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针对交流接触器发热问题,用Icepak软件建立了三维有限元数值模拟分析模型。研究了交流接触器在功率损耗的情况下,受热载荷作用时的温度分布和热应力分布,并对不同参数下进行温度和热应力的模拟。 相似文献
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通过电厂锅炉汽包温度实测和模拟汽包实验,研究汽包温度分布规律;在此基础上进行热光弹性实验和三维有限元分析,求得汽包的热应力和下降管加热应力集中系数;分析运行汽包的温差限值,为电厂锅炉的运行提供了科学依据。 相似文献
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IGBT模块封装热应力研究 总被引:2,自引:0,他引:2
IGBT模块封装多层结构的热不匹配将产生热应力从而影响器件可靠性。给出了IGBT模块热应力模拟结果及减小硅芯片热应力的方法,并计算出模块封装最佳参数及热应力与温度的关系,上述结果与温度循环实验结果一致。 相似文献
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通过电厂锅炉汽包温度实测和模拟汽包实验,研究汽包温度分布规律:在此基础上进行热光弹性实验和三维有限元分析,求得汽包的热应力和下降管加热应力集中系数,分析运行汽包的温差限值,为电厂锅炉的运行提供了科学依据。 相似文献
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文章分析了多芯片多基片固体继电器的散热物理过程及其数值模拟计算。通过对热路的优化设计,降低内热阻,可以提高固体继电器的可靠性和适用性。 相似文献
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张光 《中国电机工程学报》1993,13(1):33-37
本文利用有限元法计算了国产200MW汽轮机高中压整体转子的瞬态温度场和热应力场,绘制了过渡工况下的转子温度场和热应力场曲线,以及危险断面处温度、热应力时变曲线和热应力分布曲线,为改善200MW机组转子结构设计和机组调峰运行特性及拟定合理的启动方案,提供了理论依据。 相似文献
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由于温度分布不均匀以及封装中各层材料之间的热膨胀系数不同,使功率模块在工作中产生交变的热应力,造成焊层疲劳、键合线脱落等失效形式,因此研究模块的热特性尤为重要。热的测量是电力电子系统中最困难的工作之一,对封装结构进行电-热-力精确的仿真分析,能够准确了解对器件不同部位的温度、应力分布。采用基于电-热-力多物理场的有限元仿真,研究了封装材料、封装参数和封装结构对功率器件的温度、热阻、热应力这些热特性的影响,为优化封装设计,最终提高功率模块可靠性提供了一定的参考。 相似文献
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对矩形非均匀热流密度分布下太阳能槽式吸热管内流固耦合传热过程进行了数值模拟,得到了吸热管壁温度分布及周向和径向温度梯度。结果表明,太阳能吸热管在非均匀热流作用下其管壁温度分布不均匀,周向温度梯度在受热和非受热交界面附近有剧烈变化。吸热管热流密度的增加会导致壁面温度梯度增大,而管内换热的增强及热流密度的分布特性对温度梯度有影响。 相似文献
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本文用ADINA^[2]和ADINAT^[2]有限元程序对我国某水轮发电机的原制动环和改后制动环做 了11种工况下的温度和工况下的热应力计算,求得了制动过程中两种制动环的温度分布和热 应力分布,给出了制动环温度随时间的变化趋势和表面温度达到最高时所对应的时间,在我国首次为定量分析制动环开裂原因及评价制动环温度和热应力提供了参考数据. 相似文献
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The US Bureau of Mines has determined a method for calculating coal mine portable power cable thermal life for a specified temperature loading. This work was the culmination of a multifaceted research project involving: (1) accelerated life tests of insulation and jacket materials; and (2) steady-state and cyclical loading of cables. Composite Arrhenius curves were derived for common insulation and jacket materials to identify the key cable quality that precipitates thermal failure. Plots of temperature rise versus current for popular cable sizes were then referenced to develop a correspondence between cable life based on thermal degradation and current loading. Predictions of cable thermal life were made through integration over variable load cycles and, consequently, variable operating temperatures. This procedure may have utility for both the US Mine Safety and Health Administration (MSHA) and mining machine designers in determining the appropriate cable size for new equipment 相似文献
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环境温度和环境热阻对单芯电缆导体温度计算灵敏度的影响分析 总被引:1,自引:0,他引:1
为了定量掌握运行环境对电缆导体温度的影响程度,以IEC60287电缆稳态温升公式为基础,推导出环境温度和环境热阻对导体温度影响的局部灵敏度公式。采用局部灵敏度分析法对影响电缆导体温度的2个环境因素进行分析,并进行了电缆温升试验。理论分析与试验结果表明,稳态运行下的电缆,导体温度直接受环境温度影响,环境温度越大则影响越明显,基本呈线性递增;环境热阻对导体温度的影响比较稳定,随着加载电流增大至另一个稳态,灵敏度系数只有小幅升高。 相似文献
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The thermal considerations in specifying and loading cast-resin transformers are presented. These considerations are based on conclusions reached from performing thermal tests on a 200 kVA cast-resin transformer with imbedded thermocouples. Specifications should require that the correct insulation temperature class be applied to individual windings and that hottest spot temperatures do not exceed this insulation temperature class at rated self-cooled and forced-air kilovoltamps. Specifications should also require calculation of hottest-spot temperature rises using mathematical models verified by thermal tests on a prototype transformer representative of the design family. The loading back-test method gives higher hottest-spot temperature rises than expected from the short-circuit test method. A method to correct the data to determine the hottest-spot temperature rise using the short-circuit method is presented. A specification form is suggested, and loading equations are presented to allow predictions of loading capability and comparisons of competitive designs 相似文献
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在槽式直接产蒸汽(directsteam generation,DSG)太阳能热发电系统中,传统接收器的密封装置存在结构复杂、造价昂贵等问题。为解决这些问题,研制了新型法兰机械密封结构,详细介绍了该密封装置的结构。为分析此密封结构的可靠性,利用有限元分析软件ABAQUS的热-力耦合功能,对工作过程中法兰盖板的温度场和应力场进行了数值模拟。分析结果表明,最大的应力变化出现在法兰盖板中心的热影响区,对盖板表面裂纹有主要的影响,最大应力小于材料的许用应力235MPa。 相似文献
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This paper presents a practical thermal loading guide for distribution transformers feeding residential customers. Extensive load research data were used to estimate the thermal response of a "standard IEC distribution transformer." A strong relationship between the parameters of a load modeled by load current as a function of time and the hotspot temperature was found. Using this type of load model, a method was developed for estimating the hotspot temperature of a transformer for customers from different load classes. A method was derived to translate the thermal response of a standard IEC distribution transformer to any practical transformer. 相似文献
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环氧绝缘干式变压器线圈固化过程温度场仿真研究 总被引:1,自引:0,他引:1
为了防止生产过程中干式变压器树脂线圈的开裂、缩孔、白斑等问题,笔者研究了产生开裂等缺陷的形成内因,并根据于式变压器线圈材料性能随温度变化的特性,采用非线性分析建立了线圈浇注、固化、冷却过程瞬态温度场、热应力场三维有限元模型,并确定温度场中初始条件、边界条件,设计了一种有效模拟干式变压器浇注、固化、冷却过程中三维温度场和应力场分布的方法模拟其内部分布,从而改进干式变压器的工艺参数和性能并减少开裂等缺陷的产生。实验表明该仿真能够较好地再现线圈固化过程中的温度场和应力场分布。 相似文献
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This paper proposed an improved temperature prediction model for oil-immersed transformer.The influences of the environmental temperature and heat-sinking capability changing with temperature were considered.When calculating the heat dissipation from the transformer tank to surroundings,the average oil temperature was selected as the node value in the thermal circuit.The new thermal models will be validated with the delivery experimental data of three transformers: a 220 kV-300 MV.A unit,a 110 kV40 MV.A unit and a 220 kV-75 MV.A unit.Meanwhile,the results from the proposed model were also compared with two methods recommended in the IEC loading guide. 相似文献