氨制冷机房氨气泄漏扩散的数值模拟

本文选取氨制冷机房作为典型场景,应用计算流体力学方法研究氨气泄漏扩散规律,采用Fluent软件对无通风及上下通风情况下的制冷机房氨气泄漏扩散进行了数值模拟。分析了氨气泄漏后不同时刻制冷机房纵剖面和横截面氨气浓度分布,研究了不同泄漏量下氨气浓度随高度变化的特征,提出了氨气报警器偏上安装的建议。对比上进风下排风和下进风上排风两种应急排风方案泄漏扩散的数值模拟结果,提出了应急排风进风口偏下设置的建议。     

多联机室外机在室内安装时的设计问题分析

多联机室外机安装在空调机房内会出现由于未处理好空调室外机在机房内的通风换热和排风管道的设计等问题,导致进排风不畅,影响室外机换热,严重的会导致机组报警停机.本文针对多联机室外机在空调机房内安装设计中经常出现的问题,结合AirPak软件进行具体的分析说明.     

综合管廊通风系统流场数值模拟分析

综合管廊属于密闭型地下构筑物,需要设置合理的通风系统.本文以汉中市兴元新区陈仓路综合管廊为研究对象,建立综合舱及电力舱的数值模拟模型,利用ANSYS FLUENT软件研究自然进风、机械排风通风方式下,不同进风温度及换气次数对舱室速度场、温度场的影响.结果表明:各舱室流场形态为入口旋转流和后续活塞流,建议在通风设计时在活...     

中小型地下车库无风管通风排烟系统计

与传统的地下室通风排烟系统不同,本文介绍了一种住宅区中小型地下车库的无风管通风排烟系统设计.该设计平时采用诱导通风系统合理组织气流,火灾时转入排烟系统.排风口与排烟口、排烟机与排风机均合用,两个系统合二为一.因排风、排烟口设置在通风并道侧墙处,没有水平风管设置,可有效降低地下室层高.     

热处理车间采暖通风设计

分析热处理车间的工艺特点,制定有效的采暖通风方案。分析实际工程案例的特点,将自然通风方式与机械通风方式综合考虑。并分析该厂房的气流组织形式,合理有效的设置送排风口。并根据该厂房的特点设计工艺排风净化方案。     

某制冷机房氨气泄漏时气流组织优化分析

本文针对氨制冷压缩机低压吸气管道破裂后氨制冷剂泄漏的场景,采用计算流体力学(CFD)的方法对不同气流组织下事故通风过程进行了数值模拟,对比了不同气流组织下的事故通风有效性.计算结果表明:侧墙排风口上沿距顶在0～0.2 m范围内对污染物排除几乎没有影响.在氨制冷机房两端有门,中部有上、下两排窗的情况下,对于通风120 s...     

降低火电厂汽机房内噪声的有效措施探讨

在火电厂中,汽机机房是主要设备和操作人员的工作地点。而因为机械的运转,机房内会产生巨大的噪音,这些噪音对人体的耳膜和其他器官是有害的。但这种情况在火电厂汽机房内确实不可避免的,针对如何才能够有效降低机房内的噪声,减小对人体的伤害呢,本文就这一问题进行了探讨,提出了几种方法 ,希望能对噪声控制效果有所改进。     

电子信息机房空调通风消防设计

结合工程设计实例,介绍了电子信息机房的工作环境要求,探讨了该机房精密空调设计、通风气流组织、屏蔽通风波导窗设置、机房防漏水设计、机房灭火后排气气流组织等问题,对电子信息机房精密空调系统的设计具有一定的指导借鉴意义.     

恒隆广场空调系统设计浅析

简要介绍恒隆广场工程的概况,其空调通风设计主要包括空调负荷、空调方式、空调水系统及冷热源等内容.对于机房设置,回风系统和水系统设计进行了分析.     

自然通风方式在火力发电厂主厂房通风系统中的应用

结合工程进行自然通风计算,提出为了简化计算,完全可用中和界面在进排风口的中心面上计算的方法取代传统的假想压力法.主厂房采用自然进风、自然式屋顶通风器排风的方案,在合理的气流组织设计的前提下,不仅经济实用,而且能保证其通风效果良好.     

空分设备配套汽轮机叶轮结垢原因及处理

由于蒸汽中二氧化硅含量超标,造成空分设备配套汽轮机叶轮和流通部件结垢,导致汽轮机负荷下降,影响空分设备的正常运行。采用低压饱和湿蒸汽蒸煮的方法清除垢物,使汽轮机的负荷恢复正常。介绍汽轮机叶轮和通流部件结垢时的参数变化情况和结垢原因的分析过程,阐述蒸煮方法的实施步骤和预防措施。     

汽轮机间隙气流激振力分析

基于流体动力学,应用动量定理研究汽轮机直叶片、短扭叶片、长扭叶片以及汽轮机调节级由于间隙引起的气流激振力问题,综合考虑了叶片的各项设计参数并应用理论分析方法导出普遍适用的计算公式,解决了Alford公式中需人为选取效率系数的困难。数值实验的结果表明,所导出的计算公式是可靠的。     

90000m~3/h空分设备直接空冷器排汽管道整体应力分析方案探讨

利用CAESARⅡ应力分析软件对90000 m3/h空分设备的直接空冷器排汽管道进行了整体应力分析。根据相关标准要求及工程实践经验,考虑了管道在内压、自重、热胀、基础差异沉降、地震和风荷载等荷载作用下管道的受力情况,并通过荷载工况的组合作用,得出各个工况下管道的应力分布和各个支吊点、设备接口的受力情况,并进行了补偿器的初步选型,为90000 m3/h空分设备直接空冷器排汽管道设计提供了解决方案。     

28000m~3/h空分设备配套汽轮机运行故障分析

简介了28000 m3/h空分设备配套汽轮机的相关参数和流程,详细分析汽轮机在运行中出现的轴封汽管路堵塞、真空度波动大、真空度低和主蒸汽流道结垢等现象和原因,提出了相应的优化整改措施,确保汽轮机稳定运行。     

Performance enhancement of rooftop turbine ventilators using wind deflectors

Rooftop turbine ventilators are widely used to improve indoor air quality in residential buildings and industrial complexes. This study presents an approach to enhance the operational performance of commercially available turbine ventilators using wind deflectors. Wind deflectors guide the wind flow to minimize the forces acting on the turbine blades in a negative direction, thereby increasing the rotational speed and exhaust ability of turbine ventilators. Two different prototypes were built and experimentally analyzed, one with adjustable size that covered up to half of the turbine, and one made of flat metal sheets, which were placed in front of the turbine. Compared with traditional turbine ventilators, the results of the two different prototypes showed an average increase in air extraction rate at different wind speeds of 34 and 11%, as well as an average rise in the rotational speed of 36 and 33%, respectively. The present study clearly demonstrates the high potential of wind deflectors to enhance the efficiency of turbine ventilators, and shows that a cover-style wind deflector is the more efficient design.     

OPTIMAL SELECTION OF STEAM TURBINE EXHAUST ANNULUS AND CONDENSER SIZES BY GEOMETRIC PROGRAMMING

In this paper, a posynomial programming model is developed for the optimal selection of steam turbine exhaust annulus and condenser sizes. After formulating the general model, a numerical example is presented and sensitivity analysis is considered. A simple formula expressing the optimal cost of the condensing system as a function of selected parameters is obtained.     

Fatigue life prediction of regulating valves on the intermediate-pressure section of a 400 MW steam turbine

Fatigue life prediction of regulating valves on the intermediate-pressure (IP) section of steam turbine is presented in this paper. The transient temperature fields and stress fields of the valve body are calculated using finite element method, and the operating records of a 400 MW steam turbine located in Hubei Province of China, is used as input, and all practical operating processes including cold-startup, hot-startup, extreme-hot-startup, shutdown and emergence shutdown are considered in the FEM computations. The load patterns for the valve are determined using rain-flow counting method and the local stress–strain approach, furthermore, the cyclic stress–strain loop of the key point enduring maximum stress range is plotted. Prediction of fatigue crack-initiation life for the turbine valve is given, and the life and crack prediction are agreed with the data from practical industry inspection. It is found in the computation that the maximum stress range appears near the stiffening rib in the valve body during turbine service. This result indicates that the circumferential thermal stress concentration region is near the stiffening rib, and also implied that crack may emerge in this location. Some cracks are actually witnessed near the rib when we did inspection on the turbine valves since 2000. The fatigue life prediction is also roughly accord with our investigative data. It is concluded that the damage during turbine emergence shutdown contributes the main part to the damage fatigue capability which is defined as the number of cycles to crack-initiation in the valve due to cyclic operating conditions. The method for comprehensive study on transient temperature and stress fields and life estimation of the turbine valve is also proposed in this paper.     

Wrought Ni‐Base Superalloys for Steam Turbine Applications beyond 700 °C

The development of a new steam turbine generation for use in advanced coal fired power plants with prospective operating temperatures beyond 700 °C and a projected thermodynamic efficiency of about 55 % requires, amongst other innovations, the partial substitution of ferritic steels by wrought Ni‐base superalloys. Although Ni‐base alloys are already widely used in the aerospace industry, they are faced with demands regarding component size and operation temperature, which by far exceed current aero‐engine requirements. In this article, the potential of selected alloys for 700 °C steam turbine applications is discussed with respect to their manufacturability and mechanical performance. Hereby, the focus is on the steam turbine rotor, which probably is the most critical component. It is concluded that material solutions are available for operation conditions around 600 °C but not for temperatures of 700 °C and above. Based on these results, alloy development strategies are suggested in order to close this gap and two new alloys, DT 706 and DT 750, are introduced.     

蒸汽加热器冷凝水排放控制方法的应用与总结

介绍了武钢氧气公司现有的3种空分设备分子筛再生蒸汽加热器冷凝水排放的控制方法,分析了各自的优缺点;实际应用得出:冷凝水温度控制的排放方法在安全、稳定和节能方面都优于水位控制和疏水器控制的排放方法。     

Recent trends in repair and refurbishing of steam turbine components

The repair and refurbishing of steam generator components is discussed from the perspective of repair welding philosophy including applicable codes and regulations. Some case histories of repair welding of steam generator components are discussed with special emphasis on details of repair welding of cracked steam turbine blades and shrouds in some of the commercial nuclear power plants using procedures developed.