共查询到20条相似文献,搜索用时 125 毫秒
1.
2.
3.
偏滤器是托卡马克装置堆内的重要部件,有去除杂质、避免第一壁烧蚀的作用。在装置运行前,要对偏滤器进行烘烤以去除水分及杂质,但在烘烤过程中偏滤器靶板会产生较大的热应力。为了探究偏滤器在不同烘烤速率下的热应力变化,找到能够改善热应力的最大烘烤速率,发展了一维流动换热和三维导热耦合计算的模拟方法,对ITER偏滤器换热模块内的流动和温度分布进行分析,并进一步考察了不同烘烤速率下的热应力分布。计算结果显示,烘烤速率对ITER偏滤器的热应力有较大影响,减慢烘烤速率可以明显降低热应力,当烘烤速率小于0.1K/s时烘烤速率对热应力的影响很小。另外,纯铜中间层在烘烤过程中会发生塑性屈服现象,这会减小结构的热应力。 相似文献
4.
某电厂300 MW机组锅炉的SA299材质汽包中部距下降管400~500 mm处出现了一些裂纹,为分析锅炉启停过程汽包的应力变化,采用三维有限元分析方法,运用ALGOR软件对SA299材质的汽包在启停过程热应力和总应力的分布和变化进行了计算.结果表明:在启动过程中水位线处的热应力最大,裂纹处的热应力幅在80 MPa以内,裂纹处的热应力变化与水线处热应力变化趋势基本一致,最大热应力区域接近裂纹产生区域;启停过程中危险点处总应力最大,其应力幅为350 MPa,整个启停过程中,裂纹处的总应力不大,水位线及以下的内壁区域应力比上部和外壁更大;热应力是汽包裂纹产生的诱因之一. 相似文献
5.
建立过渡工况(起动、停车)气缸套非稳态热应力分析模型以及反映过渡工况特点的边界条件数学模型.对过渡工况下的传热和热应力以及工作循环中的温度波、波动热应力和脉动机械应力的计算结果进行了重点分析.从而对气缸套非稳态热应力做出正确的分析.表明非稳态热应力和脉动机械应力对材料引起的疲劳破坏是气缸套失效的主要原因. 相似文献
6.
7.
8.
建立过渡工况(起动、停车)气缸套非稳态热应力分析模型以及反映过渡工况特点的边界条件数学模型。对过渡工况下的传热和热应力以及工作循环中的温度波、波动热应力和脉动机械应力的计算结果进行了重点分析。从而对气缸套非稳态热应力做出正确的分析。表明非稳态热应力和脉动机械应力对材料引起的疲劳破坏是气缸套失效的主要原因。 相似文献
9.
10.
11.
12.
13.
A thermal engine with solid metal as the single-phase working substance is described. The engine can consist of nothing more than a metal tube mounted in a bearing at either end so that it is free to rotate about its axis, with a flywheel mass at its midpoint. When the tube is heated on its upper surface, the region of its maximum compressive bending stress, it will rotate and produce steady power. Compared to engines using a gas or a liquid as the working substance, this engine has the disadvantage of low thermal efficiency but the advantage of simplicity. The solid metal phase engine may be useful for converting solar energy into small amounts of mechanical energy in underdeveloped regions of the world. 相似文献
14.
Fuqiang Wang 《Solar Energy》2010,84(10):1809-1815
In the parabolic trough concentrator with tube receiver system, the heat transfer fluid flowing through the tube receiver can induce high thermal stress and deflection. In this study, the eccentric tube receiver is introduced with the aim to reduce the thermal stresses of tube receiver. The ray-thermal-structural sequential coupled numerical analyses are adopted to obtain the concentrated heat flux distributions, temperature distributions and thermal stress fields of both the eccentric and concentric tube receivers. During the sequential coupled numerical analyses, the concentrated heat flux distribution on the bottom half periphery of tube receiver is obtained by Monte-Carlo ray tracing method, and the fitting function method is introduced for the calculated heat flux distribution transformation from the Monte-Carlo ray tracing model to the CFD analysis model. The temperature distributions and thermal stress fields are obtained by the CFD and FEA analyses, respectively. The effects of eccentricity and oriented angle variation on the thermal stresses of eccentric tube receiver are also investigated. It is recommended to adopt the eccentric tube receiver with optimum eccentricity and 90° oriented angle as tube receiver for the parabolic trough concentrator system to reduce the thermal stresses. 相似文献
15.
《International Journal of Hydrogen Energy》2020,45(19):11199-11210
An elaborate numerical model with progressive damage and failure and fluid-structure coupling was developed to study the crack propagations of tubes under hydrogen static and detonation loads. The numerical model was verified with experiment in terms of crack behaviors and fracture patterns. The tube responses, crack propagations, pressure histories, crack lengths and speeds as well as the energy storages were obtained and analyzed in detailed. It was found the static load case has higher stored energy inside the tube, which causes the larger crack length and speed, as well as the severer bending deformation of tube. The forward crack first run faster under detonation load, but it will be caught up by the backward crack in the late period. The crack growths are incremental under both types of loads. However, the crack growth under detonation load has certain regular patterns, where the oscillating crack speed has a dominant frequency that can be calculated by the proposed formula. Moreover, the quantitative relationship between detonation load speed and the incremental crack growth length was revealed, which is fundamentally and practically useful. 相似文献
16.
17.
18.
对于水电站厂房这样结构复杂的大型水工结构,提出了将国外著名的大型有限元计算软件与自主开发的温度场、温度应力仿真计算程序相结合的方法,解决了在仿真中实现三维空间内混凝土跳仓浇筑的困难,并对某水电站厂房底板进行了仿真计算分析。利用此方法,工程人员可以根据具体的施工方案、浇筑顺序方便地进行温度场、温度应力仿真分析,掌握温度分布情况,及时采取减小温度应力的相应温控措施。 相似文献
19.
Mathematical Model and Its Application of Radial Effective Thermal Conductivity for Coil Heat Transfer in HPH Furnace 总被引:3,自引:0,他引:3
Wenfei Wu Fan Yu Xinxin Zhang Yi ZuoDepartment of Thermal Engineering School of Mechanical Engineering University of Science Technology Beijing Beijing P.R. China E-mail: xxzhang@me.ustb.edu.cn 《热科学学报(英文版)》2002,11(2):134-137
Temperature uniformity of steel coils in High Performance Hydrogen bell-type annealing furnace has a significant effect on their quality and production. The hot rolled coil can be considered as a periodically laminated material composed of steel layers and interface layers in radial direction. A new formula for the radial effective thermal conductivity has been proposed, which is based on surface characteristic, strip thickness and compressive stress of the rolled coil. Furthermore, it has been used to develop a heat transfer mathematical model for steel coils in the HPH furnace. The calculated annealing curves using this mathematical model are in good agreement with the experimental data. 相似文献
20.
The three-dimensional distribution of temperature, thermal deformation, and thermal stress in a workpiece during table traverse cross-feed surface grinding is computed numerically, and the effects on the dimensional accuracy, the holding force of the magnetic chuck, and the grinding cracks in the workpiece are discussed. The temperature distribution is calculated by a finite-difference method, and the distribution of thermal deformation and thermal stress is determined by a numerical method developed from the relaxation method. From the results of the analysis, it is clear that the deformation of workpieces cannot be disregarded when considering dimensional accuracy, and that the magnetic chuck is not sufficient to counteract the thermal bending of the workpiece. 相似文献