Date of Award
Master of Science in Aeronautical Engineering
Department of Aeronautics and Astronautics
Carl R. Hartsfield, PhD
A new laser absorption spectroscopy (LAS) velocimetry system, designed to obtain 2D planar velocity fields for ionized Xenon in the plume of a Hall effect thruster by probing the transition of Xe II at 834.72 nm, was implemented at the Air Force Institute of Technology (AFIT) Space Propulsion Analysis and System Simulator (SPASS) Lab vacuum chamber. A single horizontal laser sheet was used to probe singly-ionized Xenon in the plume of a Busek BHT-600 Hall thruster and obtain a histogram of estimated axial velocity, to validate the system. Similar velocities to those obtained by an earlier intrusive characterization of the thruster were observed. Hall thrusters can be characterized by analysis of their plumes; however, many analysis methods require intrusive probes. Intrusive measurements, by their nature, affect the flow of the exhaust plume and may obtain inaccurate results, or results not representative of the reality of operating in orbit. They are also subject to probe erosion by ion bombardment, limiting probe lifetimes. For these reasons non-intrusive measurements are desirable. LAS provides a method to take these measurements in a non-intrusive manner. This new system captures linear absorption data using cameras with a resolution of 2048 pixels at six different viewpoints to reconstruct the velocity field. In future research, simultaneous full-field measurements will allow observation of time-resolved velocity data of ions at all points in the plume at rates of up to 1 kHz. Hall thrusters often have different performance characteristics between laboratory vacuum chamber characterizations and actual on-orbit performance. Implementation of this system provides the first of two complimentary systems which will be used for complete particle analysis of Hall thruster plumes.
DTIC Accession Number
Leonard, Avery W., "Sheet Velocity Measurements Using Laser Absorption Spectroscopy in a Xenon Hall Effect Thruster Plume" (2019). Theses and Dissertations. 2225.