Principal Mechanism of Micro-Liquid-Layer Formation on a Solid Surface with Growing Bubbles in Nucleate Boiling

Abstract The effect of solid particle introduction on subcooled-forced flow boiling heat transfer and a critical heat flux was examined experimentally. In the experiment, glass beads of 0.6 mm diameter were mixed in subcooled water. Experiments were conducted in a range of the subcooling of 40 K, a velocity of 0.17–6.7 m/s, a volumetric particle ratio of 0–17%. When particles were introduced, the growth of a superheated liquid layer near a heat trasnsfer surface seemed to be suppressed and the onset of nucleate boiling was delayed. The particles promoted the condensation of bubbles on the heat transfer surface, which shifted the initiation of a net vapor generation to a high heat flux region. Boiling heat trasnfer was augmented by the particle introduction. The suppression of the growth of the superheated liquid layer and the promotion of bubble condensation and dissipation by the particles seemed to contribute that heat transfer augmentation. The wall superheat at the critical heat flux was elevated by the particle introduction and the critical heat flux itself was also enhanced. However, the degree of the critical heat flux improvement was not drastic.

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Wetting behaviour on a solid surface contaminated with a liquid layer

Contact Angle, Wettability and Adhesion, Volume 2 ◽

10.1201/b11975-31 ◽

2014 ◽

pp. 413-426

Keyword(s):

Liquid Layer ◽

Solid Surface

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Microscopic Activation Phenomena in Heterogeneous Nucleation

Heat Transfer: Volume 2 ◽

10.1115/ht2003-47469 ◽

2003 ◽

Cited By ~ 2

Author(s):

J. F. Lu ◽

X. F. Peng

Keyword(s):

Liquid Layer ◽

Solid Surface ◽

Heterogeneous Nucleation ◽

Bubble Formation ◽

Ultrathin Film ◽

Wall Surface ◽

Bulk Region ◽

Heating Wall ◽

Energy Peak ◽

Energy Property

The energy property in liquid near the wall was theoretically investigated to understand the effects of wall surface on inception process of nucleation or embryo bubble formation in boiling systems. Analyses indicate that the liquid near heating wall has higher pressure than in bulk region owing to existence of strong attractive forces, and this pressure could maintain a stable liquid microlayer and cause a steady energy peak near the wall. So a vapor embryo is likely to occur beyond the stable microlayer instead of exactly at the solid surface. The stable liquid layer may also be the inception structure of the ultrathin film before nucleation occurs. Fluctuations enhance the phenomenon of energy peak until the nucleation occurs, while energy peak promotes nucleation. Employing the concept of energy peak, the inception phenomena of the microlayer and the formation of embryo bubbles near solid surface were described.

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Dynamics of electrical double layer formation at a charged solid surface

Journal of Molecular Structure THEOCHEM ◽

10.1016/s0166-1280(98)90225-1 ◽

1998 ◽

Vol 430 ◽

pp. 105-111 ◽

Cited By ~ 2

Author(s):

Amalendu Chandra

Keyword(s):

Double Layer ◽

Solid Surface ◽

Electrical Double Layer ◽

Layer Formation

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High Speed Liquid Impact Onto Wetted Solid Surfaces

Journal of Fluids Engineering ◽

10.1115/1.2910278 ◽

1994 ◽

Vol 116 (2) ◽

pp. 345-348 ◽

Cited By ~ 11

Author(s):

H. H. Shi ◽

J. E. Field ◽

C. S. J. Pickles

Keyword(s):

Shock Wave ◽

Liquid Layer ◽

Solid Surface ◽

High Speed ◽

Shear Failure ◽

Soda Lime ◽

Liquid Jet ◽

Soda Lime Glass ◽

The Impact

The mechanics of impact by a high-speed liquid jet onto a solid surface covered by a liquid layer is described. After the liquid jet contacts the liquid layer, a shock wave is generated, which moves toward the solid surface. The shock wave is followed by the liquid jet penetrating through the layer. The influence of the liquid layer on the side jetting and stress waves is studied. Damage sites on soda-lime glass, PMMA (polymethylmethacrylate) and aluminium show the role of shear failure and cracking and provide evidence for analyzing the impact pressure on the wetted solids and the spatial pressure distribution. The liquid layer reduces the high edge impact pressures, which occur on dry targets. On wetted targets, the pressure is distributed more uniformly. Despite the cushioning effect of liquid layers, in some cases, a liquid can enhance material damage during impact due to penetration and stressing of surface cracks.

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