Numerical Simulation and Analysis of Flow Field during Dynamic Launching of Electromagnetic Rail Launcher Based onOverlapping Multi-block Structured Mesh

doi:10.3969/j.issn.1000-1093.2018.02.004

Abstract

Abstract: The airflow distribution and law of muzzle flow field during the dynamic launching of electromagnetic rail launcher are studied. A two-dimensional transient model of projectile under high Mach number is established based on overlapping multi-block structured mesh, DFBI and Java program. The unsteady numerical method and the reliability of data interaction are validated by taking double ellipsoid model as the object of study. The flow fields in the dynamic launching processes of four cases are simulated. The numerical results show that the complex flow fields due to the interaction of projectile nose shock wave, spherical shock wave with moving center and coronal shock wave are generated in the dynamic launching process of electromagnetic rail launcher.The shock wave is out of the muzzle from the front projectile to the tail of projectile, and the pressure distribution at the midpoint of projectile nose presents symmetry. The resistance coefficient is related to the pressure distribution which presents a weak symmetry after the shock wave being out of the muzzle, which reachs a peak at the tail of projectile. When the projectile moves in the air, and the second peak pressure is greater than the first because of the superposition of the shock wave and its reflection. The farther the distance is, the smaller the reflection period is, the slower the pressure decays. Key

Key words: electromagneticraillauncher, dynamiclaunching, computationalfluiddynamics, chimeragrid, muzzleflowfield, numericalsimulation

CLC Number:

DU Pei-pei， LU Jun-yong， FENG Jun-hong， LI Xiang-ping. Numerical Simulation and Analysis of Flow Field during Dynamic Launching of Electromagnetic Rail Launcher Based onOverlapping Multi-block Structured Mesh[J]. Acta Armamentarii, 2018, 39(2): 234-244.

References

［1］ Watt T J，Bryant M D. Modeling assumptions for railguns[J]. IEEE Transactions on Magnetics， 2007，43(1):380-383.
[2］林庆华, 栗保明. 电磁轨道炮瞬态磁场测量与数值模拟[J]. 兵工学报，2016，37(10)：1788-1794.
LIN Qing-hua, LI Bao-ming. Measurement and numerical simulation of transient electromagnetic field in railgun[J]. Acta Armamentarii, 2016, 37(10):1788-1794. (in Chinese)
[3］ Rodger D，Leonard P J．Modeling electromagnetic performance of moving rail gun launchers using finite elements[J]．IEEE Transactions on Magnetics，1993，29（1）：496-498．
[4］谭赛, 鲁军勇, 张晓, 等. 电磁轨道发射器动态发射过程的数值模拟[J]. 国防科技大学学报, 2016, 38(6):43-48.
TAN Sai, LU Jun-yong, ZHANG Xiao, et al. Numerical simulation of dynamic launching in electromagnetic rail launcher[J]. Journal of National University of Defense Technology, 2016, 38(6): 43-48.(in Chinese)
[5］ Gennady G A，Stankevich S V．Comparison between 2-D and 3-D electromagnetic modeling of railgun[J]．IEEE Transactions on Magnetics，2009，45（1）：453-457．
[6］时光，陈忠华，郭凤仪. 强电流滑动电接触下最佳法向载荷[J].电工技术学报，2014，29（1）：23-30.
SHI Guang, CHEN Zhong-hua, GUO Feng-yi. Optimal normal load of sliding electrical contacts under high current[J]. Transactions of China Electroechnical Society, 2014, 29(1):23-30. (in Chinese)
[7］田振国，孟晓永，安雪云，等. 电磁轨道发射状态下的复合导轨动态响应研究[J].兵工学报，2017，38（4）：651-657.
TIAN Zhen-guo, MENG Xiao-yong, AN Xue-yun, et al. Dynamic response of composite rail during launch process of electromagnetic railgun [J]. Acta Armamentarii, 2017，38（4）：651-657.(in Chinese)
[8］ Vassberg J C, Brodersen O P，Wahls R A， et al. Summary of the fourth AIAA CFD drag prediction workshop[C]∥The 1st AIAA CFD High-Lift Prediction Workshop. Chicago，IL, US： AIAA, 2010.
[9］徐嘉，刘秋洪，蔡晋生，等. 基于隐式嵌套重叠网格技术的阻力预测[J].航空学报，2013,34（2）：208-217.
XU Jia, LIU Qiu-hong, CAI Jin-sheng, et al. Drag prediction based on overset grids with implicit hole cutting technique[J]. Acta Aeronautica et Astronautica Sinics, 2013, 34(2): 208-217. (in Chinese)

[10］ Blanc F．Patch assembly：an automated overlapping grid assembly strategy [J]. Journal of Aircraft，2010，47（1）：110-119．
[11］ Wang J Z, Parthasarathy V. A fully automated chimera methodology for multiple moving body problems[J]. International Journal for Numerical Methods in Fluids，2000，33（7）：919-938．
[12］王莹，肖峰．电炮原理 [M]．北京：国防工业出版社，1995．
WANG Ying，XIAO Feng. Principle of electric gun[M]. Beijing: National Defense Industry Press, 1995. (in Chinese)
[13］ Blazek J. Computation fluid dynamics：principles and applications[M]. UK:Elsevier Science Ltd，2001.
[14］ Noack R W. Dirtlib：a library to add an overset capability to your flow solver[C]∥Proceedings of the 17th AIAA Computational Fluid Dynamics Conference. Toronto，Ontario, Canada：AIAA, 2005: 2005-5116.
[15］ Shih T H, Liou W W, Shabbir A, et al. A new k-ε eddy viscosity model for high Reynolds number turbulent flows[J]. Computers & Fluids, 1995, 24(3):227-238.
[16］李素循. 典型外形高超声速流动特性[M]. 北京：国防工业出版社，2007.
LI Su-xun. Hypersonic flow characteristics of typical shape[M]. Beijing: National Defense Industry Press, 2007. (in Chinese)

第39卷第2期
2018 年2月兵工学报ACTA
ARMAMENTARIIVol.39No.2Feb. 2018

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