Vapor bubble departure in forced convection boiling

Klausner, James F.; Mei, Renwei; Bernhard, Dirk; Zeng, Long

doi:10.1016/0017-9310(93)80041-r

Cited by 417 publications

(291 citation statements)

References 10 publications

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“…To satisfy a balance of estimated force components normal to the wall, a correction parameter is often used to multiply the overpressure with. 12,13 The present analysis will be shown to be accurate enough not to need such a correction parameter and is useful for the development of point force models.…”

Section: -2mentioning

confidence: 77%

“…We therefore prefer to group inertia forces not involving generalized accelerations (M 2 ) and name them the potential flow lift on the bubble. This grouping avoid the naming of individual terms of the potential lift, such as "unsteady growth force" 12,13 and "hydrodynamic force." 12 Whatever the Reynolds number, potential lift occurs and the only lift force contribution missing in our analysis stems from the vorticity contribution F 2 vort .…”

Section: E Range Of Applicability Of Derived Drag and Lift Forces Fomentioning

confidence: 99%

“…This grouping avoid the naming of individual terms of the potential lift, such as "unsteady growth force" 12,13 and "hydrodynamic force." 12 Whatever the Reynolds number, potential lift occurs and the only lift force contribution missing in our analysis stems from the vorticity contribution F 2 vort . At high-Reynolds number flows, only potential lift is important since the vorticity is confined to thin boundary layers with a thickness inversely proportional to the square root of the Reynolds number.…”

Section: E Range Of Applicability Of Derived Drag and Lift Forces Fomentioning

confidence: 99%

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Forces on a boiling bubble in a developing boundary layer, in microgravity with g-jitter and in terrestrial conditions

et al. 2012

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International audienceTerrestrial and microgravity flow boiling experiments were carried out with the same test rig, comprising a locally heated artificial cavity in the center of a channel near the frontal edge of an intrusive glass bubble generator. Bubble shapes were in microgravity generally not far from those of truncated spheres,which permitted the computation of inertial lift and drag from potential flow theory for truncated spheres approximating the actual shape. For these bubbles, inertial lift is counteracted by drag and both forces are of the same order of magnitude as g-jitter. A generalization of the Laplace equation is found which applies to a deforming bubble attached to a plane wall and yields the pressure difference between the hydrostatic pressures in the bubble and at the wall, �p. A fully independent way to determine the overpressure p is given by a second Euler-Lagrange equation. Relative differences have been found to be about 5% for both terrestrial and microgravity bubbles. A way is found to determine the sum of the two counteracting major force contributions on a bubble in the direction normal to the wall from a single directly measurable quantity. Good agreement with expectation values for terrestrial bubbles was obtained with the difference in radii of curvature averaged over the liquid-vapor interface, �(1/R2 − 1/R1)�, multiplied with the surface tension coefficient, σ. The new analysis methods of force components presented also permit the accounting for a surface tension gradient along the liquid-vapor interface. No such gradients were found for the present measurements

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Section: -2mentioning

confidence: 77%

Section: E Range Of Applicability Of Derived Drag and Lift Forces Fomentioning

confidence: 99%

Section: E Range Of Applicability Of Derived Drag and Lift Forces Fomentioning

confidence: 99%

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Forces on a boiling bubble in a developing boundary layer, in microgravity with g-jitter and in terrestrial conditions

et al. 2012

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“…where u r is the relative velocity between the bubble center of mass and the liquid phase, i.e., u r = u f -u g , and the C l is the shear lift coefficient given by [6] ( ) …”

Section: Shear Lift Forcementioning

confidence: 99%

“…For bubble departure, the force balance along the flow direction was usually considered [5], while for bubble lift-off, the force balance normal to the flow direction was crucial [6,7].…”

Section: Introductionmentioning

confidence: 99%

Bubble lift-off size in forced convective subcooled boiling flow

Situ

Hibiki

Ishii

et al. 2005

International Journal of Heat and Mass Transfer

169

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Forced convective subcooled boiling flow experiments were conducted in a BWR-scaled vertical upward annular channel. Water was used as the testing fluid, and the tests were performed at atmospheric pressure. A high-speed digital video camera was applied to capture the dynamics of the bubble nucleation process. Bubble lift-off diameters were obtained from the images for a total of 91 test conditions. A force balance analysis of a growing bubble was performed to predict the bubble lift-off size. The dimensionless form of the bubble lift-off diameter was formulated to be a function of Jacob number and Prandtl number. The proposed model agreed well with the experimental data within the averaged relative deviation of ±35.2 %.

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Nanoengineering Scalephobic Surfaces for Liquid Cooling Enhancement

Schmid,

Armstrong,

Denz

et al. 2024

Adv Materials Inter

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Crystallization fouling, a process where mineral scales form on surfaces, is of broad importance in nature and technology, negatively impacting water treatment and electricity production. However, a rational methodology for designing materials with intrinsic resistance to scaling and scale adhesion remains elusive. Here, guided by nucleation physics, this work investigates the effect of coating composition and surface structure on the nucleation and growth mechanism of scale on metallic heat transfer surfaces nanoengineered by large‐area techniques. This work observes that on hydrophilic nanostructured copper, despite its significantly enlarged surface area compared to smooth surfaces, scale formation is substantially suppressed leading to sustained, efficient cooling performance. This work reveals the mechanism through thermofluidic modeling coupled with in situ optical characterization and show that surface bubble formation through degassing is responsible for generating local hot spots enhancing supersaturation. This work then demonstrates a scalephobic nanostructured surface which reduces the accumulated surface scale mass 3.5× and maintains an 82% higher heat transfer coefficient compared to superhydrophobic surfaces with corresponding energy conversion savings. This work not only advances the understanding of fouling mechanisms but also holds promise for practical applications in industries reliant on efficient heat transfer processes.

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Vapor bubble departure in forced convection boiling

Cited by 417 publications

References 10 publications

Forces on a boiling bubble in a developing boundary layer, in microgravity with g-jitter and in terrestrial conditions

Forces on a boiling bubble in a developing boundary layer, in microgravity with g-jitter and in terrestrial conditions

Bubble lift-off size in forced convective subcooled boiling flow

Nanoengineering Scalephobic Surfaces for Liquid Cooling Enhancement

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