Development and testing of a numerical simulation method for thermally nonequilibrium dissociating flows in ANSYS Fluent

Shoev, Georgy; Bondar, Ye. A.; Oblapenko, Georgii; Кустова, Е. В.

doi:10.1134/s0869864316020013

Cited by 40 publications

(5 citation statements)

References 19 publications

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“…Here R c vibr , VT is the vibrational energy relaxation rate due to VT transitions for species c . As mentioned previously, the use of the kinetic theory based method for computation of the relaxation times in conjunction with the modified Landau–Teller formula can lead to an improvement in the modeling accuracy for strongly nonequilibrium flows. − …”

Section: Theorymentioning

confidence: 99%

“…If one derives the Landau–Teller formula within the Chapman–Enskog framework, a kinetic theory definition of VT relaxation times may be introduced. , It has been shown that VT relaxation times computed using this method are correct in terms of their qualitative behavior at higher temperatures, , and when used with a recently obtained modification of the Landau–Teller formula, can significantly improve the accuracy of numerical modeling of strongly nonequilibrium flows. − However, up to now, vibrational relaxation times computed using a kinetic theory definition have been considered only for binary mixtures of nitrogen and oxygen.…”

Section: Introductionmentioning

confidence: 99%

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Calculation of Vibrational Relaxation Times Using a Kinetic Theory Approach

Oblapenko

2018

J. Phys. Chem. A

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In the present work, a method for computation of vibrational relaxation times based on a kinetic theory definition is utilized to calculate vibrational relaxation times of molecules present in air (N 2 , O 2 , and NO) in collisions with air species particles. An overview of available experiment VT relaxation time measurements, as well as quasi-classical trajectory (QCT) calculation results, and various empirical models, is given. Different inelastic cross-section models are used for the computation of the relaxation times, and their parameters are adjusted to fit the available experimental data and QCT results. It is shown that the proposed method of calculation can give a quantitative and qualitative agreement with the available data in a wide range of temperatures; the obtained interaction parameters may be used not only for vibrational relaxation time calculation within a multitemperature framework but also for development of statespecific models for use in CFD and DSMC codes.

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Section: Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Calculation of Vibrational Relaxation Times Using a Kinetic Theory Approach

Oblapenko

2018

J. Phys. Chem. A

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“…Nevertheless, the inclusion of vibrational kinetics is fundamental for an accurate selfconsistent calculation of the gas temperature, as V-T transfers by collisions with O atoms play a crucial role in gas heating [9]. However, as shown in [59,60], vibrational relaxation in O 2 /O mixtures can be efficiently captured by the modified Landau-Teller formula [43], offering a significant simplification compared to the considerably more complex and costly STS approach. We assume a non-equilibrium Boltzmann distribution of vibrational states at T v , which is a good approximation for the first four vibrational levels at room temperature [61].…”

Section: Vibrational-translational Non-equilibriummentioning

confidence: 99%

Investigation of O atom kinetics in O₂ plasma and its afterglow

Albrechts,

Tsonev,

Bogaerts

2024

Plasma Sources Sci. Technol.

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We have developed a comprehensive kinetic model to study the O atom kinetics in an O2 plasma and its afterglow. By adopting a pseudo-1D plug-flow formalism within the kinetic model, our aim is to assess how far the O atoms travel in the plasma afterglow, evaluating its potential as a source of O atoms for post-plasma gas conversion applications. Since we could not find experimental data for pure O2 plasma at atmospheric pressure, we first validated our model at low pressure (1-10 Torr) where very good experimental data are available. Good agreement between our model and experiments was achieved for the reduced electric field, gas temperature and the densities of the dominant neutral species, i.e. O2(a), O2(b) and O. Subsequently, we confirmed that the chemistry set is consistent with thermodynamic equilibrium calculations at atmospheric pressure. Finally, we investigated the O atom densities in the O2 plasma and its afterglow, for which we considered a microwave O2 plasma torch, operating at a pressure between 0.1 and 1 atm, for a flow rate of 20 slm and an SEI of 1656 kJ/mol. Our results show that for both pressure conditions, a high dissociation degree of ca. 92 % is reached within the discharge. However, the O atoms travel much further in the plasma afterglow for p = 0.1 atm (9.7 cm) than for p = 1 atm (1.4 cm), attributed to the longer lifetime (3.8 ms at 0.1 atm vs 1.8 ms at 1 atm) resulting from slower three-body recombination kinetics, as well as a higher volumetric flow rate.

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“…Details of this technique can be found in [32]. The VT-exchange rate is calculated using the model suggested in [33], which was derived from the kinetic Boltzmann equation with the Chapman-Enskog method.…”

Section: Numerical Methods and Free-stream Conditionsmentioning

confidence: 99%