【作者】 张强；

【导师】 张连生；

【作者基本信息】 北京理工大学 ， 力学， 2016， 硕士

【摘要】 超聚能射流的概念由Minin等人首先提出,模拟研究表明:超聚能装药结构能同时提高药型罩的利用率和射流的速度,形成质量更大、速度更高的射流。他们的研究开辟了一个新的研究方向。本文以探究超聚能射流形成的内在机理为出发点,研究了截顶辅助结构和喷射式结构。以数值模拟为主要方法,研究截顶辅助罩与锥形罩、平顶罩之间的差别,以射流形成理论为辅助手段,尝试用经典射流形成理论解释超聚能射流的形成过程,寻找现有理论的局限性,寻找截顶辅助罩的本质特征。最后,对喷射结构做了机理研究和改进。射流形成理论方面,回顾总结了定常理论、准定常理论和非定常理论,编写程序实现理论计算,并与模拟结果对比,对其局限性和优势进行分析。结果表明,轴向、径向速度合成方法和有效装药绝热压缩方法均不能很好的解释模拟得到的结果。将圆柱控制体、静止面法同时应用到锥形罩最大压垮速度理论的计算中得到的结果与数值模拟结果吻合较好。针对压垮角计算公式没有考虑速度历程且稳定性差的缺陷,采用一种纯数值计算方法代替,能使程序健壮,结果可靠。对比锥形罩、平顶罩和截顶辅助罩的区别,结果表明:截顶辅助罩形成的射流形态更细长,前端速度更高。结合理论程序对一种截顶辅助罩的射流形成机理进行分析,结果表明:截顶辅助罩与锥形罩、平顶罩相比产生的射流并没有质量上优势,其特点在于前段(头部拉伸形成)细、长且速度高,中后段没有差别。进一步研究发现,在锥角50°,药型罩为铝,厚度0.5mm,辅助罩为铁,半径8mm的情况下,药型罩顶部15.5%的微元受到辅助罩的影响,压垮角、抛射角、碰撞速度均增加,但这些量的增加不会同时增加速度和质量,理论分析表明,动量和射流质量增加,而速度减小。由于受到影响的质量很少,对最终的射流影响并不明显。对喷射式装药进行了研究,其基本机理是主药型罩在辅助药型罩的斜壁面上挤压导致主药型罩沿内壁流动形成环形汇聚。针对原设计射流易断裂的、炸药作用时间过短的问题分别对主药型罩和辅助药型罩进行优化设计。优化后的结构与原结构相比有明显改进。喷射式结构优点是灵活性高,缺点是射流性能一般。更多还原

【Abstract】 The concept of hypercumulative jet was firstly proposed by Minin et al,preliminary numerical studies showed that the hypercumulative charge structure can improve the mass as well as the velocity of the jet.Their research shed light into a new field.Based on the investigation of the mechanism of the formation of the hypercumulative jet,the truncatedauxiliary and the ejective structure are studied.With the numerical simulation as the main method,the difference between the truncated liner with additional plat top,the conical liner and the liner with plat top was studied.The jet formation theory was used as an auxiliary method to explain the formation process of the formation of hypercumulative jet by classical jet formation theory.This essay is to find the limitation of the existing theory and the essential characteristics of the auxiliary liner.At last,the mechanism of the ejective structure is studied and improved too.During the study of the theory of jet formation,theories of quasi-stationary theory and unsteady theory were reviewed and summarized,and a computer program was written to compare with the results of simulations to analysis advantages and disadvantages of those theories.It has showed that the way which calculate the axial velocity and the radial velocity respectively did not work well,and the effective adiabatic compression method did not fix well either.Applying the cylindrical control body and static surface method to calculate the maximum crushing speed is a feasible method.It fixed well with simulation results.The PER theory did not consider the process of crushing speed changes.A numerical method was proposed to make up for this deficiency,made the theory program stronger.Comparison of cone-shaped liner,flat top liner and the truncated-additional liner,results show that a truncated-additional liner could form jets with higher head speed and longer body.Based on the theoretical program,the jet formation mechanism of the truncated-additional liner is analyzed.The preliminary results show that this new structure did not perform better in quantity,but it could produce a jet with higher head speed and longer body.Further study found that in the case of a specific case,15.5% of the liner mass was affected.Taylor angle,the collapse angle,and the collision speed all increased.The mass increased,but the velocity dropped.For the mass which was involved is little,the final jet did not change much.An ejective structure was studied,The basic mechanism is that the main liner be squeezed on the inclined wall surface of the auxiliary liner to cause the main liner to flow along the inner wall to form an annular aggregation.In order to solve problems appeared in simulation,the optimal design of main liner and auxiliary structure were made respectively,and worked well.更多还原