Influence of gas–surface interaction on gaseous transmission probability through conical and spherical ducts

Sharipov, Felix; Barreto, Yan Borges

doi:10.1016/j.vacuum.2015.07.015

Cited by 12 publications

(7 citation statements)

References 21 publications

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“…Intake transmission increases from about 15 to 29% as α t is reduced from 1 to 0.8 and α n is increased from 0.1 to 1. This behavior is consistent with the calculations for conical holes reported in [31]. The impact of wall accommodation add uncertainty in predicting the in-orbit performance of air-breathing systems, as α n and α t are difficult to assess with good precision and may change during the mission lifetime due to atmospheric oxygen contamination.…”

Section: Wall Temperature and Accommodationsupporting

confidence: 85%

“…Intake performance sensitivity on normal energy and tangential momentum accommodation coefficients α n and α t is visualized in Figures 12D-F. Consistently with most materials used in practical applications [31], we let α n and α t range from 0.1 to 1 and 0.8 to 1, respectively. A larger normal and a lower tangential accommodation improve intake performance.…”

Section: Wall Temperature and Accommodationmentioning

confidence: 89%

“…Tangent 1 component Tangent 2 component particle is scattered back to the external environment through the intake inlet or through the thruster exit plane. As reported in Section 2 of Supplementary Material, kernel implementation was validated against results available in literature [31]. As an example, Figure 8 shows the main distributions describing 1e5 N 2 particles dynamics of a d 1 = 9 and d 2 = 7.5 intake, from which the parameters listed in Table 1 can be extracted.…”

Section: Normal Componentmentioning

confidence: 99%

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Rarefied Flow Simulation of Conical Intake and Plasma Thruster for Very Low Earth Orbit Spaceflight

et al. 2022

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Air-breathing electric propulsion has the potential to enable space missions at very low altitudes. This study introduces to a 0D hybrid formulation for describing the coupled intake and thruster physics of an air-breathing electric propulsion prototype. Model derivation is then used to formally derive main system’s key performance indicators and estimate the figure of merit for the design of rarefied flow air intakes. Achievable performance by conical intake shapes are defined and evaluated by Monte Carlo simulations. Influence of inlet flow variation is assessed by dedicated sensitivity analyses. The set of requirements and optimality conditions derived for the downstream plasma thruster suggest concept feasibility within an achievable performance range.

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Section: Wall Temperature and Accommodationsupporting

confidence: 85%

Section: Wall Temperature and Accommodationmentioning

confidence: 89%

Section: Normal Componentmentioning

confidence: 99%

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Rarefied Flow Simulation of Conical Intake and Plasma Thruster for Very Low Earth Orbit Spaceflight

et al. 2022

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“…(2) Walls re-emit all incident particles with a cosine law assuming there is no sorption and particle migration on such areas. Even though the cosine law of emission does not apply [17,18] for all systems, this paper treats particles that are thermally accommodated by the system walls. A previous paper has shown that such conditions are experimentally attainable [6].…”

Section: A the Transport Equation Applied To Highly Rarefied Gasesmentioning

confidence: 99%

Point-to-source path tracing Monte Carlo to compute the Clausing and distribution functions in high-vacuum systems

2017

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This paper presents an approach to simulate the free molecular flow in vacuum systems by using a Monte Carlo method for solving the Boltzmann particle transport equation with no intermolecular collisions. Sometimes referred to as a point-to-source Monte Carlo path tracing in image rendering, in this paper the name is borrowed from the thermal radiation and heat transfer field, reverse Monte Carlo path tracing. It is shown that this method provides better accuracy and stability when computing the Clausing function when compared to the standard test particle Monte Carlo method used for free molecular flow. The Clausing function leads to the distribution function of positions and velocities from which the particle density map, pressure gradient, energy flux, and other local quantities can be computed. Using reverse path tracing, the particle concentration in a conical segment is computed, and the maximal flow input is determined by calculating the mean free path at the maximum density position.

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“…The transmission probability concept has been widely studied in the literature; expressions have been developed for various geometries [34][35][36] and non-diffuse gassurface interactions. [37][38][39] We restrict our investigation to purely diffuse scattering, which is likely accurate for conventional surfaces paired with gases heavier than neon. 37,40 For the purpose of this study, we chose water vapor as species 1 and air as species 2, and confirmed that the results translate to a system of helium and argon (see Fig.…”

mentioning

confidence: 99%

Numerical validation of the dusty-gas model for binary diffusion in low aspect ratio capillaries

Vaartstra

Grossman

et al. 2021

Physics of Fluids

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The dusty-gas model is an empirical formulation commonly used to describe gas flows in porous media. While experiments have validated the model for pores with high aspect ratios, a validation for near-unity aspect ratios is lacking. We used direct simulation Monte Carlo to evaluate the accuracy of the dusty-gas model for binary diffusion in low aspect ratio capillaries. Our results suggest that the dusty-gas model deviates from the Monte Carlo simulations by less than 3% for aspect ratios ! 1, thus supporting its suitability as a phenomenological model for transport in nanoporous structures in various applications such as heat transfer, catalysis, and water purification.

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Influence of gas–surface interaction on gaseous transmission probability through conical and spherical ducts

Cited by 12 publications

References 21 publications

Rarefied Flow Simulation of Conical Intake and Plasma Thruster for Very Low Earth Orbit Spaceflight

Rarefied Flow Simulation of Conical Intake and Plasma Thruster for Very Low Earth Orbit Spaceflight

Point-to-source path tracing Monte Carlo to compute the Clausing and distribution functions in high-vacuum systems

Numerical validation of the dusty-gas model for binary diffusion in low aspect ratio capillaries

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