Effect of surface tension, viscosity, pore geometry and pore contact angle on effective pore throat

Cong Chao, Xianfeng Fan

Research output: Contribution to journalArticlepeer-review


Through experimental measurement and theoretical calculation, we have investigated the effect of sur-face tension, liquid viscosity and the capillary geometry (capillary gradient and tip diameter) on the effec-tive pore throat, and the impact of the effective pore throat on pore resistance to two-phase interfacesformed from fluids with different viscosities and surface tensions. When a two-phase interface flowsin channels with varied pore diameter, capillary force is insignificant in the section of the channel withan inner pore diameter greater than the effective pore throat, and the pressure drops in this sectiondepend on capillary tip diameter, rather than the surface tension. Capillary force takes significant effecton the interface only when the pore diameter in a tapered capillary is smaller than the effective porethroat. Effective pore throat depends on fluid surface tension and the capillary geometry, but not on liq-uid viscosity. The higher the fluid surface tension, the larger the diameter of the effective pore throat. Achannel with a large tip diameter or gradient will give a large effective pore throat diameter. Fluid vis-cosity only affects the magnitude of the resistant pressure drops of fluid flows in constricted capillaries,but does not affect the effective pore throat diameter. The effective pore throat and the pressure profilemeasured in this study can be explained by the pore contact angle, but cannot be explained by the con-tact angle on a flat surface of the same materials.
Original languageEnglish
Pages (from-to)269-279
Number of pages197
JournalChemical Engineering Science
Early online date7 Jan 2019
Publication statusPublished - Apr 2019


  • Capillary resistance
  • Two-phase flows
  • Pore throat
  • Surface tension
  • Constricted capillary
  • Pore contact angle

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