浅析美国ASME规范与中国压力容器标准

介绍了美国ASME规范及中国压力容器标准,通过对两种标准体系的比较．有助于深入理解和实施ASME规范,也有助于理解我国压力容器标准的发展变化。     

浅析中美两国消防规范中消火栓给水系统设计的差异

论述了消火栓给水系统设计时中关两国消防设计规范的不同之处和美标中可借鉴之处,结合消火栓系统、消防主泵、消防稳压泵的设计和选型,讨论了如何将中关消防规范有机地结合进行涉外工程设计。     

ASME压力容器的设计计算

文章介绍了根据美国ASME规范第Ⅷ卷第一册以及和它相关联的标准来建造的压力容器的一般设计思路、计算方法和基本要求。通过对规范的剖析,明确地说明了要应用ASME规范来建造压力容器产品,设计者该如何考虑容器产品的载荷要求、设计参数、强度计算、标准件选取、液压试验压力、冲击试验要求、成型后热处理要求和焊后热处理要求。     

Technische Regeln für druckführende Bauteile — Basis und Hintergründe

Technical standards for pressure vessels – basis and background. The aim of this paper is to summarise the philosophy and the safety aspects of the German pressure vessel code. Emphasis is placed upon material selection, design, manufacture and inspection. The AD specifications, which are embodied in the German decree for pressure vessels, are compiled primarily to provide a good measure of safety to the average plant. The possible types of failure are discussed in connection with design aspects. It is shown in detail how the AD specifications account for inelastic material behaviour. A comparison between the German code and the ASME boiler and pressure vessel code shows that the stresses allowed by the German code are higher, leading in many cases to thinner walls. This is compensated for by rigorous inspection and non-destructive testing during manufacture. Regular examination completes the safety system.     

MECHANISM OF TWO-DIMENSIONAL HEAT AND MASS TRANSFER DURING CONVECTTVE DRYING OF POROUS MXDIA UNDER DIFFERENT DRYING CONDITIONS

A numerical investigation was conducted to study two-dimensional heat and mass transfer during convective drying of clay brick. The set of macroscopic equations takes into account the effect of gaseous pressure. The established numerical code has allowed us to determine effects of the surrounding air conditions (temperature, pressure and vapor concentration) on drying Kinetic and on space-time evolution of the state variables (temperature, gaseous pressure, and liquid saturation).     

MECHANISM OF TWO-DIMENSIONAL HEAT AND MASS TRANSFER DURING CONVECTTVE DRYING OF POROUS MXDIA UNDER DIFFERENT DRYING CONDITIONS

ABSTRACT

A numerical investigation was conducted to study two-dimensional heat and mass transfer during convective drying of clay brick. The set of macroscopic equations takes into account the effect of gaseous pressure. The established numerical code has allowed us to determine effects of the surrounding air conditions (temperature, pressure and vapor concentration) on drying Kinetic and on space-time evolution of the state variables (temperature, gaseous pressure, and liquid saturation).     

压力容器用封头制造质量控制和专业化生产发展方向

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。本文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。     

Modeling Fission-Gas Behavior in Metallic Fuels

The FRAS3 code, developed to model transient fission-gas behavior in oxide fuel, has been modified for application to metallic fuel. The code has been applied to analyze a series of experiments on irradiated uranium fuel, in which fission-gas bubble distributions were measured following isothermal anneals under various pressures. Comparison of the calculated bubble-size distributions to those measured indicates that grain-boundary bubbles are an important component of the observed size distributions. The calculated results agree well with the observed results in both the general nature of the distributions and their variation with pressure. Results are not is consistent for an anneal under vacuum, during which a large amount of gas was released.     

焊接接头系数浅论

本文提出了对我国规范中焊接接头系数与ASME规范区别和存在问题。     

压力容器焊接接头系数取值分析

文章根据实际工作经验,通过理论分斩,总结了ASME规范焊接接头系数取值规则,指出了我国压力容器规范中关于焊接接头系数取值存在的问题,并提出了解决方案。     

Sensitivity analysis on the thermal-hydraulic parameters governing the saturation of an engineered clay barrier system

In this paper, we study the impact a heat source makes on the thermo-hydraulic behaviour of a system composed of an engineered clay barrier and a host rock, namely an argillite. We first perform a benchmark test case with code CAST3M and code ASTER. The results of the calculations are in good agreement, except for the gas pressure. Nevertheless, gas pressure does not seem to influence the saturation process, although the saturation kinetics is governed by the darcean water flow. The saturation process is accelerated when the heat source is taken into account. More precisely, this acceleration is due to dynamic viscosity increase with heating. In a second time, five other heating sources have been tested in code ASTER. Compared with the reference calculations, some give an identical response. However, the highest heating sources provoke a desaturation phenomenon because of the air pressure increase with temperature. The liquid saturation of the engineered barrier is then delayed.     

CFD modelling of liquid fluidized beds in slugging mode

Computational Fluid Dynamics (CFD) modelling has been used to simulate a liquid fluidized bed of lead shot in slugging mode. Simulations have been performed using a commercial code, CFX4.4. The kinetic model for granular flow, which is already available in CFX, has been used during this study. 2D time-dependent simulations have been carried out at different water velocities. Simulated aspects of fluidization such as voidage profiles, slug formation, pressure drop and pressure fluctuations have been analysed. The fluid-bed pressure drop was found to be greater than the theoretical one at all velocities, in agreement with experimental observations reported for fully slugging fluidized beds. Power spectral density analysis of the pressure signal was used to investigate the development of the flow pattern and the structure of the fluid-bed with increasing fluidizing velocity. A comparison between experimental and simulated results is also reported.     

Calculation of Detonation Properties of Gaseous Explosives Using Generalized Reduced Gradient Nonlinear Optimization

In this paper, a study on the development of a numerical modeling of the detonation of C H N O‐based gaseous explosives is presented. In accordance with the numerical model, a FORTRAN computer code named GasPX has been developed to compute both the detonation point and the detonation properties on the basis of Chapman–Jouguet (C‐J) theory. The determination of the detonation properties in GasPX is performed in chemical equilibrium and steady‐state conditions. GasPX has two improvements over other thermodynamic equilibrium codes, which predict steady‐state detonation properties of gaseous explosives. First, GasPX employs a nonlinear optimization code based on Generalized Reduced Gradient (GRG) algorithm to compute the equilibrium composition of the detonation products. This optimization code provides a higher level of robustness of the solutions and global optimum determination efficiency. Second, GasPX can calculate the solid carbon formation in the products for gaseous explosives with high carbon content. Detonation properties such as detonation pressure, detonation temperature, detonation energy, mole fractions of species at the detonation point, etc. have been calculated by GasPX for many gaseous explosives. The comparison between the results from this study and those of CEA code by NASA and the experimental studies in the literature are in good agreement.     

GB/T 20801-2006《压力管道规范工业管道》总体说明

“工业管道规范”是配名“压力管道安全技术监察规程”,对工业管道实施安全监察的协调标准;是集设计、材料、制作安装、检验检查于一体的工业管道建设标准;是以国际接轨和结合国情为宗旨的压力设备基础标准;是在国内及多国家标准、行业标准、设计标准、施工验收标准、产品标准基础上制订的,以安全为目标的安全技术标准。     

执行锅炉压力容器压力管道焊工考试与管理规则时的若干问题

笔者在焊工考试和压力容器许可鉴定评审中,发现在执行锅炉压力容器压力管道焊工考试与管理规则过程中的问题,分别从焊工考试和焊工管理两方面,结合典型问题,对锅炉压力容器压力管道焊工考试与管理规则规定进行分析、解释。     

Transcritical CO2 Heat Pump Dryer: Part 1. Mathematical Model and Simulation

In this study, a mathematical model and simulation code has been developed to investigate the performance of a transcritical CO₂ heat pump dryer. The model takes into account detailed heat and mass transfer and pressure drop phenomena occurring in each component of the system. To take care of the variable heat transfer properties, the heat exchanger components were divided into several infinitesimal segments to examine the state, heat and mass balance and pressure drop for both refrigerant and air, and hence accurate results are expected. In Part 2 of the article, the model developed has been validated with experimental data and then the model was used to investigate effects of important operating parameters on the performance.     

ASME压力容器规范中国化和ASME钢材国产化

本文旨在阐明通过ASME规范,使我国的压力容器行业与国际接轨,提高我国压力容器和钢材在国内外市场的占有率。     

Viscoplastic fluid flow in irregular eccentric annuli due to axial motion of the inner pipe

Fully developed axial laminar flow of viscoplastic Herschel-Bulkley fluids in eccentric annuli between two pipes has been investigated numerically. The pipes are closed at one end and flow is due to the axial motion of the inner pipe. The annuli may be filly open or partially blocked. General non-orthogonal, boundary-fitted curvilinear coordinates have been used to accurately model the irregular annular geometry due to the presence of a flow blockage. A computer code has been developed using a second-order finite-difference scheme. An exponential model for the shear stress, valid for both yielded and unyielded regions of the flow, is used in the computation. The effects of generalized Bingham number, flow behavior index, eccentricity, and blockage height on the pressure gradient or the surge pressure have been studied and the results are presented in dimensionless form. The pressure gradient is found to decrease with increasing eccentricity. For a partially blocked eccentric annulus the pressure gradient is found to decrease with an increase in the blockage height.     

Transcritical CO2 Heat Pump Dryer: Part 1. Mathematical Model and Simulation

In this study, a mathematical model and simulation code has been developed to investigate the performance of a transcritical CO₂ heat pump dryer. The model takes into account detailed heat and mass transfer and pressure drop phenomena occurring in each component of the system. To take care of the variable heat transfer properties, the heat exchanger components were divided into several infinitesimal segments to examine the state, heat and mass balance and pressure drop for both refrigerant and air, and hence accurate results are expected. In Part 2 of the article, the model developed has been validated with experimental data and then the model was used to investigate effects of important operating parameters on the performance.     

The influence of reynolds number on the entry length and pressure drop for laminar pipe flow

A numerical analysis of the laminar flow of a Newtonian fluid in the inlet section of a circular pipe has been carried out for a Reynolds number range of 0 to 500, employing a finite element based CFD code. A new flow phenomenon has been identified at low Reynolds numbers (<50), viz, the existence of a peak in the axial pressure profile at a small distance from the entrance. Existing correlations for the entry length are shown to be insufficient and a new correlation for the entry length is proposed.