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针对电磁轨道炮超高速弹丸软回收技术难题,基于水下弹丸设计理论,介绍了弹丸软回收的工作原理,提出了基于低密度流体的超高速弹丸分段回收设计方案,给出了回收段参数的设计计算方法。结合案例,在阻力系数C_D=0.086的基础上,给出了初速2 500 m/s、最大过载不超过20 000 g的铝质弹丸的软回收技术方案。计算结果表明,利用设计的软回收技术方案,可在35 m的距离内,通过尘雾段、泡沫段、静水段和浸水纤维段4段回收装置,实现弹丸的可靠回收。 相似文献
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Huaxiang ZHANG 《等离子体科学和技术》2020,22(10):105102
The property of scrape-off layer (SOL) currents induced by a biased electrode is investigated by fully kinetic collisionless two-dimensional particle-in-cell (PIC) simulations. A reduced Vlasov–Darwin model is employed, which is capable of describing the low-frequency kinetic behavior without electromagnetic vacuum modes A linear decay distribution of electron currents parallel to the background magnetic field is exhibited. Simulation analyses indicate that the cross field ion current is a key factor in sheath formation and global current balance. The influences of electrode area, biasing voltage and plasma source on the SOL current profile are studied, respectively. Characteristic plasma parameters in the far SOL region of the EAST tokamak are used in simulations to assess the current driving ability of the electrode biasing method. Due to the limitations of computational power, the geometrical size of the simulation domain is significantly smaller than the realistic SOL, which may lead to an absence of the quasi-neutral region in the upstream plasma. At last, a heuristic method is proposed to calculate the upper bound of the total current strength. 相似文献
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实际工程中,以经验公式预估支护桩的变形,往往与实际变形有较大误差。针对邯郸市某桩锚支护工程进行了弹塑性数值模拟,并与监测结果对比分析,两者的支护桩水平位移误差约5.1%,验证了ABAQUS模拟基坑开挖的可行性。地表最大沉降量发生在约0.5倍的基坑开挖深度,沉降量约0.75倍的基坑最大变形量,进而探讨了支护锚索的应力传递规律。 相似文献
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为了研究电磁轨道炮U形铝质电枢在回收过程中可承受的过载极限,运用动力学有限元软件LS-DYNA,采用ALE算法对U形铝质电枢以不同速度侵入不同密度的回收介质进行了数值模拟,以临界形变为参考,得到了不同初速的U形铝质电枢无损回收可选介质的最大密度以及可承受的最大过载值。结果表明:随着电枢速度的提高,回收时可选用的介质密度减小,且减小幅度越来越小;在误差允许范围内,电磁轨道炮U形铝质电枢回收过程中可承受的过载极限值约为800 000 g.研究结果对电枢回收试验有重要参考意义。 相似文献
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