Static liquid hold-up and capillary rise in packed beds

A theory is presented that predicts both static liquid hold-up and capillary rise in a randomly packed bed of spherical particles. It exploits the experimental observation that the liquid that is retained in a packed bed after drainage is primarily present in the form of pendular liquid bonds between touching spheres. By considering this drained state as a network of liquid pendular bonds at critical percolation, the predictions for static liquid hold-up and for capillary rise follow naturally. The predictions for both phenomena agree well with experimental data. (C) 1998 Elsevier Science Ltd. All rights reserved.