现浇混凝土外墙与外保温板整体浇注体系

介绍一种应用于现浇混凝土剪力墙住宅体系中的外保温技术,其特点是在浇注墙体混凝土前,将聚苯保温板置于外模内侧,浇注完墙体后,保温板与墙体两者有机的结合在一起。围绕这一体系对其热工性能、结构安全、表面防裂、建筑构造、施工技术、配套材料和经济分析进行了全面研究,使其达到快捷、省工、安全和经济,是当前较为先进合理的外保温技术。     

超规格蒸压砂加气自保温系统板材在多层钢结构应用与工艺创新

蒸压砂加气混凝土外墙板是一种新型材料,其采用无机料,高温下不会释放有毒气体,无污染,无辐射,属于绿色、环保、节能产品,且为全寿命周期建筑材料,采用本材料施工的外墙实现了围护、保温、防火三效合一;无需内、外附加保温层,便可符合天津三步节能要求;蒸压砂加气混凝土外墙板作为钢结构公共建筑外墙墙体及保温材料,安装方法简单、有效、易于操作,突出了钢结构建筑的优势。     

广州亚运城台球壁球综合馆结构设计

广州亚运城台球壁球综合馆空间造型复杂,下部结构为钢筋混凝土框架结构,屋盖为刚架-支撑体系的大跨度钢结构。主结构的支承体系在馆内分设箱形内环与空间桁架外环,有效过渡环内外不共面刚架,保证屋盖构件传力的有效性和连续性,同时在屋盖面内设置高强度合金钢拉杆以提高结构的整体稳定性,并对屋盖钢结构节点进行合理设计。对在恒荷载、活荷载、风荷载、温度及地震作用下的结构计算分析可知:本结构不属于风敏感体系,地震效应明显,较薄弱点出现在竖向构件中钢管混凝土柱底和局部主刚架支座处;大跨度钢结构的温度效应也非常明显,在结构中部设置温度缝可有效减小温度应力。     

Sinusoidal geometry effects on heat transfer and environment in a cylindrical configuration

Several heat transfer expressions have been developed for the local and average Nusselt numbers in a vertical cylindrical configuration to reduce heat losses around a device. Three cases are considered: first, the two cylinders are stationary, second, the inner cylinder rotates about the vertical axis and the outer cylinder is kept stationary and third, the cylinders walls make the object of the two sinusoidal protuberances. One protuberance on the inner cylinder (external surface) and the other one on the external cylinder (internal surface). Numerical solutions are obtained for laminar natural and mixed convection using the control volume method in the case of uniform heating and uniform wall temperature. The obtained heat correlations provide a basis for estimating transfer rates for Newtonian fluids. These are obtained for restricted ranges of conditions and are compared with representative theoretical and experimental expressions.     

某混凝土圆筒塔结构设计

某工程主体混凝土结构采用圆形筒体结构,外筒为塔体外壁,内筒为电梯墙。文章详细介绍了该工程的结构体系、上部结构计算结果以及采取的工程构造措施,基础采用整体性好的桩筏基础。     

Experimental analysis of heat transfer through multiple reflecting bodies in a reactor-based cooling vault

In a nuclear reactor power plant, massive amount of heat generated in the reactor core causes the Reactor vault (RV) temperature to rise, which should be maintained at a permissible temperature range of 65°C–80°C. In order to address this issue we propose to incorporate thermal insulation, which consists of thin stainless steel (SS) sheets of 0.1?mm-thick stacked with uniform gap between them, introduced between the core and RV. The SS sheets (emissivity?=?0.05) are of highly polished, reflective type (mirror finish conforming to No. 8 as per ASTM A480/480M), which are made in the form of panels of suitable size and shape covering the entire outer contour. These types of insulations work on the principle of thermal radiation shielding Heat radiations from the reactor core falling on these reflective plates are reflected back thereby restricting the heat flux into the RV concrete. In order to estimate the effectiveness, 10 such plates are arranged over a length of 150?mm inside a casing made of an insulating material. A plate heater attached at the one end produces the desired heat transfer to analyse the thermal behaviour of the reflective plates. Thermocouples are attached to each plate to understand the temperature distribution in the system. Solidworks simulation and numerical calculations will be carried out.     

广州塔结构设计

广州塔由一座高达454m的主塔体和一个高146m的天线桅杆构成,总高度600m,为高耸结构。外筒由24根钢管混凝土斜柱、环杆、斜撑组成,内筒为椭圆型钢混凝土结构。介绍了该塔形体特点,技术难题,超出规范的设计依据,外筒、内筒、天线桅杆、楼面、钢结构防腐等主要设计内容及研究、试验情况。     

岩棉板外墙外保温防火结构的创新应用

为了提高建筑外墙外保温围护结构的防火性,使得外保温围护结构能够与墙体具有防火等级相同、耐久性与墙体使用寿命相同,选用岩棉板外墙外保温防火结构系统,采用先进的岩棉板加钢丝网锚固技术、保温层抗裂技术、内外层一体化设计及施工技术,成功地应用在具体工程中,通过竣工后检测,其传热系数、耐候性指标均达到了相关标准规定的要求,可为同类工程提供参考。     

超低温作用下LNG储罐热-结构耦合分析

在内罐泄漏等特殊工况下,预应力混凝土罐壁将直接暴露在-162℃的超低温环境中,由此产生的温度应力和变形可能会对储罐的结构安全带来威胁。因此,对LNG储罐混凝土外罐进行泄漏等低温条件下的力学验算和评估十分重要。本文利用有限元法（FEM）对内罐泄漏工况下的大型LNG预应力混凝土储罐进行热-结构耦合分析,结果表明：混凝土罐壁的降温过程较为缓慢,温度沿壁厚（0．8m）方向达到稳定需要大概一周的时间;热保护角范围以外的预应力钢绞线温度分别降低至-87℃（夏季）和-102℃冬季）;低温作用使混凝土罐壁产生较大的内力和变形,罐壁内外两侧温差越大,内力、变形越大,在设计中可通过设置热保护系统来防止其对储罐结构可能造成的破坏。研究成果对于评估超低温对混凝土外罐结构安全的影响、制定液化天然气储罐结构安全规范具有一定的指导意义。     

The effect of south wall's outdoor absorption coefficient on time lag,decrement factor and temperature variations

In this study, the effect of outdoor absorption coefficient of an opaque wall on time lag, decrement factor and temperature variations is investigated by employing a dynamic thermal-network model. The model simulates heat transfer by conduction through the wall and considers convection boundary conditions under detailed forcing functions on the wall outer and inner surfaces. The transient analysis is based on the fundamental principles of thermal circuits and the well-known analogies between the thermal and electrical laws are employed. The effect of the solar absorptivity, is examined for representative wall formations including masonry, insulation and coatings on both surfaces. The insulation is placed as one or two layers on the outer, the inner or in the mid-center of the masonry. The investigation is carried out for a wall with south orientation during the cooling season in the Mediterranean region. The analyses presume a non-sinusoidal periodical excitation that simulates precisely the effect of the outdoor environmental conditions. Computer results show how these varied aspects affect thermal inertia parameters and outdoor/indoor temperature peaks.     

相变墙体冬季传热性能评价及相变参数优化

本文从相变墙体冬季的传热过程出发,提出“保温因子”和“放热因子”评价其传热性能。然后,利用热阻法建立相变墙体在冬季的传热模型,并利用单因素分析的方法研究相变墙体内外层热阻和相变温度对“保温因子”和“放热因子”的影响,结果显示当相变墙体的作用是保温的情况下,相变层应布置在墙体的外侧,相变温度应该接近室内空气温度。当相变墙体的作用是放热的情况下,相变层应布置在墙体的内侧,相变温度应该尽量高一些。本研究可以为相变墙体的应用提供理论支持。     

Empirical validation of different internal superficial heat transfer models on a full-scale passive house

Being highly insulated, low-energy buildings are very sensitive to variable solar and internal gains. In this context, some modelling assumptions frequently used in simplified building energy simulation tools might be called into question. While higher insulation levels reduce the influence of heat transmission through opaque walls, absorption of solar and internal gains at inner wall surfaces, and indoor superficial heat transfers, become concerning. The convective and long-wave radiative heat transfer models are investigated in COMFIE, a dynamic energy simulation platform. More detailed internal heat transfer models are developed by decoupling convective and long-wave radiative heat transfers and using time-dependent coefficients. Furthermore, an empirical validation process on both simplified and detailed models is carried out using measurements from a full-scale experimental concrete passive house, addressing the model uncertainty vs. complexity issue.     

郑州绿地广场基坑支撑替换技术

郑州绿地广场基坑支护采用钻孔灌注桩挡土墙和3道钢筋混凝土内支撑,内支撑采用内环和外环两道环、中间连以系杆形成桁架.因主体设计更改,基坑支撑结构与主体结构柱位置发生冲突,需对支撑进行替换改造.根据支撑受力大小和杆件与柱的位置关系,将冲突处理分为节点替换型、杆件替换型和杆件补强型,针对不同类型提出针对性加强措施,并介绍了关键施工技术.监测结果证明,支撑轴力变化平稳,因替换引起的变形也不明显,保证了主楼顺利施工.     

广州市五山路地铁车站基坑优化分析

广州市五山路地铁车站基坑维护结构采用800mm地下连续墙,通过优化计算分析确定700mm地连墙完全可以确保基坑安全,而且对主体结构的影响进行了计算分析。计算结果证明采用700mm地连墙不仅确保基坑安全而且节约了资金,经济效益相当显著。     

平板太阳能集热器与墙体不同一体化形式分析

针对平板型太阳能集热器与建筑墙体一体化结构,在贴合式和分离式2种结合方式下,以上海地区典型气象年的典型气象日作为外扰参数,使用状态空间模型对二者的传热特性进行了研究。研究结果表明:2种形式的一体化结构的集热器以及单一集热器的出口温度和有效得热量相互差别均很小。三者出口温度最大差值为0.15℃。夏季时,分离式和贴合式一体化结构全天有效得热量分别占单一集热器的99.89%和97.22%,贴合式一体化结构集热器出口温度和有效得热量都比分离式低。而冬季则相反,且该比例为99.26%和106.65%。夏季时,分离式和贴合式一体化结构通过围护结构的传热量分别占单一墙体的90.83%和40.53%。而在冬季,该比例为96.66%和11.12%。2种一体化结构均能减弱室外气象参数波动对墙体内壁面热流的影响。尤其是贴合式,冬季内壁面热流的波动幅度仅占单一墙体的9.75%。     

两种常见墙体的热湿迁移特性分析

大多数建筑墙体均为多孔介质材料,多孔介质墙体中湿迁移与热迁移是互相耦合的过程,湿迁移对热迁移有着重要的作用,例如会使热导率明显增加,同时,热过程对湿过程也有着影响作用。基于Fourier定律、Fick定律、Darcy定律,以温度和空气含湿量为驱动势建立了多层多孔介质墙体热湿耦合迁移数学模型,对两种常见墙体（红砖墙体和加气混凝土墙体）进行计算分析。结果表明,加气混凝土墙体比红砖墙体具有更好的保温隔热性能,但更容易发生湿积累和引发湿破坏。     

双层钢板混凝土井壁力学特性分析及优化设计

将ANSYS数值模拟软件作为分析工具,以优化设计为理论指导。建立双层钢板混凝土井壁结构数学模型,将内、外钢板厚度、混凝土井壁厚度作为设计变量,材料使用的总花费作为目标函数,将混凝土和钢板的应力作为约束条件。得到双层钢板混凝土井壁结构优化设计结果,为今后高效、节约、科学、合理的设计表土层深厚立井井筒井壁结构提供指导。     

热力地沟衬砌温度的数值模拟

根据一维热传导分析 ,得出了在稳态情况下的“地沟内空气 混凝土衬砌 土壤”间的一维热传导公式。进行了二维热传导数值模拟 ,研究了在不同埋深、不同土壤性质、不同衬砌内空气温度及不同地面温度条件下地沟温度场的分布特征。确定了一维热传导公式中土壤中温度影响范围的取值。最后对地沟衬砌内、外壁温差计算公式及公式参数的取值做出了建议     

Experimental investigation of heat transfer through Nitrogen and Argon gas in a closed space reactor vault model

ABSTRACT

The main aim of this study is to analyse and understand the heat transfer in closed spaces between the main vessel and the safety vessel in a nuclear reactor by using Nitrogen and Argon gas as an insulator. For nuclear reactor cooling, researchers started moving from the hard water method to various other methods of dissipating the heat. In this study, we used a closed cube filled with nitrogen as a prototype model. Within the closed cube, a very thin pipe is used to carry the nitrogen gas and Argon gas, whose effectiveness will be measured in the study. This study is conducted into three parts, with the main thing being creating a proto-model to conduct the experiment.     

Experimental study of cooling water pipe circuits by theoretical and numerical analysis in a reactor vault

Our aim is to study the heat transfer processes in a cooling circuit. In this project, a mild steel plate of 1.1 m?×?1.1 m?×?6 mm dimensions is used. Square pipes are embedded in a liner plate, through which the water is circulated to remove heat from the reactor vault. To improve the contact between the pipes and the liner, the pipes are welded to the liner throughout their length. A heater plate simulating main vessel was placed, and the electrical heaters were laid all over the inner surface of main vessel. The square pipes were made to let the water flow through them, and the flow rate is set using a flow meter and this water is heated by convection and it is condensed by passing through a heat exchanger. Thermocouples are fixed at different locations of cooling pipes, the liner and the water inlet/outlet.