An experimental and numerical investigation of homogeneous ignition in catalytically stabilized combustion of hydrogen/air mixtures over platinum

Appel, Christoph; Mantzaras, John; Schaeren, Rolf; Bombach, Rolf; Inauen, Andreas; Kaeppeli, Beat; Hemmerling, B.; Stampanoni, Anna

doi:10.1016/s0010-2180(01)00363-7

Cited by 154 publications

(177 citation statements)

References 34 publications

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“…Raman measurements at distances less than 0.6 mm from both walls were discarded due to low signalto-noise ratio. The Raman setup was similar to that of earlier laminar H 2 /air CST studies [5].…”

Section: Laser Diagnosticsmentioning

confidence: 87%

“…The surface site density was 2.7 ‫ן‬ 10 ‫9מ‬ mol/cm 2 , simulating polycrystalline platinum [1,5]; the thick (2.2 lm) platinum layer on top of a non-porous Al 2 O 3 layer, closely resembled such a surface. For gaseous combustion, the H 2 /O 2 scheme of Warnatz et al [22] (38 reactions and nine species including N 2 ) was used.…”

Section: Chemical Kineticsmentioning

confidence: 99%

“…For gaseous combustion, the H 2 /O 2 scheme of Warnatz et al [22] (38 reactions and nine species including N 2 ) was used. The above schemes have been validated in their capacity to reproduce measured catalytic fuel conversion and homogeneous ignition in laminar channel CST [5]. Gaseous and surface reaction rates were evaluated with CHEMKIN [23] and Surface-CHEMKIN [24], respectively.…”

Section: Chemical Kineticsmentioning

confidence: 99%

“…Elementary heterogeneous reaction schemes for simple fuels (CH 4 , CO, and H 2 ) over Pt were developed and tested in their capacity to reproduce measured light-off characteristics and minor species fluxes [1][2][3], whereas combined hetero-/homogeneous schemes for CH 4 and H 2 over Pt were validated recently [4,5]. In particular, the experimental and numerical investigation of Appel et al [5] assessed the homogeneous ignition capabilities of various H 2 /O 2 hetero-/homogeneous reaction schemes. Analytical studies have further elucidated the dependence of homogeneous ignition on the controlling parameters of the channel-flow configuration [6].…”

Section: Introductionmentioning

confidence: 99%

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An experimental and numerical investigation of turbulent catalytically stabilized channel flow combustion of hydrogen/air mixtures over platinum

Appel

Mantzaras

Schaeren

et al. 2002

Proceedings of the Combustion Institute

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The turbulent catalytically stabilized combustion (CST) of fuel-lean hydrogen/air mixtures over platinum was investigated experimentally and numerically in channel-flow configurations. Experiments were performed in an optically accessible catalytic channel reactor, established by two Pt-coated ceramic plates 300 mm long and placed 7 mm apart, with incoming Reynolds numbers of 15,000 and 30,000. Planar laserinduced fluorescence of the OH radical was used to monitor the onset of homogeneous (gas-phase) ignition, one-dimensional (across the 7 mm transverse direction) Raman measurements of major species and temperature assessed the turbulent scalar transport, laser doppler velocimetry yielded the inlet velocity and turbulence, and thermocouples embedded beneath the catalyst provided the surface temperature distribution. Computations were carried out with a two-dimensional elliptic fluid mechanical code that included elementary heterogeneous and homogeneous chemical reaction schemes. Three different low-Reynolds number near-wall turbulence models were examined, in conjunction with a thermochemistry model that included a presumed-shape (Gaussian) probability density function approach for the gaseous reactions and a laminar-like closure for catalytic reactions. Comparisons between predictions and measurements have shown that key CST issues, such as catalytic fuel conversion and onset of homogeneous ignition, are strongly dependent on the particular turbulence model. Moreover, the discrepancies between predictions and measurements were ascribed to the capacity of the various turbulence models to capture the strong flow laminarization induced by the heat transfer from the hot catalytic surfaces. A turbulence model that yields good agreement with the measurements is presented as particularly suited for CST. Experiments and predictions have shown that a continuous increase of the turbulent transport led to incomplete combustion through the gaseous reaction zone with subsequent catalytic conversion of the leaked fuel and, finally, to extinction of the gaseous flame.

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Section: Laser Diagnosticsmentioning

confidence: 87%

Section: Chemical Kineticsmentioning

confidence: 99%

Section: Chemical Kineticsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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An experimental and numerical investigation of turbulent catalytically stabilized channel flow combustion of hydrogen/air mixtures over platinum

Appel

Mantzaras

Schaeren

et al. 2002

Proceedings of the Combustion Institute

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“…Desorbing intermediates and radicals may trigger chemical reactions in the gas-phase and by this open a competing reaction pathway. For instance, desorbing OH from Pt can enhance homogeneous ignition in the gas phase in catalytically supported combustion [14]. On the other hand, adsorbing radicals may quench chemical reactions in the gas-phase such as in the suppression of explosions in catalytic micro reactors [15].…”

Section: Introductionmentioning

confidence: 99%

Modeling of the Interactions Between Catalytic Surfaces and Gas-Phase

Deutschmann

2014

Catal Lett

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The catalytic surface interacts with the gasphase by a variety of chemical and physical processes. Hence, optimization of design and operation conditions of catalytic reactors do not only require the understanding of the catalytic reaction sequence but also its coupling with mass and heat transport and potential homogeneous reactions. The chemical, thermal, and mass-transport interactions between the catalytic surface and the gas-phase are discussed in terms of the individual and combined interactions. The state-of-the-art modelling of reactive flows and its coupling with the catalytic surface is summarized. The interactions are illustrated by a number of examples such as reforming of hydrocarbons, catalytic combustion, exhaust-gas after-treatment, each focusing on a special aspect of catalyst-gas interactions. The potentials and limitations of the numerical simulations will be discussed including experimental techniques for model validation.

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Hetero‐/Homogeneous Combustion

Mantzaras

2010

Handbook of Combustion

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The sections in this article are Introduction Fundamentals of Catalytic Combustion Reactor Thermal Management Hetero‐/Homogeneous Combustion in Power Generation Hetero‐/Homogeneous Kinetics Fuel‐Lean Methane Combustion on Platinum Catalytic Kinetics Gas‐Phase Kinetics Hetero‐/Homogeneous Chemistry Coupling Fuel‐Lean Hydrogen Combustion on Platinum Fuel‐Rich Methane Combustion on Rhodium Application to Practical Systems Turbulent Hetero‐/Homogeneous Combustion Conclusions Acknowledgments

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An experimental and numerical investigation of homogeneous ignition in catalytically stabilized combustion of hydrogen/air mixtures over platinum

Cited by 154 publications

References 34 publications

An experimental and numerical investigation of turbulent catalytically stabilized channel flow combustion of hydrogen/air mixtures over platinum

An experimental and numerical investigation of turbulent catalytically stabilized channel flow combustion of hydrogen/air mixtures over platinum

Modeling of the Interactions Between Catalytic Surfaces and Gas-Phase

Hetero‐/Homogeneous Combustion

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