共查询到20条相似文献，搜索用时 140 毫秒
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国产200MW汽轮发电机组调速系统基本上采用的是机械液压式调节方法，本身具有一些无法克服的不足之处，使机组的调节保安性能一直停留在一个较低的水平上。通过对之进行DEH改造。使该类型汽轮发电机组调节保安性能有了一个彻底的提高。作从多个方面对200MW汽轮发电机组DEH改造后调速保安性能的改善进行了阐述。 相似文献
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根据汽轮发电机组转子轴系的结构特点建立了一种大型转子轴系弹性连续体扭振模型 ,推导了轴系连续质量分布系统的扭振波动方程 ,进行了 3 0 0 MW汽轮发电机组轴系扭振固有特性的解析研究和计算分析 相似文献
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唐钢二炼铁#25MW汽轮发电机组采用DVR-2000A数字式励磁控制系统,其整体性能达到了对同步发电机组的最佳控制,保证了发电机组安全、连续、稳定的运行. 相似文献
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金昌斌 《江西电力职业技术学院学报》2009,22(3)
为减少氢冷汽轮发电机组运行安全的隐患,探析机组漏氢问题,分析了引起氢冷汽轮发电机漏氢的多种原因并提出对应的防范措施,从实践中总结出检测漏氢的四种方法。 相似文献
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张向红 《江西电力职业技术学院学报》2021,34(8):6-8,12
现代钢铁工业生产过程中会产生大量高温烟尘,对环境危害较大.分析我国除尘余热回收和汽轮拖动的常规状况,在此基础上开发设计了汽化烟道+翅片式双压余热锅炉+汽轮发电机组工艺,回收和利用高温烟尘产生的热能,并就设计思路、关键技术、性能比较等方面与传统工艺进行对比,为解决余热回收和汽轮驱动关键技术提供一种合理高效的方案. 相似文献
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汽轮发电机组逐渐智能化,功能不断增强,但不确定性因素和不确定性信息仍然大量存在。针对该问题,用概率神经网络（PNN）诊断汽轮发电机组故障。PNN优点较多,机器学习算法简易、方便训练,相比于传统样本处理方法,PNN可训练样本并引入训练网络,更好地确保诊断结果正确率与可信度。MATLAB仿真结果表明,PNN在保证诊断结果准确的基础上,速度更快、分类性能大幅提高,诊断效率也提高至98%。 相似文献
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近几年来,我公司对锅炉、汽轮发电机进行了较大的技术改造,新上了75t/h循环流化床锅炉和6000kw的汽轮发电机组,并且每年都有比较多的大修项目需要外包,在项目实施过程中,我们对如何控制工程质量,保护好业主的利益进行了一些探索. 相似文献
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金昌斌 《成都航空职业技术学院学报》2007,23(4):36-38
汽轮发电机组突然性振动的处理是目前发电厂常见的复杂而困难的工作。本文在参阅相关文献基础上,对振动的现象和特征、确定标准和原因分析等进行了探讨。 相似文献
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铝合金压铸模具温度场数值分析 总被引：9，自引：0，他引：9
采用PROCAST对铝合金压铸用模具在压铸过程中的温度场进行了数值模拟,对压铸边界条件和传热系统的潜热采用热焓法进行了处理,分析了在不同时刻模具的温度场分布,分析了在不同的浇注温度和不同的模具预热温度情况下对模具温度场的影响,并且预测了热应力集中的位置,对压铸工艺参数的优化提出了见解,分析了冷却水管的作用,为压铸模具的热应力分析奠定基础。 相似文献
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结合发电厂凝汽器铜管在循环冷却水中产生腐蚀破坏的实际,对腐蚀部位和非腐蚀部位的微观组织进行的金相检测表明:凝汽器铜管点蚀深度达0.125～0.138mm;在腐蚀照片上,还可见到黄铜的层式和拴式脱锌,在铜合金管的某些部位腐蚀溶除后,基体上留下了一个蚀度了的残余结构. 相似文献
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汽轮机强制冷却技术是指在汽轮机组停止后,向汽轮机内部通以适量的较低温度的空气,进行强迫对流换热,以加快汽缸和转子的温降速度。该技术在山西漳泽电力股份责任有限公司河津发电分公司国产300MW机组的运行中得以应用。实践证明,采用强制冷却代替自然冷却,可以使机组的冷却时间缩短一半以上,可以提高机组的投运率,缓解电力供需矛盾,具有明显的社会和经济效益。 相似文献
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丁春贵 《安徽科技学院学报》2008,22(4)
本文分析认为,新办本科院校会计学专业应当将其人才培养目标定位于高级与普通应用型会计人才的培养,并围绕培养应用型会计人才的目标,科学设置课程体系,合理安排教学内容. 相似文献
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高速芯片作为仪器仪表系统的主要功率元件,工作时通常会产生热量。为避免芯片温度过高导致其性能恶化,需要对芯片采取冷却。通过温度传感器集成电路测量高速芯片温度并智能调节风扇转速,采用PWM技术驱动风扇,并设计合理的风扇电源供电方案,在温度较低时可最大限度降低风扇转速和噪声水平。 相似文献
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Researchers using a goal orientation framework have hypothesized that learning goals are associated with adaptive patterns of behavior, regardless of the level of perceived ability. In contrast, perceived ability is hypothesized to moderate the relation between performance goals and patterns of adaptive or maladaptive behavior. We examined this hypothesis in two samples of seventh grade middle school students, focusing on the math domain in one sample and on the English domain in the other. Using two different statistical methods, median split and multiple regression, we found only little support for the role of perceived competence as a moderator between performance goals and patterns of behavior. Contrary to what has been suggested, we found some evidence that perceived competence moderated the relation between learning goals and behavior. Implications of these findings for recent efforts to use goal theory to reform classrooms and schools are discussed. 相似文献
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Available evidence suggests that Japanese elementary science education has shifted, in recent decades, away from lecture‐style, rote ‘teaching as telling’ toward ‘teaching for understanding’. How has this change been accomplished? Drawing on our ongoing study of innovations in Japanese elementary science instruction, we describe three features of the Japanese system that may facilitate planned change. First, we describe Japan's broad national goals for elementary education and the alignment of textbooks with these goals. We point out that Japan's national goals focus on the whole child (social, ethical and intellectual development), a breadth which, we speculate, may reduce the kind of pendulum swings between goals of academic and social development that have plagued some other countries’ educational policies. In addition, we note that the national goals are abstract and are translated into classroom practice through the collaborative work of teachers. Second, we describe three routes through which the national goals are translated into classroom practice: research lessons, teachers’ research groups, and national elementary schools. Finally, we speculate on some elements of the educational context (for example, collaborative habits and norms, beliefs about the pace and nature of change, and the practice of self‐critical reflection) that may support planned educational change in Japan. 相似文献
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In this article, we quantitatively assess education policy change in OECD countries. While research has frequently underlined the importance of international exchange for national policy development, it is yet unclear whether resulting policies are converging. By distinguishing different kinds of education policy goals, we hypothesise that indicators related to macro-level goals are more likely to converge than those related to implementation. We then analyse the development of several education policies since the 1990s. We find strong convergence of some indicators and among some groups of countries, but no clear pattern emerges. Convergence is only partially influenced by the abstractness of education policy goals, and in particular the Scandinavian countries seem to pursue their own approaches in important education policy options. 相似文献
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高温烟气在实际生产活动以及船舶、航天航空等领域均有大量涉及,而如何对其进行冷却是亟待解决的问题.本文以某实际管道内的高温烟气为研究对象,利用Fluent软件数值仿真不同喷射参数条件下管道内烟气的冷却过程,并对所得仿真结果进行对比分析.仿真结果表明:采用圆周上均匀分布8个喷孔,单个喷孔流量为0.05 kg/s时,可满足烟气冷却要求.基于数值仿真结果,设计了适用于该管道结构的冷却装置.本研究结果对管道内高温烟气的冷却处理具有参考意义,所设计的冷却装置具有实际应用价值. 相似文献
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改革开放30年,我国德育目标研究经历了共产主义德育目标期,＂天上＂与＂地面＂的争论期,规范化建设期和科学化、人本化、生活化研究期四个阶段,对德育目标的含义、德育目标的分类与分层、制定德育目标的依据、确立德育目标的原则等问题进行了研究和探索,初步确立了我国各级各类学校德育目标体系,在一定程度上体现了系统性和层次性。但是,德育目标的研究还存在着高与低的平衡,重社会规范与轻个体品德修养,理论基础缺乏科学系统完整性,目标的类型与层次研究较混乱,注重＂德目主义＂和忽视＂全面主义＂等问题。 相似文献