A large space simulator for electric propulsion testing - Design requirements and engineering analysis

Biagioni, L.; Boccaletto, Luca; Marcuccio, Salvo; Nicolini, D.; Servi, R.; Andrenucci, Mariano

doi:10.2514/6.2000-3750

Cited by 11 publications

(12 citation statements)

References 4 publications

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“…4,5 For vacuum chambers used for EP experiments, large cryogenic pumps are usually equipped as the primary pumps. There are several facility effects that have significant impact on the vacuum chamber backpressure.…”

Section: Introductionmentioning

confidence: 99%

Free molecular background flow in a vacuum chamber equipped with two-sided pumps

Cai

Boyd

Sun

2005

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Spacecraft propulsion systems, such as Hall thrusters, are designed and tested in large vacuum chambers. The pumping capacity of modern facilities makes it possible to maintain pressures as low as 10 −3 -10 −4 Pa. One fundamental concern for the vacuum chamber is the facility effects on the chamber performance. In this study, several free molecular models are developed to analyze the rarefied background flow inside a vacuum chamber equipped with two-sided vacuum pumps. These models lead to various sets of analytical results including velocity distribution functions for the background flow and formulas to compute the vacuum pump sticking coefficient. These results can be used to evaluate the performance of vacuum chambers and to aid constructing proper background flows for particle simulations of these systems. The results indicate that the background flow conditions can have a significant nonzero mean velocity and cannot be considered to be described by a Maxwellian velocity distribution. The models are applied to analyze the rarefied background flow in a specific vacuum chamber. Calculations of the sticking coefficient for flow of xenon in the vacuum chamber yield values close to 0.40 for cryogenic pumps. Several modifications of the background flow treatment for particle simulations are proposed with the aid of these analytical results.

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Section: Introductionmentioning

confidence: 99%

Free molecular background flow in a vacuum chamber equipped with two-sided pumps

Cai

Boyd

Sun

2005

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…Through statistical average, various flow parameters can be obtained finally. It can better guide the configuration optimization of electric propulsion testing vacuum system through the numerical simulation of DSMC, which has been applied in advanced research institutions abroad [8][9].…”

Section: System Optimization Based On Dsmc Methodsmentioning

confidence: 99%

Research on Key Techniques of the Verification and Testing System for Spacecraft Propulsion

et al. 2018

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Abstract. Electric propulsion is an important technology in the future space missions. The verification and testing system is mainly used for the manufacturers to fully understand the propulsion behavior in the most diverse conditions, and to indentify and eliminate potential failure modes to advance its validity and reliability, explore the applied potential for space missions. The paper presents a new verification and testing system for spacecraft propulsion and the key technologies needed to be developed are studied. The debugging data and research indicate that ultimate pressure of system is better than the 5.0×10 -6 Pa. Both the cold plate used for xenon pumping and sputtering protective system get an excellent performance in system. The DSMC numerical simulation method is verified that is beneficial to the research of optimization design and plume effect of electric propulsion in future.

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“…This is due to different thickness of propellant frost accumulated on these pumps under different working conditions. 13 Even though the nominal air-steel sticking coefficient at low temperature can be very high, the real coefficient value varies. Recent work by Walker 12 confirmed that the background pressures in LVTF vary with different numbers of thrusters and pumps in operation.…”

Section: A Introductionmentioning

confidence: 99%

Exact Solutions for Internal and External Collisionless Gas Flows

CaiKhaleel

Kecman

2009

47th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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This paper presents some recent progress on internal and external free molecular flows. The first part of this paper concentrates on steady collisionless gas flows inside arbitrary enclosures, which are either convex or concave, two-dimensional or three-dimensional, formed by several plates maintained at different temperatures. If the molecular reflections on these plates are completely diffuse, then at the final steady flow stage for any point inside the enclosures, the velocity distribution function (VDF) is completely determined, and macroscopic properties such as density, velocities, temperature and heat flux can be exactly determined by integrating the VDF with different moments. The result from this study leads to many exact solutions for internal collisionless gas flow and thermal fields, such as those inside vacuum packaged Micro-/Nano-Electro-Mechanical System (MEMS/NEMS) devices. The second part considers collisionless flows over a flat plate with a sticking coefficient, such as a cryogenic pump. We obtain the corresponding exact solutions for the flow and thermal fields. Numerical simulation results obtained with the direct simulation Monte Carlo method validate the analytical solutions. In general, the comparisons between the exact analytical solutions and the numerical results are virtually identical.

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A large space simulator for electric propulsion testing - Design requirements and engineering analysis

Cited by 11 publications

References 4 publications

Free molecular background flow in a vacuum chamber equipped with two-sided pumps

Free molecular background flow in a vacuum chamber equipped with two-sided pumps

Research on Key Techniques of the Verification and Testing System for Spacecraft Propulsion

Exact Solutions for Internal and External Collisionless Gas Flows

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