化工设备爆炸冲击波事故易损性与防控技术研究

化工企业各类型风险事故中,化工设备受到爆炸冲击波的影响进而出现火灾热辐射、爆炸冲击波、碎片等,是导致事故升级以及损坏影响扩大的根源。以某化工园区发生事故为出发点,针对化工设备受爆炸冲击波影响所产生的破坏强度表征方法、爆炸破坏载荷特点与计算以及破坏失效概率计算等进行综述,进而得到化工设备爆炸冲击波事故易损性综合计算方法。     

爆炸冲击波绕过墙体的数值模拟研究

利用ALE算法和炸药爆轰产物的JWL状态方程对爆炸冲击波绕过墙体的环流现象进行了数值模拟,得到了在爆炸物周围有障碍物的爆炸场初始发展和绕过墙体环流的情况,解析了空气冲击波的绕流规律。实验结果与数值模拟基本相符,反映了爆炸波绕过障碍物的详细过程。     

负压环境对炸药爆炸冲击波影响的实验研究

为了研究负压环境对炸药爆炸冲击波的影响,在自制可调真空度爆炸容器中进行负压爆炸实验,采用PCB压力传感器测量罐体轴线固定位置点的冲击波超压,分析了在0、-20、-40、-60、-80、-90、-99kPa等不同负压环境下罐体内测点爆炸冲击波反射超压时程曲线。结果表明,爆炸环境负压降低,测点一次、二次冲击波峰值超压随之降低,在-40kPa和-99kPa负压环境下超压降低显著;爆炸冲击波速度大小与传播介质密度相关,即环境负压越低,气体越稀薄,冲击波传播速度越快;爆炸冲击波速度随环境负压降低而升高,与超压降低强度无相关性;负压环境不改变容器内实验雷管爆炸的气体产物生成量;在近似真空环境中,爆炸冲击波主要以爆轰产物为传播介质,冲击波速度提高受限于爆轰产物运动速度,强度弱,衰减迅速。     

温度载荷与爆炸碎片冲击载荷耦合作用下储罐易损性分析

爆炸碎片和火灾热辐射是导致储罐区多米诺效应事故升级的重要致损因子。在实际爆炸碎片撞击目标储罐的事故场景中,目标储罐不止只受到爆炸碎片的撞击作用,还受到临近火灾的高温载荷作用。为研究目标储罐在高温环境下受到爆炸碎片撞击的易损性规律,本文建立了目标储罐在温度载荷和爆炸碎片冲击载荷耦合作用下的极限状态方程,并采用蒙特卡洛模拟绘制得到目标储罐在不同罐壁温度下受爆炸碎片撞击的易损性曲线,分析爆炸碎片质量、撞击速度、撞击角度对不同罐壁温度下目标储罐易损性的影响规律。结果表明：爆炸碎片质量和爆炸碎片撞击角与目标储罐易损性成负相关,爆炸碎片速度与目标储罐易损性成正相关。当研究变量为爆炸碎片质量时,在20~400℃和400~600℃两个温度范围内,罐壁温度每上升100℃目标储罐最大破坏失效概率平均增加值分别为3.7%、6.7%。当研究变量为爆炸碎片速度时,在20~600℃的温度范围内,罐壁温度每上升100℃目标储罐最大破坏失效概率平均增加值为3.9%。当研究变量为爆炸碎片撞击角时,在20~600℃的温度范围内,罐壁温度每上升100℃目标储罐最大破坏失效概率平均增加值从0.675%一直增大到7.01%。研究对评估实际事故中爆炸碎片对储罐的损伤及防控爆炸碎片引发的多米诺效应事故具有重要意义。     

几种不同爆炸冲击波作用的能量谱分析

为得到冲击波能量与目标自振频率之间的关系,利用小波包分析原理对几种不同爆炸冲击波作用进行了能量谱分析,并准确得到各频段的能量值。结果表明,能量谱在某频段的幅值越高,对自振频率在该频段的目标破坏作用就越大。结合各种结构部件的自振频率,分析各种冲击波作用的能量谱,可以选出最适合的药量和爆心距,达到高效毁伤的目的。     

高海拔环境下运动装药的爆炸冲击波特性

为了研究高海拔环境下运动装药的爆炸冲击波传播特性,利用AUTODYN有限元软件,研究了不同海拔高度及其解耦对应的低温条件和低压条件对运动装药爆炸冲击波超压场的影响规律;建立了预测低温环境和低压环境下运动装药爆炸冲击波超压的理论计算模型,并通过试验数据和数值模拟进行了对比验证。结果表明,该计算模型可以有效预测不同低温、低压以及低温和低压耦合的高海拔环境下运动装药的爆炸冲击波超压;海拔高度从0升至10000m,冲击波超压峰值平均减小35.6%,冲击波作用范围增加62.0%;随着环境温度降低,冲击波超压峰值平均增加0.43%,冲击波作用范围减小11.9%;随着环境压力降低,冲击波超压峰值平均减小36.4%,冲击波作用范围增加83.5%;不同海拔高度下装药运动速度引起的冲击波超压增大系数变化规律与解耦对应的低压条件影响规律基本相似;高海拔环境对运动装药爆炸冲击波的作用范围及超压的影响主要取决于低压条件,低温条件的影响程度较小。     

冲击波作用下HMX晶体的细观响应

用折光匹配显微技术(OMS)、表观密度浮沉法(SFM)、微聚焦CT扫描表征了HMX晶体内部缺陷尺寸、数量。结果表明,D-HMX较普通HMX含有较大尺寸内部缺陷的数量较少,普通HMX含有大量10-5mm3以上缺陷,普通HMX和D-HMX晶体均含有大量10-6mm3量级以下缺陷。利用基于细观结构的冲击波效应数值模拟方法,研究了晶体内部缺陷尺寸对其冲击波温升效应的影响。模拟结果表明,在低压条件下,等效半径为20~40μm的内部缺陷在冲击波加载下温升较高,等效半径为10~15μm的内部缺陷温升相对较低。当冲击波压力增高至5.8GPa,等效半径为10μm内部孔洞在冲击波作用下温升可达到850K以上,两者的冲击波感度接近。     

爆炸碎片撞击下受保护层防护的储罐易损性规律分析

储罐保护层是降低化工园区爆炸碎片多米诺效应事故风险的一类关键安全屏障技术。为探讨不同规格的保护层对爆炸碎片引发储罐失效概率的降低程度,建立化工储罐在铝（Al）及超高分子量聚乙烯（ultra-high molecular weight polyethylene,UHMWPE）纤维保护层防护条件下的极限状态方程与破坏失效概率模型,并用Monte-Carlo模拟方法绘制目标储罐受爆炸碎片撞击的易损性曲线,分析不同厚度、材料、层数及耦合方式的保护层对爆炸碎片事故破坏效应的影响规律。结果表明：两种材料的保护层均能显著降低目标储罐受爆炸碎片撞击的破坏失效概率,降低程度均在80%以上;保护层厚度是影响其降低程度的关键因素,在铝质保护层防护下储罐易损性对厚度变化的敏感性大于UHMWPE纤维保护层;对于总厚度相同的铝质保护层,随层数的增加,储罐破坏失效概率逐渐降低;两种材料耦合的多层保护层对储罐失效概率的降低程度大于多层铝质保护层。研究对实际工况中储罐保护层的合理选材与结构设计具有重要参考意义,并可有效提升化工设备韧性。     

水中爆炸冲击波对靶体结构的毁伤准则研究

为了准确评估水中爆炸冲击波对靶体结构造成的毁伤程度,给出了冲击波毁伤威力参量的一般形式W~n/R(W为装药质量,R为爆距,n为待定系数),并在量纲分析推导W~n/R与结构毁伤的函数关系的基础上,提出了采用W~n/R作为水中爆炸冲击波毁伤准则与判据的通用形式。利用AUTODYN软件模拟了水中爆炸冲击波分别对圆板和圆筒靶体结构的作用,对比分析了以不同冲击波毁伤威力参量作为毁伤准则与判据的等毁伤曲线。结果表明,冲击波峰压、能流密度(冲击因子)、比冲量等威力参量均不能独立作为毁伤准则与判据;基于W~n/R提出的毁伤准则与判据在评估靶体结构的毁伤程度时误差更小,均方差仅为其他准则的8%～36%;所提出的W~n/R可视为一种峰压—比冲量联合形式的毁伤准则与判据,根据不同条件n的取值在0.333～N_i之间。所提出毁伤准则和判据用于评估水中爆炸冲击波对靶体结构的毁伤时具有良好的通用性和实用性。     

负压条件下球形爆炸容器内乳化炸药冲击波参数研究

为了探究负压条件下乳化炸药冲击波参数,在4m直径可调真空度球形爆炸容器内,开展不同负压和不同药量条件下的乳化炸药内爆实验,获得冲击波的超压时程曲线,重新拟合了乳化炸药在不同负压环境下的峰值超压公式和正压冲量公式。结果表明,乳化炸药质量每减少50g,峰值超压平均下降27%;环境压力每降低20kPa,峰值超压平均下降8.66%;乳化炸药在不同负压环境下的正压冲量约为单质炸药的81.3%;负压条件下的乳化炸药峰值超压和正压冲量实验值与传统经验公式相比误差均大于10%,而基于常压实验值拟合的公式与不同工况下的实验值误差均小于4%,能够精确预测不同负压环境下乳化炸药的冲击波参数。     

In the theory of blast waves

The behavior of the blast wave from an exploding spherical volume is investigated mathematically over the entire range of blast-wave propagation. The computational method uses analytical results for a similar problem for a point explosion with counter pressure and the theory of an asymptotically equivalent point explosion. The asymptotic solution of the gas-dynamic equations away from the explosion site is matched to the initial conditions of blast-wave formation due to the disintegration of the detonation shock upon its arrival at the boundary of the exploding volume. The spatial distribution of the blast-front pressure is found for combustible gaseous systems and solid explosives. The theoretical results obtained agree quantitatively with available experimental measurements. __________ Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 4, pp. 93–99, July–August, 2006.     

整流装置谐波分析

叙述了整流装置电流波形畸变的原因,介绍了电能质量公用电网谐波治理国家标准及谐波计算方法,以某大型化工电解装置谐波计算为例,分析说明为达到国家标准,使谐波电流不超标,理论上需要24脉波整流。     

连锁效应下化工装置定量风险分析初选方法

化工过程装置定量风险分析(QRA)首先面对装置初选的问题。基于2类危险源理论和装置连锁事故的主要诱因和过程机理分析,得出化工过程装置风险主要包括二方面:装置内危险物质的数量和危险特性,装置之间的事故连锁效应。提出与化工过程装置火灾、爆炸及毒物泄漏事故相对应的3类装置固有风险指标和2类装置事故连锁风险指标。基于2类风险指标分别建立装置专项事故风险综合评价矩阵,通过矩阵计算获得各装置专项事故综合风险的相对高低,并确立装置初选的最低条件,完成装置的初选,并通过实例应用演示了该方法。     

Stability of the combustion wave in a viscoelastic medium to small one-dimensional perturbations

The problem of stability of the conversion front in a viscoelastic medium is formulated. The stability study is performed by the method of small perturbations. Nonlinear equations are derived for decrements of decay and complex frequency. Several particular cases are analyzed. A significant effect of the time of relaxation of viscous stresses on the flammability limits for both high-velocity and low-velocity regimes is demonstrated. __________ Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 4, pp. 50–60, July–August, 2006.     

Multiscale numerical investigation on failure behaviour of three-dimensional orthogonal woven carbon/carbon composites subjected to pin-loading

On the basis of the experimental results in previous work, a multiscale numerical modeling strategy on the failure behaviour of three-dimensional orthogonal woven carbon/carbon composites under pin-loading was presented. In consideration of the complexity of internal woven architecture, the finite element analysis at micro-/meso-/macro-scale levels was performed to exhibit the effective material properties and mechanical behaviour. The geometric models were reconstructed via X-ray tomography technology to obtain feasible configurations based on actual microstructure, meanwhile the models considered the fibers random arrangement in the yarn and voids stochastic distribution in the matrix. The anisotropic composites damage evolution was characterized by Murakami-Ohno damage theory. Additionally, for a further exploration on the practical bearing failure mode, the macro-scale open-hole plate model was established using mesh superposition method to expose the damage mechanism of each component in composites at hole edge, and the numerical predictions agreed reasonably well with the experimental results.     

轿车玻璃导槽密封条弯曲唇边叶片波浪问题的分析和结构优化

汽车前门玻璃导槽装车后唇边叶片出现波浪问题,造成车厢内漏风、噪声增加、影响外观。为了解决此问题,利用高度非线性分析软件—Msc. Marc分析玻璃导槽密封条的装车过程,模拟唇边叶片的波浪现象,并对其结构进行优化。装车结果表明,优化后的唇边叶片不再出现波浪现象,同时满足了密封力要求。     

Elastoplastic finite element stress analysis and strength evaluation of adhesive lap joints of hollow shafts subjected to tensile loads

The stress distributions in adhesive lap joints of dissimilar hollow shafts subjected to tensile loads have been analyzed by the elastoplastic finite element method, taking the nonlinear behaviors of the adhesive and the hollow shafts into consideration. A prediction method for the joint strength has been proposed based on the Mises equivalent stress distribution in the adhesive and the frictional resistance between the adhesive and the shaft after rupture of the adhesive. In the experiments, three different kinds of adhesive lap joints were made, i.e. the inner and outer hollow shafts were aluminum alloy/aluminum alloy, steel/steel, and steel/aluminum alloy combinations, and the tensile strength of each joint was measured. From the numerical calculations, in the case of the two hollow shafts made of the same material, the tensile strength increases with an increase of Young's modulus of the shaft and in the case of the two hollow shafts made of different materials, the tensile strength increases when the inner hollow shaft of larger Young's modulus is bonded to the outer one of smaller Young's modulus. Also, the effects of the overlap length and the inner diameter of the inner shaft on the tensile strength of the joint are discussed. By comparing the predicted values of the tensile strength with the experimental results, it was shown that the proposed prediction method could estimate the tensile strength of the adhesive lap joints of hollow shafts within an error of about 15%.     

Three-Dimensional Simulation of the Non-Isothermal Cast Film Process of Polymer Melts

A modeling system is proposed to simulate the non-isothermal three-dimensional cast film process of viscous polymer melts. The finite element method (FEM) is used to solve the system and the numerical results are compared with the experimental measurements, including temperature, velocity fields, and final film shape. It is found from these results that the model is able to predict the film shape accurately under the steady-state processing conditions. The model considers the flow in the thickness direction, shear-thinning, non-isothermal effect, self-weight, and viscous dissipation, but it excludes die swell at the die exit, elasticity of materials, crystallization, and film sag. Using the model, the influence of temperature variation, draw ratio, and air gap length on the final film shape is also investigated.     

蒸汽凝液闭式回收技术在化工装置中的应用

蒸汽冷凝液闭式回收技术是采用由具有独特技术的共网器、自力增压器和内部具有压力平衡、消除气蚀等构件的闭式回收贮罐等构成的闭式回收系统,将蒸汽冷凝液全部回收.采用该技术可消除跑冒滴漏,减少热量损失15%～30%,避免凝液溶氧二次腐蚀;回收得到的蒸汽冷凝液先用于工业管线和设备的伴热,替代传统的蒸汽伴热,伴热后的热水再进行深度利用达到节能的目的.     

支架沉降对大口径煤气管道结构安全性的影响

针对大口径煤气管道由于支架地基严重沉降而引起的自内力和强度安全问题,进行有限元模拟、强度评定和沉降规律研究。计算实际支架相对沉降导致的管道变形和应力分布,基于塑性失效等安全裕度准则,对应力进行分类强度评定。通过试探加载法,估算出中间支架单个鞍座的下拉载荷约等于管道自重的三倍。绘出管道底部典型位置的最大当量应力随中间支架相对沉降量的变化曲线,结果显示各处当量应力对支架沉降的响应基本呈线性规律,表明支架沉降引起的管道自内力相当于比例加载。同时发现,应力越高的位置对支架沉降越敏感,即随相对沉降量的增加会变得更加危险(?)据此提出垫高鞍座和局部补强的改造措施并获得良好效果。