2008 14th Symposium on Electromagnetic Launch Technology最新文献_第7页

High-Speed Macroparticle Destruction in a High-Current Pulse Discharge 大电流脉冲放电中的高速宏粒子破坏

2008 14th Symposium on Electromagnetic Launch Technology Pub Date : 1900-01-01 DOI: 10.1109/elt.2008.131

V. Obukhov, A. V. Ovchinnikov, A. F. Piskunkov, A. Pertsev, N. P. Shishaev

{"title":"High-Speed Macroparticle Destruction in a High-Current Pulse Discharge","authors":"V. Obukhov, A. V. Ovchinnikov, A. F. Piskunkov, A. Pertsev, N. P. Shishaev","doi":"10.1109/elt.2008.131","DOIUrl":"https://doi.org/10.1109/elt.2008.131","url":null,"abstract":"The possibility of spacecraft's electrodynamic shielding (EDS) against high-speed orbital debris has been investigated both experimentally and theoretically. The laboratory EDS device is made as a flat two-electrode discharge unit. Its external electrode serves as the first shield in the incident particles' way while the internal electrode has a \"brush\" of thin conductors contacting it and directed towards the first electrode to meet particles with their free ends. Successful tests of the EDS were carried out at the speed of the coming aluminium particle ~2.0 km/s sized Oslash7.8times12 mm (mass ~1.7 g) while the voltage of about 5 kV was applied to the EDS electrodes from a capacitor battery of 4 mF (stored energy 50 kJ). Interelectrode distance ranged 60-75 mm and free ends of the \"brush\" conductors were separated from the external electrode by 1-2 mm, i.e. less distance than the size of the particle model. At the impact of the model particle EDS electrodes are short-circuited and the said capacitor is discharged with the following parameters of the discharge pulse: current up to ~250 kA, pulse duration ~70 mus. At these parameters an obstacle in the form of an aluminium plate 4 mm thick simulating a space object's hull remained intact while without this discharge it was perforated. Two theoretical approaches to the description of the discharge initiated by an incident particle with the eventual particle's destruction are proposed considering processes of its melting (evaporation) and deceleration. The comparison of theoretical discharge current integral with a real experimental value shows that the proposed notions describe the situation quite reasonably.","PeriodicalId":170049,"journal":{"name":"2008 14th Symposium on Electromagnetic Launch Technology","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134556143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Effects of Pressure-Dependent Contact Resistivity on Contact Interfacial Conditions 压力相关接触电阻率对接触面条件的影响

2008 14th Symposium on Electromagnetic Launch Technology Pub Date : 1900-01-01 DOI: 10.1109/elt.2008.34

K. Hsieh, S. Satapathy, M. Hsieh

{"title":"Effects of Pressure-Dependent Contact Resistivity on Contact Interfacial Conditions","authors":"K. Hsieh, S. Satapathy, M. Hsieh","doi":"10.1109/elt.2008.34","DOIUrl":"https://doi.org/10.1109/elt.2008.34","url":null,"abstract":"Adequate contact pressure needs to be applied at electrical contacts to overcome contact separation force due to current constriction effects. In the railgun operation, the initial contact pressure is provided by the interference pressure between the armature and the rail. As the magnetic field is established in the bore, the electromagnetic force provides the contact pressure, as the initial contact pressure reduces due to wear or contact melting. Excessive initial contact pressure may delay the motion of the armature and cause overheating of the armature. On the other hand, insufficient initial pressure would result in contact separation of armature and rail. The contact interface is never perfectly smooth. It only contacts at discrete asperities at micro scale and at discrete points due to deformation of the contact interface at macro scale. The interface characteristics are different from the bulk behavior. A detailed model of contact resistivity is essential to compute the interfacial current density and temperature distributions accurately. A contact resistivity model was developed that is a function of contact pressure, the hardness of the softer contact member, average bulk resistivity, and contact constants. The model was implemented into the code EMAP3D. This paper presents the simulation results of the startup of a sample railgun with and without contact resistivity.","PeriodicalId":170049,"journal":{"name":"2008 14th Symposium on Electromagnetic Launch Technology","volume":"117 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124934663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

3-D Electromagnetic Analysis of Armatures and Rails for High Launch Energy Applications 高发射能量电枢和轨道的三维电磁分析

2008 14th Symposium on Electromagnetic Launch Technology Pub Date : 1900-01-01 DOI: 10.1109/elt.2008.12

H. Liu, M. C. Lewis

引用次数: 0

The ISL Rapid Fire Railgun Project RAFIRA Part I: Technical Aspects and Design Considerations ISL快速火力轨道炮项目RAFIRA第一部分:技术方面和设计考虑

2008 14th Symposium on Electromagnetic Launch Technology Pub Date : 1900-01-01 DOI: 10.1109/elt.2008.88

M. Schneider, M. Woetzel, W. Wenning, D. Walch

引用次数: 29

Electromagnetically Driven Expanding Ring with Pre-Heating 电磁驱动预热膨胀环

2008 14th Symposium on Electromagnetic Launch Technology Pub Date : 1900-01-01 DOI: 10.1109/elt.2008.119

D. Landen, D. Wetz, S. Satapathy, S. Levinson

引用次数: 3

Progress Towards an End-to-End Model of an Electrothermal Chemical Gun 电热化学枪端到端模型的研究进展

2008 14th Symposium on Electromagnetic Launch Technology Pub Date : 1900-01-01 DOI: 10.1109/elt.2008.66

A. Porwitzky, M. Keidar, I. Boyd

引用次数: 16

Analysis and Optimization of Thrust Characteristics of Tubular Linear Electromagnetic Launcher for Space-Use 空间用管状直线电磁发射器推力特性分析与优化

2008 14th Symposium on Electromagnetic Launch Technology Pub Date : 1900-01-01 DOI: 10.1109/elt.2008.16

B. Kou, Liyi Li, Chengming Zhang

{"title":"Analysis and Optimization of Thrust Characteristics of Tubular Linear Electromagnetic Launcher for Space-Use","authors":"B. Kou, Liyi Li, Chengming Zhang","doi":"10.1109/elt.2008.16","DOIUrl":"https://doi.org/10.1109/elt.2008.16","url":null,"abstract":"Release-launch is a fundamental operation in space platform. Not like traditional land-base launcher, space-base launcher is more flexible and more efficient. Tubular linear electromagnetic launcher (TLEML), which provides higher force density, simple structure and no unilateral magnetic force, compared with the flat linear electromagnetic launcher, is more suitable for space platform. It can easily meet the demand such as little volume, light weight and high control precision. This paper analyzes and optimizes the thrust characteristics of tubular linear permanent magnet synchronous motors (TL-PMSM) for electromagnetic launcher, including different topologies, interior PMs (IPM) and surface-mounted PMs (SPM). First, build up the finite element model for the two kinds of TLEML and calculate the magnetic field. Then thrust force fluctuation figures are obtained by finite element analysis considering the pole/arc ratio, the pole pitch and the inner diameter/outer diameter ratio of the stator. The result shows that it can improve the thrust characteristic and decrease the cogging force by optimizing the parameters of the motor.","PeriodicalId":170049,"journal":{"name":"2008 14th Symposium on Electromagnetic Launch Technology","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122222565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Structural Mechanics of Railguns in the Case of Discrete Supports 离散支承情况下轨道炮的结构力学

2008 14th Symposium on Electromagnetic Launch Technology Pub Date : 1900-01-01 DOI: 10.1109/elt.2008.78

L. Tumonis, M. Schneider, R. Kačianauskas, A. Kačeniauskas

{"title":"Structural Mechanics of Railguns in the Case of Discrete Supports","authors":"L. Tumonis, M. Schneider, R. Kačianauskas, A. Kačeniauskas","doi":"10.1109/elt.2008.78","DOIUrl":"https://doi.org/10.1109/elt.2008.78","url":null,"abstract":"Numerical calculations concerning the dynamic behavior of a railgun are presented. At the first stage, the structural problem can be decoupled from electromagnetic phenomena as well as from the local projectile behavior. The magnetic pressure repelling the rails from each other and expanding with the speed of the projectile serves as a boundary condition for purely mechanical calculations. The particularity of the investigation is represented by the type of railgun housing. For some years the ISL has been using laboratory housings of an open design allowing, for instance, to take flash radiographs during launch. The repelling forces are mainly taken by discrete supports in the form of steel bolts. These bolts are connected to bars made of glassfiber-reinforced plastics (GRP), while the rails are mounted on these bars. A 2D finite element model of a complex housing was developed in this work. Bars, including rails, are described by plane stress elements, while bolts, playing the role of discrete elastic supports, are presented by truss elements. The model is implemented using the ANSYS code. Deformation properties of the rail section and elastic supports are examined by considering a static solution, assuming constant loading. Differences between 2D and conventional beam models being of importance for this kind of problem are briefly discussed. Transient analysis was performed for a set of constant loading velocities (600 m/s up to 1600 m/s) and for the experimentally derived transient loading profile. The latter was obtained in the railgun experiments performed using the ISL- railgun EMA3 with a caliber of 15 times 30 mm2 and typical muzzle velocities up to 1600 m/s as well as peak currents of about 600 kA.","PeriodicalId":170049,"journal":{"name":"2008 14th Symposium on Electromagnetic Launch Technology","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114727819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Section Crossing Drive with Fuzzy-PI Controller for the Long Stroke Electromagnetic Launcher 基于模糊pi控制器的长行程电磁发射器截面交叉驱动

2008 14th Symposium on Electromagnetic Launch Technology Pub Date : 1900-01-01 DOI: 10.1109/elt.2008.73

Liyi Li, Junjie Hong, Hongxin Wu, Peng Li, Xiaopeng Li

引用次数: 11

Electric Current Induced Liquid Al Deposition, Reaction and Flow on Cu Rails at Rail-Armature Contacts in Railguns 在轨道炮的轨道-电枢接触处，电流诱导液态铝在铜轨道上沉积、反应和流动

2008 14th Symposium on Electromagnetic Launch Technology Pub Date : 1900-01-01 DOI: 10.1109/elt.2008.35

I. Dutta, L. Delaney, B. Cleveland, C. Persad, F. Tang

{"title":"Electric Current Induced Liquid Al Deposition, Reaction and Flow on Cu Rails at Rail-Armature Contacts in Railguns","authors":"I. Dutta, L. Delaney, B. Cleveland, C. Persad, F. Tang","doi":"10.1109/elt.2008.35","DOIUrl":"https://doi.org/10.1109/elt.2008.35","url":null,"abstract":"When a railgun is fired, the aluminum armature typically undergoes melting at the rail-armature contacts and deposits liquid metal on the rails. Rail-life is affected by these deposits. Localized aluminum armature melting has been attributed to current crowding and localized Joule heating. This paper reports on (1) characterization of debris on fired rails and their role in rail damage, and (2) experiments to elucidate the role of electric current in the transport of liquefied armature material along the rail surfaces. A miniature static railgun model was constructed by wrapping an Al foil around a quartz core, and placing the Al foil in contact with two thin film Cu stripes deposited on Si substrates. In this arrangement, the Cu thin films simulated the surface skins on the two rails, whereas the Al foil represented the skin of the armature. The circuit was subjected to a constant current under high vacuum and various ambient temperatures. The part of the Al foil in contact with Cu melts quickly due to Joule heating, and the liquefied Al starts flowing down the negative rail. In all instances, the direction of liquid flow was from the positive to the negative terminal. The kinetics of Al migration was measured, and it was found that the activation energy for Al migration is close to that for self-diffusion in liquid Al. The observed liquid transport is attributable to liquid electromigration under the influence of the applied current.","PeriodicalId":170049,"journal":{"name":"2008 14th Symposium on Electromagnetic Launch Technology","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122302603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 11