On the influence of non equilibrium in the free stream conditions of high enthalpy oxygen flows around a double-cone

Ninni, Davide; Bonelli, Francesco; Colonna, G.; Pascazio, G.

doi:10.1016/j.actaastro.2022.09.017

Cited by 18 publications

(9 citation statements)

References 67 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In order to assess the fidelity of the presented new model of the quasi-stationary expressions ( 11) -( 12) for the GRRs, we performed a comparison between the surface heat fluxes computed by different models and codes. The first numerical result is taken from [10] and is denoted as "Ninni, 2022." Additionally, we repeated the simulation with the HyCFS code being developed at ITAM.…”

Section: Comparison To Other Numerical Resultsmentioning

confidence: 99%

“…The cutoff harmonic oscillator model is employed for the diatomic molecules' vibrational energy 𝑒𝑒 𝛼𝛼 𝑣𝑣 = ℏ𝜔𝜔 𝑞𝑞 (𝑞𝑞 + 1 2 ⁄ ), where 𝜔𝜔 𝑞𝑞 is the oscillator frequency and 𝑞𝑞 is the vibrational quantum number. Though it leads to some inaccuracies, it is widely used to describe molecule internal vibrations when complex chemical reactions are studied [9,10]. On the other hand, this model yields analytical expressions for final quantities (reaction and relaxation rates), which makes the parametric analysis clear.…”

Section: Diatomic Gas Dissociation Modelmentioning

confidence: 99%

See 1 more Smart Citation

Gasdynamic equations with the number of gasdynamic variables exceeding the number of summational invariants

Gorbachev,

Shoev

2023

E3S Web Conf.

View full text Add to dashboard Cite

An asymptotic new method of solving the generalized Boltzmann equation previously developed by the authors is presented, and its difference from the traditional Chapman-Enskog method is discussed. The application of this new method is considered by an example of an O2/O dissociating mixture flow with separation around a double cone. A comparison with available literature and experimental data is presented. The computed and measured surface heat fluxes are found to be in reasonable agreement. The computed surface heat flux is analyzed through comparisons to numerical results of other researchers and codes.

show abstract

Section: Comparison To Other Numerical Resultsmentioning

confidence: 99%

Section: Diatomic Gas Dissociation Modelmentioning

confidence: 99%

Gasdynamic equations with the number of gasdynamic variables exceeding the number of summational invariants

Gorbachev,

Shoev

2023

E3S Web Conf.

View full text Add to dashboard Cite

show abstract

“…(2003) or Ninni et al. (2022) among others, the axial and normal grid spacings can be progressively refined until grid independence is observed. Such an approach is not computationally convenient for DSMC, which requires grids that resolve the local mean free path.…”

Section: Simulation Details: Geometry and Flow Conditionsmentioning

confidence: 99%

“…For CFD, a grid refinement study for these axisymmetric flows is relatively straightforward. For example, as shown by Nompelis et al (2003) or Ninni et al (2022) among others, the axial and normal grid spacings can be progressively refined until grid independence is observed. Such an approach is not computationally convenient for DSMC, which requires grids that resolve the local mean free path.…”

Section: Grid-independence Studymentioning

confidence: 99%

“…Also, the separation region was well predicted for most experimental cases. Various investigators further improved the numerical predictions by refining the simulation conditions, for example, by accounting for partial vibrational energy accommodation at the wall (Nompelis et al 2003), non-uniformity of the free stream (Nompelis et al 2003), better characterization of the non-equilibrium in the free stream (Candler et al 2002;Ninni et al 2022) and updated thermochemical models (Gao et al 2021). However, the agreement between experiments and computations was shown to worsen as the free stream enthalpy was increased (Nompelis et al 2010).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Near-continuum, hypersonic oxygen flow over a double cone simulated by direct simulation Monte Carlo informed from quantum chemistry

et al. 2023

View full text Add to dashboard Cite

A large-scale, fully resolved direct simulation Monte Carlo (DSMC) computation of a non-equilibrium, reactive flow of pure oxygen over a double cone is presented. Under the simulated near-continuum conditions, the computational demands are shown to be significant because of the wide range of length scales that must be resolved. Therefore, robust grid adaption capabilities and efficient parallelization of the Stochastic PArallel Rarefied-gas Time-accurate Analyzer (SPARTA) code that is utilized in this work are essential. The thermochemical and transport collision models were selected for efficiency and simplicity. First-principles data, obtained from the highly accurate direct molecular simulation method, were used to inform the collision models’ parameters. Importantly, because SPARTA implements molecular collision models using collision-specific energies, the resulting macroscopic relaxation rates were evaluated a posteriori via zero-dimensional heat bath simulations. The comparisons of surface properties, namely heat flux and pressure, show very close agreement with previous computational fluid dynamics (CFD) results. Differences with the measurements were found to be similar to the CFD simulations. The unresolved discrepancy with the measurements could be due to inconsistent free stream conditions with the actual experimental data or missing physical phenomena altogether, for example atomic and molecular oxygen electronically excited states, three-dimensional effects, or more complex gas–surface interactions. As shown in this work, the advantages of obtaining a DSMC particle solution for these flows reside in the method's ability to be directly informed from first principles and to seamlessly describe internal energy non-equilibrium for all modes. With the advent of exascale computing and beyond, particle methods will be an increasingly important tool to verify the validity of physical assumptions in reduced-order models via fully resolved, experimental-scale simulations, down to the level of molecular-level distributions.

show abstract

Influences of thermochemical non-equilibrium effects on Type III shock/shock interaction at Mach 10

Li,

Sun,

Dai

et al. 2024

Acta Astronautica

View full text Add to dashboard Cite

On the influence of non equilibrium in the free stream conditions of high enthalpy oxygen flows around a double-cone

Cited by 18 publications

References 67 publications

Gasdynamic equations with the number of gasdynamic variables exceeding the number of summational invariants

Gasdynamic equations with the number of gasdynamic variables exceeding the number of summational invariants

Near-continuum, hypersonic oxygen flow over a double cone simulated by direct simulation Monte Carlo informed from quantum chemistry

Influences of thermochemical non-equilibrium effects on Type III shock/shock interaction at Mach 10

Contact Info

Product

Resources

About