《钢制压力容器用封头》标准综述

本文从编制思路、标准特点和与国外同类标准的差异以及各类封头内表面积，容积，质量计算等方面对JB4746《钢制压力容器用封头》进行了介绍，分析与评价。     

标准椭圆封头工艺增厚问题的讨论

通过对压力容器用标准椭圆封头的设计、采购、制造过程的阐述,指出了封头在设计、制造过程中存在的问题,提出将简体名义厚度做为封头名义厚度,从而满足压力容器制造的安全性与经济性,避免封头制造和使用方由于工艺增厚而引发价格纠纷。     

日本JISB8247—1997封头标准与我国封头标准的差异及评述

1　前言由于我国要从日本进口一定数量的压力容器 ,我国的封头标准有些内容也参照了日本ＪＩＳＢ82 47标准。因此 ,了解ＪＩＳＢ82 47-1997版封头标准的修订情况 ,和我国的封头标准进行对比、分析 ,学习和借鉴日本标准中正确、合理、先进的内容 ,将有助于我国封头标准的修订。现将两国标准的差异加以评述 ,和同行商榷。　　 2　两国封头标准的差异和评述　　 2 1　标准的名称日本的封头标准 (以下简称日本标准 )以封头的用途命名为《压力容器用封头》。中国则以封头的形状或加工成形方法命名为《椭圆形封头》、《旋压封头》等。显然 ,中国…     

中国石油化工总公司产品企业标准 冷旋压封头技术条件

1 主要内容与适用范围本标准规定了冷旋压封头制造、检验的技术要求。本标准适用于钢制压力容器用冷旋压封头的制造和检验。非压力容器用冷旋压封头亦可     

压力容器用封头制造质量控制和专业化生产的发展方向

中国法规首次对压力容器等特种设备用封头实施制造资格许可和强制的监督检验制度。根据法规标准的规定 ,对压力容器封头制造质量控制和专业化生产发展方向的要求作一系统的综述 ,以提高压力容器产品的整体质量 ,确保特种设备安全万无一失     

钢制压力容器用封头模具间隙量及热收缩量的控制

在压力容器用封头模具的设计、制造中，对其间隙量的控制将直接影响封头模具的使用寿命及封头的质量。     

大容量电站锅炉锅筒厚壁球缺封头制造工艺

介绍了大容量电站锅炉锅筒厚壁球缺封头制造工艺,成功进行了厚壁球缺封头直接压制的技术创新,减少了材料消耗,进一步提高了锅炉和压力容器制造工艺水平。     

压力容器非标准型椭圆封头简便作图参数选择

对于压力容器制造中的非标准型椭圆封头曲线几何作图放样,本文介绍一种简便作图参数选择方法,所绘制图形完全符合当前国家标准GB150-1998《钢制压力容器》和JB/T4746-2002《钢制压力容器用封头》标准的要求。     

压力容器封头接管内伸长度的近似计算

在压力容器制造中,许多接管是装在压力容器的封头上,而绝大多数压力容器中使用的是标准椭圆型封头。这种椭圆型封头曲面半径变化范围大,尤其在顶端大R到近直边的小r的过渡部位曲率半径变化更大。按GB150—89标准规定,在小r的部位,即封头边缘10％范围的部位不允许开孔。但有的设备由于公称直     

对凸形封头最小厚度验收标准的看法和建议

在长期使用GB150—1998《钢制压力容器》和JB／T4746—2002《钢制压力容器用封头》标准的过程中，发现标准中关于凸形封头最小厚度的验收规定存在一些问题，易产生误判，造成不必要的损失。本文提出对这些问题的看法并提出若干修改建议。     

The smart-orifice meter: a mini head meter for volume flow measurement

Differential pressure based flow meters generally consist of a flow restriction element which generates a differential pressure and a pressure transducer, externally piped to the restriction, which measures the flow related differential pressure. The smart-orifice mini head meter presented takes advantage of silicon technology by incorporating a differential pressure microsensor. In contrast to conventional head meters, it represents a single compact and economic device for general flow meter applications, in particular where small size is of concern. Computational fluid dynamics analyses were applied to develop a non-standard orifice design and prototypes of the smart-orifice were fabricated. The performance of the mini head meter in water flow measurement was determined in a computer supported test bench facility. It was compared to the results predicted by the simulation, as well as to a conventional head meter arrangement with externally mounted pressure transducer, including measurements with water at elevated temperature and different absolute line pressures. The results are very promising and verify the competitiveness of the smart-orifice as a mini head meter.     

钢坯修磨机磨头压下系统仿真及试验研究

介绍了钢坯修磨机磨头液压压下系统的工作原理,提出压下过程中采用位置、压力复合控制,提高了工作效率.针对砂轮位置扰动引起的多余惯性力,及其磨头自身重力、摩擦力和惯性力对修磨力的影响,采用三通比例减压阀开环控制压力,系统压力波动较大的问题,提出在三通比例减压阀控制压力的基础上叠加闭环控制的方法进行改进,实现了对磨头压下力的精确控制,使系统在位置扰动下能够保持良好的跟随特性,满足了性能要求,利用AMESim软件对系统进行了建模和仿真研究,确定了控制器参数,用试验验证了仿真结果,并已成功应用于国产板坯修磨机上.     

压裂泵泵头体弹性有限元分析

重点介绍了压裂泵泵头体在同一内压作用下,各处发生的塑性变形和产生的残余应力的大小是不一样的,利用ANSAYS软件试算的方法确定泵头体的弹性极限压力,获得了泵头体在小于弹性极限内压的压力作用下的有限元弹性模拟模型,从而发现压裂泵泵头体的危险部位在缸腔和阀腔相贯部位,能够很好地解释现场发生的泵头体开裂现象.     

Analysis of Rarefied Effects of a Nano-scale Magnetic Head/Disk

When the decrease in the space between magnetic head and disk arrived at 10 nm or less, which is much lower than the mean free path of gas molecules, the gas flow presents distinctive features against the macro features because of the rarefied effects. The modified Reynolds equation considering rarefied gas effect is used to calculate the rarefied region of a negative pressure magnetic head working in the distance of 10 nm. Inverse Knudsen number was adopted to calculating the ratio of the rarefied area. According to the numerical results, discussions and analyses are then presented to reveal the rarefied effect on the working performances of a magnetic head. The results show that the magnetic head works in the slip-flow and transition regions and moves to the transition region with the increase in velocity. Furthermore, the maximum rarefied effects occur at the side edges where the flying height is thinner and pressure is lower, rather than in the minimum flying height on the rear. The results also show that with considering the rarefied effects, the load-carrying capacity of the magnetic head and the maximum pressure decrease significantly, but the minimum pressure slightly changes.     

单晶连铸工艺压头分析

建立并分析了保证液体金属充型的静压头模型和稳定牵引阶段的动力学压头模型,以纯铝单晶连铸的典型工艺参数和物性参数进行验证,结果表明,静压头大于动力学压头,提出了变压头操作的原则。     

组合载荷作用下碟形封头的稳定性分析

对于受外压和局部载荷联合作用下的压力容器封头稳定性设计问题,以低温液化气体储罐的外筒体为例,采用有限元方法,对受外压及支座反力作用的碟形封头进行了线性和非线性稳定性分析,计算了封头的临界失稳外压和临界失稳轴向力并考察了支座垫板的作用。结果发现对于常见的3支座或4支座,支座的存在对封头的临界失稳外压几乎没有影响;封头因外压发生失稳和因轴向支座反力发生失稳是互相独立的;支座上有无垫板对封头的临界失稳外压影响不大,但垫板能够提高封头的临界失稳轴向力。此外,为便于工程设计,给出了不同直径和厚度的碟形封头临界失稳支座反力。     

高压容器筒体与封头连接区可靠性分析

建立了高压容器筒体与封头结构的有限元分析模型.采用蒙特卡罗法(Monte-Carlo Method),分析了输入随机变量对高压容器筒体与封头结构可靠性的影响.结果表明:工作压力对筒体与封头连接区可靠性的影响较大,是高压力容器筒体与封头结构失效的主要因素.     

清洗机斜盘轴向柱塞泵流道的流场仿真与结构优化设计

分析了清洗机斜盘轴向柱塞泵出水端吸液阀流道的流场力学特性并对其流场进行了数值仿真。在流场仿真结果基础上,对现有泵头文丘里流道的喉管直径与进口直径的收缩比、喉管段长度、渐缩角度和渐扩角度进行了优化。计算机仿真及实验结果表明：优化方案达到了减小文丘里流道压力损失和溢流阀平衡压力的目标,提升了清洗机斜盘轴向柱塞泵整体性能。     

BRAIN INJURY BIOMECHANICS IN REAL WORLD VEHICLE ACCIDENT USING MATHEMATICAL MODELS

This paper aims at investigating brain injury mechanisms and predicting head injuries in real world accidents. For this purpose, a 3D human head finite element model （HBM-head） was developed based on head-brain anatomy. The HBM head model was validated with two experimental tests. Then the head finite element（FE） model and a multi-body system （MBS） model were used to carry out reconstructions of real world vehicle-pedestrian accidents and brain injuries. The MBS models were used for calculating the head impact conditions in vehicle impacts. The HBM-head model was used for calculating the injury related physical parameters, such as intracranial pressure, stress, and strain. The calculated intracranial pressure and strain distribution were correlated with the injury outcomes observed from accidents. It is shown that this model can predict the intracranial biomechanical response and calculate the injury related physical parameters. The head FE model has good biofidelity and will be a valuable tool for the study of injury mechanisms and the tolerance level of the brain.