Échanges de chaleur dans l'hydrogène bouillant sous pression atmosphérique

Weil, L.; Lacaze, Albert

doi:10.1051/jphysrad:01951001209089000

Cited by 13 publications

(6 citation statements)

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“…After several iterative tests we arrived at the expected results of the new correlation (15), namely a coefficient of 0.86 and an average error of 84%, which is considered convincing results.…”

Section: New Correlationmentioning

confidence: 69%

“…A new correlation (15) has been presented allowing the calculation of the heat transfer coefficient as a function of the heat flux and the thermal-physical characteristics of hydrogen, giving convincing results.…”

Section: Discussionmentioning

confidence: 98%

“…Sets of experimental assemblies have been developed to study nucleate boiling, to identify the beginning of boiling and the limit of critical flux. An overall review and collection of experimental data relating to nucleate boiling [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31], ONB [21,26,28,30], and CHF [20,24,26,[28][29][30][31][32][33], was made for the pool boiling of hydrogen under saturation conditions.…”

Section: Review Of Experimental Data and Correlationsmentioning

confidence: 99%

“…An exhaustive review of the experimental data was made, presented in table 1, totaling 1200 points and concerning the nucleate pool boiling of hydrogen under saturation conditions. In this study, the pressure varies from 6.9×10 3 to 11×10 5 Pa, the heat flux extends over a range of 70 to 220×10 3 W/m², the temperature difference ΔT is limited between 0.03 and 27.93 K. The analysis of the experiments showed that different geometries were chosen for the body of the heating element, we note a tube [17], a ribbon [19], a cylinder [25], a sphere [22], wires [15,20,22], plates [16,18,[29][30][31] and the most used are disks [21][22][23][24][26][27][28]. These heating elements were made of various materials such as Lead, Platinum, Aluminum alloy, Chromel A, Teflon, Glass, Bronze, Steel, Stainless Steel, Manganin and the one that comes back the most is Copper.…”

Section: The Nucleate Boiling Reviewmentioning

confidence: 99%

“…4. Heat flux vs difference temperature of experiment data [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] The comparison of the experimental data with that predicted of the heat flux and the HTC by each of the chosen correlations, will be done with the error and correlation coefficient parameters defined below:…”

Section: Comparison With Correlationsmentioning

confidence: 99%

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Survey on the nucleate pool boiling of hydrogen and its limits

Baki

2020

Journal of Mechanical and Energy Engineering

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Nucleate pool boiling is a very efficient transfer regime with low temperature gradients, bounded between two heat flux values and which border transitions to other regimes, this phenomenon is well framed with correlations; our study aims to clarify the applicability of this regime to liquid hydrogen and to develop reliable correlations for a useful and qualitative agreement. An exhaustive review on the nucleate pool boiling of hydrogen and the limits of this regime, whether are the onset nucleate boiling (ONB) and the critical heat flux (CHF) was made, allowing the collection of more than 1400 points from experimental setups, highlighting a variety of parameters. Five predictive correlations were drawn from the literature, graphical and statistical comparisons were made, two in five reveal acceptable results. After analysis of the experimental data, new correlations were developed and compared with the data collected, convincing results were obtained and discussed. A simple form was expressed for the heat flux , shows better predicted values; convincing results of the (CHF) have been found on modified Kutateladze correlation (1948), and the CHF value reaches a maximum of 148×103 W/m² for a reduced pressure at 0.35; a nucleate boiling correlation suitable for hydrogen has been developed.

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Section: New Correlationmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 98%

Section: Review Of Experimental Data and Correlationsmentioning

confidence: 99%

Section: The Nucleate Boiling Reviewmentioning

confidence: 99%

Section: Comparison With Correlationsmentioning

confidence: 99%

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Survey on the nucleate pool boiling of hydrogen and its limits

Baki

2020

Journal of Mechanical and Energy Engineering

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Heat transfer characteristics of boiling nitrogen and neon in narrow annuli

1965

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The boiling characteristics of liquid neon and nitrogen in vertical annuli ranging between 0.006 and 0.080 in. wide were studied. The center tube wall, submerged to various depths, formed the boiling surface. Observations suggested a convective heat transfer mechanism, and correlation by a Dittus-Boelter equation form proved successful.Interest in cryogenically cooled magnets is rapidly increasing in view of the substantial energy reduction achieved at low temperatures. The compactness and low resistivity obtainable with cryomagnets are necessary to obtain very high field strengths in the order of lo" oersteds or higher.Magnets may be maintained at their desired temperatures by removing the required energy input as sensible heat in a fluid or as latent heat. Air, water, or kerosene are used for magnets operating at ambient temperatures. Removal of the heat generated in cryogenic magnets by means of a boiling liquid offers two major advantages over the use of a fluid utilizing sensible heat transfer: a lower temperature difference can be maintained between the boiling liquid and the magnet surface, hence, a lower resistivity, and a much smaller volume of coolant is required.At 30°K. the onIy fluid refrigerants are helium, hydrogen, and neon. Hydrogen and neon are more suitable from the heat transfer point of view, but safety considerations preclude the use of liquid hydrogen until more operating experience with cryomagnets is obtained. Other refrigerants are available for operation at higher cryogenic tempeatures. Some cryogenically cooled magnets have been operated at 78°K. by using liquid nitrogen as a coolant.The investigation was divided into two parts: 1. Study of pool boiling on a short vertical pipe with liquid nitrogen and neon. 2. Study of nitrogen and neon boiling in narrow annuli.The first part of this study was presented at the A.1.Ch.E. National Meeting, Pittsburgh, Pennsylvania (1 ) . This paper will present the second part of the study covering the various factors affecting the boiling performance in narrow annuli.The technical literature contains many studies and analyses of heat transfer to boiling liquids. These studies take many forms such as surveys (2, 3 ) , theoretical analyses ( 4 , 5, 6, 7, 8), experimental work (9, 10, 11, 1 2 ) , and statistical analyses ( 1 3 , 1 4 ) . Heat transfer to boiling cryogenic liquids has been thoroughly reviewed by Class et al. ( 2 ) and Richards et al. ( 3 ) . Both conclude that there are large variations in the magnitude of heat flux and in the shape of the heat flux VS. temperature difference curves, obtained by different investigators. These differences may be due to uncontrolled parameters such as surface roughness and contamination.The study of heat transfer to boiling liquids flowing in narrow channels is limited. The following is a brief review of the pertinent literature in this area. L.A. Wenzel is at Lehigh University, Allentown, Pennsylvania. (1) when short round tubes and rectangular channels having an equivalent diameter of 0.332 and 0.091 in., r...

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