管道无损检测与评价技术

为适应国内石油化工企业大量管道检测维护的急需，介绍了国际上有关管道在线无损检测、运行监视及泄漏检测的新技术、新设备和其应用情况与发展动态     

简谈超高压管道系统的设计及安装

我国目前尚无超高压管道的设计标准及规范,文章根据我公司实际承担的两套高压聚乙烯装置的实际设计及现场施工经验,结合BASELL超高压设计标准,针对设计压力大于等于32．5MPa的超高压管道系统的使用标准、连接方式、储存和运输、现场安装,以及超高压管道支架安装等的特殊要求进行了简要介绍。     

城市供水管网爆管和折管数据库管理系统的设计与实现

以Visual Basic语言为平台,利用其数据访问特性,开发了城市供水管网爆管、折管数据库管理系统.阐述了系统的设计思想、总体架构以及具体功能的设计与实现.该系统不仅能够对爆管、折管的事故数据进行分类检索与查询,还能同时生成相应的分析图形与报表,对于管网事故管理工作是一种便捷有效的辅助工具.     

顶管技术在铜鼓岭水库涵管改造中的运用

介绍了铜鼓岭水库放水涵管渗漏和闸阀老化锈蚀情况,结合该工程使用顶管技术进行涵管改造的实践,介绍了顶管施工的设计,施工工艺流程和运用条件。     

常压管道取样器的设计及运用

利用Solidworks软件对常压管道取样器管道内矿浆流场进行仿真分析,对比取样器在现场的实际使用效果,证明取样器的结构设计方法是合理的。该方法为设计其它类型的取样器提供了一定的指导。     

Influence of initial ovality on creep life of P92 pipe bends subjected to in-plane bending

Initial ovality is an inevitable problem in the process of pipe bends manufacturing which results in the stress redistribution of the pipe bends working at high temperature. In order to study the influence of ovality on creep life of pipe bends, full-size creep experiment of P92 pipe bend subjected to in-plane bending has been conducted. The creep strains and outside diameters of dangerous positions have been measured. The microstructures of three different positions of the pipe bend were compared through SEM and the results showed the number and size of the carbide precipitation were the largest at the flank of the pipe bend, which indicated that the creep damage developed fastest at the flank. The modified Kachanov–Robatnov constitutive equations were used to stimulate the creep of P92 pipe bends with FEA software. The representative stress, damage and multiaxiality distributions of the pipe bends have been discussed. The FEA results were consistent with the experimental results and the influence of initial ovality on creep life of P92 pipe bends were analyzed. The results showed that creep life of pipe bends reduced by the increase of ovality and their relationship coincided with the parabolic law.     

Primary study on holdup measurement of ^235U in pipe using γ-ray spectrometry and Monte Carlo simulation

The pipe holdup measurement is very important for decommissioning nuclear facilities and nuclear-material control and accounting. The absolute detection efficiencies （εsp） of full-energy γ rays peak under different source density distribution function have been simulated using the Monte Carlo （MC） software, and the counting rates （no） of the characteristic γ rays have been measured using the γ spectrometer followed by the calculation of the holdup. The holdup is affected by the energy of γ rays, distance at which they are detected, pipe material, thickness, and source distribution of pipe, especially source distribution at a short distance. The comparative test of ^235U reference materials on the inner wall of Fe and A1 pipes （the total mass of ^235U is 44.6 mg and 222.8 mg, respectively） have been accomplished using this method. The determined result of ^235U is 43.2mg （U0.95rel=5.4%） and 216.2mg （U0.95rel= 3.2%）, respectively, which are in accordance with the reference values.     

The inhibitory effect of carbon monoxide contained in hydrogen gas environment on hydrogen-accelerated fatigue crack growth and its loading frequency dependency

The effect of carbon monoxide (CO) contained in H₂ gas as an impurity on the hydrogen-accelerated fatigue crack growth of A333 pipe steel was studied in association with loading frequency dependency. The addition of CO to H₂ gas inhibited the accelerated fatigue crack growth due to the hydrogen. The inhibitory effect was affected by the CO content in the H₂ gas, loading frequency, and crack growth rate. Based on these results, it was revealed that the inhibitory effect of CO was governed by both competition between the rate of fresh surface creation by the crack growth and the rate of coverage of the surface by CO and time for hydrogen diffusion in the material to the crack tip with reduced hydrogen entry by CO.     

空分设备冷箱内管道变形和防范措施

随着单套空分设备规模的不断增长,冷箱内管道变形对空分设备正常运行的影响问题也越来越突出。文章详细分析了空分设备冷箱内管道变形的原因,从空分设备的设计制造和操作方面,提出了相应的防范措施。     

Two-Point Linearization Method for the Analysis of Pipe Networks

This note proposes a new method for snapshot analysis of water distribution systems based on the commonly used gradient method. The proposed method uses a secant (intersecting the head-loss function in two points) instead of a tangent to approximate the pipe head-loss function. A theoretical model is developed for the flow range in which the secant approximates the head-loss function without exceeding a given allowable error. This scheme allows a tradeoff to be made between the allowable error and the number of iterations required to achieve convergence. The proposed method is applied to an example network to illustrate its application and benefits. It is argued that the number of iterations required to find a solution can be reduced significantly in both snapshot and extended-period simulations.