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Electric field induced deformation of a water drop: The role of surface wettability
Drop deformation due to the presence of an electric field plays significant role in the formation of partial discharges. In this work we will perform computational study on the effect of the surface wetting behaviour on partial discharges from sessile drops.
drop that is placed on a surface spreads forming a spherical cap. The degree of the droplet’s spread
depends on the wetting behaviour of the surface per se. A drop placed on a hydrophobic surface (see panel a,
E= 0 kV/cm) spreads less compared to the case of being deposited on a hydrophilic surface (see panel
b, E= 0 kV/cm. Under the effect of an electric field the water drop deforms and elongates in the direction
of the electric field (see panel a and b). At a critical electric field strength the deformed droplet intensifies
locally the electric field leading to partial discharge inception that might lead to an electric breakdown under
specific conditions (see panel c). This critical field strength is lower for the case of the hydrophobic surface
compared to the hydrophilic one. This indicates that changing the wetting properties of a conductor influences
its performance in terms of partial discharge generation.
drop that is placed on a surface spreads forming a spherical cap. The degree of the droplet’s spread depends on the wetting behaviour of the surface per se. A drop placed on a hydrophobic surface (see panel a, E= 0 kV/cm) spreads less compared to the case of being deposited on a hydrophilic surface (see panel b, E= 0 kV/cm. Under the effect of an electric field the water drop deforms and elongates in the direction of the electric field (see panel a and b). At a critical electric field strength the deformed droplet intensifies locally the electric field leading to partial discharge inception that might lead to an electric breakdown under specific conditions (see panel c). This critical field strength is lower for the case of the hydrophobic surface compared to the hydrophilic one. This indicates that changing the wetting properties of a conductor influences its performance in terms of partial discharge generation.
We aim to conduct a computational study of the sessile drop deformation under the effect of an electric
field. Drop deformation will be studied under the effect of non-homogeneous electric field. The results of the
study will be compared to already obtained results for the case of homogeneous electric field. Moreover, the
effect of the slippery behaviour of a surface being quantified with contact angle hysteresis, will be investigated.
We aim to show that contact angle hysteresis is a determinant factor for the critical field strength at which a
partial discharge occurs. The student will have the chance to join a multidisciplinary team and work within an
exciting and interesting project that combines aspects of different disciplines.
Type Theory: 20%, Experiments: 80%
We aim to conduct a computational study of the sessile drop deformation under the effect of an electric field. Drop deformation will be studied under the effect of non-homogeneous electric field. The results of the study will be compared to already obtained results for the case of homogeneous electric field. Moreover, the effect of the slippery behaviour of a surface being quantified with contact angle hysteresis, will be investigated. We aim to show that contact angle hysteresis is a determinant factor for the critical field strength at which a partial discharge occurs. The student will have the chance to join a multidisciplinary team and work within an exciting and interesting project that combines aspects of different disciplines. Type Theory: 20%, Experiments: 80%
Christos Stamatopoulos, High Voltage Laboratory, ETH Zurich
Office: ETL H31.1
Email: stamatoc@ethz.ch
Tel: +41 44 632 2975
Christos Stamatopoulos, High Voltage Laboratory, ETH Zurich Office: ETL H31.1 Email: stamatoc@ethz.ch Tel: +41 44 632 2975