Education - Colloquium - WPI Only
Tuesday, June 25, 2013
11:00 AM-12:00 PM
Even if the phenomenon of flow electrification has been investigated for a rather long time, it still remains a worrying phenomenon for various industrial activities like hydrocarbon or liquefied gas transfer, or cooling system with insulating liquids such is the case in high power transformers.
The flow electrification phenomenon is the convection, due to a flow, of a part of the electrical double layer appearing at the inner wall of a pipe or a channel. Indeed when a liquid is in contact with a solid, a physicochemical reaction appears which lead to an electric charge in the solid (one part of the double layer) and the opposite charge in the liquid (the other part of the double layer). In fact the charge in the liquid are generally separate in two zones : one very close to the solid wall which is called the compact layer and the thickness of which is so small that it cannot be affected by the flow ; the other one, called the diffuse layer, has a thickness proportional to the square root of the electrical resistivity of the liquid. Thus in the case of insulating liquid this layer can be rather thick. The flow electrification is the convection of this diffuse layer.
Then, even if the current generated by this convection is rather small, often in the order of pA, the voltage reach by some insulated part could be important due to the very small charge dissipation. These high voltages can under certain conditions generate electrical discharges and lead to electrostatic hazards
Suggested Audiences: College
Last Modified: June 6, 2013 at 10:33 AM