高加管板与封头过渡倒角对管板应力分布的影响

U型管卧式高压给水加热器管板水侧边缘存在应力集中现象.为减少应力集中对管板的损伤,降低制造厂的生产成本,通过研究管板(与水室封头连接侧)倒角半径R的取值,寻找到合适的R,从而使高压给水加热器管板水侧边缘应力分布趋于合理.     

远红外烤管的应用探讨

本文综合论述了目前荧光灯生产工艺流程中,烤管工序采用的电阻线直接加热和气体火焰直接加热所存在的弊病,分析和论证了将远红外加热技术应用到烤管工序中的可行性。并将已被少数制灯行业采用的SiC涂料型板式远红外加热器(以下简称SiC板)和SHQ乳白石英玻璃管状远红外加热器(以下简称SHQ管)作了实验比较,证实了在烤管工序中采用SHQ管加热器所能获得的经济效益、社会效益,使中小型制灯行业的烤管工序进入一个新的领域。     

废热锅炉非对称管板的热-结构耦合有限元分析

本文采用有限元分析方法对废锅的非对称管板进行了9种工况的分析,以图示的形式给出了温度场的分布情况,并对各种工况相应路径上的应力强度进行了评定,计算结果表明在管程压力和温差的共同作用下,应力最大点出现在管箱筒体与管板连接位置,由于布管数量少,设备直径小,由非对称结构引起的管板应力和温度场的非对称分布并不明显。     

某汽轮机大型管板带极堆焊数值模拟及工艺优化

管板堆焊技术是低压加热器制造的关键技术,文章利用FORTRAN语言编制了一个新热源,基于SYSWELD软件模拟管板带极堆焊的温度场和应力应变场,计算出反变形量,并将其运用到产品上。     

高压给水加热器管板单元的有限元分析

高压给水加热器管板上换热管呈正三角形排布.采用ANSYS通用有限元软件,对任意三根管子围成的单元进行分析.首先计算单元上的瞬态温度场,然后将节点温度作为载荷求解模型热应力;还有热载荷和机械载荷同时作用时的应力.得出布管区的管板温度能够在短时间内达到平衡;在管板与管子连接处热应力影响较大;耦合后应力主要受热应力影响,且随...     

300MW机组高压加热器管板 管箱和筒体组合结构的应力分析

本文对300MW机组高压加热器管板、管箱和筒体的组合结构分别用解析法和有限元法进行应力分析.解析法把组合结构简化为轴对称问题.管板由开孔板和圆环组成.用板壳理论的方法求解出应力和位移分布.并编制了FOPTRAN语言计算程序.有限元法取组合结构的四分之一做三维分析.用ADINAT程序分析温度分布,用SAP5程序计算出应力和位移分布.绘制应力和挠度分布曲线.通过比较,证明以上两种方法的计算结果基本相符.     

平板太阳集热器列阵的二维模型与热性能

本文分析了管板式太阳集热器列阵的流动与传热。考虑了支管流量分布不均匀、吸热板二维导热及浮升力等因素,建立了离散型的二维数学模型,求得了数值解。计算结果表明,集热器列阵的布置方式和支管流量分布的均匀性对列阵的热性能有很大的影响。逆流布置(U型)的列阵由于流动的短路现象而使热效率明显降低。计算所得的数值结果与实验结果符合良好。     

炉膛燃烧温度场三维可视化监测方法模拟研究

为了利用火焰图像监测装置检测到的炉膛燃烧辐射能分布图像信息重建三维燃烧温度场，作者提出了一种针孔成像条件下的快速方法计算CCD（Charge-Coupled Device，电荷耦合器件）靶面接收的辐射能。成像像素接收到的系统网格单元的辐射能的份额的计算结果和辐射能图像计算结果均体现了成像过程的方向选择性和辐射能传递规律的作用。针对炉膛燃烧三维温度场重建的严重病态问题建立了一种基于Tikhonov正则化的求解方法，对于单峰型三维温度分布重建模拟计算结果表明，即使辐射图像检测包含均方差达到0.11的误差，温度场重建误差仍能维持与测量误差基本相当的水平，温度分布可视化质量较高，各种图像检测组合方式的重建结果比较显示，炉膛四角沿高度方向每隔5m左右交叉对角布置两个辐射图像采集装置，能够获得较好的全炉膛温度场可视化结果。     

油田火筒加热炉大开孔封头强度研究

油田火筒加热炉密集大开孔封头的设计计算,因没有相应的强度计算标准在一定程度上限制了我国油田火筒加热炉技术的发展。本文利用板壳元模型分别对无任何加强的大开孔封头,有火筒加强的大开孔封头和有十字加强筋的大开孔封头,进行了有限元强度分析计算。理论与实验研究结果表明,本文建立的有限元模型用于大开孔封头强度分析是可行的,计算结果与实测吻合较好,实际应力没有超过材料的许用应力。     

高压加热器管束泄漏的原因

高压加热器属压力容器，是利用汽轮机不同段位抽出的蒸汽对给水进行加热，最终达到锅炉所要求的给水温度和品质，使蒸汽热量得到了充分的利用，提高了整个循环的热效率。高压给水加热器（简称高加）由于工作在高温高压的环境下，所以比较容易发生管束泄漏故障。高压加热器运行中常见的加热器管系泄漏，换热管、管子与管板的泄漏是存在的普遍问题。本文对产生高加泄漏的原因进行了分析，并根据实际运行情况提出了预防和解决的措施。     

Simple method for spectral evaluation of radiant energy emitted from far infrared heaters

It is necessary to know the spectral emissivity of a heater to ensure efficient heating. This paper proposes a useful method for spectral evaluation of radiation energy emitted from far infrared heaters. The measurement device consists of one radiometer and two band‐pass filters. In order to confirm the experimental results, numerical simulations were also carried out with the spectral emissivity of the heaters and the respective spectral sensitivities of the radiometers. The results obtained by these methods show that the far infrared heater radiates high amounts of energy in the far infrared region even at high temperature. It means far infrared heaters can transmit power effectively to materials which exhibit high emissivity in the far infrared region. This method can classify a type of far remote infrared heaters with the near infrared/far infrared energy ratio. By using this data, the authors also proposed a simple identification method of spectral emissivity of far infrared heaters. This inverse method can obtain a rough value of the spectral emissivity of commercial heaters while maintaining the heating conditions. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.20396     

烧结-热等静压炉结构优化与仿真

通过对烧结-热等静压炉石墨发热体的优化设计,改善石墨筒内温度场的均匀性,以解决实际生产中存在的石墨筒内温度分布不均匀、底部空间和靠近两个炉门侧空间温度偏低的问题,并对石墨发热体改进前后石墨筒内温度场分布情况进行了数值仿真。结果显示,改进后石墨筒内及整炉烧结制品表面温度场均匀性得到明显的改善,减少了由于炉门处未布置发热体所带来的影响。     

尾水管扩散段结构变化对低水头混流式水轮机性能的影响

为探究低水头混流式水轮机尾水管扩散段底板抬起角对其性能的影响,结合西南某水电站增效扩容项目,在保证尾水管扩散段上下面角度不变的前提下,拟定了两套扩散段底板抬起角方案,利用相关软件建立了高效区内导叶开度为35°时水轮机的水体模型,并对其进行了流场数值模拟。结果表明,尾水管扩散段底板抬起角对水轮机效率影响不大,对水轮机出力和尾水管回能系数影响较大;随着底板抬起角的增加,相同水头下水轮机出力逐渐减小;在低水头(小流量)时,有适当的底板抬起角比没有时更有利。     

Design and Analysis of Infrared Heating with Overlapping Heater Array Scheme for Industrial Application

A recently developed infrared (IR) local heating method is fairly effective to reduce springback of advanced high strength steel in manufacturing processes of car chassis. Although parabolic heaters, consisting of an IR lamp located on the focus of a parabolic reflector, can reduce springback in stamping processes, non-negligible temperature changes are generated in the heated area. For this reason, an improved heater has been required for the IR heating method. In this work, an overlapping heater array is designed to solve the problem of the parabolic heater for the IR local heating method. The overlapping heater array can reduce the temperature change in the heated area. In the overlapping heater array, the parabolic heaters are connected in series. The connected parabolic heaters are then placed on both sides of a thin sheet metal and intersected to reduce the temperature change. In order to design a more efficient overlapping heater array, a simple design parameter was employed. The numerical and experimental verifications have shown that the overlapping heater array drastically reduces the temperature change in the heated area.     

加热炉炉管节能改造和防护技术探讨

某油田拥有200多台火(管)筒式加热炉,由于腐蚀老化、负荷增大以及热洗周期缩短等原因,加热炉损坏和高能耗问题日益突出,每年耗气近9500×104m3,且现场多次发生加热炉着火事故。据统计,损坏的加热炉中,炉管烧损鼓包占53%,烟炉管、封头、烟箱、烟囱腐蚀减薄或穿孔占32%,由此判断炉管是加热炉的易损部件。加热炉炉管鼓包是因为结垢导致炉管上部局部过热以及环境温度变化过大,炉管和弯头等部位的腐蚀主要是因为溶解氧腐蚀、垢下腐蚀及硫酸露点腐蚀。根据加热炉损坏的原因,提出了通过使用FHC-D型红外线新型节能涂料、物理防垢设备、直燃式燃烧器辐射管、炉管高温和泄漏监测装置等防护措施,有效控制炉管损坏问题,并预防因炉管烧穿而引起的火灾事故;此外,在加热炉运行管理中,建议通过推广低温常温集输、加热炉交替使用、合理调整天然气和空气配比等方式,达到减缓结垢速度、保护炉管的目的。     

Conception of thermoelectric flux meters for infrared radiation measurements in industrial furnaces

To help optimise the design and command of infrared (IR) emitters which are frequently used in industrial installations [A.C. Metaxas, Foundations of Electro-Heat a Unified Approach, John Wiley, Chichester, 1996; H. Lihan, Infrared surface pasteurisation of Turkey frankfurters, Innovative Food Science and Emerging Technologies 5 (3) (2004) 345–351; F.M. Schmidt, Y. Le Maoult, S. Monteix, Modelling of infrared heating of thermoplastic sheet used in thermoforming process, Journal of Materials Processing Technology 143–144 (2003) 225–231; M.T. Brogan, P.F. Monaghan, Thermal simulation of quartz tube infrared heaters used in the processing of thermoplastic composites, Composites Part A: Applied Science and Manufacturing 27 (4) (1996) 301–306; S. Le Person, J.R. Puiggali, M. Baron, M. Roques, Near infrared drying of pharmaceutical thin films: experimental analysis of internal mass transport, Chemical Engineering and Processing 37 (3) (1998) 257–263; K. Esser, E. Haberstroh, U. Hüsgen, D. Weinand, Infrared radiation in the processing of plastics: precise adjustment—the key to productivity, Advances in Polymer Technology 7 (2) (1987) 89–128; D. Blanc, P. Laurent, J. Andrieu, J.F. Gerard, Convective and radiant (IR) curing of bulk and waterborne epoxy coatings as thin layers, part II: infrared curing polymer, Engineering and Science 39 (12) (1999) 2487–2497], this paper aims at presenting the development, the construction, the calibration, and the test of flux meters designed to make “in situ” measurements of infrared radiation in industrial furnaces. These sensors must be able to measure high heat flux in difficult thermal ambiances, and be adapted to the characterization of existing processes, therefore the output signal has to directly reflect the IR received flux. The sensible part is made with a semiconductor thermoelectric module which offers a great sensitivity. While the top part of the module is exposed to convection and infrared radiation, the bottom is stuck on a metallic mass. Three different devices have been developed. The first one uses a water cooling circuit to maintain the bottom at a constant temperature. Then, two autonomic devices are developed to allow an on-line assessment of the system state. A flux meter using a paraffin buffer to maintain the reference temperature is designed to measure global heat flux. The third device presented has a floating reference temperature and uses two thermoelectric modules. A mathematical model has also been developed in order to analyse the three different flux meters with regard to the different levels of convective and radiative heat flux. Our flux meters are relevant to test IR furnaces. They can measure up to 50 kW m⁻² heat flux in more than 120 °C ambient. Autonomous sensors can help characterise and adjust existing installations. They are also interesting tools for maintenance shift.     

桥式远红外加热固化烘道的设计

本文介绍了桥式远红外加热固化烘道设计的基本原理和方法,强调了在烘道结构形式和技术参数设计及加热器等选用时应注意的问题。     

Thermomagnetic Convection in Square and Shallow Enclosures for Electronics Cooling

Combined temperature and magnetic field gradients established in ferrofluids induce thermomagnetic convection. We report a comparative numerical analysis of steady-state convection carried out for a square and a shallow enclosure under zero-gravity conditions. Two symmetrically placed, discrete, constant-flux flush-mounted heaters on the bottom wall of the cavities represent power-dissipating devices in electronics/MEMS applications. The sidewalls serve as heat sinks. A line dipole placed below the bottom wall is the field-source. The role of the magnetic field, the thermal boundary conditions, and the enclosure dimensions in influencing heat transfer are revealed through a comparative thermal-fluidic analysis in different convection-dominated operational regimes.     

Short communication simple transient thermal model for solar colector/storage water heaters

This note presents a simple transient model for predicting the thermal performance of some novel solar water heaters which combine both collection and storage of solar energy. These heaters consist of either (i) an insulated rectangular tank whose top surface is blackened and suitably glazed, or (ii) an insulated open shallow tank with black bottom/inner sides and a top glass cover (shallow solar pond). the heaters are adequately covered with an insulation during the night to reduce the heat losses. the proposed model is based on different characteristic equations during sunshine and off-sunshine hours. It is seen that the model predicts the water temperature in close agreement with the experimental observations and earlier theoretical investigations.     

富氧燃烧对投运混煤锅炉低负荷稳燃性的影响

火焰筒头部结构对预混燃烧性能有重要影响,为了探讨旋流器与火焰筒扩张角相互作用关系,试验研究了扩张角为35°（渐扩）、90°（突扩）的火焰筒分别匹配旋流数为0.55,0.75旋流器对燃烧性能的影响。试验结果表明：渐扩火焰筒总压损失较突扩火焰筒减小约3.4%~4.4%,且匹配较小旋流数具有更高的总压恢复系数;突扩火焰筒较渐扩火焰筒具有更低的贫油熄火极限,且无论突扩火焰筒还是渐扩火焰筒,匹配较大旋流数旋流器后均具有更低的熄火极限;突扩型火焰筒温度场对旋流器适应性好,各旋流数下均获得较均匀温度场,出口温度分布系数为0.134 1~0.141 6;渐扩火焰筒温度场对旋流器适应性差,匹配较小旋流数旋流器后温度场均匀性更好,出口温度分布系数为0.135 7;突扩火焰筒NOx排放量更低,且匹配小旋流数旋流器更佳;渐扩火焰筒CO和碳氢化合物（UHC）排放更低,且匹配大旋流数旋流器更佳。