High Heat Flux Testing of B_4C/Cu and SiC/Cu Functionally Graded Materials Simulated by Laser and Electron Beam

B4C, SiC and C, Cu functionally graded-materials (FGMs) have been developed by plasma spraying and hot pressing. Their high-heat flux properties have been investigated by high energy laser and electron beam for the simulation of plasma disruption process of the future fusion reactors, And a study on eroded products of B4C/Cu FGM under transient thermal load of electron beam was performed. In the experiment, SEM and EDS analysis indicated that B4C and SiC were decomposed, carbon was preferentially evaporated under high thermal load, and a part of Si and Cu were melted, in addition, the splash of melted metal and the particle emission of brittle destruction were also found. Different erosive behaviors of carbon-based materials (CBMs) caused by laser and electron beam were also discussed.

Manufacturing and High Heat Flux Testing of Brazed Flat-Type W/CuCrZr Plasma Facing Components

Water-cooled flat-type W/Cu Cr Zr plasma facing components with an interlayer of oxygen-free copper（OFC） have been developed by using vacuum brazing route.The OFC layer for the accommodation of thermal stresses was cast onto the surface of W at a temperature range of 1150oC-1200 oC in a vacuum furnace.The W/OFC cast tiles were vacuum brazed to a Cu Cr Zr heat sink at 940 oC using the silver-free filler material Cu Mn Si Cr.The microstructure,bonding strength,and high heat flux properties of the brazed W/Cu Cr Zr joint samples were investigated.The W/Cu joint exhibits an average tensile strength of 134 MPa,which is about the same strength as pure annealed copper.High heat flux tests were performed in the electron beam facility EMS-60.Experimental results indicated that the brazed W/Cu Cr Zr mock-up experienced screening tests of up to 15 MW/m^2 and cyclic tests of 9 MW/m^2 for 1000 cycles without visible damage.

Preliminary High Heat Flux Tests of Small-Scale Be/Cu Mock-Ups

China, as one of the members of ITER （international thermonuclear experimental reactor） project, one of the most important construction tasks is the fabrication of the first wall panel and shield blankets, which is the key engineering technology of ITER construction and might be one of the crucial issues of the future reactor too. Since 2004, an associated research team including Southwestern Institute of Physics （ SWIP ）, Ninxia Non-ferrous Metal Co. Itd and Chinese Institute of Engineering Physics, as well as Nuclear Power Institute of China has been established. Up to now, several series of interlayer for hot isostatic press （ HIP ） connection of beryllium and CuCrZr alloy have been tested. They are titanium film or coating, Cu coating and Al or AISiMg alloy etc. The bonding strength （tensile or shear strength ） of HIPed Be/Cu joints is up to 100 MPa.

Evaluation of Surface Cracks Using Magnetic Flux LeakageTesting

The magnetic field distribution characteristics of surface cracks with various widths are discussed based on finite element (FEM) results. The crack depth was 0.20 mm, the width range was from 0.02 to 1.00 mm. The results showed that crack width and lift-off (the distance between surface and sensor) will influence signals. Discussed in this paper is the influence of various lift-off parameters on the peak to peak values of the normal component in magnetic flux leakage testing. The effects can be applied to evaluate surface breaking cracks of different widths and depths. An idea is presented to smooth narrow, sharp crack tips using alternating current (AC) field magnetization.

Advances in magnetic flux leakage testing technology

Magnetic flux leakage(MFL)testing technology has the advantages of simple principle,easy engineering implementation and low requirements on the surface of the detected workpiece.Therefore,it has been one of the research hotspots in the field of non-destructive testing(NDT)and widely used for testing long distance pipelines.This paper presents the development of MFL tesing technology from the aspects of basic theory,influencing factors,magnetization technology,signal processing,etc.The problems to be solved and the future development are summarized,which can provide reference for the research and system development of MFL testing technology.

A Dynamics Study of a Magnetic Flux Leakage(MFL) Signal and its Application to Defect Location Discrimination in Steel Pipes MFL Testing Equipment

Difference processing was used to the direct current magnetic flux leakage （DC-MFL） signal, emanating from the defects machined artificially on the internal and external surfaces of a steel pipe. Consequently, the loea-tion discriminating index 8 was provided to identify the defect whether it is on the internal surface or the external one. Three characteristics, shape, depth and orientation of the defect, were discussed through a series of experiments on the artificial defects, such as transverse notches, oblique notches and pits on the steel pipe. The approach has been verified effective to address the defect location identifying problem, albeit the limits on the accuracy assessment to those natural defects on steel pipes in service.

Speed Measurement Feasibility by Eddy Current Effect in the High-Speed MFL Testing

It is known that eddy current effect has a great influence on magnetic flux leakage testing(MFL).Usually,contacttype encoder wheels are used to measure MFL testing speed to evaluate the effect and further compensate testing signals.This speed measurement method is complicated,and inevitable abrasion and occasional slippage will reduce the measurement accuracy.In order to solve this problem,based on eddy current effect due to the relative movement,a speed measurement method is proposed,which is contactless and simple.In the high-speed MFL testing,eddy current induced in the specimen will cause an obvious modification to the applied field.This modified field,which is measured by Hall sensor,can be utilized to reflect the moving speed.Firstly,the measurement principle is illustrated based on Faraday’s law.Then,dynamic finite element simulations are conducted to investigate the modified magnetic field distribution.Finally,laboratory experiments are performed to validate the feasibility of the proposed method.The results show that Bmz(r1)and Bmx(r2)have a linear relation with moving speed,which could be used as an alternative measurement parameter.

油气管道组合缺陷漏磁检测信号数值模拟研究

为解决管道组合缺陷之间漏磁检测信号互相干扰,难以识别的问题,采用有限元方法建立仿真模型,研究管道内外、不同形状缺陷以及内外组合缺陷邻近情况下的漏磁场检测信号规律。研究结果表明:管道缺陷的漏磁检测信号在其轴向和径向分量上均存在显著差异;组合缺陷的检测信号存在相互干扰且具有一定的叠加性;当缺陷深度约为管壁厚的10%、25%、40%时,轴向信号干扰距离分别约为缺陷长度的1倍、2倍、3倍,径向信号干扰距离均约为长度的4倍,组合缺陷径向信号的互相干扰程度大于轴向信号,缺陷深度对轴向信号的影响大于径向信号。研究结果可为油气管道组合缺陷的识别提供理论依据。

Quantitative Interpretation for the Magnetic Flux Leakage Testing Data Based on Neural Network

In order to interpret the magnetic flux leakage (MFL) testing data quantitatively and size the defects accurately, some defect profiles inversion methods from the MFL signals are studied on the basis of the neural network.Because the wavelet ba- sis function neural network (WBFNN) has good accuracy in the forward calculation and the radial basis function neural network (RBFNN) has reliable precision in the inversion modeling respectively,a new neural network scheme combining WBFNN and RBFNN is presented to solve the nonlinear inversion problem for the MFL data and reconstruct the defect shapes.And such details as the choice of wavelet basis function,the initialization of the weight value and the input normalization are analyzed,the train- ing and testing algorithm for the network are also studied.The inversion results demonstrate that the proposed network scheme has good reliability to interpret the MFL data for some defects.

用RCPT研究功能梯度混凝土抗氯离子渗透性能

用非稳态迁移法(NSSM)和自然浸泡法评定功能梯度混凝土(FGC)的抗氯离子渗透性能都存在局限性,但快速氯离子渗透试验法(RCPT)没有局限性。该研究用RCPT法对基于各种胶凝材料的FGC的电通量进行了大量测试并得到如下结论:提出了FGC的电通量计算公式;FGC的电通量反映了FGC的抗氯离子渗透性能,FGC的电通量越低则其抗氯离子渗透性能越高;碱激发矿渣(AAS)砂浆具有极好的抗氯离子渗透性能,其氯离子渗透系数可低至2.1×10^(–13)m^(2)/s。

大型变速抽水蓄能发电电动机不同转速下三维端部电磁场和损耗研究

大型变速抽水蓄能发电电动机端部区域漏磁和构件损耗较高,为了研究不同转速时大型变速抽水蓄能发电电动机三维端部电磁场和端部构件损耗的变化规律,本文建立326 MW变速抽水蓄能发电电动机三维端部瞬态电磁场的数学模型,研究变速抽水蓄能电机在发电机工况下不同转速时定转子端部构件磁密的变化规律,确定变速抽水蓄能电机端部构件涡流密度的分布情况,探究变速抽水蓄能电机在发电机工况下不同转速时定子压圈、定子环板、转子护环以及转子齿压板等端部构件损耗的变化规律。采用相同的计算方法对小容量10 MW变速抽水蓄能发电电动机进行研究,通过试验测试和计算结果的对比验证了本文计算方法的可行性。

新型Sn-Zn系焊铝锡膏的制备

研制了一种新型Sn-Zn系焊铝锡膏.根据焊铝锡膏成分组成特点,以Sn-Zn系无铅锡粉为基础,对助焊膏中活性剂、活性盐、表面活性剂和溶剂等添加剂进行筛选,通过正交试验对其组分进行优化并制备出焊铝锡膏.结果表明:活性剂部分,有机胺A质量的增加会降低钎料在240℃和260℃下的润湿性;活性盐部分,锌盐和亚锡盐有利于扩大钎料铺展面积,但添加铵盐会降低钎料的润湿性;表面活性剂部分,添加OP-10的实验效果要优于添加油酸酰胺的实验效果.基于以上研究结果自制出的焊铝锡膏可用于低温钎焊1060铝,焊接质量良好,界面处未见明显焊接缺陷,且焊铝锡膏具有良好的存储稳定性.研究结果可为铝合金钎焊用焊铝锡膏的应用和开发提供理论和技术支持.

弧板型电容式鼓位探测器的结构设计方法研究及特性分析

高通量试验堆采用控制鼓部件作为功率调节装备,通过改变控制鼓与堆芯的相对角度,可调节堆内的核反应性。控制鼓的旋转角度信号是高通量堆运行过程中最重要的待测参数之一,该信号需由鼓位探测器进行识别。电容传感技术可应用于角度信号测量,本文基于弧板构型,进行了电容式鼓位探测器结构的初步设计,明确了鼓位探测器边缘效应的影响范围,提出了边缘误差的补偿方法,完成了鼓位探测器的结构改进设计,获得了电容式鼓位测量系统的总体性能。研究结果表明,完成边缘误差补偿后,在0°~180°的角度范围内,电容式鼓位测量系统的最大测量误差在±0.004°以内,可满足高通量堆控制鼓鼓位的测量精度需求。

油气管道漏磁数据处理和缺陷识别量化方法的研究进展

漏磁法是最稳定的无损在线检测技术之一,用于评估油气管道的健康状况。从通道基线校正、异常值判别、数据缺口的恢复和滤波四个方面阐述了漏磁数据预处理的方法和步骤;结合漏磁数据缺陷的峰谷值等显性特征,总结了不同特征提取方法下缺陷信号的本质特征;介绍了基于支持向量机、神经网络、图像处理和形态学等方法构建缺陷反演模型。最后,从数据预处理和缺陷识别量化两方面展望了漏磁信号处理未来的研究方向。

全钨ITER朗缪尔探针的高热负荷测试及损伤行为

本文研究了全钨ITER朗缪尔探针在高热负荷条件下的耐热性能、绝缘性能和损伤行为。利用核工业西南物理研究院的60 kW电子束测试平台,对探针在10 MW/m^(2)稳态热负荷、20 MW/m^(2)瞬态热负荷及15 MW/m^(2)高参数稳态热负荷下进行模拟测试。实验结果表明,全钨朗缪尔探针能够承受10 MW/m^(2)热负荷100分钟、20 MW/m^(2)热负荷300次循环以及15 MW/m^(2)热负荷3000次循环。在15 MW/m^(2)条件下,探针表面在前1000次循环中无明显损伤,但在3000次循环后出现裂纹,且部分探针表面发生再结晶现象。研究表明,现有全钨朗缪尔探针的设计能够满足当前ITER装置的服役条件,但面对未来DEMO堆更加苛刻的条件可能还需要进一步优化。

1958-2022年黄河头道拐水文站水沙特征分析及预测

[目的]探究黄河头道拐水文站径流量与输沙量演变特征,为区域水资源合理规划提供理论依据。[方法]基于1958—2022年径流输沙数据,采用非参数检验方法与CEEMDAN法研究了头道拐水文站水沙趋势、突变及周期变化特征,并通过水沙月值数据构建Informer预测模型。[结果](1)年径流量与年输沙量的M-K统计量分别为-3.380,-5.067。年径流量和年输沙量分别于1986年、1968年和1986年发生突变,下降率分别为36%,44.38%和61.32%。(2)使用CEEMDAN法对径流量与输沙量年值序列进行分解后均得到3个IMF分量与1个RES分量,水沙序列的3个IMF分量平均周期分别为3.69 a,7.67 a,30 a和3.41 a,7.5 a,26 a;水沙月值序列经过分解后得到7个IMF分量,短周期为3.46月与3.61月,长周期为226.33月与184.50月,主导周期为7.25月和8.09月。(3)模型构建后发现径流的预测精度高于输沙,原因是输沙量受影响因素众多,变动幅度更大,较径流量预测难度大。[结论]黄河头道拐水文站水沙存在显著下降趋势,主要归因于降水影响,且序列突变节点与上游水库建成密切相关。

青海省多年地表感热通量的时空变化特征

选取青海省35个气象站观测数据,基于CHEN-WENG感热系数方案,计算了1980—2017年青海省地表感热通量。利用小波分析、Mann-Kendall突变检验和经验正交函数法(Empirical Orthogonal Function,EOF),对感热通量的时空变化特征及其影响因子进行分析。结果表明:(1)1980年以来,青海省全年和各季节感热通量总体上均呈上升趋势,并具有28 a的主周期和约18 a的副周期,冬季的周期变化较为复杂;(2)全年和各季节感热通量与地气温差存在显著相关性,2004—2017年受地气温差增大的影响上升;(3)全年、春季和秋季感热通量与风速存在显著相关性,1980—2004年受风速减小的影响感热通量下降;(4)夏季降水与感热通量呈显著负相关;(5)从空间上看,全年以及春季感热通量呈现出显著的东西分异,秋、冬季表现出一定程度的南北分异。

不同衰减函数的钢丝绳漏磁信号自适应降噪

讨论了双曲线函数、指数函数、线性函数3种不同衰减函数对钢丝绳漏磁信号降噪效果的影响,对损伤含噪信号进行自适应移位平均降噪,并使用信噪比、互相关系数对降噪效果作了对比分析。结果表明,针对所用的2种漏磁信号,使用双曲线函数的降噪信号信噪比最大可达14.104 1 dB与10.834 9 dB,大于指数函数与线性函数所得的对应信噪比值,且得到的输出曲线平滑,具有更好的降噪效果。同时,随着噪声增大,使用双曲线函数的降噪信号互相关系数更快地接近1,具有更好的动态特性。

数据驱动的脉冲风洞气动热试验数据分析方法探索

脉冲风洞的有效运行时间短,气动热测量信号易受干扰,通常采用人工判读的方式在大量的脉冲风洞测热试验数据中遴选有效数据,数据分析过程效率低、标准不统一。研究基于中国航天空气动力技术研究院1 m量级炮/激波双模式风洞气动热试验数据开展信号特征分析,确定了Fourier变换后的电压信号、总压-热流相关系数曲线、热流时间导数等参数对流动起止时间、运行模式分界时间、信号质量等关键信息的表征作用。在此基础上,基于卷积神经网络和密度基聚类算法,发展了传感器信号有效性判断模型、风洞有效运行时间段选取算法和传感器信号取值区间选取算法,实现了脉冲风洞气动热试验数据的智能处理。结果表明,智能算法对传感器信号有效性的判断准确度达到98%;针对3568条原始试验曲线进行处理,智能算法与人工方式得到的热流均值差异小于10%的数据约占91%,具有应用于风洞试验的价值。

第二宇宙速度再入高焓烧蚀试验

针对国内无法进行高焓气动热地面试验的难题,中国航天空气动力技术研究院研究团队利用磁等离子动力加热器、高频感应加热器和电弧加热器相结合的试验技术,实现了第二宇宙速度再入气动热环境的复现。试验技术在采用ϕ60 mm-SR90 mm等热流驻点模型时,可实现气流焓值范围8~87 MJ/kg,热流密度范围500~6800 kW/m2,驻点压力范围1~66 kPa,获得了4种典型防热材料烧蚀性能随高焓流场参数的变化规律,印证了碳硅复合热解防热材料的高焓烧蚀机理。在气流总焓一定的情况下,防热材料的烧蚀率随热流密度的增大而增大;在热流密度一定的情况下,防热材料的烧蚀率随总焓的增大而减小。该试验技术已经服务于探月后续项目,同时可应用于高温非平衡效应研究中,更可为将来的载人登月和深空探测提供设备基础和技术储备。