电子测压器与铜柱测压器在膛压测试中结果差异分析

火炮膛压作为火炮和弹药的内弹道重要参数,在研制、生产、交付、存储校验等环节都需要测量。针对当前同时采用放入式铜柱测压器和电子测压器测量某一批弹药时,电子测压器峰值出现散布较大,而铜柱测压法一致性好的问题,在分析两种测压法测压原理的基础上,利用铜柱动态校准数据作用到其ANSYS模型上修正了铜柱的Johnson-Cook模型参数;分析发现出现差异时电子测压器测量的压力变化率时程曲线不同,铜柱实际测试形变量与施加压力时程曲线作用于模型得到的形变量一致。研究表明:同时测量某一批弹药时,电子测压器比铜柱测压器出现压力峰值散布大的原因是由膛压上升过程变化率不同导致铜柱的应变率不同造成的。     

弹尾弹射装置间隙密封的火药气体动力学

针对弹尾开孔安装用于侵彻数据回收的弹射装置后,存在的弹射间隙会使弹体内的测试装置受到火药气体侵蚀破坏的问题,设计了间隙密封结构,对流经间隙的火药气体进行了气体动力学的建模分析,并对密封结构进行了膛压和密封空腔压强测试。结果表明:火药燃烧产生的气体为可压缩性气体,在药室和收缩的间隙通道中为亚声速流动状态,而在扩张的密封空腔中为超声速流动状态;在弹底火药气体温度为2 166.5 K、密度为360 kg/m3、压强为242.9 MPa的条件下,经过密封装置的密封后,密封空腔内的残余气体压强为0.49 MPa。试验所得密封空腔内的最大压强为0.18 MPa,与模型计算结果基本吻合。     

发射药床冲击破碎过程的数值模拟

发射装药挤压破碎是导致膛炸的根本因素,发射药床的破碎动力学是发射安全性理论研究的基础之一.以离散元法为基础,模拟了发射药床的自然堆积过程,获得了发射药床的密实堆积构型;将密实构型下的发射药床离散成弹簧-球单元系统,应用Mohr-Coulomb型破坏准则,对发射药床动态压缩模拟试验装置中的发射药粒在动态载荷下的挤压破碎过程进行数值仿真,并对数值计算结果进行后处理,实现了模拟药室中发射药粒挤压破碎过程数值计算的动画显示,再现了发射药床冲击破碎动力学过程,仿真结果与试验结果吻合较好,验证了论文理论与模型的正确性,为进一步研究发射药床的破碎规律提供了重要的理论基础和计算手段.     

复合射孔压力加载下铜柱测压计测试实验和数值分析

进行基于铜柱测压和实测压力时间曲线的石油井射孔压裂实验,建立铜柱测压计的数学模型,并 采用交互式计算方法得出其作用过程的解析解。分析结果表明,井下射孔压裂过程中,压力上升沿很陡,活塞 在外部压力达到峰值时,速度很大,会继续压缩铜柱直到速度为零。活塞的运动可以分为加速和减速撞击2 个过程。活塞的最大速度决定了铜柱测压计最终测试值,且与速度成正比。射孔脉冲压力加载过程中铜柱测 压计的误差取决于压力上升时间、脉冲宽度、峰值压力等影响因素。火炮膛压加载下铜柱测压计误差较小。     

发射药床冲击破碎过程的数值模拟

发射装药挤压破碎是导致膛炸的根本因素,发射药床的破碎动力学是发射安全性理论研究的基础之一.以离散元法为基础,模拟了发射药床的自然堆积过程,获得了发射药床的密实堆积构型；将密实构型下的发射药床离散成弹簧球单元系统,应用Mohr-Coulomb型破坏准则,对发射药床动态压缩模拟试验装置中的发射药粒在动态载荷下的挤压破碎过程...     

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针对国家标准GB/T18215.1-2000中规范的"差压式流量计示值修正公式",从以下方面进行了讨论: (1)干气体流量检测示值修正公式; (2)湿气体干部分流量检测示值修正公式; (3)气体组分改变时流量检测示值修正公式.国标中规范的修正公式是建立在: "当气体的温度、压力变化时,其密度也随着发生改变,相同的差压值(设计状态与工作状态)所对应的流量值是不同的".本文认为:当气体工作温度、压力等参数偏离设计条件时,同一质量流量在节流装置前后产生的设计状态与工作状态差压是不同的.这一基础要领的分岐,影响着所有修正公式.     

模块装药火炮膛内两相燃烧模型及压力波模拟

为详细了解新型模块装药火炮膛内发射过程中各模块区及中心可燃管区着火、燃烧现象以及压力波动情况,建立了准二维两相流内弹道燃烧理论模型。模拟结果表明,膛底与膛口压力、压力差数值计算结果与实验结果吻合得很好。     

不同泄压条件对方管内爆炸压力特性的影响

为研究泄压膜约束条件对甲烷/空气预混气体爆炸压力特性的影响，在方形火焰燃烧传播测试管道中布置压力传感器，开展不同泄压膜材料、泄压膜层数及泄压口位置实验。结果表明:牛皮纸和聚丙烯薄膜约束泄爆过程中，每增加一层泄压膜，管道内最大泄爆压力平均上升11.2%和12.3%。各强度泄压膜约束条件下，管道内最大泄爆压力随着泄压口位置接近点火端，均呈现Z形规律，当泄压口设置在距尾部端面0.25 m时，各曲线达到最小值，当泄压口设置在距尾部端面0.50 m时，各曲线出现最大值。     

基于ALE方程的动网格膛口流场数值研究

基于ALE(Arbitrary Lagrangian-Eulerian Equation)方程的有限体积法,采用高精度Roe方法及结构化动网格,利用嵌入网格技术及动边界条件,对弹丸由膛内高压气体推动射出到完全飞高初始流场的整个过程进行了数值模拟.根据数值结果绘制了膛口流场密度和压力分布的时序图,形象地再现了膛口流场中初始激波、弓形激波及膛口冲击波,以及接触闻断、漩涡和剪切层等的动力学发展过程.结果基本反映了膛口流场的典型变化特征,为进一步研究真实膛口流场(如带化学反应、湍流等)奠定了基础.     

基于离散单元法的发射装药挤压破碎模拟实验

为了揭示发射装药破碎引起的膛炸现象,急需进行相应装药结构下发射装药挤压破碎数值模拟研究。以硝胺花边十九孔发射药为研究对象,基于离散单元法建立了发射装药挤压破碎模拟系统,同时进行了发射装药动态挤压破碎实验,通过数值模拟与实验获得了不同冲击载荷下的破碎发射装药和挤压应力;分别对获得的破碎发射装药进行了密闭爆发器数值模拟和实验。结果表明:模拟与实验获得的发射装药挤压应力时间历程、密闭爆发器压力时间曲线和起始动态活度比的一致性较好,实验验证了发射装药挤压破碎模拟系统的有效性及合理性。该模拟系统具有重大工程应用价值,为高能发射装药冲击破碎过程和发射装药发射安全性研究奠定了基础。     

Numerical modeling of the processes within the combustion chamber of a solid propellant rocket engine during the stabilization of the design operation mode

Comprehensive numerical modeling of the processes occurring in the combustion chamber of a solid propellant rocket engine during the stabilization of the design operation mode is performed. The self-consistent problem considered includes nonstationary operation of an ignition device, warmup and ignition of a solid propellant charge followed by its nonstationary burning, nonstationary threephase homogeneous-heterogeneous flow of the combustion products in the combustion chamber, in the nozzle, and behind the engine nozzle unit, engine depressurization, and nozzle unit plug blowing-out. The results of the calculations are presented.     

燃烧轻气炮多级渐扩型燃烧室流场特性数值研究

为了分析多级渐扩型燃烧室结构对燃烧轻气炮氢氧燃烧特性的影响, 通过计算流体力学方法, 分别对采用传统圆柱型燃烧室和多级渐扩型燃烧室的燃烧轻气炮氢氧燃烧发射过程进行数值模拟。对比结果表明, 多级渐扩型燃烧室结构能够明显地减小燃烧室压力波动幅度, 提高氢氧燃烧稳定性; 多级渐扩型燃烧室内形成回流区, 可以减小气流轴向运动速度; 火焰扩展形态与渐扩型结构相吻合, 燃烧反应区表面变化平稳; 多级渐扩型燃烧室结构对氢氧火焰传播过程和压力波动现象有着重要影响。     

A ballistic compressor-based experiment for the visualization of liquid propellant jet combustion above 100 MPa

 This paper describes the components and operation of an experimental setup for the visualization of liquid propellant (LP) jet combustion at pressures above 100 MPa. The apparatus consists of an in-line ballistic compressor and LP injector. The ballistic compressor, based on a modified 76 mm gun, provides high-pressure (ca. 55 MPa) clear hot gas for the jet ignition. A piston (projectile) is fired toward a test chamber beyond the barrel’s end, and its rebound is arrested in a transition section that seals the test chamber to the barrel. The LP jet is injected once the piston is restrained, and combustion of the jet further elevates the pressure. At a preset pressure, a disc in the piston ruptures and the combustion gas vents sonically into the barrel. If a monopropellant is used, the jet injection-combustion process then resembles liquid rocket combustion but at very high pressures (ca. 140 MPa). This paper discusses the ballistics of the compression and compares experimental results to those predicted by a numerical model of the apparatus. Experimentally, a pressure of 70 MPa was achieved upon a 12.5 volumetric compression factor by firing a 10 kg piston into 1.04 MPa argon using a charge of 75 g of small-grain M1 propellant. Received: 16 December 1996/Accepted: 15 July 1997     

Two-phase flows in gun barrel: Theoretical and experimental studies

In the paper theoretical and numerical model of two-phase flow of solid granular propellant and its products of combustion in the gun barrel during interior ballistic cycle is given. Two cases are considered: base ignition of propellant charge and ignition by igniter. The theoretical model includes the balance equations of mass, momentum and energy for both phases, as well as necessary constitutive laws. The igniter efflux in the propellant chamber is obtained by incorporation in the model the two-phase flow model of igniter function. The convergent, unconditionally stable, numerical procedure is formed to solve the system of equations of the theoretical model. An original procedure of numerical grid adaptation to the flow field increase, caused by the projectile motion down the gun bore, is developed. The TWOPIB code for the computation of whole interior ballistic cycle of ammunition is developed. Four kinds of experimental investigations were carried out:igniter function in open air, flamespreading through propellant charge in the fibreglass tube during base ignition or during ignition by igniter, and firing of 100 mm APFSDS projectile. Verification of the theoretical–numerical approach by the comparison with experimental data is carried out. The great number of computational results is presented for the parameters that can not be measured, but which are necessary for more complete understanding of examined processes. The presented theoretical–numerical access enables, not only the complete optimisation of propellant charges, but more successful solutions of many interior ballistic problems.     

膛内等离子体点火及燃烧增强过程数值模拟

在初始点火过程中 ,假设等离子体为充分发展射流流动 ,因而可采用积分近似模型进行描述。而在随后的膛内燃烧过程中通过以经验公式给出等离子体混合长度的方法来处理等离子体的运动 ,并给出了合适的相间阻力及传热公式。通过在计算网格设计中引入了自适应方法提高了数值解精度。计算膛压曲线与实验符合良好。相对常规内弹道情形 ,等离子体能量的注入使在不同时刻膛内的气、固两相速度、压力和膛底温度等出现提高 ,这是等离子体注入后对内弹道的增强过程。计算结果为固体工质电热化学炮的弹道设计提供了理论依据。     

等离子体发生器放电参数对推进剂燃烧特性的影响

揭示了电热化学炮所用的等离子体发生器初始放电参数对推进剂燃烧特性的影响规律。实验主要在密闭药室里进行 ,研究了等离子体发生器中毛细管初始几何尺寸以及输入电能发生变化时 ,推进剂的燃烧行为发生的变化规律。研究结果表明 ,推进剂的燃烧行为对等离子体发生器初始放电参数有较强的依赖性。     

喷嘴结构对液氧煤油火箭发动机高频燃烧不稳定性的影响

为了筛选高压补燃循环液氧煤油火箭发动机的喷嘴,在喷注单元低压高频燃烧不稳定性模拟实验系统上开展实验,研究了喷嘴结构对燃烧稳定性边界的影响。实验使用气态空气与氧气的混合物作为氧化剂,加热的煤油蒸汽作为燃料;喷嘴为全尺寸气液同轴直流离心式喷嘴,模拟燃烧室与真实燃烧室的固有声学频率相等。根据测量模拟燃烧室内的脉动压力区分大幅振荡、小幅振荡和稳定工作。研究结果表明,喷嘴长度、缩进室长度和入口节流嘴直径对高频燃烧不稳定性裕量有很大影响,并存在相对最佳值。     

Study on the influences of interaction behaviors between multiple combustion-gas jets on expansion characteristics of Taylor cavities

The purpose of this study is to investigate means of controlling the interior ballistic stability of a bulk-loaded propellant gun(BLPG).Experiments on the interaction of twin combustion gas jets and liquid medium in a cylindrical stepped-wall combustion chamber are conducted in detail to obtain time series processes of jet expansion,and a numerical simulation under the same working conditions is also conducted to verify the reliability of the numerical method by comparing numerical results and experimental results.From this,numerical simulations on mutual interference and expansion characteristics of multiple combustion gas jets(four,six,and eight jets) in liquid medium are carried out,and the distribution characteristic of pressure,velocity,temperature,and evolutionary processes of Taylor cavities and streamlines of jet flow Held are obtained in detail.The results of numerical simulations show that when different numbers of combustion gas jets expand in liquid medium,there are two different types of vortices in the jet flow field,including corner vortices of liquid phase near the step and backflow vortices of gas phase within Taylor cavities.Because of these two types of vortices,the radial expansion characteristic of the jets is increased,while changing numbers of combustion gas jets can restrain Kelvin-Helmholtz instability to a certain degree in jet expansion processes,which can at last realize the goal of controlling the interior ballistic stability of a BLPG.The optimum method for both suppressing Kelvin-Helmholtz instability and promoting radial expansion of Taylor cavities can be determined by analyzing the change of characteristic parameters in a jet flow field.     

高速液体受限射流扩展形态研究

采用一种火药燃烧驱动液体喷射的新装置及其测试系统，研究受限空间中高速惰性液体射流的扩展结构。观察了环境反压、液体粘性、喷嘴结构等参量对射流扩展形态的影响，分析了射流雾化机理。研究结果对改进燃烧室设计及控制燃烧稳定性有一定的指导意义。