A Hybrid Simulation Model for Electromagnetic Launchers Including the Transient Inductance and Electromotive Force

Tosun, Nail; Polat, Hakan; Ceylan, Doğa; Karagoz, Mustafa; Yildirim, Baran; Gungen, Ibrahim; Keysan, Ozan

doi:10.1109/tps.2020.3016930

Cited by 21 publications

(19 citation statements)

References 20 publications

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“…Hundertmark et al [11] used time and position-dependent conductivity function in the airarmature region to simulate the transients due to the armature movement. In the previous study [12], we obtained a lumped VSE resistance through a similar conductivity function to enhance the simulation model's accuracy and verified with experiments.…”

Section: Introductionmentioning

confidence: 83%

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A Comparison of Velocity Skin Effect Modeling With 2-D Transient and 3-D Quasi-Transient Finite Element Methods

Tosun

Ceylan

Polat

et al. 2021

IEEE Trans. Plasma Sci.

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Analysis of the velocity skin effect (VSE) in electromagnetic launchers (EMLs) requires a 3-D transient finite element method, unlike magnetic skin and proximity effects. However, VSE is dominant at high speeds, and this creates convergence problems when moving or deformed mesh physics is used in a transient FEM in the 3-D analysis. Commercial finite element software cannot solve the electromagnetic aspects of such a high-speed application with a transient solver in 3-D. Although 2-D approximations can be used, such an approximation overestimates VSE resistance due to geometry simplifications. In this study, we proposed a novel quasi-transient 3-D FEM model where the air-armature region's conductivity is varied to emulate the high-speed motion of the armature. Results showed that 2-D approximation; overestimates the VSE resistance by almost 40%. The proposed VSE model has been included in the EML model, and simulation results compared for experimental results with different EMLs, EMFY-1 and EMFY-2, and showed good agreement.

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Section: Introductionmentioning

confidence: 83%

“…Then, the VSE resistance is calculated in 3-D with quasi-transient FEM. The fitted VSE resistances are added to the 3-D static FEM simulations like in [12], [13] individually as a figure of merit. The constructed model is compared with experimental results to evaluate the performances of VSE models.…”

Section: Introductionmentioning

confidence: 99%

A Comparison of Velocity Skin Effect Modeling With 2-D Transient and 3-D Quasi-Transient Finite Element Methods

Tosun

Ceylan

Polat

et al. 2021

IEEE Trans. Plasma Sci.

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“…As EML inductance increases with the armature movement, as shown in (14). The inductance gradient can be calculated with 3-D FE, using flux-counting method as demonstrated in [6].…”

Section: A Common Features 1) Eml Modelingmentioning

confidence: 99%

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

Tosun¹,

Keysan²

2023

Preprint

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<div>Simulations are crucial in the electromagnetic launcher (EML) researches on account of extreme physical conditions. More energy into the system adds weight to the model’s accuracy as the operation risk rises. 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 current injection. However, experiments showed that the H-shaped bus changes inductance calculations. A careful examination is made to reveal the physical reasoning of 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 different 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.</div>

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“…For that reason, breech voltage measurements have a clear slope correlated with armature acceleration. The EMF discussions are mentioned in [4], interested readers can find more detail in that article.…”

Section: Literature Surveymentioning

confidence: 99%

Muzzle Voltage Characteristics of Railguns

Tosun¹,

Keysan²

2021

Preprint

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Muzzle voltage is an essential diagnostic tool used in both contact resistance modeling and transition determination. However, it is challenging to stem the necessary meanings from the collected measurements. In this study, EMFY-3 launch experiments are used to model muzzle voltage characteristics to understand the transition mechanism better. These experiments have muzzle energies in the range between 1.69-2.85 MJ in ASELSAN Electromagnetic Launcher Laboratory. Six different launch tests with various rail current waveforms that ranged between 1.5-2.1 MA are used to investigate different scenarios. Some parameters which affect muzzle voltage are calculated with the 3-D Finite Element Method (FEM), i.e., rail mutual inductance $\mathrm{L_m}$. Muzzle voltages are decomposed into subsections; each subsection is calculated with proper models. Simulation results are coherent with experimental measurements. Findings are compared with previous studies, and differences are explained with possible reasons. Even though we could not conclusively resolve which physical quantity starts to transition, the study showed that transition does not form a specific muzzle velocity, armature action integral, or down-slope rail current ratio.

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A Hybrid Simulation Model for Electromagnetic Launchers Including the Transient Inductance and Electromotive Force

Cited by 21 publications

References 20 publications

A Comparison of Velocity Skin Effect Modeling With 2-D Transient and 3-D Quasi-Transient Finite Element Methods

A Comparison of Velocity Skin Effect Modeling With 2-D Transient and 3-D Quasi-Transient Finite Element Methods

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

Muzzle Voltage Characteristics of Railguns

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