Capillary bridges between spherical particles under suction control: Rupture distances and capillary forces

This study focuses on properties of axisymmetric capillary bridges between spherical particles in the pendular regime under suction control. Using the toroidal approximation in combination with the governing Young-Laplace equation, analytical expressions for the rupture distance (dependent on the suction) and for the capillary force (dependent on the suction and the interparticle separation distance) have been obtained that do not involve any calibrated coefficient. The developed analytical expressions are effective for values of the dimensionless suction larger than 10 4. To predict capillary forces and rupture distances for a wider range of values of the dimensionless suction, closed-form expressions for rupture distances and capillary forces have been obtained by curve-fitting to a large dataset of numerical solutions of the Young-Laplace equation. It is shown that these expressions can also be employed for capillary bridges between spheres with unequal radii when the Derjaguin radius is employed