Critical heat flux predictions during blowdown transients

Leung, Joseph Y.-T.; Gallivan, Kyle A.; Henry, Robert E.; Bankoff, S. G.

doi:10.1016/0301-9322(81)90038-0

Cited by 14 publications

(5 citation statements)

References 11 publications

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“…In the regime with q''<CHF, HTC typically increases with q'', as the solid surface interacts with an increased number of liquid and vapor pockets, maximizing the opportunity to transfer heat and mass across the liquid wedges of the multiple wetting lines. At CHF, the HTC is drastically reduced, which induces a significant and often destructive surface temperature increase [17][18][19] called dry-out.…”

Section: Introductionmentioning

confidence: 99%

Boiling heat transfer on superhydrophilic, superhydrophobic, and superbiphilic surfaces

Betz¹,

Jenkins²,

Kim³

et al. 2013

International Journal of Heat and Mass Transfer

464

180

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With recent advances in micro-and nanofabrication, superhydrophilic and superhydrophobic surfaces have been developed. The statics and dynamics of fluids on these surfaces have been well characterized. However, few investigations have been made into the potential of these surfaces to control and enhance other transport phenomena. In this article, we characterize pool boiling on surfaces with wettabilities varied from superhydrophobic to superhydrophilic, and provide nucleation measurements. The most interesting result of our measurements is that the largest heat transfer coefficients are reached not on surfaces with spatially uniform wettability, but on biphilic surfaces, which juxtapose hydrophilic and hydrophobic regions. We develop an analytical model that describes how biphilic surfaces effectively manage the vapor and liquid transport, delaying critical heat flux and maximizing the heat transfer coefficient. Finally, we manufacture and test the first superbiphilic surfaces (juxtaposing superhydrophobic and superhydrophilic regions), which show exceptional performance in pool boiling, combining high critical heat fluxes over 100 W/cm

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Section: Introductionmentioning

confidence: 99%

Boiling heat transfer on superhydrophilic, superhydrophobic, and superbiphilic surfaces

Betz¹,

Jenkins²,

Kim³

et al. 2013

International Journal of Heat and Mass Transfer

464

180

View full text Add to dashboard Cite

show abstract

“…If q'' is increased beyond CHF, the HTC is drastically reduced because heat is no longer transferred convectively but radiatively. This causes a significant and often destructive surface temperature increase [22][23][24] , called dry-out and recently seen in Fukushima, Japan 25 . Similar considerations can be made for condensation, where the transition from dropwise condensation to film condensation drastically reduces HTC.…”

Section: Characterization Of Phase Change Heat Transfermentioning

confidence: 99%

Surface engineering for phase change heat transfer: A review

Attinger

Frankiewicz

Betz

et al. 2014

MRS Energy & Sustainability

323

195

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Among numerous challenges to meet the rising global energy demand in a sustainable manner, improving phase change heat transfer has been at the forefront of engineering research for decades. The high heat transfer rates associated with phase change heat transfer are essential to energy and industry applications; but phase change is also inherently associated with poor thermodynamic efficiencies at low heat flux, and violent instabilities at high heat flux. Engineers have tried since the 1930's to fabricate solid surfaces that improve phase change heat transfer. The development of micro and nanotechnologies has made feasible the high-resolution control of surface texture and chemistry over length scales ranging from molecular levels to centimeters. This paper reviews the fabrication techniques available for metallic and siliconbased surfaces, considering sintered and polymeric coatings. The influence of such surfaces in multiphase processes of high practical interest, e.g. boiling, condensation, freezing, and the associated physical phenomena are reviewed. The case is made that while engineers are in principle able to manufacture surfaces with optimum nucleation or thermofluid transport characteristics, more theoretical and experimental efforts are needed to guide the design and cost-effective fabrication of surfaces that not only satisfy the existing technological needs, but also catalyze new discoveries.

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“…Reducing costs and runtime and achieving required accuracy are three main purposes of them. Leung et al (1981) studied acoustic impact techniques for increasing the accuracy of FT states modeling in CODA code [8]. However, regarding its very small meshing, acoustic methods are time-consuming and are not used any more.…”

Section: Introductionmentioning

confidence: 99%

“…Acoustic phenomenon is used in accommodation of very short time and very small body meshing. This accommodation is determined by Courant's criterion [8,20]:…”

Section: Introductionmentioning

confidence: 99%

Study of Fast Transient Pressure Drop in VVER-1000 Nuclear Reactor Using Acoustic Phenomenon

Sangestani

Rahgoshay

Vosoughi

et al. 2018

Science and Technology of Nuclear Installations

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This article aims to simulate the sudden and fast pressure drop of VVER-1000 reactor core coolant, regarding acoustic phenomenon. It is used to acquire a more accurate method in order to simulate the various accidents of reactor core. Neutronic equations should be solved concurrently by means of DRAGON 4 and DONJON 4 coupling codes. The results of the developed package are compared with WIMS/CITATION and final safety analysis report of Bushehr VVER-1000 reactor (FSAR). Afterwards, time dependent thermal-hydraulic equations are answered by employing Single Heated Channel by Sectionalized Compressible Fluid method. Then, the obtained results were validated by the same transient simulation in a pressurized water reactor core. Then, thermal-hydraulic and neutronic modules are coupled concurrently by use of producing group constants regarding the thermal feedback effect. Results were compared to the mentioned transient simulation in RELAP5 computer code, which show that mass flux drop is sensed at the end of channel in several milliseconds which causes heat flux drop too. The thermal feedback resulted in production of some perturbations in the changes of these parameters. The achieved results for this very fast pressure drop represent accurate calculations of thermoneutronic parameters fast changes.

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Critical heat flux predictions during blowdown transients

Cited by 14 publications

References 11 publications

Boiling heat transfer on superhydrophilic, superhydrophobic, and superbiphilic surfaces

Boiling heat transfer on superhydrophilic, superhydrophobic, and superbiphilic surfaces

Surface engineering for phase change heat transfer: A review

Study of Fast Transient Pressure Drop in VVER-1000 Nuclear Reactor Using Acoustic Phenomenon

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