Theoretical analysis on hydraulic transient resulted by sudden increase of inlet pressure for laminar pipeline flow

Hydraulic transient, which is resulted from sudden increase of inlet pressure for laminar pipeline flow, is studied. The partial differential equation, initial and boundary conditions for transient pressure were constructed, and the theoretical solution was obtained by variable-separation method. The partial differential equation, initial and boundary conditions for flow rate were obtained in accordance with the constraint correlation between flow rate and pressure while the transient flow rate distribution was also solved by variable-separation method. The theoretical solution conforms to numerical solution obtained by method of characteristics (MOC) very well.     

Modeling of fluid dynamics interacting with ductile fraction propagation in high pressure pipeline

This paper presents a computational model for the fluid dynamics in a fractured ductile pipe under high pressure. The pressure profile in front of the crack tip, which is the driving source of crack propagation, is computed using a nonlinear wave equation. The solution is coupled with a one dimensional choked flow analysis behind the crack. The simulation utilizes a high order optimized prefactored compact-finite volume method in space, and low dispersion and dissipation Runge-Kutta in time. As the pipe fractures the rapid depressurization take place inside the pipe and the propagation of the crack-induced waves strongly influences the outflow dynamics. Consistent with the experimental observation, the model predicts the expansion wave inside the pipe, and the reflection and outflow of the wave. The model also helps characterize the propagation of the crack dynamics and fluid flows around the tip of the crack.     

Slip-line field solution for ultimate bearing capacity of a pipeline on clay soils

A slip-line field solution is presented for the ultimate bearing capacity of the pipeline on a purely-cohesive clay soil, taking into account of circular configuration of the pipe, the pipe embedment, and the pipe-soil interfacial cohesion. The derived bearing capacity factors for a smooth rigid pipe may degenerate into those for the conventional rectangular-shaped strip footing while the pipe embedment approaches zero. Parametric studies indicate that, the pipe-soil interfacial properties have much influence on the bearing capacity for the pipe foundation on clayedy soils.     

基于周向SH0导波的管道轴向缺陷定量表征*

随着管道服役时间的增加，其损伤逐渐累积，最终导致泄漏或爆炸事故。引入导波在线监测管道损伤是确保其安全运行的重要保障。周向零阶水平剪切(CSH0)波具有不易频散、对管道轴向缺陷敏感等优秀特性，非常适用于管道轴向缺陷的定量表征。该文 基于周向SH0导波在管道的传播特性，通过有限元模拟和试验对管道周向SH0模态导波与轴向缺陷的定量关系展开研究。结果表明：管道曲率半径越大，周向SH0模态的传播特性越接近板中SH0模态的传播特性；导波信号的反射系数和透射系数对轴向缺陷的长度和深度均呈现单调变化。依此建立了缺陷定量表征的关系云图，可用于评估缺陷尺寸。     

Primary pressure wave in a fluid after actuation of a pipeline valve

This paper considers the variation in the velocity, density, and pressure of an inviscid compressible fluid due to flow acceleration or deceleration after a change in the flow area of a valve installed on the pipeline with rigid walls. Expressions are given for the amplitude of the primary compression or rarefaction wave resulting form the change in flow area of the valve.Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 1, pp. 78–84, January–February, 2005     

Rheology of low viscosity,high concentration brown coal suspensions

The paper describes how the theology of low concentration brown coal suspensions can be exploited to produce high concentration, low viscosity suspensions which are attractive as a potential coal-water fuel. Brown coal suspensions with solid concentrations approaching those of bituminous black coal have been prepared. The high inherent water content ( 60 wt %) and macroporosity of the brown coal have been reduced by thermal and chemical means. The hydrophobicity of the coal surface has been increased sufficiently to reduce the tendency for swelling and water uptake. This, together with densification, has allowed the solids content to be progressively improved from 30 wt % solids with raw coal to 65 wt% solids with modified coals while maintaining the viscosity of the suspension at a low level. The high solid concentration was achieved without additives.     

天然气管道止裂构件的分析和设计

在钢制天然气输送管道上，经常应用机械止裂构件来防止可能发生的裂纹迅速扩展事故，这些止裂构件的作用是减小管壁开裂后的张开变形，降低裂纹驱动力的峰值，其结果使止裂可能发生，这被认为是在不能阻止裂纹起裂的情况下，防止裂纹扩展灾难性破坏的第二道防线，基于流体／结构／断裂耦合计算程序ＰＦＲＡＣ，该文发展了分析这些止裂构件的方法，推导含平面初曲率三维曲梁的动力学有限元模拟并结合入ＰＦＲＡＣ程序之中，用来模拟这     

动载下韧性撕裂在三种管线钢材中传播阻力的研究

阐述了用实验确定在常温及静载和动载条件下韧性撕裂在三种管线钢材中传播时的断裂比能值。实验中采用了销钉加载双面开槽的双悬脊梁(DCB)试件。应用能量平衡法对实验结果进行了分析。考察了加载速率和试件厚度对撕裂韧性的影响。结果表明,管线钢材对韧性撕裂传播的阻力在动载条件下增大,对较薄的试件及应变率敏感性较高的材料其增大更为明显。对于纯剪切断裂的传播来说,撕裂韧性一般随试件厚度的增大而增加。     

海底管道离地点的接触条件探讨

海底管道的铺设分析和提升分析都用到管道和海床之间的接触条件，这个同时含有挠度、转角和弯矩的接触条件，在一般的力学模型中是很难理解的．考虑海床变形，通过海床和管道的变形分析，给出这种接触条件的真实背景和使用条件．     

基于累积前景理论的石油管道路径方案优选

建立以一种基于前景理论的石油管道输送路径方案优选方法.首先依据决策者对各个属性的期望,将具有清晰数、区间数和语义短语三种形式的决策矩阵转化成为前景决策矩阵.其次,再利用主客观赋权偏差最小的思想,构建组合赋权模型,计算各个属性的权重;然后,根据决策者对待收益和损失的不同风险态度,计算各个方案的累积前景值.最后,以石化某油田外输管道路径方案问题为实例,介绍了该方法的决策流程,为解决同类工程方案优选问题提供了一种新的途径.