Electrostatic Charge Generation in Hydrocarbon Liquids

摘要

A novel method was developed to study the electrification of hydrocarbon liquids. The apparatus is a coaxial cylinder flow generator which contains the test fluid. It is geometrically similar to a Couette viscometer. The electrically grounded, inner metal cylinder (bob) was rotated within an electrically floating metal cup. The induced charge was measured as the electrical potential difference across a capacitor attached to the cup wall. The charging potential was measured as a function of the bob speed, the width of the annulus, and the electrical conductivity of the hydrocarbon liquid. Potentials in the range of 0.1 to 100 volts were obtained. The charging potential was found to increase approximately linearly with bob speed and with gap width, and to decrease approximately as the square root of the conductivity. The observations are compatible with dimensional arguments for the system when combined with a theoretical consideration of the double layer structure. In one series of experiments, the conductivity of toluene was varied by doping with calcium dodecyl sulfosuccinate, a constituent of Shell Anti-Static additive. This provided a method by which the electrical conductivity could be varied without altering the solvent.