Weak and strong ignition of hydrogen/oxygen mixtures in shock-tube systems

Grogan, Kevin; Ihme, Matthias

doi:10.1016/j.proci.2014.07.074

Cited by 67 publications

(38 citation statements)

References 22 publications

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“…The low-temperature ignition of a hydrogen-air mixture behind an incident shock wave is explained in the present work by the supersonic character of fl ow behind the wave front, by the presence of a turbulent boundary layer, and, correspondingly, by the temperature increase in the near-wall region, which is confi rmed by the results of numerical simulation [16,17]. Among other possible reasons for the initiation of low-temperature ignition we may mention the turbulent character of gas fl ow in the contact region of the shock tube that separates the propelling and test gases, which may create ignition sites in this region with their subsequent merging.…”

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confidence: 61%

Ignition of Hydrogen–Oxygen Mixtures Behind the Incident Shock Wave Front

Павлов

Gerasimov

2016

J Eng Phys Thermophy

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Experimental investigation of the ignition of a stoichiometric hydrogen-oxygen mixture behind an incident shock wave in a shock tube at pressures p = 0.002-0.46 MPa and temperatures T = 500-1000 K is carried out. The existence of three limits of ignition typical of the ignition of hydrogen-oxygen mixtures in a spherical vessel is noted. It is shown that at pressures p ≥ 0.1 MPa the ignition of a hydrogen-oxygen mixture begins at a much lower temperature than the ignition of a hydrogen-air mixture. The measured induction times agree well with theoretical estimates.Introduction. Investigation of the ignition of hydrogen-oxygen mixtures in shock tubes behind the incident shock wave front is of both theoretical and practical interest. In particular, the creation of hypersonic passenger airplanes requires the development of new effi cient engines burning hydrogen fuel [1]. The supersonic character of fl ow of a gaseous mixture behind the incident shock wave front explains the attractiveness of the use of a shock tube for carrying out experiments related to the practical implementation of hydrogen ignition under conditions of a hypersonic fl ight [2]. The majority of research works concerned with the study of the process of ignition of combustible mixtures in shock tubes were carried out behind refl ected shock waves where the gas is at rest relative to the shock tube walls [3]. In a recent work [4], measurement of the limits of ignition and times of induction of hydrogen-air mixtures was made behind incident shock waves, as well as a comparison of the obtained results with the results of experiments conducted behind refl ected shock waves. Studies reporting on experimental works associated with ignition of hydrogen-oxygen mixtures behind refl ected shock waves are very few [5][6][7], whereas the data that would have been obtained behind incident shock waves are lacking completely.The aim of the present work is to determine the ignition limits and induction times in stoichiometric hydrogenoxygen mixtures behind the incident shock wave front and to compare the results obtained with those related to pertinent experiments with hydrogen-air mixtures.Experimental. Experiments on studying the process of ignition of hydrogen-oxygen mixtures were carried out on a shock tube (inner radius r = 28.5 mm) consisting of a high-pressure chamber of length 1 m and a low-pressure chamber of length 4.5 m separated by a diaphragm. The low-pressure chamber is fi lled with a test gas and the high-pressure one, with a propelling gas. When the diaphragm is ruptured, in the low-pressure chamber a shock wave starts to propagate, as well as to compress and heat the mixture being investigated. The test facility is equipped with systems of evacuation, preparation, and bleeding-in of gas mixtures, instrumentation for recording emission and absorption spectra, measuring the shock wave velocity, and recording the pressure profi le. The schematic diagram of the facility and description of the measuring equipment are given in [4].Experiments were carri...

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confidence: 61%

Ignition of Hydrogen–Oxygen Mixtures Behind the Incident Shock Wave Front

Павлов

Gerasimov

2016

J Eng Phys Thermophy

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“…This is generally attributed to the high sensitivity of the ignition delay to fluctuations, inherited from the very high activation energies of reactions 6 for the first loop and 8 for the second loop controlling the auto-ignition. Future study should clearly address whether the propensity for hot spots observed experimentally for this regime is due mainly to coupling to hydrodynamic scale fluctuations [30,[33][34][35], molecular non-equilibrium effects, or the acceleration of slow reactions by quantum tunneling effects [36,37], or a combination of these.…”

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confidence: 99%

Non-equilibrium effects on thermal ignition using hard sphere molecular dynamics

Murugesan

Sirmas

Radulescu

2019

Combustion and Flame

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“…The criterion by Meyer 85 and Oppenheim seemed to be applicable for C 2 H 2 /O 2 . For this mixture, a new critical value was found: Grogan and Ihme (2015) performed numerical simulations of reflected shock-induced ignition. They found good agreement of their numerical results for stoichiometric H 2 /O 2 at p 5 = 100 kPa and 300 kPa with Meyer and Oppenheim's criterion.…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%