双排平直翅片管换热器换热和流动性能的三维稳态模拟

利用三维稳态模拟研究了叉排和顺排布置形式、几何尺寸和雷诺数ReD对双排平直翅片管换热器换热和流动特性的影响。研究结果表明:尾流区面积是影响换热量的主要因素,其原因是尾流区的风速很小,部分空气无法被主流带走,造成了空气和翅片间的温差很小,努塞尔数NuD接近零;顺排管换热器前排管的尾流区较宽,并与后排管的连接形成宽度为D的尾流通道,形成了比叉排管换热器大的尾流区面积,因而前者的换热效果比后者差。在几何参数中,翅片间距对换热量的影响最为显著,因为翅片间距较大时,管前和管侧会产生向下游移动的马蹄形漩涡,显著强化了换热;流动方向或垂直于流动方向的管间距的减小,会增大前排管尾流区对后排管的影响,从而恶化传热。     

Photocatalytic degradation kinetics of Rhodamine B catalyzed by nanosized TiO<Subscript>2</Subscript> film

A fixed bed photocatalytic reactor was designed,and dynamic fast scan of UV-Vis adsorption spectrum was adopted to study the photocatalytic degradation dynamic behavior of Rhodamine B,a kind of dye generally recognized as to be degraded difficultly ,on the surface of nanosized TiO2 thin film,The results indicate that the photocatalytic degradation process of Rhodamine B does not comply with the first-order reaction kinetic process ,As a result,a kinetic model of Rhodamine B photocataly tic degradation ,reaction is brough forward ,and the model is proved by the theoretical deduction and experiment.     

“纳米材料绿色印刷制版技术”及其发展历程

纳米材料绿色印刷制版技术(下称“纳米绿色制版技术”)是近年来新兴的绿色环保印刷技术，纳米材料绿色制版技术具有非感光、无污染、低成本、工艺简捷的特点，堪称“印刷业的革新”。文章介绍了纳米材料绿色制版技术的概念特点、发展现状及其应用前景。     

Transient pressure analysis for the reactor core and containment of a HTGR after a primary loop pressure boundary break accident

The pressure variances in the reactor core and containment of a High Temperature Gas-cooled Reactor (HTGR) after a primary loop pressure boundary break accident determine the structural integrity and safety of the reactor. Based on mass conservation, energy conservation and state equations, explicit formulae for the transient pressure and temperature variances in the pressure vessels were deduced, and a set of differential equations for the transient pressure and temperature variances in the containment were developed. Numerical simulation was also conducted to investigate the transient pressure and temperature variances in the pressure vessels and containment. The results show that energy transformation due to expansion work cannot be neglected. The maximum pressure in the containment could increase by 40 percent due to blockage caused by air in the containment. Detailed numerical simulations of the transient pressure and temperature variance in the reactor core flow passages were also conducted. The results show that the pressures acting on the reactor core and containment are below acceptable values.     

浅析金属屋面施工技术

金属屋面系统适用于大跨公共建筑。对工程实例铝镁锰合金板直立锁边屋面系统进行了详细介绍,阐述了屋面系统的构造、建筑技术要求的适应性、施工技术及质量控制等重点内容,为同类工程的设计提供了参考和借鉴。     

Calculation of Turbulent Flow with Pseudo-spectral Method

This paper deals with the numerical simulation of incompressible turbulent boundary flow of a flat plate with the pseudo-spectral matrix method. In order to appear more than 10 nodes in the turbulent base-stratum and transition of 43×43 computational grids,a coordinate transformation is put up from physical panel to computational panel. Several zero turbulent models are computed comparatively. The results are credible when comparing with the previous methods.     

A brief introduction to neutron activation analysis in China

The history, the major achievements in both methodology and applications, the current trends and future perspectives of neutron activation analysis (NAA) in China are briefly described.     

船体复杂外板成型评价方法

船体复杂外板的成型评价是曲面外板成型加工的必要环节,能为外板的二次加工提供依据.结合水火弯板加工工艺,提出了一种成型评价方法.该方法先通过三维空间变换,实现目标曲面与检测曲面的匹配.然后,利用多项式拟合与参数分解方法,实现检测曲面偏差量的分解.最后,给出了成型率的计算方法,实现对检测曲面成型度的评价.实验结果表明,本方法能对复杂外板加工过程中的横向、纵向以及扭向成型情况进行客观的评价,而且本方法的评价指标与加工工艺紧密结合,可作为曲面外板加工参数的推理依据.     

SCWR for Future LargeScale Nuclear Power Generation

The ambitious nuclear power program motivates the Chinese nuclear community to develop advanced reactor concepts of generation IV, in order to ensure the longterm, stable and sustainable development of nuclear power. The supercritical watercooled reactor (SCWR) has favorable features in economics, sustainability and technology availability. It is the logical extension of the existing PWR technology and has very promising perspectives in largescale power generation in China. This paper describes the main features of SCWR. New designs of SCWR core structure and fuel assemblies are proposed. Preliminary analysis using a coupled neutronphysics/thermalhydraulics method is carried out and shows a good feasibility of the new design proposal.     

乏风瓦斯热逆流反应器的流动压力损失特性

分析了热逆流反应器压力损失的组成和机理,上下集气箱内和陶瓷床内部的摩擦阻力损失和陶瓷床进出口的局部损失,建立了各部分压力损失的相应公式并根据实验数据进行了计算.结果表明:陶瓷床进出口的局部流动损失远小于摩擦阻力损失,因此可以在损失分析时忽略以使问题简化;下集气箱中的摩擦阻力损失明显大于上集气箱和陶瓷床,并且对进口流速的增长最为敏感,在总损失中占据首位;给出了热逆流反应器的总压力损失计算公式,应用该式可对不同流量工况下的总损失进行计算.