大口径管道直管段制作技术应用

针对大口径管道施工过程中存在施工周期长,施工难度大,工程成本高等问题,提出一种新型优化管段分段技术和管段组对方案。结果表明:该制作技术能保证大口管道安装施工顺利进行;有效地解决现有大口径套管安装过程中的技术难题。该方法具有创新性、实用性、可靠性等优点,在工程建设的许多领域,具有推广应用价值。     

一种钛白粉转窑煅烧尾气余热利用新装置

钛白粉煅烧转窑尾气的高湿、高硫、高酸露点的特性使得转窑尾气余热利用过程中换热器寿命不理想。在总结已有尾气余热利用方式存在问题的基础上,提出了一种长寿命、易维护的套管式热管余热利用装置,该装置由彼此分离的换热套管通过弯头、法兰连接成为整体,尾气垂直横掠双层套管段,与高硫、高湿的尾气通过相变介质的相变完成热量由尾气向取热介质的转移,产生钛白粉生产工艺所急需的蒸汽,双层管的相变换热套管对比单层管的重力热管换热器寿命明显延长;连接换热套管的单层管弯头不与高湿、高硫尾气换热,大大减轻了尾气对单层管的腐蚀。换热器应用在3.6 m×58 m的钛白粉煅烧窑上,每年可以产生0.9 MPa的水蒸气1.12万t,为企业带来可观的经济效益。     

改进型冷却水管坝后预留槽设计与应用

冷却水管坝后预留槽施工关系到冷却水管连接、坝面外观和后期封堵等问题。采用传统的预留槽布置方案,需要进行预埋木盒的制作、安装以及拆除后的二期混凝土回填等工作,这些工作费工费时,且容易产生质量缺陷。介绍了一种改进型预留槽施工工艺,即在冷却水管外露端头绑扎土工布代替传统的预埋木盒。分析比较表明,该方法可有效减少施工成本和缩短工期,具有很强的推广价值。     

核电厂聚乙烯管道设计方法及标准简介

随着聚乙烯管道在三门核电厂、大亚湾核电厂中的试应用成功，大量的新建核电厂及核电厂改造项目均将聚乙烯管道作为海水冷却水管道系统的首选管材，自主研制核电厂聚乙烯管技术标准迫在眉睫。本文介绍了核电聚乙烯管道的发展历史和应用现状，对比了核安全3级聚乙烯管道和非核安全相关聚乙烯管道、城市燃气与给水聚乙烯管道技术标准的设计方法及适用范围，探讨了中国目前聚乙烯管技术标准与核3级聚乙烯管道技术标准的差异与差距，为核电厂聚乙烯管道的设计制造与标准研制提供参考。     

Transient safety evaluation of the heat pipe microreactor – Potential energy source for hydrogen production

Recently, microreactor designs have been receiving significant attention in the nuclear industry due to their potential advantages in certain applications. These nuclear reactor designs have been considered to provide reliable and sustainable power for on-site installation and operation. Microreactors may be utilized to provide heat and power to hydrogen production, remote communities, and industrial facilities such as military installations, disaster relief zones, and are being considered for underwater and deep space operation as well. However, these designs and concepts remain largely untested and unproven in the commercial industry. Further research and development are still required to prove microreactor designs are safe and reliable for commercial use. Different cooling technologies have been taken into consideration for microreactor concepts since the 1960s, mainly for federal space reactor projects such as LEGOLRCS, HOMER, and KRUSTY. This work provides thermal hydraulics and analysis for the Idaho National Laboratory's MAGNET (Micro-reactor Agile Non-nuclear Experimental Testbed) facility. The MAGNET facility is currently being developed to duplicate a microreactor design using heat pipe cooling technology. Our main goal is to examine the response of the test facility under steady-state and transient operation conditions. We constructed our own estimated model of the MAGNET geometry using a software coupling method made up of MOOSE/SAM software systems. The steady state results of this work have been published in a former article. The new results mainly focus on the transient states. By communicating with the Idaho National Laboratories, we upgraded the geometry of MAGNET heat pipes. This not only verifies the design of the facility under such conditions but also benchmarks the modeling capability of the MOOSE/SAM code system that can be potentially used to model other microreactor concepts in the future.     

CMC jackets for metallic pipes – A novel approach to prevent the creep deformation of thermo-mechanically loaded metals

Steel materials suffer extensive creep by the application at temperatures of about 700?°C and pressures about 350?bar in a power plant environment. The presented concept overwraps a steel pipe with a ceramic matrix composite (CMC) jacket in order to support the steel pipe and provide high temperature strength. Finite Element simulations show the influence of the wall thickness of CMC jacket and the coefficient of thermal expansion (CTE) on circumferential stresses within the hybrid metal ceramic pipe. Suitable fiber and matrix materials were studied, composites fabricated and mechanical properties determined. Finally, a prototype was designed in order to confirm the feasibility of the concept. The lifetime of a pure steel pipe was increased by more than four-fold by the additional CMC jacket.     

碳纤维增强环氧树脂复合材料修复N80Q钢管的力学性能

为考察碳纤维增强环氧树脂复合材料对环状腐蚀的N80Q钢管的修复效果,采用数值分析和全尺寸爆破试验对修复后的力学性能进行了研究,分析了缺陷轴向长度、缺陷深度和修复层厚度对修复效果的影响。结果表明:碳纤维增强环氧树脂复合材料对N80Q钢管的修复效果显著,经试验测试, 6 mm深缺陷的N80Q管道由碳纤维增强环氧树脂复合材料修复后爆破压力值提高了0.985倍;缺陷轴向长度对N80Q管道修复后的强度影响较小,随着缺陷轴向长度的增加,管道爆破压力值仅下降了3.5%;而缺陷深度对N80Q管道修复后的强度影响较明显,与无缺陷管道相比, 6 mm深缺陷管道修复后爆破压力值下降了9.9%, 7 mm深缺陷管道修复后爆破压力值下降了20.6%。     

高粘度流体横掠麻面管的传热与流动特性研究

采用三维数值模拟方法,研究不同Re(381、572、763、954、1144)下凹坑直径d(1.8、2.0和2.2 mm)、深度h(0.9、1.0和1.1 mm)、轴向距离p(10、12和14 mm)、周向距离l(5.236、6.283和7.854 mm)与布置型式(叉排、顺排)对高粘度润滑油横掠麻面管流动与传热的影响。结果表明:外壁周期性凹坑的存在使得麻面管油侧换热增强,同时减阻效果明显;相比于光管,当Re=381～1 144时,麻面管油侧Nu增加了28.6%～55.4%,阻力系数f减小了0.59%～26.9%,综合换热性能指标η为1.05～1.59。     

Advances of nanofluids in heat exchangers—A review

Recently, many researchers have focused on their studies on the analysis of nanofluid flows due to their participation in the enhancement of heat transfer rates in industrial processes. The ordinary fluids, such as water, mineral oils, and so on, are known for their low thermal conductivity in heat transfer processes. A significant enhancement in the thermal properties of ordinary fluid may be obtained by adding nanoparticles having a diameter of less than 100 nm or suspension of fibers. Better spreading, wetting, dispersion, and stability and with acceptable viscosity are the main advantageous properties of nanofluids on a solid surface. The nanofluids are encountered in various thermal engineering systems such as in heat exchangers, refrigeration, thermal management of fuel cells, cooling of nuclear reactors, microelectromechanical systems, and others. In particular, the thermal conversion is known as a great application of nanotechnology, and many studies have been achieved with such fluids in heat exchangers. Therefore, this paper aims to present a global insight into the different applications of nanofluids in various heat exchangers, that is, heat pipe and plate-fin heat exchangers. All research works have been summarized into three main parts: laminar, transition, and turbulent nanofluid flow regimes.     

海底用喷涂聚氨酯硬泡保温配重管的节点补口技术

针对海洋油气输送用聚氨酯硬泡喷涂保温配重管铺设过程中节点补口进行改进研究,介绍了一种聚氨酯硬泡喷涂保温配重管节点结构和施工工艺。主要采用聚氨酯硬泡保温半瓦和浇注聚氨酯弹性体进行节点补口,节点补口性能测试验证效果良好,满足海底油气管道铺设要求。