Evaluation of limits for effective flame acceleration in hydrogen mixtures

Dorofeev, S.B.; Кузнецов, М.; Алексеев, В. И.; Ефименко, А.А.; Breitung, W.

doi:10.1016/s0950-4230(01)00050-x

Cited by 105 publications

(47 citation statements)

References 16 publications

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“…13), the cell size 25 at Á D 0:75 is 21 mm, so that the decrease in the experimental impulse data at low equivalence ratios can not be explained by cell size effects. Following the work of Dorofeev et al, 28 the magnitude of the expansion ratio was examined for these mixtures. However, calculations for lean hydrogen-air showed that the expansion ratio is always higher than the critical value de ned 28 for hydrogen mixtures.…”

Section: Comparisons With Multicycle Experimentsmentioning

confidence: 99%

“…Following the work of Dorofeev et al, 28 the magnitude of the expansion ratio was examined for these mixtures. However, calculations for lean hydrogen-air showed that the expansion ratio is always higher than the critical value de ned 28 for hydrogen mixtures. Instead, the results may be explained by the transition distance of the mixtures.…”

Section: Comparisons With Multicycle Experimentsmentioning

confidence: 99%

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Analytical Model for the Impulse of Single-Cycle Pulse Detonation Tube

Wintenberger

Austin

Cooper

et al. 2003

Journal of Propulsion and Power

170

100

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An analytical model for the impulse of a single-cycle pulse detonation tube has been developed and validated against experimental data. The model is based on the pressure history at the thrust surface of the detonation tube. The pressure history is modeled by a constant pressure portion, followed by a decay due to gas expansion out of the tube. The duration and amplitude of the constant pressure portion is determined by analyzing the gasdynamics of the self-similar ow behind a steadily moving detonation wave within the tube. The gas expansion process is modeled using dimensional analysis and empirical observations. The model predictions are validated against direct experimental measurements in terms of impulse per unit volume, speci c impulse, and thrust. Comparisons are given with estimates of the speci c impulse based on numerical simulations. Impulse per unit volume and speci c impulse calculations are carried out for a wide range of fuel-oxygen-nitrogen mixtures (including aviation fuels) of varying initial pressure, equivalence ratio, and nitrogen dilution. The effect of the initial temperature is also investigated. The trends observed are explained using a simple scaling analysis showing the dependency of the impulse on initial conditions and energy release in the mixture. = time taken by the rst re ected characteristic to reach the thrust surface t 3 = time associated with pressure decay period t ¤ = time at which the rst re ected characteristic exits the Taylor wave U CJ = Chapman-Jouguet detonation velocity u = ow velocity u e = exhaust velocity u 2 = ow velocity just behind detonation wave V = volume of gas within detonation tube X F = fuel mass fraction ® = nondimensional parameter corresponding to time t 2 = nondimensional parameter corresponding to pressure decay period°= ratio of speci c heats 1P = pressure differential 1P 3 = pressure differential at the thrust surfacé = similarity variablȩ = cell size 5 = nondimensional pressure ½ e = exhaust density ½ 1 = initial density of reactants ¿ = nondimensional time ct=L Á = equivalence ratio

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Section: Comparisons With Multicycle Experimentsmentioning

confidence: 99%

Section: Comparisons With Multicycle Experimentsmentioning

confidence: 99%

Analytical Model for the Impulse of Single-Cycle Pulse Detonation Tube

Wintenberger

Austin

Cooper

et al. 2003

Journal of Propulsion and Power

170

100

View full text Add to dashboard Cite

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“…Channels with obstacles are often used to study the flame acceleration and DDT in a controlled manner [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Considerable effort has been devoted to identifying the range of phenomenological behaviour of such flames and to deciphering the underlying mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Fast turbulent deflagration and DDT of hydrogen–air mixtures in small obstructed channel

Teodorczyk

Drobniak

Dąbkowski

2009

International Journal of Hydrogen Energy

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An experimental study of flame propagation, acceleration and transition to detonation in hydrogen-air mixture in 2 m long rectangular cross section channel filled with obstacles located at the bottom wall was performed. The initial conditions of the hydrogen-air mixture were 0.1 MPa and 293 K. Three different cases of obstacle height (blockage ratio 0.25, 0.5 and 0.75) and four cases of obstacle density were studied with the channel height equal to 0.08 m. The channel width was 0.11 m in all experiments. The propagation of flame and pressure waves was monitored by four pressure transducers and four in house ion probes. The pairs of transducers and probes were placed at various locations along the channel in order to get information about the progress of the phenomena along the channel. To examine the influence of mixture composition on flame propagation and DDT the experiments were performed for the compositions of 20%, 25% and 29.6% of H 2 in air by volume. As a result of the experiments the deflagration and detonation regimes and velocities of flame propagation in the obstructed channel were determined.

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“…These considerations were followed by many years of theoretical code development, such as GASFLOW [48], DET-3D [49], and COM3D [50] and experimental investigations, such as the RUT experiments in Russia [51][52][53][54][55]. The conclusion can be drawn from these theoretical and experimental efforts that a large-volume hydrogen detonation following a core meltdown accident can be managed by the reactor containment of existing modern PWRs, like the Konvoi-PWRs of Kraftwerk Union [56].…”

Section: Hydrogen Detonationmentioning

confidence: 99%