【作者】 李小林；

【导师】 陈冬群；

【作者基本信息】 国防科学技术大学 ， 物理电子学， 2009， 硕士

【摘要】 螺线管型爆磁压缩发生器(HEMCG)具有较大的初始电感、能量放大倍数比其它类型的EMCG大、且体积小、结构紧凑、带负载能力强等特点。单级HEMCG输出脉冲时间长、幅值高,通常用来产生强磁场,广泛应用于高能量密度物理实验研究。本文从理论和实验两个方面对单级HEMCG的输出特性进行了研究,该研究填补了教研室在MA量级HEMCG研究的空白;并对其脉冲调制技术进行了初步研究,以探索由长脉冲陡化得到短脉冲的新途径,这些工作为今后的进一步研究打下了良好的基础。在理论上,主要分析计算了装置运行过程中的各种损耗,包括临近效应、趋肤效应、温度效应等欧姆损耗和跳匝、高压击穿和磁扩散等非欧姆损耗。计算中将非欧姆损耗等效为欧姆损耗,在电路中以等效电阻表示。对装置电感、电流、电阻率和温度等参数进行了计算,结果与实验基本相符,可以起到指导设计制作、预测实验效果的作用。通过数值计算优化装置结构参数,设计了一种直接馈电长脉冲HEMCG-80,其总长度525 mm,外径140 mm;定子线圈用导电截面1.5 mm2的绝缘铜导线绕制而成,长450 mm,内直径80 mm;电枢采用工业纯铝管材,长515 mm,内直径34 mm,壁厚4 mm。实验上, HEMCG-80初始电流为3.6 kA,初始电感128.7μH,填装8701炸药560 g时,在100 nH负载上得到上升时间75.2μs、峰值1.87 MA的脉冲电流;初始输入能量为0.834 kJ,磁通0.463 Wb,负载能量174.8 kJ,负载上最终磁通为0.187 Wb,对应的磁通压缩系数为40.4%;8701炸药能量密度为5.17 MJ/kg,则化学能转化为电磁能的效率为6%;HEMCG-80能量放大约209.6倍,电流放大约519.4倍,发生器活力值为12.65。另外对HEMCG-80长脉冲调制的脉冲变压器+电爆炸丝方案和脉冲变压器+炸药切断开关+电爆炸丝方案进行了理论分析及电路模拟比较,由电爆炸丝消耗的能量和负载上得到的电功率说明后一种方案更具优势。并对基于后一种方案的脉冲变压器和切断开关进行了初步的实验研究。脉冲变压器的作用是升压,将尽可能多的能量耦合到不同的负载,这就要求变压器有比较好的绝缘和高的耦合系数,特别是用于调制EMCG输出的脉冲变压器还要求原边电感尽可能低以利于发生器更好的工作。设计制作的同轴电缆脉冲变压器原边电感440 nH,副边电感约4μH,耦合系数为0.84。与HEMCG-80联合实验在4μH负载上得到上升时间75μs、峰值72 kA的电流脉冲,变压器能量传输效率为26.8%。设计、加工了两种作用时间在μs级的炸药切断开关,分别是导爆索切断开关和平板炸药切断开关。并用电容器作为电源对炸药切断开关放电进行了初步的实验研究,实验表明成功切断上升时间50μs、幅值24~31 kA的电流脉冲,在4μH负载上得到上升沿十几μs、幅值十几kA的脉冲。开关切断时间1~3μs,切断电阻1~2 ?。HEMCG-80带100 nH负载实验与理论计算结果基本相符,误差在可接受的范围内,进一步验证了理论分析的正确性。其与电缆脉冲变压器联合实验表明,需要研制一种原边电感更小、耦合系数更高和耐压更好的脉冲变压器,以期在副边得到更多的能量。初步的炸药切断开关实验表明开关性能优良,但由于时间和实验条件有限,以及爆炸实验的单次性,对开关在不同条件下的性能还需要更进一步的研究。在各部件单独研究成熟的基础上进行整体实验,用HEMCG+脉冲变压器+切断开关方案得到较高的电流脉冲输出是今后工作和研究的方向。更多还原

【Abstract】 Helical explosively-driven magnetic flux comepression generator(HEMCG) has larger initial inductance,and the energy amplification factors are larger than those of other types of explosively-driven magnetic flux compression generator(EMCG),furthermore it has small volume , compact construction and better load adaptability.Single stage HEMCG’s outputing pulse has long risetime and high peak current,which is used to generate intense magnetic field,and has wide applications in high energy density physics(HEDP).Some basic theoretical and experimental work is carried out on the performance of single stage HEMCG in this dissertation.The investigation fills up the blankness of our staff room;further more,the preliminary experiment researches on pulse modulation technologies of HEMCG is also carried out and seek after the new approach which could gain short pulse by erecting long pulse, these works set a good foundation for the further researches.In theory,the various losses are analyzed and calculated,including ohmic loss(such as proximity effect、skin effect and temperature effect) and non-ohmic loss(such as turn-skipping、high voltage breakdown and magnetic diffusion).In calculation,the non-ohmic loss is equivalent to ohmic loss and shown as an equivalent resistance in the circuit.The parameters of the device such as inductance、current、resistivity、temperature and so on are calculated,the results are basically consistent with previous experimental results on devices of this kind.On the foundation of numerical calculation optimazing structral parameters,one direct feeding long pulse HEMCG-80 with the length of 525 mm and the outer diameter of 140 mm is designed;the stator with the length of 450 mm and the inner diameter of 80 mm is wound by the polyvinyl chloride insulated copper wire with 1.5 mm2 cross-section.In experiment,when the initial current injected into HEMCG-80 is 3.6 kA,the inductance of the device is 128.7μH and the mass of high energy explosive 8701 is 560 g,a pulse current with 75.2μs risetime and 1.87 MA peak value is obtained on the 100nH load.This result indicates that the initial input electric energy is 0.834 kJ and the load received energy is 174.8 kJ;the initial magnetic flux is 0.463 Wb and the ultimate magnetic flux on the load is 0.187 Wb,so that the corresponding compression coefficient of magnetic flux is 40.4%;because the energy density of 8701 explosive is 5.17 MJ/kg,the conversion efficiency from chemical energy to electromagnetic energy is 6%;while the energy amplification coefficient of HEMCG-80 is 209.6,the current is amplified by 519.4 times,the vim of HEMCG-80 is 12.65.In addition,the scheme that pulse transformer+electric exploding wire opening switch(EEOS) is compared with pulse transformer+explosively driven opening switch (EDOS)+EEOS,it illustrates that the latter has more advantages according to EEOS dissipation energy and load’s electric power . Preliminary researches on pulse transformer and opening switch which based on the latter scheme are carried out.In order to lift voltage and couple more energy to loads,the pulse transformer will need good insulation and high coupling coefficient,at the same time,the low primary inductance is suit for the EMCG working effectively.So the coaxial-cable pulse transformer is designed,which primary inductance is 440 nH,the secondary inductance is 4μH,the coupling coefficient is 0.84.In the union experiment with HEMCG-80,the current pulse with 75μs risetime and 72 kA peak value is obtained on 4μH load,the energy transmission efficiency of transformer is 26.8%.Two kinds of the EDOS are designed to modulate the output of HEMCG-80,which are detonator cord opening switch and flat plate explosively driven opening switch.The preliminary experiments are carried out,and the power supply is capacitor,the results indicate that the current pulse with 50μs risetime and 24~31 kA peak value can be cut off triumphantly and the current pulse with tensμs risetime and tens kA peak value is gained on 4μH load.The opening time is 1~3μs,the opening resistance is 1~2 ?,the average dissipation energy per groove is about 0.125~0.34 kJ.The experiment result of HEMCG-80 with 100 nH load is generally consistent with the theoretical analysis.The results of the union experiment with coaxial-cable pulse transformer and HEMCG-80 indicate that a sort of pulse transformer with lower primary inductance、higher coupling coefficient and better insulation should be examined and developed.The results of preliminary experiments indicate EDOS has perfect performance,because the limitations of time and experiment condition,the performance of EDOS under diverse status needs farther investigations . When experiments on all parts of the scheme are fairly finished in the future,the union experiment will be put in practice . Obtaining considerable current pulse with HEMCG+pulse transformer+opening switch scheme is the direction of future work and research.更多还原