Detonability of H/sub 2/-air-diluent mixtures

Tieszen, Sheldon R.; Sherman, M.P.; Benedick, W.B.; Berman, Marshall

doi:10.2172/6345574

Cited by 16 publications

(25 citation statements)

References 2 publications

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“…In the past, high explosives have been used to initiate detonations in hydrogen-air mixtures. For example, in the Heated Detonation Tube (HDT), Tieszen et al (1987) typically used 40 gm of explosives for most hydrogen-air mixtures and up to 80 gm for very lean mixtures. We can compare driver energetics with previous work that employed high-explosive initiators by measuring the amount of energy released by the HTCF gas driver.…”

Section: Gas Driver Energymentioning

confidence: 99%

“…The data covers the hydrogen-air composition range from 15 percent to 55 percent hydrogen. Also included in the figure are experimental data from the SSDA (Ciccarelli et al, 1994) and from Sandia's HDT (Tieszen et al, 1987). The plot of cell size versus hydrogen mole fraction results in the classical "U"-shaped curve where the minimum corresponds to the stoichiometric composition.…”

Section: Detonation Cell Size Measurementsmentioning

confidence: 99%

“…For this reason, most of the detonation research was limited to these conditions (Tieszen et al, 1987). Calculations by Yang (1992) have shown that under certain accident scenarios local compartment temperatures in excess of 373K can occur.…”

Section: Introductionmentioning

confidence: 99%

“…In an extension to the work done by Knystataus, Tieszen et al (1987), using a 45-cm diameter detonation tube, increased the cell size data base for hydrogen-air including the effect of steam dilution, initial pressure, and initial temperature. The maximum temperature investigated by Tieszen et al (1987) was 373K, so no defrnite conclusions concerning the effect of temperature on cell size could Two-and three-dimensional numerical simulations of detonation phenomena reproduce the cellular structure that has been observed experimentally (Oran et al, 1981;Fujiwara et al, 1989). Although encouraging, these codes have not yet been sufficiently refmed to the point where they can be used as predictive tools.…”

Section: Introductionmentioning

confidence: 99%

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Detonation cell size measurements in high-temperature hydrogen-air-steam mixtures at the BNL high-temperature combustion facility

Ciccarelli¹,

Ginsberg²,

Boccio³

1997

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The High-Temperature Combustion Facility (HTCF) was designed and constructed with the objective of studying detonation phenomena in mixtures of hydrogen-air-steam at initially high temperatures. The central element of the HTCF is a 27-cm inner-diameter, 21.3-m long cylindrical test vessel capable of being heating to 700K f 14K. A unique feature of the HTCF is the "diaphragmless" acetylene-oxygen gas driver which is used to initiate the detonation in the test gas.Cell size measurements have shown that for any hydrogen-air-steam mixture, increasing the initial mixture temperature, in the range of 300K to 650K, while maintaining the initial pressure of 0.1 MPa, decreases the cell size and thus makes the mixture more detonable. The effect of steam dilution on cell size was tested in stoichiometric and off-stoichiometric (e.g., equivalence ratio of 0.5) hydrogen-air mixtures. Increasing the steam dilution in hydrogen-air mixtures at 0.1 MPa initial pressure increases the cell size, irrespective of initial temperature. It is also observed that the desensitizing effect of steam diminished with increased initial temperature. A 1-dimensional, steady-state Zel'dovich, von Neumann, Doring (ZND) model, with full chemical kinetics, has been used to predict cell sue for hydrogen-air-steam mixtures at different initial conditions. Qualitatively the model predicts the overall trends observed in the measured cell size versus mixture composition and initial temperature and pressure. It was found that the proportionality constant used to predict detonation cell size from the calculated ZND model reaction zone varies between 10 and 100 depending on the mixture composition and initial temperature.iii NUREG/CR-639 1 EXECUTIVE SUMMARYThe High-Temperature Hydrogen Combustion Research Program, jointly funded by the U.S. Nuclear Regulatory Commission (NRC) and the Japanese Nuclear Power Engineering Corporation (NUPEC) which is sponsored by the Ministry of International Trade and Industries (MITI), is a 5-year program at Brookhaven National Laboratory (BNL)with the objective of studying detonation phenomena in mixtures of hydrogen-air and steam under prototypical severeaccident conditions. The principal experimental facility used in research program is the High-Temperature Combustion Facility (HTCF). A smaller facility, Le., the Small-scale Development Apparatus (SSDA), was constructed to support the design of the larger HTCF and to obtain preliminary experimental data. Experiments in the SSDA are complete and the results are reported in NUREG/CR-6213. Both the SSDA and the HTCF were designed to study detonations in gaseous mixtures of hydrogen-air and steam at temperatures up to 700K. The actual maximum initial gas temperature employed in this program has been 650K.The central element of the HTCF is a 27-cm inner-diameter and 2 1.3-m long cylindrical test vessel designed for a maximum allowable working pressure of 10.0 MPa at 700K. The test vessel is heated by electric heating blankets which are fastened to the test vessel. T...

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Section: Gas Driver Energymentioning

confidence: 99%

Section: Detonation Cell Size Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Detonation cell size measurements in high-temperature hydrogen-air-steam mixtures at the BNL high-temperature combustion facility

Ciccarelli¹,

Ginsberg²,

Boccio³

1997

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“…Experimental data are also available for detonation cell sizes in many different mixtures (Stamps et al 1991, Tieszen et al 1987, Akbar et al 1997, Pfahl et al 1998. Detonation cell size is a key predictor of Deflagration to Detonation Transitions (DDT).…”

Section: Validation: Combustion Model Output Comparison Tomentioning

confidence: 99%

Flammable Gas Refined Safety Analysis Tool Software Verification and Validation Report for Resolve Version 2.5

Bratzel¹

2000

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95/01454 Detonation cell size measurements and predictions in hydrogen-air-steam mixtures at elevated temperatures

Ciccarelli¹,

Ginsberg²,

Boccio³

et al. 1995

Fuel and Energy Abstracts

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The present research reports on the effect of initial mixture temperature on the experimentally measured detonation cell size for hydrogen-air-steam mixtures. Experimental and theoretical research related to combustion phenomena in hydrogen-air-steam mixtures has been ongoing for many years. However, detonation cell size data currently exists for hydrogen-air-steam mixtures up to a temperature of only 400K. Severe accident scenarios have been identified for light water reactors (LWRs) where hydrogen-air mixture temperatures in excess of 400K could be generated within containment. The experiments in this report focus on extending the cell size data base for initial mixture temperatures in excess of 400K. The experiments were carried out in a 10-cm inner-diameter, 6.1-m long heated detonation tube with a maximum operating temperature of 700K and spatial temperature uniformity of _14K. Detonation cell size measurements provide clear evidence that the effect of hydrogen-air initial gas mixture temperature, in the range 300K-650K, is to decrease cell size and, hence, to increase the sensitivity of the mixture to undergo detonations. The effect of steam content, at any given temperature, is to increase the cell size and, thereby, to decrease the sensitivity of stoichiometric hydrogen-air mixtures. The hydrogen-air detonability limits for the 10-cm inside-diameter test vessel, based upon the onset of single-head spin, decreased from 15 percent hydrogen at 300K down to about 9 percent hydrogen at 650K. The one-dimensional ZND model does a very good job at predicting the overall trends in the cell size data over the range of hydrogen-air-steam mixture compositions and temperature studied in the experiments.

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Detonability of H/sub 2/-air-diluent mixtures

Cited by 16 publications

References 2 publications

Detonation cell size measurements in high-temperature hydrogen-air-steam mixtures at the BNL high-temperature combustion facility

Detonation cell size measurements in high-temperature hydrogen-air-steam mixtures at the BNL high-temperature combustion facility

Flammable Gas Refined Safety Analysis Tool Software Verification and Validation Report for Resolve Version 2.5

95/01454 Detonation cell size measurements and predictions in hydrogen-air-steam mixtures at elevated temperatures

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