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Hydrogen-Oxygen detonation

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Hydrogen-Oxygen detonation
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CC Attribution - NonCommercial - ShareAlike 3.0 Germany:
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Production PlaceFreiburg

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Abstract
The underlying physical experiment consists of a tube filled with hydrogen and oxygen. Both react and build a detonation front, moving to the right. The mathematical model consists of the compressible Euler equations with reactive source terms. They are solved by a finite volume scheme on an unstructured grid. Next to the detonation front the grid is locally refined and the refinement zone is moving with the front. Different geometries (e.g. with obstacles inside) of the tube are considered.
Keywords
Numerical analysisWaveOcean current
Finite element methodOcean currentModel theoryMixture modelComputer animation
Mixture modelMatching (graph theory)Time domainPopulation densityProduct (business)PressureComputer animation
Vapor barrierWaveComputer animation
AreaVapor barrierMatching (graph theory)Population densityTime zone
Group actionTime zonePopulation densityVapor barrierComputer animation
Complex (psychology)Mass flow rateVapor barrierClosed setComputer animation
19 (number)Computer animation
Mechanism designComputer animation
PiConcentricRadical (chemistry)Water vaporNumerical analysisTheoryObservational studyLoop (music)Mass flow rate
Pairwise comparisonResultantAirfoilFood energyComputer animation
Pairwise comparisonResultant
Transcript: English(auto-generated)
The simulation of the unstable behavior of detonation waves is a challenging subject of current research. The simulation models a detonation of an arbitrary unburned gas mixture.
This simple example already indicates the characteristic features we have to deal with. The four clippings of the domain show the dynamically adapted mesh, the reactant and the product of the chemical reaction, the density and the pressure.
Everything else being the same the detonation wave now meets a cascade of barriers. The fine areas of the adaptive mesh are marked yellow. They are located at the shock patterns that appear in the density below. The bar chart compares the numerical cost of the displayed simulation with the cost of a fictitious simulation based on a uniformly refined mesh.
A closer look at the density and the reaction zone between burned and unburned gas.
We observe a transition from a detonation to a deflagration behind the first barrier.
Applying the new visualization approach of texture transport we can analyze the complex time-dependent flow. We see above, the flow in the whole channel, below, a close-up inside the cascade of barriers.
The next simulation of a hydrogen-oxygen detonation with a detailed reaction mechanism involves 9 molecules and 48 elementary reactions. In general, simulations of realistic reactive flow problems are very demanding. Only modern numerical methods allow numerical studies of such phenomena.
The pictures from above show the adaptive mesh, pressure, the concentrations of hydrogen, water, hydrogen radical and the released chemical energy. The released chemical energy updated step-by-step displays the typical detonation cells.
This pattern can also be observed in experiments. The qualitative comparison with the smoke foil of STRALO suggests that the simulation is able to reproduce the experimental results.