The Field-Trap Effect in Heat Transfer under Conditions of Boiling of Dielectric Liquids in External Electric Fields

The field-trap effect under conditions of boiling of dielectric liquids in nonuniform electric fields

“…In view of this, the bubbles arising in the region of strong field move to the region of weak field where they grow to the departure size to provide for an increase in local heat transfer. Such a mechanism is observed in the cited experiments [1,2] in the boiling of liquid nitrogen at a flat conducting surface with single projections leading to a local nonuniformity of electric field on a heated surface.…”

“…A new peculiar effect was observed in [1,2] in the investigation of heat transfer under conditions of boiling of liquid nitrogen in nonuniform electric fields: the superheating of the heated surface θ o.b. corresponding to the onset of boiling decreased with increasing field intensity, and the maximal local coefficients of heat transfer were observed at points of minimal field intensity on the heated surface.…”

“…corresponding to the onset of boiling decreased with increasing field intensity, and the maximal local coefficients of heat transfer were observed at points of minimal field intensity on the heated surface. In [1,2], this phenomenon was referred to as the field-trap effect, and the following qualitative explanation was offered: viable vapor bubbles arise at points of maximal field intensity with lower values of superheating θ o.b. than those in the absence of the field and are then caused by electrophoretic forces to move to regions of minimal intensity, where they grow to the departure size to provide for an increase in the local coefficient of heat transfer.…”

“…than those in the absence of the field and are then caused by electrophoretic forces to move to regions of minimal intensity, where they grow to the departure size to provide for an increase in the local coefficient of heat transfer. In so doing, the mechanism of displacement of bubbles into field traps was not analyzed as such in [1,2]. It is the objective of this study to analyze the mechanisms of the effect identified above.…”

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The mechanism of field-trap effect under conditions of boiling of dielectric liquids in a nonuniform electric field is discussed, which was experimentally observed in [1,2]. According to the data of [1, 2], an external electric field initiates the process of boiling up of liquid, with the growth of vapor bubbles to the departure size occurs mainly in regions with low values of electric field (in field traps).

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