Influence of helium cooling channels on magnetohydrodynamic flows in the HCLL blanket

One of the blanket concepts proposed to be tested in ITER as part of the test blanket module program of the European Union is the helium cooled lead lithium blanket design. In this configuration the so called breeder units are arranged in an array, separated by a stiffening grid, to form blanket modules. The deposited thermal energy is removed by helium flowing at high pressure and speed in channels integrated both in the walls and in cooling plates that subdivide the breeder units into flat ducts where the lead lithium circulates under the influence of the strong plasma confining magnetic field. This gives rise to magnetohydrodynamic (MHD) phenomena whose effects on flow distribution have to be investigated to evaluate the performance of the proposed design. The established MHD flow is affected by the presence of helium channels in cooling and stiffening plates that results in non-homogeneous wall conductance.In support to the conceptual study of a liquid metal blanket, numerical investigations of fully developed MHD flows in a central cross-section of breeder units have been performed, taking into account both the presence of helium channels in the walls and the multi-channel effects caused by the exchange of currents through walls separating different fluid domains.     

Construction and initial operation of MHD PbLi facility at UCLA

A magnetohydrodynamic flow facility MaPLE (Magnetohydrodynamic PbLi Experiment) that utilizes molten eutectic alloy lead–lithium (PbLi) as working fluid has been constructed and tested at University of California, Los Angeles. The loop operation parameters are: maximum magnetic field 1.8 T, PbLi temperature up to 350 °C, maximum PbLi flow rate with/without a magnetic field 15/50 l/min, maximum pressure head 0.15 MPa. The paper describes the loop itself and its major components, basic operation procedures, experience of handling PbLi, initial loop testing, flow diagnostics and current and near-future experiments. The obtained test results of the loop and its components have demonstrated that the new facility is fully functioning and ready for experimental studies of magnetohydrodynamic, heat and mass transfer phenomena in PbLi flows and also can be used in mock up testing in conditions relevant to fusion applications.     

准静态液态金属锂铅在SLL包层中的流动换热

依据国际热核聚变实验堆（ITER）的中国单冷准静态液态锂铅实验包层模块（Single-coolant Lithium Lead,SLL）,研究液态金属工质锂铅在磁场作用下,不同的第一壁热流密度对缓慢流动的液态锂铅流动和传热特性的影响,为热工水力设计提供参考。研究表明,液态金属处于准静态缓慢流动时,第一壁热流密度的增加使得流道整体的温度有所提高,特别是靠近第一壁的L1流道的温度增加幅度最大;L1流道温度和速度变化剧烈,产生变化较大的感应磁场和感应电流密度,对应的洛伦兹力影响了流动换热。     

Numerical investigation of liquid metal magnetohydrodynamic flow in multilayer flow channel inserts

In the high temperature liquid metal blanket of fusion-based hydrogen production reactor (named FDS-III), there is a remarkable feature that the multilayer flow channel inserts (MFCI) as function component are put into the breeding zone. The low thermal conductivity of MFCI can prevent the internal PbLi's heat conduct to the outside. So the outlet temperature can achieve high temperature around 1000 °C for high efficient production of hydrogen. However, the flow of liquid metal meandering through the MFCI will cause complex magnetohydrodynamic (MHD) effect under the strong fusion magnetic field. Liquid metal MHD effect is a key issue which should be concerned in high temperature breeder blanket (HTL). In this work, a numerical study was carried out to investigate the MHD effect of liquid metal PbLi in the MFCI. The MHD flows with typical modified geometry of the HTL MFCI were considered. The characteristics of flow and induced current fields were analyzed, and the pressure drop was evaluated. It also can be seen that the conductivity of the MFCI will have great impact on liquid metal flow's current and velocity distributions.     

ITER双功能液态锂铅实验包层系统故障模式影响分析

实验包层模块允许放置在ITER中实验的前提是其对ITER的安全以及对工作人员和环境不构成显著影响。ITER要求各参与方的实验包层模块在实验前必须提交安全分析报告,进而获取安全许可证。在中国双功能锂铅实验包层模块(DFLL-TBM)设计基础上,采用了故障模式影响分析(FMEA)方法对DFLL-TBM进行了安全评估与分析,得到所有可能导致严重后果的假设始发事件,验证了确定论安全分析所选择的三个参考事件可以包络所有的假设始发事件。     

ITER中国液态锂铅实验包层模块氚提取系统设计

ITER中国液态锂铅实验包层模块氚提取系统(TES)是通过含0.1%H2的低压氦吹洗气流,在鼓泡器中将液态锂铅内产生的氚交换和载带出来,进入同位素分离系统连接进行氚提取.给出了该系统总体参数、工艺流程、辅助设施等设计.     

Computational studies of thermoelectric MHD driven liquid lithium flow in metal trenches

The LiMIT system (Lithium/Metal Infused Trenches) is an innovative plasma-facing component for tokamak divertors, recently proposed at the University of Illinois. Thanks to the coupling of two metals having different Seebeck coefficients, the device is able to generate internal thermoelectric currents as a response to an incoming heat flux from the plasma. One of the two metals is liquid lithium and the second metal is a solid composing the trenches (tungsten, or molybdenum, or stainless steel, etc.). Together with the high toroidal magnetic field, the liquid lithium is propelled by a JxB electrodynamic force inside the solid trenches. In the present work we present a numerical characterization of the device. The diffusion–advection of heat is solved together with the Navier–Stokes equations forced by the JxB electrodynamic force, comprising the thermoelectric contribution. We report parametric plots to show the influence of the toroidal magnetic field and of the plasma heat flux. It is found that the average flow velocity of the liquid lithium peaks at a critical magnetic field, always lower than 1.0 T, and then decreases with an inverse law in the range of tokamak-relevant fields. The flow velocity of the lithium increases with a square-root law versus an increasing heat flux. The heat transfer coefficient of the cooling channels is parametrically investigated, revealing that coefficients higher than >4000 W/m² K are needed for the device in order to withstand heat fluxes of 10 MW/m².     

ITER双功能液态锂铅实验包层系统PIE-PIT分析

ITER要求各参与国的实验包层模块在实验前必须提交安全分析报告(含确定论分析和概率论分析),进而获取安全许可证.结合中国双功能锂铅实验包层模块的具体特点,采用了假设始发事件-潜在影响表(PIE-PIT)分析方法对DFLL-TBM进行了安全评估与分析,已验证确定论安全分析所选择的三个参考事件是否可包络PIE-PIT分析得到的严重事故序列.     

高温包层内多层插件流道内液态铅锂MHD流动数值分析

包层是聚变反应堆能量转换和提取的关键部件,聚变高温制氢堆(FDS-Ⅲ)高温液态铅锂包层(HTL)中采用创新型多层插件(MFCI)技术,由SiC_f/SiC组成的流道插件使液态铅锂实现了1 000℃左右出口温度,从而达到更高的热电转换效率和制氢能力。液态金属磁流体动力学效应MHD效应是HTL包层的重点问题之一。本文以高温包层结构为参考,采用FDS团队自主开发的磁流体动力学与热工水力学耦合模拟软件MTC,对高哈特曼数下典型多层插件流道内的液态铅锂MHD流动特性进行了数值模拟,分析了不同插件电导率对流道之间电磁耦合现象的影响。     

Experimental and numerical studies of pressure drop in PbLi flows in a circular duct under non-uniform transverse magnetic field

Experiments and three-dimensional (3D) numerical simulations are performed to investigate the magnetohydrodynamic (MHD) characteristics of liquid metal (LM) flows of molten lead-lithium (PbLi) eutectic alloy in an electrically conducting circular duct subjected to a transverse non-uniform (fringing) magnetic field. An indirect measurement approach for differential pressure in high temperature LM PbLi is first developed, and then detailed data on pressure drop in this PbLi MHD flow are measured. The obtained experimental results for the pressure distribution are in good agreement with numerical simulations. Using the numerical simulation results, the 3D effects caused by fringing magnetic field on the LM flow are illustrated via distributions for the axial pressure gradients and transverse pressure differences. It has been verified that a simple approach for estimation of pressure drop in LM MHD flow in a fringing magnetic field proposed by Miyazaki et al. [22] i.e., a simple integral of pressure gradient along the fringing field zone using a quasi-fully-developed flow assumption, is also applicable to the conditions of the present experiment providing the magnetic interaction parameter is large enough. Furthermore, for two different sections of the LM flow at the entry to and at the exit from the magnet, it is found that the pressure distributions in the duct cross sections in these two regions are different.     

基于MPS方法的液态铅铋合金内气泡上升流数值模拟

移动粒子半隐式(MPS)方法捕捉多相流体动力学相界面的能力比传统网格方法具有明显优势.本研究采用MPS方法,使用FORTRAN语言自编程序,对单个氩气气泡在液态铅铋合金内从静止到充分发展整个过程中的瞬态动力学行为进行二维数值模拟,得到气泡变形特性与上升速度的关系.结果表明:在气泡上升过程中,气泡由球形先变成酒窝形状,最...     

Pressure Drop of Liquid Mercury MHD Power Generators

This paper deals with experimental studies of performance characteristics of both constant-area (34×7×295 mm) and diverging-area (23×7 to 43×7×295 mm) MHD power generators with liquid mercury as working fluid, with particular reference to the pressure drop created in the inlet and outlet ducts as well as inside the generator channel, and comparisons are made with various theoretical results. Discussions are presented on the following aspects. In respect of the constant-area channel, pressure drop in laminar and turbulent flow inside the channel, transition Reynolds number for given Hartmann number, pressure drop in the inlet duct and eddy current created near the end of electrode, output electrical power. For diverging channel, applied magnetic field intensity required for zero pressure drop inside the channel, pressure distribution inside the channel, output electrical power in the case of zero pressure drop. The experimental conditions were as follows: Re10<⁵ and Ha<60.     

ITER中国液态锂铅实验包层模块液态金属流动MHD效应数值模拟

为研究国际热核聚变实验堆(ITER)的中国双功能锂铅实验包层模块(DFLL-TBM)中液态金属磁流体动力学(MHD)效应,对在强磁场环境下磁流体动力学效应对液态金属LiPb流动和传热的影响进行数值模拟和分析.主要包括三部分:(1) 建立模拟液态金属磁流体的磁感应方程数学模型和程序简介;(2) 对液态LiPb MHD流体在全模块内流动的数值模拟,给出了速度场和压力场分布,重点考察和分析局部的流动特点和对传热的影响;(3) LiPb在进口供给联箱内的流场的数值模拟,对供给联箱的分流作用给出了初步的估算和评价.     

中国低活化马氏体钢CLAM在液态锂铅中腐蚀的初步实验研究

液态金属锂铅包层是最具发展潜力的聚变堆包层之一,其首选结构材料为低活化铁素体/马氏体钢,而它与液态锂铅的相容性是聚变堆材料研究领域的关键问题之一.本文介绍中国低活化马氏体钢CLAM在液态金属锂铅回路DRAGON-1热对流工况下的实验情况及500 h 480 ℃下初步腐蚀实验结果,并与同样工况下316L奥氏体钢腐蚀结果进行了对比分析.结果显示CLAM钢与液态锂铅的相容性优于316L钢.     

全自动液态金属控制在核反应堆中的应用

根据空间快堆的具体特点,采用液态金属锂为控制材料.本文分析了反应堆的启动特性、燃耗补偿特性、应对失流事故和超功率事故的特性,验证了全自动液态金属控制用于反应堆控制的可行性.     

Preliminary Analysis of Liquid Metal MHD Pressure Drop in the Blanket for the FDS

Preliminary analysis and calculation of liquid metal Li17Pb83 magnetogydrodynamic (MHD) pressure drop in the blanket for the FDS have been presented to evaluate the significance of MHD effects on the thermal-hydraulic design of the blanket.To decrease the liquid metal MHD pressure drop,Al2O3 is applied as an electronically insulated coating onto the inner surface of the ducts.The requirement for the insulated coating to reduce the additional leakage pressure drop caused by coating imperfections has been analyzed.Finally,the total liquid metal MHD pressure drop and magnetic pump power in the FDS blanket have been given.     

液态铅铋共晶合金中纳米颗粒的热泳运动研究

采用液体中的固体颗粒热泳理论,对铅铋共晶合金(LBE)中金属纳米颗粒的热泳现象进行研究。计算LBE中不同种类纳米颗粒的热泳速度,并观察不锈钢纳米颗粒在不同流体中的热泳速度。对LBE中不同种类纳米颗粒热泳速度的计算结果表明,LBE中纳米颗粒的热泳速度随着温度梯度的增加而增加,随粒径的减小而增加;不锈钢颗粒的热泳速度要比碳纳米管颗粒低两个量级,与铜纳米颗粒的热泳速度相近。对不锈钢纳米颗粒在不同流体中热泳速度的计算结果表明,不锈钢颗粒在LBE中的热泳速度要比在水和四氟乙烷中低1个量级,比在机油和乙基乙二醇中高2个量级。     

液态铅铋共晶合金中纳米颗粒的热泳运动研究

采用液体中的固体颗粒热泳理论,对铅铋共晶合金(LBE)中金属纳米颗粒的热泳现象进行研究。计算LBE中不同种类纳米颗粒的热泳速度,并观察不锈钢纳米颗粒在不同流体中的热泳速度。对LBE中不同种类纳米颗粒热泳速度的计算结果表明,LBE中纳米颗粒的热泳速度随着温度梯度的增加而增加,随粒径的减小而增加;不锈钢颗粒的热泳速度要比碳纳米管颗粒低两个量级,与铜纳米颗粒的热泳速度相近。对不锈钢纳米颗粒在不同流体中热泳速度的计算结果表明,不锈钢颗粒在LBE中的热泳速度要比在水和四氟乙烷中低1个量级,比在机油和乙基乙二醇中高2个量级。