Heat transfer from a sphere in the intermediate dynamics region of a rarefied gas

Koshmarov, Yu. A.; Svirshevskii, S. B.

doi:10.1007/bf01186485

Cited by 13 publications

(8 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, with the introduction of helium in the source, the Kn Ag value dropped quickly due to frequent Ag–He collisions and a relatively low Ag mean thermal velocity (factor

in the second term of Equation (10)). As a result, throughout the studied helium flow rates, the silver expansion regime could be characterized as transient between free molecular and hydrodynamic (continuous) regimes, where the latter could be considered at Kn < ~10 −3 [ 62 ]. This is important for the present study, as the probability of silver gas-phase cluster formation increases strongly in the He-Ag mixture jet.…”

Section: Resultsmentioning

confidence: 99%

“…For comparison, the parameters for two extreme cases, a free molecular silver flow and a continuous helium jet in the hydrodynamic regime (Kn << 1), are shown. The first regime was described with well-established solutions [ 62 , 64 ], while for the latter case, the solution [ 65 ] for a dense, inviscid wind tunnel jet was used. Several results can be remarked on here.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Silver Vapor Supersonic Jets: Expansion Dynamics, Cluster Formation, and Film Deposition

et al. 2023

View full text Add to dashboard Cite

Supersonic jets of metal vapors with carrier gas are promising for producing nanostructured metal films at relatively low source temperatures and high deposition rates. However, the effects of the carrier gas on the jet composition and expansion dynamics, as well as on film properties, remain virtually unexplored. In this work, the free-jet expansion of a mixture of silver vapor with helium in a rarefied regime at an initial temperature of 1373 K is investigated through mass spectrometry and direct-simulation Monte Carlo methods. Introducing the carrier gas into the source is found to result in a transition from a collisionless to a collision-dominated expansion regime and dramatic changes in the Ag jet, which becomes denser, faster, and more forward-directed. The changes are shown to be favorable for the formation of small Ag clusters and film deposition. At a fairly high helium flow, silver Ag2 dimers are observed in the jet, both in the experiment and the simulations, with a mole fraction reaching 0.1%. The terminal velocities of silver atoms and dimers are nearly identical, indicating that the clusters are likely formed due to the condensation of silver vapor in the expanding jet. A high potential of supersonic Ag-He jets for the deposition of nanostructured silver films is demonstrated. The deposited jet Ag2 dimers appear to serve as nucleation centers and, thus, allow for controlling the size of the produced surface nanostructures.

show abstract

“…However, with the introduction of helium in the source, the Kn Ag value dropped quickly due to frequent Ag–He collisions and a relatively low Ag mean thermal velocity (factor

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Silver Vapor Supersonic Jets: Expansion Dynamics, Cluster Formation, and Film Deposition

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Papadopoulos et al [5] predicted a significant surface erosion at 40 km altitude for a 70 degree half-angle, 26m-diameter blunt cone with a 8.6 km/s speed. It was found that the microscopic DSMC heat transfer results agree better with the Koshmarov and Svirshevskii (K-S) [8] and free-molecule (F-M) [9] models than the modified Kavanau model [10]. Migita et al [7] demonstrated the Eulerian and Lagrangian hybrid approach to simulate supersonic dusty flows over a 1-m sphere.…”

Section: Dsmc Dusty Flow Simulation For Non-stop Mars Sample Return Mmentioning

confidence: 99%

DSMC Dusty Flow Simulation for Non-stop Mars Sample Return Mission

Ozawa¹,

Suzuki²,

Takayanagi³

et al. 2011

AIP Conference Proceedings

View full text Add to dashboard Cite

Articles you may be interested in DSMC aero-thermo-dynamic analysis of a sample-return capsule AIP Conf.Abstract. At Japan Aerospace Exploration Agency, a non-stop Mars sample return project has been planned. In the project, sampling of Martian dust particles is planned between 35 and 45 km, and the impact of Martian dust particles on a shock structure and aerodynamics for a spacecraft must be clarified. In this work, a mechanism for hypersonic dusty flow simulations in DSMC has been developed, and hypersonic dusty flows were simulated for clear weather and dust storm conditions using two dust-surface interaction models at the descent altitude. It was found that although the impact of dust particles on the shock structure and drag is negligible, the total heat flux is increased with the consideration of dust particles.

show abstract

“…The effects of rarefaction and compressibility on the energy transfer of spheres in supersonic low-Reynolds-number flow were studied experimentally, among others, by Drake & Backer (1952), Kavanau (1955), Avleeva (1970) and Koshmarov & Svirshevskii (1972). Based on the experimental results and known sphere energy transfer in free molecular flow, Sauer (1951), Kavanau (1955) and Koshmarov & Svirshevskii (1972) developed semi-empirical correlations for the sphere energy transfer coefficient applicable in broad ranges of Mach and Reynolds numbers. These equations are often used to predict energy transfer of solid particles in gas-solid particle flows (Carlson & Hoglund 1964;Volkov et al 2005;Ozawa et al 2011;Ching et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Aerothermodynamics of a sphere in a monatomic gas based onab initiointeratomic potentials over a wide range of gas rarefaction: transonic, supersonic and hypersonic flows

Sharipov

Volkov

2022

J. Fluid Mech.

View full text Add to dashboard Cite

Aerothermodynamic characteristics of a sphere such as drag and energy transfer coefficients are calculated for Mach numbers varying from 1 to 10 over a wide range of the gas rarefaction degree spanning the free molecular, transitional and near hydrodynamic flow regimes. The effects of major factors determining the gas flow are studied using the direct simulation Monte Carlo method. To reveal the effect of gas species, the simulations are performed based on ab initio interatomic potentials for helium, neon, argon and krypton, as well as based on the hard sphere model. The impact of the accommodation coefficients is evaluated by applying the Cercignani–Lampis model of gas–surface interaction. The calculations are carried out for several values of the free stream and sphere temperatures. It is found that the effects of gas species on the drag and energy transfer coefficients are approximately 3 % and 6 %, respectively. The accommodation coefficients in the Cercignani–Lampis model strongly affect all aerothermodynamic characteristics. The drag and energy transfer coefficients calculated for different accommodation coefficients vary within 30 % and 200 %, respectively. It is found that the variation of the tangential momentum and normal energy accommodation coefficients can induce an increase of the drag coefficient compared to the case of diffuse gas–surface interaction. In hypersonic flows, the drag coefficient varies within 30 % when the sphere temperature varies from the free stream temperature to the stagnation temperature. The drag and energy transfer coefficients are found to be non-monotonic functions of the free stream temperature.

show abstract

Heat transfer from a sphere in the intermediate dynamics region of a rarefied gas

Cited by 13 publications

References 2 publications

Silver Vapor Supersonic Jets: Expansion Dynamics, Cluster Formation, and Film Deposition

Silver Vapor Supersonic Jets: Expansion Dynamics, Cluster Formation, and Film Deposition

DSMC Dusty Flow Simulation for Non-stop Mars Sample Return Mission

Aerothermodynamics of a sphere in a monatomic gas based onab initiointeratomic potentials over a wide range of gas rarefaction: transonic, supersonic and hypersonic flows

Contact Info

Product

Resources

About