設備上，具有保持潤滑與排除污染物等功用。在本研究的目的是為了更清楚了解具迴油溝之橡膠旋轉軸唇型密封元件的基本流動行為與迴油機制。理論模型包含潤滑流體的流場分析及唇部橡膠的應力作用和變形分析。數值模擬執行由商業計算流體力學軟體ESI-CFD- ACE+®整合流固耦合模型，模擬潤滑油體及橡膠的交互作用。實驗中利用一開始用空氣端及油端皆充滿油的測試機台來測試各轉速下的迴油率，以此迴油率當做油封性能的指標。為了證實流固耦合模型對流場行為的模擬分析有顯著的影響，此研究比較應力模型及剛體模型的三維流場結構及壓力分布。在轉速範圍從1000到6000 rpm，實驗量測與模擬的迴油率皆隨著轉增加而提升，且在高轉速下，流固耦合模型預測的迴油率比剛體模型更加接近實驗值。相對於非變形模型的情況下，流固耦合模型在更高的旋轉速度下考慮流固耦合可能會導致油膜厚度變大，進而產生更大的迴油率，本研究將深入探討唇型油封流體流動的特性和橡膠變形所帶來的影響。

Ribbed helix lip seals for rotating shafts have been widely used to retain oil and exclude contaminants in many applications throughout the industry. The objective of this study is to better understand the basic flow behavior associated with the pumping process of a ribbed helix lip seal. The theoretical model consists of a flow analysis of the lubricating film of the hydraulic fluid in conjunction with a stress analysis of the lip seal distortion. The complicated mechanical interaction between the oil flow and rubber deformation was simulated using a coupled fluid-structure approach implemented in a commercial computational fluid dynamics (CFD) code CFD-ACE+â. The flow characteristics and rubber deformation around a ribbed helix lip seal were fully resolved in a pumping-rate test environment, where both air and oil sides were filled with oil initially. The three-dimensional pressure field solved by the model via the coupled flow-stress analysis were compared with the predictions obtained from the model via the nondeformable rubber assumption to elucidate the significant effect of the fluid-structure interaction on accurate simulation of the oil pumping behavior. In the rotating speed ranging from 1000 to 6000 rpm, both measured and calculated pumping rates increase with the shaft speed for a ribbed helix lip seal. As compared to the baseline case, calculations with considering the fluid-structure interaction at higher rotary speeds can result in thicker oil films, and in turn produce greater pumping rates.

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