  The field trap effect on the microcavity surface under the action of an
electric field is not conducive to boiling heat transfer. This numerical study
found that using conducting-insulating microcavity surfaces in an electric
field removes the field trap effect, increasing the critical heat flux by more
than 200%. Bubble behavior and heat transfer mechanisms on heating surfaces
were further explored. The results show that a large electrical force can be
generated at the junction of the conducting and insulating surfaces under the
action of the electric field, which drives the bubbles in the cavity to
departure quickly from the heating surface and avoids the formation of a vapor
block. As the electric field intensity increases, the contact line produces
pinning, which facilitates the formation of multiple continuously open
vapor-liquid separation paths on the heating surface, resulting in a
significant enhancement of the boiling heat transfer performance. Finally, a
modified correlation equation is proposed to predict the critical heat flux
under non-uniform electric field.
