- Capillary pressure
In
fluid statics , capillary pressure is the difference inpressure across the interface between twoimmiscible fluids, and thus defined as:p_c=p_{ ext{non-wetting phase-p_{ ext{wetting phase.In oil-water systems, water is typically thewetting phase, while for gas-oil systems, oil is typically the wetting phase.The
Young–Laplace equation states that this pressure difference is proportional to thesurface tension , gamma, and inversely proportional to the effective radius, r, of the interface, it also depends on the wetting angle, heta, of the liquid on the surface of the capillary.:p_c=frac{2gamma cos heta}{r}The equation for capillary pressure is only valid under capillary equilibrium, which means that there can not be any flowing phases.
ee also
*
Capillary action
*Capillary number
*Leverett J-function
*Young–Laplace equation References
* Kim Kinoshita, Electrochemical Oxygen Technology p139, John Wiley & Sons, Inc. 1992.
* [http://www.articleworld.org/index.php/Capillary_pressure Capillary pressure equations]
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