Stewart Joel B, Pecora Collin
U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005, USA.
Rev Sci Instrum. 2015 Mar;86(3):035108. doi: 10.1063/1.4914898.
Explosively driven shock tubes present challenges in terms of safety concerns and expensive upkeep of test facilities but provide more realistic approximations to the air blast resulting from free-field detonations than those provided by gas-driven shock tubes. Likewise, the geometry of conical shock tubes can naturally approximate a sector cut from a spherically symmetric blast, leading to a better agreement with the blast profiles of free-field detonations when compared to those provided by shock tubes employing constant cross sections. The work presented in this article documents the design, fabrication, and testing of an explosively driven conical shock tube whose goal was to closely replicate the blast profile seen from a larger, free-field detonation. By constraining the blast through a finite area, large blasts (which can add significant damage and safety constraints) can be simulated using smaller explosive charges. The experimental data presented herein show that a close approximation to the free-field air blast profile due to a 1.5 lb charge of C4 at 76 in. can be achieved by using a 0.032 lb charge in a 76-in.-long conical shock tube (which translates to an amplification factor of nearly 50). Modeling and simulation tools were used extensively in designing this shock tube to minimize expensive fabrication costs.
爆炸驱动激波管在安全问题和测试设施的昂贵维护方面存在挑战，但与气体驱动激波管相比，能更逼真地模拟自由场爆炸产生的空气冲击波。同样，锥形激波管的几何形状能自然地近似于从球对称爆炸中切出的一个扇形，与采用恒定横截面的激波管相比，与自由场爆炸的冲击波剖面更吻合。本文介绍的工作记录了一种爆炸驱动锥形激波管的设计、制造和测试，其目标是紧密复制从更大规模的自由场爆炸中看到的冲击波剖面。通过将爆炸限制在有限区域内，可以使用较小的炸药量模拟大型爆炸（大型爆炸会带来重大的破坏和安全限制）。本文给出的实验数据表明，在76英寸长的锥形激波管中使用0.032磅炸药，能够非常接近76英寸处1.5磅C4炸药产生的自由场空气冲击波剖面（这相当于放大系数近50）。在设计该激波管时广泛使用了建模和仿真工具，以尽量降低昂贵的制造成本。
