Film boiling from a downward-facing curved surface in saturated and subcooled water

El‐Genk, Mohamed S.; Глебов, А. Г.

doi:10.1016/0017-9310(95)00136-w

Cited by 6 publications

(4 citation statements)

References 13 publications

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“…Both test sections are made of copper. The film boiling heat transfer coefficients from our experiments are larger than those from El-Genk and Glebov's experiments [17]. If the film boiling regime were strictly laminar in our experiments, the heat transfer coefficients should have been smaller than those from their experiment.…”

Section: Resultscontrasting

confidence: 62%

“…Figure 12 presents the film boiling heat transfer coefficients derived from the two experiments. The diameter of the test section in our experiments is the same as the curvature diameter of the test section in El-Genk and Glebov [17]. However, their test section was not a full downward-facing hemisphere, but rather a bottom piece whose edge angle was 9.88°.…”

Section: Resultsmentioning

confidence: 94%

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Film Boiling on Downward Quenching Hemisphere of Varying Sizes

Kim

Suh

Rempe

et al. 2004

12th International Conference on Nuclear Engineering, Volume 3

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Film boiling heat transfer coefficients for a downwardfacing hemispherical surface are measured from the quenching tests in DELTA (Downward-boiling Experimental Laminar Transition Apparatus). Two test sections are made of copper to maintain low Biot numbers. The outer diameters of the hemispheres are 120 mm and 294 mm, respectively. The thickness of all the test sections is 30 mm. The effect of diameter on film boiling heat transfer is quantified utilizing results obtained from the test sections. The measured data are compared with the numerical predictions from laminar film boiling analysis. The measured heat transfer coefficients are found to be greater than those predicted by the conventional laminar flow theory on account of the interfacial wavy motion incurred by the Helmholtz instability. Incorporation of the wavy motion model considerably improves the agreement between the experimental and numerical results in terms of heat transfer coefficient. In addition, the interfacial wavy motion and the quenching process are visualized through a digital camera.

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Section: Resultscontrasting

confidence: 62%

Section: Resultsmentioning

confidence: 94%

Film Boiling on Downward Quenching Hemisphere of Varying Sizes

Kim

Suh

Rempe

et al. 2004

12th International Conference on Nuclear Engineering, Volume 3

View full text Add to dashboard Cite

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“…When the gap size is less than 7 mm, the bottom surface of the acrylic vessel is easily deformed by the impact of the saturated fluid. Thus, there is an addi- -genk and Glebov (1996) Quenching water Curved copper Local and surface average Nusselt numbers were correlated in terms of the Rayleigh and Jacob numbers Yang et al (1997) Direct joule heating water (slightly subcooled)…”

Section: Experimental Apparatusmentioning

confidence: 99%

Subcooled pool boiling of water on a downward-facing stainless steel disk in a gap

Su¹,

Wu²,

Sugiyama³

2008

International Journal of Multiphase Flow

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“…A radiation to liquid through a gas film and a conductive heat transfer are involved into the calculation of total heat flux to model the heat transfer during film boiling. The film thickness as a function of wavelength, the departing vapor size and frequency are determined from empirical analysis results [14][15] .…”

Section: Modelsmentioning

confidence: 99%

Integrated fluid-thermal-structural numerical analysis for the quenching of metallic components

Gao

Fabijanic

Hilditch

et al. 2011

J. Shanghai Jiaotong Univ. (Sci.)

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The quenching of a metal component with a channel section in a water tank is numerically simulated. Computational fluid dynamics (CFD) is used to model the multiphase flow and the heat transfer in film boiling, nucleate boiling and convective cooling processes to calculate the difference in heat transfer rate around the component and then combining with the thermal simulation and structure analysis of the component to study the effect of heat transfer rate on the distortion of the U-channel component. A model is also established to calculate the residual stress produced by quenching. The coupling fluid-thermal-structural simulation provides an insight into the deformation of the component and can be used to perform parameter analysis to reduce the distortion of the component.Quenching is a common manufacturing process to obtain unique service performance properties of metallic parts by controlling the amount and the morphology of micro-structural constituents. As it is a complex multi physics problem, it is essential to couple fluid, thermal, phase transformation, microstructural and mechanical behaviour to describe the unusual complex phenomenon. The phase transformation during quenching and the final phase constituents result in different microstructures, which depend on cooling rate and chemical composition of the steel. The cooling rate at part surface highly depends on the flow and the thermo-physical properties of quenchant and the thermo-chemical reactions occurring at the interface. Non-uniform heat transfer and phase transformation associated with large temperature gradients can lead to the difference in variation of volume (expansion or contraction) within component and, as a result, produce high residual stresses in quenched steels. The internal stresses can produce distortion and even cracking. Each of the phenomena included in the quenching process and the coupling of some individual physical problems has been addressed by numerical methods [1][2] . There are a number of simulation works focusing on phase transformation, microstructure, residual stress and mechanical behaviour [2][3][4][5][6][7] . Due to the studies on the theory and the numerical simulation of the individual events that occur during quenching and the computational method for fast and accurate prediction of the multi-physical phenomenon in the last three decades, the simulation of quenching process became realistic and several commercial software packages had been developed to be capable of simulating quenching process, such as DANTE, DEFORM-HT, FORGE, HEARTS, SYSWELD and Quench Simulator. However, most studies consider the quenching process as a thermalmicrostructural-mechanical problem [1][2] and these software are incapable of coupling with dynamic characteristics of fluid in quenching tank, which determines the local cooling rate at part surfaces.Coupling quenching simulations with computational fluid dynamics (CFD) is a major interest [8][9] . However, fluid-thermal simulation in most of the research is focused on single phase l...

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Film boiling from a downward-facing curved surface in saturated and subcooled water

Cited by 6 publications

References 13 publications

Film Boiling on Downward Quenching Hemisphere of Varying Sizes

Film Boiling on Downward Quenching Hemisphere of Varying Sizes

Subcooled pool boiling of water on a downward-facing stainless steel disk in a gap

Integrated fluid-thermal-structural numerical analysis for the quenching of metallic components

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