Primary electric propulsion thrust subsystem definition

Masek, T. D.; Ward, J. W.; Kami, S.

doi:10.2514/6.1975-405

Cited by 1 publication

(5 citation statements)

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“…The momentum-weighted divergence loss term [hcosi 2 mv ] contains all jet vector losses, and differences from the current-weighted divergence was characterized. The proposed analysis was compared to past performance methodologies, with similarities to previous architectures formulated by Masek et al in the ion thruster community [18], Belan et al from the Kharkov Aviation Institute [25], and a contemporary methodology by Hofer and Gallimore [40,47].…”

Section: Discussionmentioning

confidence: 99%

“…An analogous expression was used to estimate thrust of the NSTAR ion thrusters onboard NASA's Deep Space 1 by including factors to estimate the effect of multiply charged ions and beam cosine losses [61]. These factors were similar those in the formulation of thrust by Masek et al and are related to the ratio P B = 1=2 for a bimodal ion population [18]. The formulations of T=P and I sp in Eqs.…”

Section: E Evaluating Exchange Parameters and Thruster Performancementioning

confidence: 98%

“…(13) to be expressed in terms of the average voltage utilization efficiency and in Eq. (18). The average voltage utilization in Eq.…”

Section: Decoupling Voltage Utilization and Current Utilization Frmentioning

confidence: 99%

“…Although cancels in the energy efficiency term, it is shown in Eqs. (18) and (19) to reveal the physical nature of the voltage and current utilization inherent in the thrust efficiency:…”

Section: Decoupling Voltage Utilization and Current Utilization Frmentioning

confidence: 99%

“…Analytical factorization of ion thruster efficiency was described as early as 1975 by Masek et al in a review of ion thruster performance [18]. Anode thrust efficiency was factored into the product of energy efficiency and propellant utilization efficiency using Newton's second law, with terms accounting for losses due to doubly charged ions and beam divergence.…”

Section: Historical Perspective and Recent Effortsmentioning

confidence: 99%

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Methodology and Historical Perspective of a Hall Thruster Efficiency Analysis

Brown

Larson

Beal

et al. 2009

Journal of Propulsion and Power

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A Hall thruster performance architecture was developed based on separation of the total thrust directed along thruster centerline into mass-weighted and momentum-weighted terms. With this formulation, the total thruster efficiency equation was analytically decomposed to explicitly account for the effects of energy conversion losses, plume divergence, and the velocity distribution function of the propellant jet. Thruster efficiency is defined as the product of 1) energy efficiency, 2) propellant efficiency, and 3) beam efficiency. Energy efficiency comprises losses due to ionization processes and losses that manifest as Joule heating, and contains no information about the vector properties of the jet. Propellant efficiency incorporates losses from dispersion in the jet composition and is unity for 100% ionization to a single ion species. The effect of neutrals on dispersion of the jet velocity distribution function in propellant efficiency is introduced in the neutral-gain utilization. The beam efficiency accounts for divergence of the jet and is ideal when the ion velocity vectors are parallel to the thrust axis. Plume divergence is defined as a momentum-weighted term, and the approximation as a charge-weighted term is characterized. The efficiency architecture is derived from first principles and is applicable to all propulsion employing electrostatic acceleration, including Hall thrusters and ion thrusters. Distinctions and similarities to several past methodologies are discussed, including past ion thruster analyses, early Russian performance studies, and contemporary architectures. To illustrate the potential for enhanced understanding of loss mechanisms and ionization processes with an array of farfield plume diagnostics, a case study is presented of low-discharge voltage operation from a 6 kW laboratory Hall thruster. Nomenclature A = spherical shell surface area element in the plume E 1 = voltage exchange parameter E 2 = mass exchange parameter F = thrust density vector in the plume F = Faraday constant, 96; 485 C=mol of charge f j = normalized ion mass flow fraction of jth ion species fv = velocity distribution function of ions and neutrals g = Earth's gravitational constant at sea level, 9:806 m=s 2 I Axial = axial component of beam current parallel to thruster centerline I Beam = integrated beam current I d = anode discharge current I sp = total specific impulse J = current density in the plume at angular position j = propellant charge state index, 0, 1, 2, 3, etc., for Xe 0 , Xe 1 , Xe 2 , Xe 3 M = molecular weight of propellant, Xe 0:1313 kg=mol _ m i = mass flow rate of ions, where P _ m j _ m i for j 1 to the jth ion species _ m j = mass flow rate of jth species _ m T = total mass flow rate to the anode and cathode, where P _ m j _ m T for j 0 to the jth ion species _ m = mass flux at angular position P d = discharge power to the anode P jet = jet power P loss = power lost to Joule heating processes P min = minimum power required to sustain ionization Q = average charge of propellant ions R = downst...

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Section: Discussionmentioning

confidence: 99%

Section: E Evaluating Exchange Parameters and Thruster Performancementioning

confidence: 98%

“…(13) to be expressed in terms of the average voltage utilization efficiency and in Eq. (18). The average voltage utilization in Eq.…”

Section: Decoupling Voltage Utilization and Current Utilization Frmentioning

confidence: 99%

“…Although cancels in the energy efficiency term, it is shown in Eqs. (18) and (19) to reveal the physical nature of the voltage and current utilization inherent in the thrust efficiency:…”

Section: Decoupling Voltage Utilization and Current Utilization Frmentioning

confidence: 99%

Section: Historical Perspective and Recent Effortsmentioning

confidence: 99%

See 3 more Smart Citations