Kinetics of gas bubble motion in a capillary

Two flow regimes were discovered by measuring flow rate v of water through thin capillaries containing small gas bubble. The first regime is realized at a low pressure drop DeltaP. when the main resistance to flow is created by the wetting film. The estimate of its thickness makes it possible to det ermine the parameters of the isotherm of the electrostatic component of the disjoining pressure corresponding to the constant charge of the film-gas i nterface and potential of the quartz surface, which requires the applicatio n of a new calculation procedure. As DeltaP increases, an advancing meniscu s forms contact angle of 50 degrees -60 degrees due to the him rupture when it reaches critical pressure in the thinnest part near the meniscus. In th is case. the rate vis controlled by the flow in the filled part of a capill ary, although some additional viscous drag is also created by the film movi ng in front of advancing meniscus. The longer the hubble, the greater this contribution.