Electrohydrodynamic pumping of cable oil

Abstract Electrohydrodynamic pumping of a heated cable oil was demonstrated in a geometry similar to that of an underground pipe-type cable. The apparatus consisted of a closed channel approximately 5 m in length containing a 1.8 m pumping electrode. When driven with a three phase high voltage supply, the pump produced a steady oil circulation in the channel despite the fact that natural convection and flow instability severly disturbed the temperature gradients inside the fluid. A theory for electric pumping which neglects these disturbances was in fair agreement with experimental results. Extrapolation of these results to higher electric fields indicates that EHD pumping will produce oil velocities high enough for forced cooling of underground pipe cables.