1500m3球壳板曲率超标球罐有限元应力分析与强度校核

对1500m3曲率超标球罐在水压试验和设计压力工况下进行了有限元应力分析计算,并根据应力分析设计方法进行了强度校核。结果表明应力强度合格,但最大应力点偏移到超标曲率最大点处。参考应力分析计算结果,提出了球壳板曲率超标球罐的处理措施。     

某型号换热器回程水室应力分析及强度校核

研究了某型号管壳式换热器的回程水室,运用有限元软件Ansys分析了该回程水室在稳态下的温度场及其在温度载荷与压力载荷共同作用下的应力场。根据ASME规范和相关判据对回程水室关键部位进行了应力分析及安全评定。计算结果表明,该回程水室的设计在安全范围之内,符合规范要求,这为回程水室的工程设计提供了理论基础。     

高压容器主螺栓的有限元应力分析

文章对高压容器的重要部件一主螺栓用有限元法作了应力分析,并将完好的螺栓与螺纹局部受损后的螺栓进行比较,得出了螺栓中应力沿螺纹轴向的变化规律,为高压螺栓的设计和使用提出了改进建议。     

基于ANSYS的立式厚壁压力容器应力分析

应用ANSYS软件分析了立式厚壁压力容器工作时筒体与封头的应力分布。结果表明:最大等效应力处于在筒体的内壁区域;等效应力从筒体或封头内壁到筒体或封头外壁呈近乎线性下降。筒体与封头的连接处附近外壁和内壁的等效应力变化最大。     

含纵向内裂纹管道的应力分析及应力强度因子研究

裂纹是压力管道中常见的缺陷形式,其失稳扩展将引起灾难性事故。以断裂力学基本理论为依据,采用1/4节点法和二维奇异单元建立了含纵向内裂纹管道的有限元分析模型,对含裂纹管道进行了应力分析,并对裂纹尖端的应力强度因子进行了分析计算。研究结果对于压力容器及管道的安全分析具有重要的参考价值。     

光滑弯管应力的有限元分析

应用大型通用有限元分析软件 ANSYS,对光滑弯管在内压、弯矩组合载荷作用下进行应力计算和分析 ,找到光滑弯管整体受力规律 ,以供工程配管设计时参考     

推进剂储罐应力强度与疲劳寿命分析

为研究压力、疲劳、腐蚀及裂纹等因素对服役期内推进剂储罐性能的影响,针对某在用四氧化二氮卧式储罐,通过有限元软件建立储罐的仿真计算模型,对储罐进行应力应变强度、疲劳寿命及极限压力分析计算,明确储罐最大应力应变出现在拱顶人孔和筒体的焊缝处,最大应力及应变随压力载荷、使用年限及裂纹深度增加而增大,储罐所能承受的极限压力随使用年限及裂纹深度增加而减小,腐蚀率越大,储罐应力应变增加的增量及极限压力减小的速率越明显,通过对影响推进剂储罐服役性能的关键因素仿真分析,为推进剂储罐实际应用的可靠性分析提供依据,针对推进剂储罐服役提出使用建议。     

椭圆形截面柱壳的应力分析

椭圆形截面柱壳容器常用于储罐、槽车等。 GB1 50 -1 998《钢制压力容器》附录 D对其有设计标准 ,但标准附录未能考虑封头对容器的加强作用 ,由此算得的计算壁厚对容器长度与横向尺寸之比较小的容器 ,结果十分保守。利用有限元分析程序 AN SYS对盛装浓硝酸的椭圆形截面槽车进行了有限元分析 ,计算结果表明 ,封头对柱壳的加强作用十分明显 ,其加强范围是全柱壳范围的 ,加强作用使柱壳的整体应力水平急剧下降 ,满足强度要求的计算壁厚不到 GB1 50计算结果的一半。     

基于有限元的三通管应力分析与强度评定

通过三通的有限元分析,获得了内压作用下三通的应力分布特性;依据ASME Ⅷ-Ⅱ《美国压力容器规范分析》进行应力强度评定,工程应用表明,采用有限元分析软件能很好地解决设备开孔产生的应力问题,特别是当管口承受复杂外载荷情况下的应力计算.     

Combustion of a liquid fuel in a rectangular channel

The possibility of flame spread over the surface of a liquid fuel (n-butanol) in two-phase flow with a gaseous oxidizer in a narrow rectangular channel is demonstrated. The results of a detailed experimental study of combustion in this system are given. Dependences of the flame propagation speed on the initial temperature and oxidizer and fuel flow rates are obtained.     

矩形窄缝近壁附近汽泡运动现象及分析

为了深入了解矩形窄缝流道窄边加热区和非加热区附近的流动和换热特性,文中采用高速摄像仪观察和分析了矩形窄缝流道内窄边近壁面附近汽泡的运动行为。研究结果表明,窄边近壁面附近汽泡的运动形式较为复杂,汽泡可向窄边近壁面或流道中央或竖直方向运动,这种汽泡运动形式的多样性,有利于加热区和非加热区附近流体的交混;描述并建立了汽泡受力物理模型,分析了窄边近壁面汽泡的运动机理。     

Reconstruction of hydrodynamic flow profiles in a rectangular channel using electrochemical methods of analysis

We propose a theoretical method for reconstructing the shape of a hydrodynamic flow profile occurring locally within a rectangular microfluidic channel based on experimental currents measured at double microband electrodes embedded in one channel wall and operating in the generator-collector regime. The ranges of geometrical and flow parameters providing best conditions for the flow profile determination are indicated. The solution of convection-diffusion equation (direct problem) is achieved through the application of the specifically designed conformal mapping of spatial coordinates and an exponentially expanding time grid for obtaining accurate concentration and current distributions. The inverse problem (the problem of flow profile determination) is approached using a variational formulation whose solution is obtained by the Ritz's method. The method may be extended for any number of electrodes in the channel and/or different operating regimes of the system (e.g. generator-generator).     

Diffusion from a viscous stream flowing through a rectangular channel

The problem of the diffusional deposition from laminar strems flowing through rectangular channels with various aspect ratios has been studied. Axial diffusion has been neglected and an analytical solution which is valid near the entrance of the channel obtained. The effect of the aspect ratio on the deposition is given and the results compared with the existing numerical solutions.     

有限长矩形压力容器的应力分析法

对有限长承受内压的矩形压力容器，本文提出了同时考虑矩形容器６个面相互作用的分析计算方法。用所编制的程序计算了一个实际的矩形容器，得到了满意的结果。     

一种协同式强化表面的换热特性

根据场协同理论发展了一种新型强化换热表面,对其紊流流动和换热特性进行了实验测定,考察了翅片倾角、通道高度和Reynolds数的影响,并且在相同泵功条件下进行了强化效果评价。结果表明,在翅片倾角β=0～23.2°范围内,强化效果随翅片倾角单调增加,但是随Re的增大而单调减小。对于一定的翅片倾角,通道高度大者呈现较好的低功耗、高换热率特性。     

低压矩形截面容器的设计计算

本文主要介绍低压拉撑矩形容器在其内拉撑加强件处于非对称的情况下，以应力分析为准，通过简化，取其最薄弱截面作为计算模型。按照单位撑矩形容器计算公式进行应力校核，其平板部分薄膜应力和弯曲应力的任何组合都限定为小于规范许用应力１．５倍，对于具有加强件的拉撑杆的应力限于不得大于设计温度下材料屈服限的２／３。以此求解的壳板壁厚满足化纤工艺对设备结构和制造方面的特殊要求。     

废热锅炉管板结构应力分析与强度评定

应用ANSYS有限元软件对温度与压力载荷共同作用下的废热锅炉结构进行3D建模与热-结构耦合的数值模拟,得到了整个模型的应力分布云图。在最大应力位置附近或沿管板厚度方向选取不同路径,并对路径上的应力值进行线性化处理,根据JB 4732—1995《钢制压力容器-分析设计标准》对整体模型和管板结构分别进行了应力强度评定。应力分析与强度评定的结果表明,管板的结构设计能够满足强度要求。     

Theory and calculation of fabric strength

A theory of biaxial stretching of fabric taking account of the extensibility of the warp and weft threads and the structural changes occurring in the fabric during deformation is presented. The problem of calculating the loads arising in a fabric undergoing stretching is solved for a fabric with prescribed structure and density over the warp and weft and with prescribed linear density and deformation characteristics of the threads. The fabric strength is calculated as a limiting state.     

Experimental investigation of cocurrent two-phase flow in a vertical rectangular channel

New time averaged data of two-phase flow in bubbly and slug regimes are presented. A modified dual spherical tipped optical fiber probe is used to measure local void fractions, gas velocity and bubble sizes. Hot film anemometry was used to measure the local mean liquid velocity axially. The void fraction, gas and liquid velocities values were presented as averages over the long and short dimensions respectively. Also core values of these variables are presented along the smaller dimension of 12.7 mm, near the plane of symmetry of the longer dimension, to show the most general trend of the different bubbly and slug flow runs. Bubble sizes obtained experimentally were compared with predictive models applied to circular geometries and were found to have a reasonable agreement. It was also interesting to find that local void fractions measured using hot film anemometers were comparable to those found by optical fiber probes. Frequencies of interfacial passage of bubbles and slugs are presented which show rather flat profiles across the channel. It is hoped that these data can be further used in predictive two-phase two-fluid models in the future. Lastly of interest is the fact that slip values near the boundaries were shown to be less than 1.0 for some cases in bubbly flow similar to those observed in circular geometries.