PARTICLE TRANSIT-TIME DISTRIBUTIONS IN SINGLE PORES BY THE RESISTIVE PULSE TECHNIQUE

The aim of this paper is to explore the potential of the resistive pulse technique (Coulter principle) for studying flow through single pores of sizes relevant to flow in natural porous media. The Coulter principle has traditionally been used for counting and sizing particles, while we relate the particle transit time in long pores to flow properties. The transit times of monodisperse polystyrene spheres transported in Poiseuille flow through pores with diameters 3.1 and 27 μm and corresponding lengths 9.5 and 540 μm have been measured. Particle transit time distributions are analyzed in terms of hydrodynamic and electrokinetic contributions to the transit time and they compare well with the basic assumptions about the flow. Radial migration of particles (motion transverse to streamlines) is shown to be an important effect, while electrokinetic effects become significant at low pressures in the small pore. © 1990.