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提出了电站锅炉部件及系统的可靠性计算模型,包括承压部件强度的可靠性计算模型、非承压部件的可靠性计算模型和锅炉系统的可靠性计算模型.锅炉承压部件的可靠性计算,考虑了设计量离散性的影响,使用概率设计法计算承压部件强度设计的可靠性.锅炉非承压部件的可靠性计算,使用了历史寿命数据统计法和非参数法的计算模型.锅炉系统的可靠性计算采用了串联系统的可靠性计算模型.给出了电站锅炉承压部件、锅炉易损件、锅炉耐用件、锅炉子系统、锅炉主机和锅炉系统的可靠性计算公式与计算实例.实现了在设计阶段定量计算锅炉部件和系统的可靠性.为电站锅炉的可靠性分析、可靠性设计与可靠性改进提供了依据. 相似文献
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目前电力系统网格计算平台没有构建数据处理模块,影响网格计算速度,为此提出节能减排目标下新型电力系统网格计算平台构建方法。首先根据网格计算技术以及目前电力计算要求设计出网格计算平台框架,然后详细阐述平台中的实时数据采集服务器、网格计算服务器、计算协调模块以及数据管理服务器,最后根据平台需求设计出网格计算软件体系系统,即虚拟数据库,将软件系统添加到平台中,实现节能减排目标下新型电力系统网格计算平台的构建。实验结果表明,所提方法的CPU数量对计算速度的影响小、网格计算所需时间短以及加速比大,具有较好的性能。 相似文献
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本文通过介绍AutoCAD软件在锅炉强度计算、热力计算、水动力计算中的应用 ,使读者在锅炉计算手算时掌握一点技巧 ,提高计算速度、准确性 ,使锅炉的设计更加合理 ,效率更高。 相似文献
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《电力信息与通信技术》2015,(1)
青海送变电工程公司在以往工程计算数据的基础上,利用计算机软件编程技术发展快、操作简单、运算快、精度高的优点,开发了涵盖牵张力和牵引力计算、弧垂计算、连续爬坡弧垂修正计算、布线计算等10项计算模块的张力放线计算软件,通过在张力放线计算软件中设置各计算参数计算公式,设计人性化的操作界面,按设定计算功能快速准确得出计算结果,在架线施工中得到了广泛应用,有效减少技术人员复杂繁琐的计算过程,提高了计算效率。 相似文献
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汽车有害排放浓度数值计算,影响因素众多,有设计参数、运行参数、燃烧参数、测试参数、程序的调整参数等,要提高计算精度,就要抓住影响计算精度的主要因素,找出其变化规律。这样,可以缩短计算时间,提高计算精度。 相似文献
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绍了电厂设计中短路电流计算的基本步骤:包括基本参数的描述、电路元件标么值的计算、短路点短路电流的计算;并介绍了短路电流的计算方法:如基准值的选取、短路阻抗标么值计算、等值阻抗图的简化等。通过短路电流计算的基本步骤和计算方法的介绍使电气设计人员对纷繁复杂的短路电流计算有了清晰的思路和可靠的方法,解决了电气设计人员在短路电流计算时无从下手的困难。 相似文献
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提出了一种发动机通用性能仿真软件的开发思路,并基于此完成了软件开发工作。基于C++语言,设计了一种面向对象的通用程序框架,可以实现多种仿真计算功能,包括稳态下的一维详细计算、容积法计算、实时计算及瞬态计算。气缸、进排气道、管接头、涡轮增压器等主要组件包含多种计算模型,可以根据建模需求进行选择。针对某型中速柴油机,详细介绍了软件性能计算的操作流程,并将计算结果与试验数据进行对比。结果表明,软件有较高的计算精度,而且实时计算功能完全能满足实时分析的要求,实时率可以达到3.92。 相似文献
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屋面作为建筑外围护结构保温隔热体系的一个重要组成部分,其保温隔热性能直接影响到建筑保温隔热性能及其能耗。本文根据国家"十一五"科技支撑计划项目"村镇建筑节能及改善室内热环境关键技术研究"中对河南地区村镇建筑围护结构的调查结果,归纳总结了不同时期、不同材料、不同构造做法的村镇建筑的屋面形式的保温隔热性能,依据试验数据对比得出不同材料及构造做法的保温隔热性能的优劣,从农村建筑的经济、技术、材料、节能意义等方面分析了屋面保温隔热技术在我国广大农村推广实施的重要性和必要性,并对建筑材料的发展方向和趋势提出了建议和意见。 相似文献
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After turning on a room heating system (e.g. central heating) a thermal transient phenomenon takes place on the wall–room system, until it reaches a final thermal equilibrium state. The temperature profiles on the wall cross‐section, starting from an initial profile, corresponding to the initial thermal equilibrium state, come gradually through successive intermediate temperature profiles, to a final temperature profile corresponding to the final thermal equilibrium state. These intermediate, nonlinear and time‐dependent temperature profiles characterize the wall thermal transient state and describe the dynamic thermal behaviour of the wall–room system. The mass of the air in the room is negligible, compared to the mass of the surrounding walls, so the dynamic behaviour of the room–wall system is imposed by the corresponding thermal dynamic behaviour of the walls. The influence of this thermal transient state is important for the room heating behaviour because it acts as a thermal flywheel attenuating and smoothing the room temperature variations. In the present work, using the integral method, analytical expressions yielding the temperature profiles, and the duration of the transient state as a function of thermal and structural characteristics have been developed. Conclusions were drawn on the dynamic thermal behaviour of the room–wall system. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
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针对太阳能富集地区居住建筑外墙构造特点和室外综合温度条件,以拉萨地区为例进行研究,提出了采暖居住建筑非平衡保温节能墙体构造,其中南墙不做保温、东西墙和北墙采用外保温。在对当地典型居住建筑形式和围护结构现状调研基础上,采用南墙兼顾延迟时间和传热系数,东西墙、北墙单位面积等净失热量的分析方法,确定了非平衡外墙的传热系数,并对以此设计的非平衡保温构造总净热损失和内表面温度进行了分析。给出了非平衡保温构造的计算与分析方法,为同类地区非平衡保温构造设计提供了方法和理论依据。 相似文献
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《Applied Thermal Engineering》2000,20(13):1193-1211
A procedure is presented for analyzing the effective thermal capacitance, the time constant and the thermal delay of buildings into components corresponding to discrete sections of the envelope (i.e. the roof or a whole wall of a specified orientation), to envelope parts of different compositions (i.e. the brickwork and the concrete parts of the envelope), or even to the layers of the exterior multilayer walls. Correlations are also developed, which express the dynamic thermal parameters of buildings in terms of the thickness of exterior wall layers and the surface percentage of envelope parts with different compositions. The effective layer thickness is introduced, the increase of which causes negligible increase in the building thermal capacitance. The developed procedure is based on finite-difference solution of a rigorous set of coupled differential equations describing the dynamic thermal behaviour of buildings. The analysis made quantifies the thermal contribution of every element of the envelope and may improve its thermal behaviour if the related conclusions are taken into consideration in the design of buildings. 相似文献
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The thermal performance of a south-facing direct-gain room with shape-stabilized phase change material (SSPCM) plates has been analysed using an enthalpy model. Effects of the following factors on room air temperature are investigated: the thermophysical properties of the SSPCM (melting temperature, heat of fusion and thermal conductivity), inner surface convective heat transfer coefficient, location and thickness of the SSPCM plate, wall structure (external thermal insulation and wallboard material) etc. The results show that: (1) for the present conditions, the optimal melting temperature is about 20 °C and the heat of fusion should not be less than 90 kJ kg−1; (2) it is the inner surface convection, rather than the internal conduction resistance of SSPCM, that limits the latent thermal storage; (3) the effect of PCM plates located at the inner surface of interior wall is superior to that of exterior wall (the south wall); (4) external thermal insulation of the exterior wall obviously influences the operating effect and period of the SSPCM plates and the indoor temperature in winter; (5) the SSPCM plates create a heavyweight response to lightweight constructions with an increase of the minimum room temperature at night by up to 3 °C for the case studied; (6) the SSPCM plates really absorb and store the solar energy during the daytime and discharge it later and improve the indoor thermal comfort degree at nighttime. 相似文献
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Fins are the extended surfaces that are utilized to afford a significant increase in the surface area for heat transference between a heated source and a colder ambient liquid. To enhance the heat transference rate from the exterior surface of a circular conduit, radial, or concentric annular fins are used. Fins are utilized in heat exchanging devices like superheaters, electrical equipment, computer CPU heat sinks, car radiators, refrigeration, and heat exchangers. Motivated by these applications, the current paper explores the thermal attribute of an annular fin with variable thermal conductivity. The framed equations are articulated in terms of nonlinear ordinary differential equations. One of the most effective techniques, the differential transformation method has been implemented to find the analytical solution. The domination of nondimensional parameters on the thermal gradient of the fin has been analyzed graphically. Furthermore, the variation in radial and tangential stress in an annular fin for various dimensionless parameters has been examined with a graphical explanation. Results reveal that the thermal gradient of fin increases for improved values of variable thermal conductivity parameters. The greater values of thermogeometric parameters result in a higher heat transfer. 相似文献