空泡溃来水锤的VOF计算方法

空泡溃灭水锤是核电厂冷却循环系统中较常出现的一种严重的水锤事故，空泡的形成和溃灭是复杂的两相、瞬态过程，对于这一现象的分析是相当困难的。作者尝试着把蒸汽泡的边界看成是冷水流动的自由面，在自由面上考虑蒸汽的凝结。     

蒸汽发生器给水系统中汽泡的形成与溃灭

文章对蒸汽发生器给水系统中由于蒸汽泡的溃灭而造成的水锤现象作了分析。根据实验,用液面的波动、变质量水柱的加速运动和孤立蒸汽泡的溃灭等三个模型描述了汽泡的形成与溃灭。计算结果和国外某些核电站事故分析中的估算值相当接近。     

核电站输热管系中蒸汽泡溃灭模拟实验

管路热力输运系统中可能同时出现汽－液两相。当汽－液两相可能接触且存在温差时，会导致汽相急剧冷凝相变，引起蒸汽泡溃灭水锤，导致管系结构破坏。核电站中有大量布局十分复杂的热力输运管道，由于各种原因，蒸汽泡形成和溃灭极易发生。本文针对核电站热力输运管道中汽－液接触后蒸汽饱的形成条件以及溃灭造成的影响进行了分析，用摄影追踪流动显示方法再现了管道中流向发生急剧改变处被冷水隔离的高温蒸汽泡。由于急剧冷凝使得蒸汽体积急剧收缩，环绕的水体产生猛烈碰撞，并监测到该过程中局部压力所产生的瞬间峰值。由于水体对撞运动和逆压梯度，该过程会反复发生多次。利用VOF方法，计算模拟了二维管道系统中蒸汽泡形成的过程。核电站管路的设计和实际操作维护应及时诊断和避免上述问题的发生。     

快堆钠池自由液面波动的三维数值模拟

采用ＶＯＦ方法成功地模拟出了含有各种复杂进、出口流边界及各种障碍物的三维液面波动，并可用部分单元体法求解任意形状容器内含自由液面的液体运动。针对影响快堆钠池液面波动的各种因素，可给出不同工况下液面的波动形状，钠浪波动的最高位置和最低位置以及钠浪涌的量级。本文提供了ＶＯＦ数值方法的主要原因，在ＮＡＳＡ－ＶＯＦ３Ｄ的基础上开发了计算分析程序，及快堆钠液面波动的部分计算结果。     

核电厂蒸汽管道中水团冲击（水锤）的分析

蒸汽管道中夹带有水，可能会产生严重的水锤现象，以致造成管道或管道部件以及其约束件的损坏或丧失功能，对核电厂的安全运行是一个潜在的危害因素。提供了一种描述蒸汽管中水团的形成过程和水团对管道冲击力的计算方法，并给出了一个计算实例。     

快堆钠回路水锤程序开发与应用

研究开发了快堆钠回路水锤分析专用程序WHA。该程序在一维特征线法（MOC）传统的压力波传播数学模型中补充了钠腔－气腔外边界模型，并采用气泡离散模型模拟低压液柱分离中的蒸汽穴的生成与溃灭。程序用FORTRAN90语言对快堆实验钠回路ESPRESSO中由于阀门的快速开启与关闭引起的压力波传播进行了分析计算。计算结果表明：将钠腔－气腔引入水锤压力波传播的数学模型进行程序计算的结果是合理的。     

快堆钠回路水锤程序开发与应用

本文在基于一维特征线法（MOC）的传统的压力波传播的数学模型中补充和完善了钠腔-气腔外边界模型，同时采用了气泡离散模型模拟低压液柱分离形成的蒸汽穴的生成与溃灭。在此基础上编制了专用程序WHA，利用该程序对快堆实验钠回路中由于阀门的快速开启与关闭引起的压力波的传播进行了分析计算，计算结果的合理性表明了包括钠腔-气腔在内的水锤压力波传播的数学模型的有效性和程序计算的可行性。     

注氟MOSFET的质子辐照效应

对干Ｏ２和Ｈ２＋Ｏ２栅氧化注Ｆ的Ｓｉ栅Ｐ沟和Ｎ沟ＭＯＳＦＥＴ进行了８ＭｅＶ和１２ＭｅＶ质子辐照试验，通过分析阈电压和Ｌｄｓ－Ｖｇｓ亚阈特性的辐射响应，发现ＭＯＳ结构栅介质中Ｆ的引入能明显抑制辐射感生氧化物电荷的积累和Ｓｉ／ＳｉＯ２界面态的产生，导致ＰＭＯＳＦＥＴ较小的阈电压负向漂移和ＮＭＯＳＦＥＴ阈电正向回漂，且不受质子辐照能量的影响。     

核电厂蒸汽管道中水团冲击(水锤)的分析

蒸汽管道中夹带有水,可能会产生严重的水锤现象,以致造成管道或管道部件以及其约束件的损坏或丧失功能,对核电厂的安全运行是一个潜在的危害因素。提供了一种描述蒸汽管中水团的形成过程和水团对管道冲击力的计算方法,并给出了一个计算实例。     

核电厂蒸汽管道中水团冲击(水锤)的分析

蒸汽管道中夹带有水,可能会产生严重的水锤现象,以致造成管道或管道部件以及其约束件的损坏或丧失功能,对核电厂的安全运行是一个潜在的危害因素。提供了一种描述蒸汽管中水团的形成过程和水团对管道冲击力的计算方法,并给出了一个计算实例。     

Simulation of central sloshing experiments with smoothed particle hydrodynamics (SPH) method

Liquid sloshing phenomena can be observed whenever a liquid in a container has an unrestrained surface and can be excited. A particular type of sloshing motion can occur during the core meltdown of a liquid metal cooled reactor (LMR) and can lead to a compaction of the fuel in the center of the core possibly resulting in energetic nuclear power excursions. This phenomenon was studied in series of “centralized sloshing” experiments with a central water column collapsing inside the surrounding cylindrical tank. These experiments provide data for a benchmark exercise for accident analysis codes. To simulate “centralized sloshing” phenomena, a numerical method should be capable to predict the motion of the free surface of a liquid, wave propagation and reflection from the walls. In this study, a meshless method based on smoothed particle hydrodynamics (SPH) for the simulation of a 3D free surface liquid motion has been developed. The proposed method is applied to the simulation of “centralized sloshing” experiments. Simulation results are compared with the experimental results as well as with results of computations performed with the 3D code SIMMER-IV which is an advanced reactor safety analysis code that implements the traditional mesh-based numerical method. In a series of numerical calculations it is shown that overall motion of the liquid is in a good agreement with experimental observations. Dependence on the initial and geometrical symmetry is studied and compared with experimental data.     

Magnetic fields in the Planck theory of sonoluminescence

Sonoluminescence(SL) observed in the cavitation of water may be explained by the Planck theory of SL that treats the bubbles as collapsing miniature masers having optical waves standing in resonance with the dimensions of bubble cavity,Microwaves are created from the Planck energy of the standing waves provided the bubble wall may be treated as a perfect blackbody surface.In the ultraviolet,liquid H2O is srongly absorbent and the bubble approaches a Planck blackbody enclosure.The micrwaves are created at frequencies proportional to the bubble collapse velocity and are absorbed by the dipoles of the H2O and other bubble wall molecules.Intense electric fields develop as the liquid H2O bubble wall undergoes dielectric polarization.By this theory,free electrons are created in SL as the electric fields breakdown;the presence of free electrons is required if any magnetic field effect is to be observed in SL.Both local and global magnetic effects on SL are described.The local effect is based on the magnetic pressure due to the electrons moving as currents inside the bubble.The global effect is an accumulatio of local effects at the voids throughout the liquid H2O causing a reduction in the bulk modulus.Numerical solutions of the Rayleigh-Plesset(R-P) equation are presented that show the effect of applied magnetic field on SL to be the global effect causing a reduction in the bulk modulus.Consistent with the Planck theory of SL,the R-P simulations show the suppression of Sl intensity with magentic field to be parabolic and the SL intensity to be linear with collapse velocity.     

上海同步辐射装置次谐波聚束腔中二次电子倍增效应的模拟

上海光源直线加速器采用一个次谐波聚束腔组成预注入器[1],其性能的稳定性和可靠性直接关系到电子束流的品质.二次电子倍增效应是其不稳定性的原因之一,为考察其中的二次电子倍增效应,将上海光源次谐波聚束腔与最普通的重入式谐振腔进行对比.结果表明,在实际使用的工作范围内,优化次谐波腔形状可有效抑制其中的二次电子倍增效应.进一步的考察表明,腔体结构的圆滑设计是抑制二次电子倍增的原因.     

Experimental investigation of the characteristics of the through part of a liquid-metal target based on a lead-bismuth alloy

The results of experimental investigations of the through part of a full-scale liquid metal target of an accelerator-control system, where the working cavity of the target communicates directly with the particle accelerator cavity, are presented. Two design variants were investigated — with vertical and horizontal orientation of the target axis in space and spinning of the flow in front of the nozzle adapter located in front of the entrance of the eutectic into the working cavity of the target. The profiles obtained for the free coolant surface with liquid metal flowing through vertically and horizontally positioned targets are presented. It is confirmed that when the pressure of the free surface of the liquid metal corresponds to the pressure in the accelerator cavity it is possible that liquid metal will not flow into the cavity simulating the connecting piece for inflow of accelerated particles with the piece oriented vertically or horizontally. __________ Translated from Atomnaya énergiya, Vol. 103, No. 3, pp. 186–192, September, 2007.     

A novel fault current limiter topology design based on liquid metal current limiter

The liquid metal current limiter (LMCL) is regarded as a viable solution for reducing the fault current in a power grid. But demonstrating the liquid metal arc plasma self-pinching process of the resistive wall, and reducing the erosion of the LMCL are challenging, not only theoretically, but also practically. In this work, a novel LMCL is designed with a resistive wall that can be connected to the current-limiting circuit inside the cavity. Specifically, a novel fault current limiter (FCL) topology is put forward where the novel LMCL is combined with a fast switch and current-limiting reactor. Further, the liquid metal self-pinch effect is modeled mathematically in three dimensions, and the gas-liquid two-phase dynamic diagrams under different short-circuit currents are obtained by simulation. The simulation results indicate that with the increase of current, the time for the liquid metal-free surface to begin depressing is reduced, and the position of the depression also changes. Different kinds of bubbles formed by the depressions gradually extend, squeeze, and break. With the increase of current, the liquid metal takes less time to break, but breaks still occur at the edge of the channel, forming arc plasma. Finally, relevant experiments are conducted for the novel FCL topology. The arcing process and current transfer process are analyzed in particular. Comparisons of the peak arc voltage, arcing time, current limiting efficiency, and electrode erosion are presented. The results demonstrate that the arc voltage of the novel FCL topology is reduced by more than 4.5 times and the arcing time is reduced by more than 12%. The erosions of the liquid metal and electrodes are reduced. Moreover, the current limiting efficiency of the novel FCL topology is improved by 1%‒5%. This work lays a foundation for the topology and optimal design of the LMCL.     

Doppler反馈系数的计算和实验检验

文章提出了一种利用国外发表的现存的多群数据直接计算都卜勒反馈系数的插值併群方法胍酝ü惹蟮ジ龉舱穹宓挠行Ч舱窕侄蟮拥淖龇ú煌?后者比较烦杂,计算量大。为了检验所用的方法,将计算结果化为~(238)U的有效共振积分,再与实验测量作比较。比较的量包括:室温时对应各种UO_2棒直径的有效共振积分,高温时对应各种温度的有效共振积分及其温度系数。结果表明,理论计算和实验符合较好。所编制的程序称Doppler,有PDP和CYBER两个版本,现均已投入使用。     

低温等离子体改性聚乙烯表面的自由基过程

以电子自旋共振波谱仪(ESR)为主要手段,研究了聚乙烯等五种聚合物等离子体改性过程中表面自由基的生成及转化。等离子体辐照的聚合物首先在表面生成烷基自由基,当与空气接触时,烷基自由基转化成过氧化自由基,在聚合物表面引入极性基因是通过过氧化自由基的反应完成的。     

天光Ⅱ-B光源的初步实验

天光Ⅱ-B是在天光Ⅱ-A的油箱侧面建立而成,利用原有的Marx发生器,以及新建的脉冲形成线、主开关、脉冲传输线、负载腔构成一条新的实验线路。在保留装置原有泵浦激光能力的基础上,可同时进行X-pinch相关实验研究。脉冲形成线内导体为同轴线结构,特征阻抗6 Ω,工作介质为去离子水,研制了一种真空水压的方式对形成线进行灌注,有效消除形成线内水中的气泡。采用Rogowski线圈对流过金属丝负载的电流进行测量。本文进行了天光Ⅱ-B在真负载下的初步实验。结果表明,在对Marx电容器充电70 kV时,输出电流269 kA,脉宽约50 ns,上升沿≤30 ns,丝负载对电流利用率约80%。     

Method for Condensation of the Macroscopic Transport Cross-Sections for Criticality Analyses of FBR MONJU by the Code NSHEX

The problem with the energy-group approximation effect in the criticality analysis of the FBR MONJU by the discrete-ordinate transport code NSHEX has been studied. In order to reduce the existing energy-group collapsing effect in the 18 and 7-group results for the effective multiplication factor, a new algorithm for condensation of the macroscopic transport cross-sections has been proposed and verified. This work presents the definition of the new collapsing algorithm, results from the verification tests and a short discussion from the viewpoint of consistency of the algorithm with the specific finite-difference method of the code NSHEX. According to the presented results, the new collapsing algorithm can be recommended for condensation of the transport cross-sections from 70 into fewer energy-group structures.     

Diagnosis of individual cell frequencies in a coupled cavity chainwithout introducing objects into the cavity

This paper presents a new method to diagnose cell frequencies in a cavity without a probe inside the cavity. The equivalent circuit model of a coupled cavity chain is used to estimate the cell frequencies and couplings between cells in terms of the measured passband performance. Two assumptions used to simplify the numerical process are that the next nearest neighbor couplings between the cells are taken as zero and the quality factors of cells are unchanged in the tuning procedure and defined in advance. This method can simplify the tuning process and makes possible the tuning of a sealed cavity. The procedure has been verified with numerical and experimental examples and can be used as a guide to adjust the normal modes and field flatness in a real cavity