Space charge density in dielectric and conductive liquids flowing through a glass pipe

Flow electrification phenomena in the case of conductive and dielectric liquids flowing through an insulating pipe are compared. A theoretical model, which takes into account the development time of the diffuse layer in the case of a laminar flow, is compared with streaming current measurements. Experiments are conducted with water (electrical conductivity 0.2<σ<1.4 mS/m) and heptane (53<σ<1010 pS/m) flowing through a 32 μm-radius glass pipe. Evolution of the space charge density at the wall ρw in function of the liquid conductivity σ is analysed. Results show that the intensity of flow electrification depends mainly on the space charge density at the wall and the liquid electrical conductivity.