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ENCIT 2018
Brazilian Congress of Thermal Sciences and Engineering
Advances on the Development of an Impulsive Thrust-stand for Electric Propulsion Application
Submission Author:
Diogo Leon Oliveira Soares , SP
Co-Authors:
Diogo Leon Oliveira Soares, Rodrigo Intini Marques
Presenter: Diogo Leon Oliveira Soares
doi://10.26678/ABCM.ENCIT2018.CIT18-0168
Abstract
This paper reports on the characterization of a thrust-stand that can measure impulses from 14 μNs up to 79 μNs with a maximum resolution of 50 nNs in a vacuum chamber. The thrust-stand is based on a torsion balance and will be used for pulsed plasma thruster tests. Previous works reported a calibration using cylindrical electrodes and a precision balance with accuracy of 0.1 mg in atmospheric pressure. The calibration in vacuum is paramount as this will be the test condition for the electric thrusters and also due to the influence of the cryogenic and rotary vacuum pumps vibration. Preliminary calibration was performed to ensure agreement with previous works. A displacement sensor with a measuring range of 10.05 μm and a maximum resolution of 0.013 μm was used to measure the oscillation amplitude of the arm of the thrust balance and a transfer function was then obtained. The damping ratio was evaluated but its large variability induced errors when comparing with the fitting curve and possible solutions for this issue were given to mitigate this problem. The impulse bits measured by the thrust-stand were in good agreement with the input impulses. The uncertainty of the measurements reinforced the fact that a magnetic damper is necessary in order to reduce initial undesired oscillations.
Keywords
Thrust-stand, Electric Propulsion, Pulsed Plasma Thruster, characterization, Vacuum
