共查询到20条相似文献,搜索用时 0 毫秒
1.
核电厂在严重事故时会有大量氢气释放到安全壳中,为研究氢气在安全壳内的分层、混合、复合等复杂现象,OECD发起了SETH-2项目。在SETH-2框架内,PANDA实验台架上进行的ST1_7_2实验利用氦气替代氢气,来模拟竖直空气射流对氢气层侵蚀的过程。本文使用CFD技术对该实验进行了数值模拟,并分析了浮升力湍流模型以及不同湍流Schmidt数对模拟结果的影响。研究结果表明:数值模拟较好地再现了实验的侵蚀过程,但射流的侵蚀速率小于实验的侵蚀速率;使用不考虑浮升力的湍流模型进行模拟的结果显示,氦气层迅速被空气射流稀释,与实验现象不符,表明在定义湍流模型时必须考虑浮升力;不同湍流Schmidt数对ST1_7_2实验的数值模拟结果存在一定影响,但影响不大。 相似文献
2.
3.
对系统材料表面受到高注量X射线辐照时产生的空间电荷层振荡现象进行了数值模拟,得到了发射电子为单能、连续谱、沿轴向发射及呈余弦角度分布发射条件下的计算结果,并对计算结果进行了分析,总结给出了空间电荷层振荡特性的一般规律,给出了空间电荷层振荡问题的物理解释:空间电荷层的存在必然会存在振荡,每一个轴向电子速度值确定一个振荡频率,对应电子的份额决定振荡的幅度大小;单能电子沿轴向发射是最容易观察到空间电荷层振荡现象的情况,一旦考虑发射电子的角度分布,振荡频谱就可近似为连续谱在时域上观察不到明显的振荡现象。 相似文献
4.
中国先进研究堆矩形通道流场数值计算分析 总被引:1,自引:1,他引:0
通过SIMPLE数值方法,编制程序,对中国先进研究堆(CARR)全流道进行流场数值模拟.采用对CARR的单个冷却剂通道进行单相水的数值传热计算,并递增地改变流道入口流速,计算获得与入口流速对应的流道速度场与温度场分布,展现其变化规律,分析入口流速对流道热工水力参数分布的影响.采用所编制的程序,对板式燃料组件构成的窄矩形通道进行数值模拟,由此来确定热工水力设计需要的一些反应堆安全参数.这些安全参数为反应堆事故监测系统提供必要的热工过程状态信息,也为CARR提供必要的数据参考. 相似文献
5.
6.
孙朝明 《核电子学与探测技术》2016,(6):628-633
不清晰度是评价射线检测图像质量的一个重要指标,尤其是对于数字射线检测技术而言;在射线检测实际应用中,不清晰度值通常用双线型像质计来测量,但现行技术标准所规定的测量方法还有待进一步明确或完善。为探究双线型像质计的使用原理、双线型像质计影像与不清晰度间的关联,构建了双线型像质计与刀口工具的射线成像模型,利用数值模拟方法获取了特定射线源特性、透照布置所对应的两种测试工具的响应,然后进行了不清晰度的测量与对比分析。结果表明,由于射线源焦点强度分布的不同,特定不清晰度值下双线型像质计影像的可识别程度会有所不同,但基本上可使用双线型像质计响应曲线的20%调制度作为分限能力的定量判据。 相似文献
7.
8.
《Journal of Nuclear Science and Technology》2013,50(11):840-845
The adsorption behavior of Cs onto quartz was investigated with the use of a high performance liquid chromatograph. The surface-based distribution coefficient (Ka) of Cs onto quartz was determined in the solution of which pH ranged from 6 to 11 and ionic strength from 10?3 M to 10?1 M. The Ka values were found to increase with increasing pH and with decreasing ionic strength. The obtained data were successfully analyzed by an electrical double layer model and the optimum parameter values of the double layer electrostatics and adsorption reactions were obtained. The adsorption mechanisms of alkali metal ions was discussed on the basis of the present analysis. 相似文献
9.
CEFR3层水平热屏蔽热工流体的数值研究 总被引:1,自引:1,他引:0
中国实验快堆(CEFR)采用池式结构,钠池分为冷钠池和热钠池,冷、热钠池之间的3层水平热屏蔽层既是热池的冷边界,也是冷池的热边界,其内部的热工流体直接影响着冷池和热池内的温度分布。针对CEFR满功率运行工况,利用CFX软件,对1/4区域水平热屏蔽层内的热工流体进行三维数值模拟,冷池边界为360℃,热池边界取490和516℃两种方案,数学模型采用RNGk-ε模型。与现有结果相比,由于考虑了对流换热,所得到的平均温度低于设计温度。 相似文献
10.
The moving direction of double seal door (DSD) of International Thermonuclear Experimental Reactor (ITER) remote handling transfer cask will change suddenly at the guide rail inflexion position (GRIP), where the force of hydraulic pole also will change significantly. The structure may damage and the system will possible be failed when the DSD moving through GRIP which is a mutant site. Based on special constitution, restriction conditions and working process of DSD, kinematics simulation and analysis were done by software ADAMS. The DSD moving equations were built based on the degree of freedom (DOF) of DSD mechanism system, and then the force of DSD moving were calculated in theoretical analyzing. By the above simulation and theoretical calculation the stress distribution of guide rail and hydraulic pole were obtained, at the same time optimization design of GRIP was confirmed according to the force analysis results. The above-mentioned analysis process and results not only provide technical data for the optimization design and the prototype manufacture of DSD, but also provide the examples and references of theoretical calculation and kinematics analysis for other important components of ITER. 相似文献
11.
用Monte—Carlo方法模拟了外中子源在次临界堆中的倍增过程。通过对多种外中子源输入的模拟计算,研究分析了ADS系统中次临界堆的物理特性。 相似文献
12.
13.
14.
《等离子体科学和技术》2016,18(6):611-616
Accelerator grid structural and electron backstreaming failures are the most important factors affecting the ion thruster's lifetime.During the thruster's operation,Charge Exchange Xenon(CEX) ions are generated from collisions between plasma and neutral atoms.Those CEX ions grid's barrel and wall frequently,which cause the failures of the grid system.In order to validate whether the 20 cm Lanzhou Ion Propulsion System(LIPS-200) satisfies China's communication satellite platform's application requirement for North-South Station Keeping(NSSK),this study analyzed the measured depth of the pit/groove on the accelerator grid's wall and aperture diameter's variation and estimated the operating lifetime of the ion thruster.Different from the previous method,in this paper,the experimental results after the 5500 h of accumulated operation of the LIPS-200 ion thruster are presented firstly.Then,based on these results,theoretical analysis and numerical calculations were firstly performed to predict the on-orbit lifetime of LIPS-200.The results obtained were more accurate to calculate the reliability and analyze the failure modes of the ion thruster.The results indicated that the predicted lifetime of LIPS-200's was about 13218.1 h which could satisfy the required lifetime requirement of 11000 h very well. 相似文献
15.
HT-7U超导托卡马克装置真空室热烘烤结构数值模拟与分析 总被引:2,自引:0,他引:2
在等离子体运行前.为了提高真空室的本体真空度,获得一个高真空等离子体运行环境,必须对真空室进行250℃壁处理烘烤.除去吸附在器壁表面上的杂质。基于此,本文提出了电阻丝和气流加热两种烘烤方案,并对其结构进行了数值模拟和分析.得出了真空室烘烤时的加热功率、温度分布和热应力情况,为HT-7U和同类超导托卡马克装置真空室烘烤结构的工程设计和优化提供了理论参数依据。 相似文献
16.
针对核电厂液态流出物在受纳水体中的稀释扩散问题, 常采用平面二维数值模拟法进行分析, 计算所得流场往往有水文测验资料进行验证, 但对于半衰期较长的核素, 衰变减少的份额较少, 计算范围的大小对计算结果的影响较大。本文结合工程实例, 选取大小不同的两个计算域, 分别进行数值模拟计算, 并对计算所得流态、浓度场分布、浓度通量以及总量守恒进行分析。结果表明, 在计算能力范围内, 应选取较大的计算域; 在满足计算精度和效率的条件下, 排放口距计算边界宜大于80 km的范围。该结果可供核电厂液态流出物排放选择计算范围时进行参考。 相似文献
17.
18.
水面综合散热系数、糙率、涡粘性系数和热扩散系数是温排水数值模拟过程中的重要参数,各参数的正确选择与计算直接影响到温排水数值模拟成果的准确性。以沿海某核电厂为例,分析各参数的取值对1 ℃最大温升面积模拟结果的影响,并对各参数的灵敏度进行分析,以期对后续沿海核电工程的温排水数值模拟工作提供参考。 相似文献
19.
Based on the electron‘s radial force equilibrium, the profiles of radial electric field in OH and LHCD phase are calculated by using a simulation code. The dependences of radial electron field on electron density and its profile and different current ratio, Irf/Ip, are given. The connections between the improvement of plasma confinement and the modified radial electric field by LHCD are discussed by comparing the calculated results with the experimental results. 相似文献
20.