Imbibition Dynamics in a U-Groove Microchannel with Sudden Enlargement

Imbibitiondynamics in a rectangular U-groove that isconnectedto a sudden enlargement and complicated by the presence of Concus-Finn(CF) filaments is investigated using many-body dissipative particledynamics. For open-ended sudden enlargement, four flow types are identifiedand depend on the contact angle & theta;(y), the criticalangle & theta;(f) associated with the occurrence of CF filaments,and the critical angle & theta;(c) associated with the occurrenceof main flow. First, for & theta;(y) > & theta;(f) and & theta;(y) > & theta;(c), the corner flowisabsent, and the main flow stops at the end of the small U-groove.Second, for & theta;(c) > & theta;(y) > & theta;(f), the corner flow vanishes, but the main flow occurs. Third,for & theta;(f) > & theta;(y) > & theta;(c), the corner flow takes place in the large U-groove, but themainflow is still absent. Fourth, for & theta;(y) < & theta;(f) and & theta;(y) < & theta;(c), both thecorner and main flows appear in the large U-groove. Additionally,the flow dynamics is greatly influenced by the length of the largeU-groove (l (e)). For closed-ended suddenenlargement, similar findings can be obtained. However, the outcomeof the third case is altered for sufficiently small l (e), and the sudden enlargement can eventually be filled.

Automated summary

Investigation of imbibition dynamics in a U-groove connected to a sudden enlargement and complicated by the presence of CF filaments is conducted using many-body dissipative particle dynamics. Four different flow types are identified depending on the contact angle θ(y), the critical angle θ(f), and the critical angle θ(c). The flow dynamics is greatly influenced by the length of the large U-groove (l(e)).