共查询到11条相似文献,搜索用时 156 毫秒
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核电工程的防脆断设计和在役缺陷评价主要应用线弹性断裂力学,并基于材料断裂韧性进行评价。材料断裂韧性需通过试验测定,首先采用落锤试验和V型缺口冲击试验共同确定参考温度,或采用主曲线法确定参考温度,然后将参考温度和材料温度作为变量建立关系式描述材料的断裂韧性。主曲线法能通过较少的试样试验得到材料的断裂韧性,并具有较高的置信度,因此在工程中已得到越来越多的应用。文中采用ASTM E1921标准,应用主曲线法测量了某核电厂主管道材料的参考温度,确定了材料的断裂韧性,并与ASME第Ⅺ卷附录G中的断裂韧性进行比较。结果表明,采用主曲线法得到的材料断裂韧性更高,工程应用中减少了保守裕度,提高了经济性。 相似文献
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The design against brittle fracture and in-service defect evaluation of nuclear power engineering mainly use linear elastic fracture mechanics, and the evaluation is based on the fracture toughness of the material. The fracture toughness of the material needs to be determined by testing. First, the reference temperature is determined by the drop weight test and the V-notch impact test, or by master curve method, then the reference temperature and the material temperature are used as variables to establish a relationship to describe the fracture toughness of the material. The master curve method can obtain fracture toughness through the fewer sample tests and the higher confidence, so it has been used more and more in engineering. In this paper, the ASTM E1921 standard was used to measure the reference temperature of the main pipeline material of a nuclear power plant using the master curve method. The fracture toughness of the material was determined, and compared with the fracture toughness in Appendix G of ASME Volume Ⅺ. The results show that the fracture toughness of material obtained by the master curve method has higher value, and the conservative margin is reduced in engineering, so economy is improved. 相似文献
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钠-空气热交换器是钠冷快堆事故余热排出系统的重要设备之一,与外界环境一起构成事故下反应堆余热的最终热阱。由于钠-空气热交换器的换热管采用垂直布置的翅片管结构,空气在不同位置处冲刷换热管的流速以及角度不同,导致其传热特性及阻力特性与传统翅片管换热器有很大不同。本文以钠-空气热交换器工程设计需求为研究背景,设计了两种试验件分别进行空气冲刷角度为90°和30°时翅片管束传热与流动阻力特性试验研究。试验结果表明:对于相同管排,空气冲刷角度为90°时的翅片管的换热系数及阻力系数明显大于空气冲刷角度为30°时的翅片管;对于相同空气冲刷角度下的不同换热管排,第2排翅片管的换热系数最大。本文研究为钠-空气热交换器的设计及优化提供了理论依据。 相似文献
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Sodium-air heat exchanger is one of the important equipment in the decay heat removal system of sodium-cooled fast reactor, which together with the external environment constitutes the final heat trap for the residual heat of a reactor. Due to the vertically arranged finned tube structure adopted by the heat exchanger tubes of the sodium-air heat exchanger and the difference of the flow direction and velocity of the air at the different positions, the heat transfer and resistance characteristics are very different from of traditional finned tube heat exchanger. In this paper, based on the engineering design requirements of sodium-air heat exchanger, two kinds of experimental specimens were designed to study the heat transfer and flow resistance characteristics of finned tube bundles with air flow angles of 90° and 30°. The experimental results show that the heat transfer and resistance coefficients of the same finned tube with air flow angles of 90° are significantly greater than those of the finned tube with air flow angles of 30°. For the same air flow direction, the second finned tube has the largest heat transfer coefficient. The research provides a theoretical basis for the design and optimization of sodium-air heat exchanger. 相似文献
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在压水堆换料过程中,乏燃料组件要通过水下通道完成从反应堆厂房到乏燃料水池的运输。为获得乏燃料组件在换热条件较恶劣的承载器顶角区域的传热特性,开展了试验研究,测量得到了2 400~20 000 W/m2不同热流密度下承载器顶角区域3根燃料棒顶部的沸腾换热系数,并拟合得到沸腾传热关联式。研究结果可为今后工程应用中评估燃料组件在转运过程中的热工安全状态和表面最高温度提供参考。 相似文献
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参照波浪管单管换热的实验数据,选用Fluent软件中的不同湍流模型和壁面处理方法,对波浪管换热器的换热系数和压降进行计算,通过比较计算结果,确定可用于波浪管内流动传热特性模拟的计算方法。在此基础上,进一步分析流体在波浪管内部的流场结构和传热特性。分析结果表明:RNG k-ε模型配合增强壁面处理方法得到的计算结果与实验值最为接近;与直管相比,波浪管的换热系数和阻力系数的增加幅度在低Re下较大,而在高Re下较小,其中换热系数和阻力系数增加幅度最大的位置均出现在各弧段交接处,即曲率反向的位置。计算结果可为强化传热管设计及其优化提供支撑。 相似文献