Thrust Stand for Electric Propulsion Performance Evaluation

Markusic, Thomas E.; Jones, Jonathan D. G.; Cox, Matthew

doi:10.2514/6.2004-3441

Cited by 12 publications

(10 citation statements)

References 4 publications

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“…The mechanism is generally a pendulum, either standard [3][4][5][6][7], inverted [8][9][10], or torsional [11][12][13][14], and calibration is accomplished through application of a set of weights. By contrast, high-thrust chemical engines are generally tested with load cells (e.g., [15]).…”

mentioning

confidence: 99%

Thrust Stand Characterization of the NASA Evolutionary Xenon Thruster

Diamant¹,

Pollard²,

Crofton³

et al. 2011

Journal of Propulsion and Power

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Direct thrust measurements have been made on the NASA Evolutionary Xenon Thruster using a standard pendulum-style thrust stand constructed specifically for this application. Values have been obtained for the full 40-level throttle table, as well as for a few offnominal operating conditions. Measurements differ from the nominal NASA throttle table 10 values by 3.1% at most, while at 30 throttle levels, the difference is less than 2.0%. When measurements are compared with throttle table 10 values that have been corrected using recently obtained ion beam current density and charge-state data, they differ by 1.2% at most, and at 37 throttle levels, they differ by 1.0% or less. Thrust correction factors calculated from direct thrust measurements and from recently acquired plume data agree to within measurement error for all but one throttle level. Measurements of thrust due to cold flow, neutralizer, and discharge-only operation are also presented.Nomenclature A e = neutralizer exit aperture area c = neutral mean thermal speed C cf = cold flow thrust correction for offaxis flow= load cell reading F T , F = thrust g = acceleration due to gravity at sea level H = dimension J b = ion beam current k = Boltzmann constant, also ratio of specific heats l = distance from pivot to counterweight center of mass L C = dimension L CG = distance from pivot to thruster center of mass L F = distance from pivot to thruster centerline L S = dimension M e = moments due to gas and electrical connections m CW = counterweight mass _ m d = discharge chamber mass flow rate m n , m = neutral atomic mass _ m n = neutralizer mass flow rate m T = thruster mass p e = pressure at neutralizer exit q = elementary charge R = accelerator grid aperture radius, also specific gas constant t = accelerator grid aperture thickness T n = neutral gas temperature T o = neutralizer gas stagnation temperature u e = neutralizer gas effective exhaust velocity V b = ion beam voltage V bps = beam power supply voltage X C = dimension X S = dimension Y = dimension = angle = thrust correction factor for beam divergence = total thrust correction factor = dimension " = angle relative to aperture centerline = pendulum angle = angle = angle from grid centerline

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mentioning

confidence: 99%

Thrust Stand Characterization of the NASA Evolutionary Xenon Thruster

Diamant¹,

Pollard²,

Crofton³

et al. 2011

Journal of Propulsion and Power

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show abstract

“…Torsion balances have shown very high sensitivity, making them particularly useful for micropropulsion applications. Torsional thrust stands are inherently more stable than inverted pendulum thrust stands [7] and offer a balance between high-thrust measurement sensitivity and low environmental noise sensitivity [19,38].…”

Section: Torsional Pendulum Thrust Standsmentioning

confidence: 99%

Recommended Practice for Thrust Measurement in Electric Propulsion Testing

Polk

Pancotti

Haag

et al. 2017

Journal of Propulsion and Power

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The accurate, direct measurement of thrust or impulse is one of the most critical elements of electric thruster characterization, and it is one of the most difficult measurements to make. This paper summarizes recommended practices for the design, calibration, and operation of pendulum thrust stands, which are widely recognized as the best approach for measuring micronewton-to millinewton-level thrust and micronewton-per-second-level impulse bits. The fundamentals of pendulum thrust stand operation are reviewed, along with the implementation of hanging pendulum, inverted pendulum, and torsional balance configurations. The methods of calibration and recommendations for calibration processes are presented. Sources of error are identified, and methods for data processing and uncertainty analysis are discussed. This review is intended to be the first step toward a recommended practices document to help the community produce high-quality thrust measurements.

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“…The micro-thrust measurements for EP devices often have been made by measuring deflection of the mechanism to which the thruster is mounted and converting that deflection to thrust through some suitable calibration. The mechanism is generally a pendulum which can be classified as hanging pendulum [2]- [4], inverted pendulum [5], [6], and torsional pendulum [7], [8]. Calibration is usually accomplished through application of a set of weights, pendulum impact and electrostatic fins [9].…”

Section: Introductionmentioning

confidence: 99%

Effect of Temperature on Rotation Loss in a Superconducting Device for Microthrust Measurement of Electric Propulsion System

Yang

Wang

et al. 2015

IEEE Trans. Appl. Supercond.

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Accurate measurement for long-term accumulating momentum of electrical propulsion (EP) requires the microthrust stand with high performance. A microthrust-measuring device using high-temperature superconductor magnetic levitation (HTSML) is designed to remove connecting interferences for better evaluation of EP thrusters. Levitating rotation loss is the main factor that affects measuring accuracy of the HTSML device. In this paper, we propose a new method to measure the accumulating momentum. A vacuum experimental setup that can control the temperature of YBCO bulk was built up to investigate the rotation loss at low speed. Effects of temperature and field cooling (FC) height on the coefficient of friction μ are analyzed. By analyzing the basic phenomenon of the rotation friction in the low speed range less than 30 Hz, the low speed rotation can be divided into three different phases. When the rotation frequency is closed to the natural frequency of the HTSML device, oscillation happens and leads to serious rotation loss. The friction loss after the oscillation is very steady and can be used in the measurement of accumulating momentum. The large FC height and temperature can diminish the rotation loss, and increasing FC height could diminish rotation loss dependence of temperature. Although the experimental measurements show good repeatability, large rotation loss (10 -4 ∼10 -3 ) in the experimental setup means that this setup should be further improved.

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Thrust Stand for Electric Propulsion Performance Evaluation

Cited by 12 publications

References 4 publications

Thrust Stand Characterization of the NASA Evolutionary Xenon Thruster

Thrust Stand Characterization of the NASA Evolutionary Xenon Thruster

Recommended Practice for Thrust Measurement in Electric Propulsion Testing

Effect of Temperature on Rotation Loss in a Superconducting Device for Microthrust Measurement of Electric Propulsion System

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