(124f) Capillary-Driven Flow in Supported Capillary Pipes

A capillary-driven open channel flow is possible at low Bond number where the cylindrical free surface is supported by a solid structure such as a helical wire or polygonal array of straight wires. The initial penetration of the meniscus into the support structure is seen to be consistent with Washburn kinetics. The maximum possible steady state flow rate in a structure is dependent on the range of stable Laplace pressures. The stability of the supported free surface is studied experimentally in a Plateau tank for zero Bond number in order to compare with theoretical predictions of the stability limits. At zero Bond number the static stability limits are seen to depend on a few geometric factors and the contact angle. Possible applications of supported capillary pipes in the areas of microfluidics and microgravity will be discussed.