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Coilgun Acceleration Model Containing Multiple Interacting CoilsA coilgun operates by pulsing current through an axially-arranged series of independently-controlled coils inductively interacting with a small, electrically-conductive, azimuthally-symmetric projectile to accelerate it to high velocities. The electrical circuits are programmed to pulse current through the coils in such a way so as to impart further electromagnetic acceleration in each stage. A method is developed to calculate the mutual inductance between the coils and between each coil and the projectile. These terms are used to write a system of first-order ordinary differential equations governing the projectile velocity and the current flow in each coil. While the inclusion of the electromagnetic interactions between coils significantly complicates the equation set as more coil sets are included in the problem, casting the problem symbolically in mass matrix form permits solution using standard numerical Runge-Kutta techniques. Comparing a projectile with a single-turn to that comprised of nine-turns, the inductance of the former is much smaller, but this leads to a greater induced projectile current. The lower inductance and greater current appear to offset each other with little difference in the acceleration profile for the two cases. For the limited cases studied, coils with a discharge half-cycle equal to the time for a projectile to transit from one coil to the next yield increased efficiency.
Document ID
20190000731
Document Type
Conference Paper
Authors
Polzin, Kurt A.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Cipriano, Amanda B.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Martin, Adam K.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Liu, Connie Y.
(Georgia Inst. of Technology Atlanta, GA, United States)
Date Acquired
February 14, 2019
Publication Date
January 7, 2019
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
M18-7139
Meeting Information
Meeting: AIAA SciTech Forum 2019
Location: San Diego, CA
Country: United States
Start Date: January 7, 2019
End Date: January 11, 2019
Sponsors: American Inst. of Aeronautics and Astronautics
Distribution Limits
Public
Copyright
Public Use Permitted.
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