Multiple temperature descriptions of reaction rate constants with regard to consistent chemical-vibrational coupling

Knab, O.; Fruehauf, H.-H.; Jonas, S.

doi:10.2514/6.1992-2947

Cited by 24 publications

(16 citation statements)

References 6 publications

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“…Although the vibrational-vibrational (V-V) energy redistribution is known to play only a secondary role in vibrational energy exchange, the multi-vibrational temperature option has been retained to allow a consistent coupling between dsmcFoam and hy2Foam. The formulation that has been implemented to account for V-V energy transfer is the one of Knab et al [25,26]. The source term designated by Q m, V−V may be written as (18) where N A is the Avogadro number, R is the universal gas constant, and P m,l represents the assessed exchange probability whose recommended value is a constant equal to 10 −2 [27].…”

Section: Two-temperature Modelmentioning

confidence: 99%

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A Two-Temperature Open-Source CFD Model for Hypersonic Reacting Flows, Part One: Zero-Dimensional Analysis

et al. 2016

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A two-temperature CFD (computational fluid dynamics) solver is a prerequisite to any spacecraft re-entry numerical study that aims at producing results with a satisfactory level of accuracy within realistic timescales. In this respect, a new two-temperature CFD solver, hy2Foam, has been developed within the framework of the open-source CFD platform OpenFOAM for the prediction of hypersonic reacting flows. This solver makes the distinct juncture between the trans-rotational and multiple vibrational-electronic temperatures. hy2Foam has the capability to model vibrational-translational and vibrational-vibrational energy exchanges in an eleven-species air mixture. It makes use of either the Park TTv model or the coupled vibration-dissociation-vibration (CVDV) model to handle chemistry-vibration coupling and it can simulate flows with or without electronic energy. Verification of the code for various zero-dimensional adiabatic heat baths of progressive complexity has been carried out. hy2Foam has been shown to produce results in good agreement with those given by the CFD code LeMANS (The Michigan Aerothermodynamic Navier-Stokes solver) and previously published data. A comparison is also performed with the open-source DSMC (direct simulation Monte Carlo) code dsmcFoam. It has been demonstrated that the use of the CVDV model and rates derived from Quantum-Kinetic theory promote a satisfactory consistency between the CFD and DSMC chemistry modules.

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Section: Two-temperature Modelmentioning

confidence: 99%

“…The vibrational-electronic energy added or removed by chemical reactions to species m is translated into an additional source term to appear in the NSF equations as seen in Equation (25). It takes the following form [30,31] …”

Section: Chemistry-vibration Coupling: the Park Ttv Modelmentioning

confidence: 99%

A Two-Temperature Open-Source CFD Model for Hypersonic Reacting Flows, Part One: Zero-Dimensional Analysis

et al. 2016

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“…The most interesting feature of the CVDV approach is discussed thoroughly by Knab, et al 26 . This feature is the fact that a physically consistent approach to vibration-dissociation coupling requires that the assumed change to the rate of dissociation from its thermal equilibrium state implies something about the rate at which vibrational energy is created and removed by dissociation and recombination.…”

Section: B Vibration-dissociation Couplingmentioning

confidence: 99%

“…Several generalizations exist to this methodology that extend the baseline model to include effects like exchange reactions, such as the CVCV 26,27 and CVDEV 28,29 models. As a beginning effort, we have considered only the CVDV baseline model of Marrone and Treanor, but incorporation of such additional features can easily be made.…”

Section: B Vibration-dissociation Couplingmentioning

confidence: 99%

A Computational Analysis of Thermochemical Studies in the LENS Facilities

MacLean

Holden

Wadhams

et al. 2007

45th AIAA Aerospace Sciences Meeting and Exhibit

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A review has been presented detailing the comparisons between numerical prediction and experimental data collected in the LENS facilities for a program focusing on thermochemical modeling of the flow in the reflected shock tunnel facility at high enthalpy. Comparisons have been provided for several studies made in the LENS-I facility including fundamental laser diode measurements of freestream nitric oxide concentration, temperature, and velocity; measurements on a two-dimensional cylinder; and measurements of laminar shock-wave/boundary layer interaction on a double cone geometry. The freestream velocity of the facility is found to be predicted to an accuracy of 2.5% or better for well-tailored conditions at all enthalpy levels, but the static temperature is significantly over-predicted for high enthalpy flows. Despite this, good agreement is obtained with all measurements for a two-dimensional cylinder. For the double cone model, the effect of vibration-dissociation coupling with the T-T V and CVDV models has been investigated. The choice of coupling model has impact for the lower enthalpy case, but in the high enthalpy case, it is unclear whether the discrepancy with the measurements is attributable to the coupling in the interaction region or the understanding of the freestream conditions.

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“…Vibrational-vibrational (V-V) energy transfer is denoted by Q m, V−V and modelled according to the formulation given by Knab et al [26,27], as described in [4]. In Equation (14), Q h−e , Q m, e−V , and Q e−i stand for the energy exchange between free-electrons and heavy-particles, free-electrons and the vibrational mode, and the vibrational energy removal due to electron impact ionisation, respectively.…”

Section: Energy Transfersmentioning

confidence: 99%

A Two-Temperature Open-Source CFD Model for Hypersonic Reacting Flows, Part Two: Multi-Dimensional Analysis

et al. 2016

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hy2Foam is a newly-coded open-source two-temperature computational fluid dynamics (CFD) solver that has previously been validated for zero-dimensional test cases. It aims at (1) giving open-source access to a state-of-the-art hypersonic CFD solver to students and researchers; and (2) providing a foundation for a future hybrid CFD-DSMC (direct simulation Monte Carlo) code within the OpenFOAM framework. This paper focuses on the multi-dimensional verification of hy2Foam and firstly describes the different models implemented. In conjunction with employing the coupled vibration-dissociation-vibration (CVDV) chemistry-vibration model, novel use is made of the quantum-kinetic (QK) rates in a CFD solver. hy2Foam has been shown to produce results in good agreement with previously published data for a Mach 11 nitrogen flow over a blunted cone and with the dsmcFoam code for a Mach 20 cylinder flow for a binary reacting mixture. This latter case scenario provides a useful basis for other codes to compare against.

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Multiple temperature descriptions of reaction rate constants with regard to consistent chemical-vibrational coupling

Cited by 24 publications

References 6 publications

A Two-Temperature Open-Source CFD Model for Hypersonic Reacting Flows, Part One: Zero-Dimensional Analysis

A Two-Temperature Open-Source CFD Model for Hypersonic Reacting Flows, Part One: Zero-Dimensional Analysis

A Computational Analysis of Thermochemical Studies in the LENS Facilities

A Two-Temperature Open-Source CFD Model for Hypersonic Reacting Flows, Part Two: Multi-Dimensional Analysis

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