Computation of streaming current in oil pipes

The calculation of steaming current in oil pipes is involved in solving the charge conservation equation. It is a nonlinear equation without accurate analytical solution under turbulent-flow condition. Based on some reasonable simplifications, an approximate analytical expression for the equation and a due formula for streaming current are derived. It is proved with experimental results that the formula can accurately predict the streaming current, thus providing a method that is able to reliably and conveniently compute streaming electrification in oil pipe.