Eddy Current Effects in the Laminated Containment Structure of Railguns

Landen, D.; Satapathy, S.

doi:10.1109/tmag.2006.887449

Cited by 28 publications

(6 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If there is even a small amount of rail displacement during the launch, there is a significant chance that the contact between the rails and the armature would break, endangering the operation. Thus the containment can be modeled as air, if the containment is non-conductive [20][21][22] and rails are considered as rigid, static bodies. However, it should be noted that the current density distribution inside the rails is changing throughout the FIG.…”

Section: Fig 3 Eml Simulation Strategiesmentioning

confidence: 99%

A Revised Inductance Distribution Analysis of Medium-Large Caliber Electromagnetic Launchers including a Large Bus Structure

Tosun¹,

Keysan²

2023

Preprint

View full text Add to dashboard Cite

<p> </p> <p>An important application for large-scale pulse power supplies (PPS) is electromagnetic launchers (EMLs). These de- vices utilized stored several MJs of electrochemical energy into linear mechanical energy. Because of extreme physical conditions, simulations are crucial in electromagnetic launcher (EML) research. As the operation risk rises, more en- ergy into the system adds weight to the model’s accuracy. In this paper, the electromagnetic impact of the bus structure is discovered in a recently developed EMFY-3 electromagnetic launcher, is presented. An H-shaped bus structure is used for the current injection. However, experiments showed that the H-shaped bus changes inductance calculations. A careful examination is made to reveal the physical reasoning behind the bus impact. We hypothesize that the rail portion surrounded with bus geometry has less inductance than the rest due to the eddy current created by rail current transients, which should be calculated carefully through numerical calculations, i.e., 3-D Finite Element Method (FEM). Two dif- ferent simulation models were constructed to test the hypothesis. Moreover, rail currents, breech, and muzzle voltages are measured to investigate electromagnetic calculations. Results showed a good agreement with experiments where the bus structure was modeled explicitly. That aspect showed that the bus structure should be well-examined when multiple PPS are connected. </p>

show abstract

Section: Fig 3 Eml Simulation Strategiesmentioning

confidence: 99%

A Revised Inductance Distribution Analysis of Medium-Large Caliber Electromagnetic Launchers including a Large Bus Structure

Tosun¹,

Keysan²

2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Electromagnetic drag is the force associated with the eddycurrent brake mechanism at the conductive containment [15]. This force can have more drastic effects than the aerodynamic drag if the conductive containment is not laminated.…”

Section: Sensitivity Analysismentioning

confidence: 99%

Inductance Gradient Calculations of EMFY-3 Electromagnetic Launcher

Tosun¹,

Keysan²

2021

Preprint

View full text Add to dashboard Cite

<div>ASELSAN Inc. has been working on electromagnetic launch technologies since 2014. The first prototype, EMFY-1, has a 25 mm × 25 mm square bore and 3-m-length rails. The second prototype, EMFY-2, has a 50 × 50 mm square bore and 3-m-length. In this paper, a recently developed prototype, EMFY-3, is presented, which has a 50 × 75 mm rectangular bore and 6-m-length. The input energy of the PPS is doubled to 8 MJ, and the 2.91 MJ muzzle energy is obtained up to now. Rail currents, breech, and muzzle voltages are measured to investigate electromagnetic calculations. Velocity curves are captured with Doppler radar, which enables us to establish propulsive inductance gradient L0pr transients empirically. The results confirm that L0 pr is constant throughout the launch, as no significant breaking mechanism occurs with the non-magnetic containment. However, a slight variation (%2 at maximum) happens from one launch to another with different rails’ current magnitudes. The transition phenomenon is a candidate for the drop in the L0 pr, as it occurs more likely at launches with higher linear current densities.</div>

show abstract

“…The term ∂LR ∂X is known as the inductance gradient based on the electrode geometry. This constant is commonly used in railgun studies to estimate the Lorentz force based on the armature current [23]. However, the armature of a railgun is a solid body of constant geometry, while a RailPAc has deformable plasma arc as an armature.…”

Section: Actuation Mechanismmentioning

confidence: 99%

Effects of anchoring and arc structure on the control authority of a rail plasma actuator

Choi¹,

Gray²,

Sirohi³

et al. 2017

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

Experiments were conducted on a rail plasma actuator (RailPAc) with different electrode cross sections (rails or rods) to assess methods to improve the actuation authority, defined as the impulse generated for a given electrical input. The arc was characterized with electrical measurements and high-speed images, while impulse measurements quantified the actuation authority. A RailPAc power supply capable of delivering ∼1 kA of current at ∼100 V was connected to rod electrodes (free-floating with circular cross-section) and rail electrodes (flush-mounted in a flat plate with rectangular cross-section). High-speed images show that the rail electrodes cause the arc to anchor itself to the anode electrode and transit in discrete jumps, while rod electrodes permit the arc to transit smoothly without anchoring. The impulse measurements reveal that the anchoring reduces the actuation authority by ∼21% compared to a smooth transit, and the effect of anchoring can be suppressed by reducing the gap between the rails to 2 mm. The study further demonstrates that if a smooth transit is achieved, the control authority can be increased with a larger gap and larger arc current. In conclusion, the actuation authority of a RailPAc can be maximized by carefully choosing a gap width that prevents anchoring. Further study is warranted to increase the RailPAc actuation authority by introducing multiple turns of wires beneath the RailPAc to augment the induced magnetic field.

show abstract

Eddy Current Effects in the Laminated Containment Structure of Railguns

Cited by 28 publications

References 2 publications

A Revised Inductance Distribution Analysis of Medium-Large Caliber Electromagnetic Launchers including a Large Bus Structure

A Revised Inductance Distribution Analysis of Medium-Large Caliber Electromagnetic Launchers including a Large Bus Structure

Inductance Gradient Calculations of EMFY-3 Electromagnetic Launcher

Effects of anchoring and arc structure on the control authority of a rail plasma actuator

Contact Info

Product

Resources

About