Open AccessBehaviour of electrical double layer under oil flow and voltage application inside a capacitive sensor
Author(s) -
Metwally Ibrahim A.,
Leblanc Paul,
Paillat Thierry
Publication year - 2015
Publication title -
iet science, measurement and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.418
H-Index - 49
eISSN - 1751-8830
pISSN - 1751-8822
DOI - 10.1049/iet-smt.2014.0048
Subject(s) - capacitive sensing , materials science , voltage , electrode , space charge , transformer oil , analytical chemistry (journal) , flow (mathematics) , mechanics , electrical engineering , optoelectronics , transformer , electron , chemistry , physics , engineering , chromatography , quantum mechanics
This study presents an experimental investigation of the behaviour of electrical double layer (EDL) under oil flow and voltage application inside a capacitive sensor. This sensor is incorporated in a closed‐loop filled with fresh transformer oil. The sensor configuration allows a potential application for risk assessment. The behaviour of EDL is investigated by recording the streaming and the capacitive current waveforms for grounded and energised middle copper‐electrode cases and at different oil‐flow velocities and temperatures. The effect of direct and alternating voltage energisation is examined for different wave shapes and frequencies. In addition, the physicochemical reaction coefficient, the wall space–charge density and the accumulated charges inside the sensor are calculated by the static and the dynamic methods. The results are interpreted in terms of EDL evolution, physicochemical reaction at the solid–liquid interface, relaxation time of charges and electron emission from the negatively energised electrode. The results reveal that the calculated wall space–charge density slightly decreases with the increase in the oil‐flow velocity, contrary to the physicochemical reaction coefficient. For the case of AC energisation, the results show that there is an innocuous effect of the generated harmonic voltages on the oil‐flow electrification phenomenon.