DSMC Modeling of Gasdynamics, Radiation and Fine Particulates in Ionian Volcanic Jets

Zhang, J.; Goldstein, David; Varghese, Philip L.; Gimelshein, Natalia; Gimelshein, S. F.; Levin, Deborah A.; Trafton, L. M.

doi:10.1063/1.1581612

Cited by 8 publications

(7 citation statements)

References 23 publications

(30 reference statements)

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“…The initial conditions for each case are defined by the relative collision velocity and the SO 2 internal energy. Relative collision velocities of 1,2,4,8,9,10,12,16,22,30,45,60, and 80 km/s were studied. The initial SO 2 internal energies considered were 1.44, 7.20, 28.79, 57.57, and 86.36 kcal/mol.…”

Section: Md/qct Methodology and Simulation Conditionsmentioning

confidence: 99%

“…Since Io's atmosphere is rarefied, its planetary gas dynamics is modeled using the Direct Simulation Monte Carlo (DSMC) approach. Comprehensive planetary physics modeling through the use of DSMC by Austin et al, 2, 3 Zhang et al, [4][5][6][7] Moore et al, [8][9][10][11] and Walker et al 12,13 has been ongoing to study the complex phenomenology of Io's energetic, but rarefied atmosphere.…”

Section: Introductionmentioning

confidence: 99%

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DSMC implementation of MD/QCT generated energy distributions for SO₂+ O collisions

Parsons

Levin

2013

44th AIAA Thermophysics Conference

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The unique atmospheric conditions on the Jovian moon Io, ranging from cold surface temperatures to hyperthermal interactions with the Jovian plasma torus, make it of significant scientific interest. Direct Simulation Monte Carlo (DSMC) is typically used to model the rarefied Ionian atmosphere. Collisions between SO2 and O are a dominant mechanism in the composition of the atmosphere. However, the accuracy of existing DSMC models in determining molecular internal energy distributions is unknown. As such, Molecular Dynamics/Quasi-Classical Trajectory (MD/QCT) studies are conducted to generate energy distributions for collisions between SO2 and O. These distributions are presented and compared to common existing DSMC models and it is found that the MD/QCT-based distributions may present an improvement. Then, an approach for sampling from the new MD/QCT-based distributions in DSMC is developed. DSMC simulations are conducted for a 0-D heat bath with thermal non-equilibrium and a 2-D counterflow with conditions similar to Io to examine the effect of the new MD/QCT energy distributions.

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Section: Md/qct Methodology and Simulation Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

DSMC implementation of MD/QCT generated energy distributions for SO₂+ O collisions

Parsons

Levin

2013

44th AIAA Thermophysics Conference

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“…and is β 0.1, we find that the particle rate at the vent for 70 μm particles is N∕w 2 ≈ 4000 particles · m −2 · s −1 . For the present purpose, we will assume the plume to be purely ballistic, and defining (as observed) roughly a hemispherical shell of height h. To ascend and descend a height h under gravity takes a time τ ≈ 2.8h∕g 0.5 , and thus a steadystate plume has a particle population Nτ spread over an area of 2πh 2 (nonsteady conditions (e.g., [17]) could of course lead to temporary depletion and enhancements). Hence, the area density of particles in the shell is ∼2N∕g 0.5 h 1.5 , or for h 100 km and z 5 km, it is equal to 5000 m −2 .…”

Section: B Accelerated Particlesmentioning

confidence: 99%

“…For h 100 km, we find r max 70 μm, that is, smaller than a grain of sand (mass ≈ 10 −9 kg). We note also an independent analysis [17], simply balancing drag against weight just above the vent, suggesting 30 μm. Impact with an individual particle of this size will not be catastrophically damaging to a space vehicle (applying damage equations [18] for hypervelocity impact suggests that, at a typical flyby speed of 18 km · s −1 , such a small particle would have a penetration depth of only 0.4 mm).…”

Section: B Accelerated Particlesmentioning

confidence: 99%

Io Volcanic Plumes: Spacecraft Flythrough Hazard Evaluation

Lorenz

2015

Journal of Spacecraft and Rockets

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“…The DSMC method is a numerical approach for solving low Knudsen number fluid flows. The Io DSMC studies are ongoing, led by Prof. David Goldstein and in collaboration with the authors, with comprehensive planetary physics modeling through the use of DSMC by Austin et al, 3,4 Zhang et al, [5][6][7][8] Moore et al, [9][10][11][12] and Walker et al 13,14 These DSMC simulations require accurate chemistry modeling for determining collision and reaction cross section data. 15 There is a lack of reliable data for SO 2 dissociation, however, at the higher collision energies found in the Ionian atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Molecular Dynamics Based Chemistry Models for DSMC Simulation of the Atmosphere of Io

Parsons

Levin

Duin

2012

43rd AIAA Thermophysics Conference

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A significant process in the formation of the unique atmosphere of Io, a Jovian moon, is collision-induced dissociation of sulfur dioxide. The rarefied nature of the Ionian atmosphere makes its simulation by the Direct Simulation Monte Carlo method (DSMC) the method of choice. However, there is a lack of reliable data on collisions, particularly reaction and collision cross sections needed for DSMC, of Ionian species at the conditions seen in its atmosphere. As such, collisions between SO2 and O are studied through two separate methods: Molecular Dynamics/Quasi-Classical Trajectories (MD/QCT) and ReaxFF, a molecular dynamics method utitlizing a force field for reactive systems. Five possible reaction paths are considered: atomization of the SO2 molecule, dissociation to SO, dissociation to O2, and the formation of SO3, and an exchange reaction leading to SO and O2. Relative velocities and initial SO2 internal energies relevant to Io's atmospheric conditions are used. The results from each chemistry model are analyzed and compared to each other, in particular the reaction cross sections and equivalent variable hard sphere cross sections. In general, higher collision energies are found to cause atomization of the SO2. In addition, dissociation to SO is a significant process for many of the studied cases, but dissociation to O2 is mostly a negligible process. Finally, formation of SO3 occurs only at low impact velocities. The chemistry and collision models developed from the MD/QCT and ReaxFF methods are then implemented in DSMC 0-D, time-dependant and 2-D axisymmetric simulations under conditions relevent to the Ionian atmosphere. The results of these analyses are examined, and compared to results obtained using the baseline Total Collisional Energy (TCE) model and the previous results of Deng et al. 1 It is found that the new MD/QCT and ReaxFF based models predict less SO2 dissociation than previous models, and that simulated Ionian atmospheric structure is sensitive to the total cross section model.

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DSMC Modeling of Gasdynamics, Radiation and Fine Particulates in Ionian Volcanic Jets

Cited by 8 publications

References 23 publications

DSMC implementation of MD/QCT generated energy distributions for SO₂+ O collisions

DSMC implementation of MD/QCT generated energy distributions for SO₂+ O collisions

Io Volcanic Plumes: Spacecraft Flythrough Hazard Evaluation

Analysis of Molecular Dynamics Based Chemistry Models for DSMC Simulation of the Atmosphere of Io

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DSMC Modeling of Gasdynamics, Radiation and Fine Particulates in Ionian Volcanic Jets

Cited by 8 publications

References 23 publications

DSMC implementation of MD/QCT generated energy distributions for SO2+ O collisions

DSMC implementation of MD/QCT generated energy distributions for SO2+ O collisions

Io Volcanic Plumes: Spacecraft Flythrough Hazard Evaluation

Analysis of Molecular Dynamics Based Chemistry Models for DSMC Simulation of the Atmosphere of Io

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Product

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DSMC implementation of MD/QCT generated energy distributions for SO₂+ O collisions

DSMC implementation of MD/QCT generated energy distributions for SO₂+ O collisions