这项工作得到了韩国国家研究基金会 (NRF) 资助的韩国政府 (MSIP: 科学、信息和通信技术和未来规划部) (No。NRF-2016M2B2A9911771)。

1. 实验程序 4 , 5 , 6 <ol> 准备步骤 <li> <ol> 检查实验设备。在测试矩阵的基础上, 仔细检查测试矩阵的测试条件, 如失水事故的大小, SBL 大小, 虹吸断路器的类型, 和存在的孔口, 在实验之前。此外, 测试, 以确认仪器和设备的组件工作正常, 没有数据噪音或故障. </li>
		<li> 使用安装在下部水箱中的回流泵将上部水箱装入水中. </li>
		<li> 卸下 SBL 内的剩余空气。使用真空泵和缓冲室去除 SBL 的残余空气. </li>
		<li> 检查上部水箱的初始水位。用附在油箱上的尺子. </li>
	</ol> </li> <li> 测试步骤 <ol> <li> 在管道系统的末尾打开阀门. </li>
		<li> 在控制室采用数据采集系统, 在虹吸破断现象期间, 检查测量数据, 如水位、流量、压力变化。如果没有流出的冷却剂, 第一个实验结束。最后, 用给定的测试条件记录所获得的实验结果. </li>
	</ol> </li> <li> 更改测试变量 (SBL 大小、失水事故大小、孔口存在和失水事故位置), 如下所示。
	<ol> <li> 将 SBL 的大小依次更改为2、2.5、3、4、5和 6; 给定的 SBL 在 图 2 中, 在位置2的法兰处连接到主管道. 
		注: 使用螺栓和螺母的法兰接头, 改变了实验变量, 如 SBL 尺寸、失水大小和孔板的存在。因此, 这些过程是手动进行的. </li>
		<li> 重复步骤 1.1.1 1.2.2 直到完成所有 SBL 大小的实验. </li>
		<li> 在位置为1的失水事故中, 将失水事故的大小依次更改为6、8、10、12、14和16英寸; 给定的减速器通过法兰接头连接到主管道上3位置 图 2 . </li>
		<li> 重复步骤 1.1.1-1.3.2 直到所有失水事故大小的实验完成. </li>
		<li> 安装通过上部水箱底部的法兰接头连接到主管道的孔板 (或卸下孔) 
		注: 前一步的实验是在孔口没有 (或存在) 的情况下进行的。因此, 应安装 (或删除) 的孔板下一次试验。
		<ol> <li> 要执行此工作, 请确保上部水箱中没有水. </li>
		</ol> </li> <li> 重复步骤 1.1.1-1.3.4。为了确认 SBL 和失水事故的影响, 在孔的存在 (或缺席), 重复上一步. </li>
		<li> 将失水事故更改为位置 2, 因为前一步的实验已经在失水事故位置1进行。更改下一次试验的失水位置. 
		注: 在实验装置中, 构造了两个失水位置。每个失水管道与一个隔离蝶阀连接到一个主管道系统。
		<ol> <li> 要更改失水事故的位置, 请关闭位于失水位置1处的隔离蝶阀, 然后在失水事故位置打开阀门 2. </li>
		</ol> </li> <li> 重复步骤 1.1.1-1.3.6. </li>
	</ol> </li> </ol> 2。运行模拟程序 <ol> <li> 单击程序图标以执行虹吸式断路器模拟程序. 
	注意: 该过程在 补充视频 1 中演示。如图所示, 模拟程序的初始屏幕由4按钮 (显示参数、运行、手动和退出) 组成。当用户单击 #39; 显示参数和 #39; 按钮时, 将打开一个新的命令窗口, 其中包含参数列表。用户可以修改和确认变量的数值。#39; 运行和 #39; 按钮通过将输入参数替换为包含的公式来执行计算。#39; 手动和 #39; 按钮用于通知使用和程序版本, 以及 #39; 退出和 #39; 按钮关闭程序。结果显示在和 #39; 显示结果和 #39; 窗口. </li>
	<li> 单击 #34; 显示参数和 #34; 按钮. </li>
	<li> 考虑到给定的模拟条件, 更改输入数据. </li>
	<li> 单击 #34; 运行和 #34; 按钮. </li>
	<li> 检查 #39 中的水位图形状; 显示结果和 #39; 窗口。程序按时间组织结果值, 并自动绘制图形。
	<ol> <li> 通过图形的形状, 直观地确认虹吸破碎的可能性; 如果水位或低于高度始终具有相同的值, 直到最终, 在给定的条件下, 虹吸断裂是可能的。请参见 图 3 . </li>
	</ol> </li> <li> 检查和 #39 中的其他输出; 显示结果和 #39; 窗口。请注意, 有八选项 (水位、低于高度、压力、流速、风速、two-phase 混合速度、数量和摩擦力) 来检查输出。使用复选框选择图形类型. 
	注意: 通过图可以看出每个值随时间变化的情况, 容易掌握虹吸式破碎现象. </li>
	<li> 根据时间单击和 #34 确定输出的特定值; 在特定时间和 #34 中计算; 按钮。输入所需的时间并根据设定的时间检查结果. </li>
	<li> 通过单击 #34 保存所有模拟结果数据; 保存数据和 #34; 按钮. 
	注意: 结果以文本文件的形式保存, 并将模拟条件保存在一起. </li>
</ol>

<ol>
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作者没有什么可透露的。

虹吸断路器是一种被动操作的安全装置, 用于防止管道破裂事故发生时的冷却液损失。然而, 这是很难适用于当代研究反应堆, 因为没有实验的实际规模的研究反应堆。因此, 实际的实验是由 POSTECH 和 KAERI 进行的。试验的目的是确定虹吸破断在实际规模上是可行的, 并确定影响虹吸破碎的因素。实验结果表明, 失水的大小和 SBL 大小是影响低于的主要因素。
虹吸破碎的计算过于复杂, 因为有许多参数需要考虑。以往的研究没有提出一个令人满意的理论模型的虹吸断裂。为此, 从实际的虹吸式破碎机实验结果, 建立了一个能分析实际虹吸破断现象的理论模型。理论模型基于流体力学和 two-phase 流的奇泽姆模型。从伯努利方程出发, 可以推导出流动速度。此外, 还可以从考虑 two-phase 流动的理论模型计算出其他重要变量, 如容积流速、水位和低于高度。
然后, 在理论模型的基础上开发了一个仿真程序。将仿真结果与实验结果进行了比较, 表明该理论模型能较好地分析实际虹吸破断现象。仿真结果可作为判断研究堆对管道破裂事故安全性的依据, 该程序可用于虹吸式断路器的设计。
然而, 新开发的理论模型和仿真程序是从实际规模的实验中发展而来的, 其主管尺寸为16。为了验证模拟程序在不同尺度上的适用性, 我们正在为小型虹吸式断路器试验准备一个新的实验装置, 小型化以前的实际规模实验设施。将考虑广泛的 C 因子和奇泽姆系数 B, 包括现有实验的范围。

使用板式燃料的反应堆的数量, 如约旦研究和训练反应堆 (JRTR) 和 KiJang 研究反应堆 (KJRR), 最近有所增加。为了方便地连接板式燃料 , 研究堆需要一个核心向动。由于研究反应堆需要主冷却系统的净正吸头, 一些冷却系统组件可能会安装在反应堆下面。然而, 如果管道破裂发生在反应堆下面的主冷却系统中, 虹吸效应会导致冷却剂的连续排水, 从而导致反应堆暴露在空气中。这意味着残余的热量不能被去除, 这可能导致严重的事故。因此, 在发生冷却剂事故时, 必须有防止发生严重事故的安全装置。虹吸式断路器是一种安全装置。它能有效地防止水的抽放, 利用空气的涌流。整个系统称为虹吸破碎系统。
对改进研究堆安全性进行了若干研究。麦当劳和貂1进行了一次实验, 以确认虹吸式破碎阀作为一个主动断路器的性能。尼尔和斯蒂芬斯2在小型管道中使用虹吸断路器作为被动操作装置进行了实验。樱井3提出了一个分析模型, 用于分析在完全分离的水下水流模型下的虹吸断裂。
虹吸破碎是非常复杂的, 因为有许多参数需要考虑。此外, 由于实际研究反应堆的实验尚未进行, 因此很难将以往的研究应用于当代的研究反应堆。因此, 以往的研究没有提出一个令人满意的理论模型的虹吸断裂。为此, 进行了实际实验, 建立了理论模型。
为探讨虹吸式断路器对研究堆的影响, 由浦科技大学 (POSTECH) 和韩国原子能研究所 (KAERI)4,5 进行了实际规模验证实验. ,6。图 1是虹吸断路器试验的实际设备。图 2显示了设施的示意图, 其中包括设施标记。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/55972/55972fig1.jpg"> 
图1。虹吸式破碎示范试验装置.主要管道尺寸为 16, 并安装一个亚克力窗口进行观察。该孔是一种用来描述压降的装置。因此, 在上部水箱的底部有一个孔组件。<a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55972/55972fig1large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/55972/55972fig2.jpg"> 
图2。实验装置的原理图.给出了测量点的位置。这些数字表明这些有关地点;点0表示虹吸断路器的入口, 点1表示水位, 点2表示虹吸断路器和主管道的连接部分, 点3表示失水位置。<a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55972/55972fig2large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
虹吸断路器试验装置由上罐、下罐、管路系统和回流泵组成。上部坦克的容量是 57.6 m3。底部区域和深度分别为 14.4 m2 (4 m x 3.6 m) 和 4 m。较低的油箱和失水事故的位置位于8.3 米以下的上部坦克。下槽容量为 70 m3。在实验中, 较低的水箱被用来储存水。下油箱与回流泵相连。下部水箱中的水被泵入上层水箱。管道系统的主要管道尺寸为16。虹吸断路器 (SBL) 的末端位于11.6 米高的低管断裂点之上。此外, 在管道上安装了亚克力窗口以进行可视化, 如图 1所示。
安装了几个设备来测量物理信号。使用了两个绝对压力传感器 (APTs) 和三差压传感器 (DPTs)。为了测量水质量流量, 采用了超声波流量计。数据采集系统被用来获取所有的测量数据在250毫秒的时间间隔。除了测量设备外, 还安装了摄像头进行观察, 并在上部水箱的内壁上附一把尺子, 以检查水位。
试验中考虑了各种失水事故和虹吸断路器 (SB) 的尺寸、虹吸开关类型 (线/孔) 以及反应器燃料和管路破裂点的存在。为了验证失水和 SBL 大小的影响, 采用了不同大小的失水和 SBL。失水事故的大小从6到 16, SBL 的大小从2到6不等。在实验中, 采用了虹吸式断路器的线型和孔型, 但本研究的以下内容只考虑了 JRTR 和 KJRR 中使用的 SBL 型。作为实验结果的一个例子,图 3是一个包含压力和水流速率数据的图。实验于2013年10月4日进行, 实验数据样本为 LN23 (线型 SB, 无孔, 12 失水, 2.5 SBL)。
通过实验数据, 建立了能预测虹吸破断现象的理论模型。理论模型以伯努利方程开始。从伯努利方程得到流体的流速, 通过将流体的流速乘以管道面积, 可以得到容积流速。此外, 还可以利用容积流速来获得水位。理论模型的基本概念如下。然而, 由于虹吸破碎现象是一个 two-phase 的流动, 有额外的点需要考虑。为了考虑 two-phase 流分析模型, 进行了精度验证试验。由于奇泽姆模型比均质模型更精确, 因此采用奇泽姆模型对该现象进行分析。根据奇泽姆模型, two-phase 乘数公式表示为公式 17。在这个等式, ф代表 two-phase 乘数, ρ代表密度, 并且 X 代表质量。
<img alt="Equation 1" src="/files/ftp_upload/55972/55972eq1.jpg">(1)
p 类 = "jove_content" > 在奇泽姆模型中, 包含了随质量流变化的系数 B。最后, 推导了奇泽姆系数 B 与反应器设计条件之间的相关公式, 是理论模型的一个重要观点。换言之, 实验的另一个目的是获取数据, 以确定设计条件与奇泽姆系数 B 之间的关系。从试验结果出发, 建立了设计条件与奇泽姆系数 B 之间的相关公式。由此建立的理论模型可以较好地预测虹吸断裂现象。
此外, 还开发了一个具有图形用户界面 (GUI) 的仿真程序。通过在图 3中绝对压力数据的转换, 可以将此现象划分为三阶段: 冷却剂的损耗 (单相流动)、虹吸断裂 (两相流) 和稳态。因此, 该算法的主要计算过程包括一个与实际现象的三阶段相对应的三步过程。包括计算过程中, 描述模拟过程的整个算法如图 48所示。
使用该软件 (请参见补充视频 1) 开始模拟, 用户输入与设计条件相对应的输入法参数, 输入参数存储为固定值。如果用户在输入参数后进行模拟, 程序将执行第一步计算。第一步是单相计算, 即在管道破裂后, 由于虹吸效应造成的冷却剂损失的计算。这些变量由理论模型 (如伯努利方程、质量流保存、等) 自动计算, 并从用户输入的参数中进行计算。计算结果按用户指定的时间单位依次存储在计算机存储器中。
如果水位下降低于位置 0, 这意味着单相流动的结束, 因为空气开始冲进 SBL 在这一刻。因此, 单相流动的第一步, 直到水位达到0位。当水位处于0位时, 这意味着低于高度为零。低于高度是 SBL 的入口与虹吸断裂后上部水箱水位的高度差。换言之, 低于高度表明在虹吸破断过程中水位下降的幅度。因此, 低于高度是一个重要的参数, 因为它将允许直接确定的数量的冷却剂损失。因此, 该程序根据低于高度确定第一步计算的结束。
如果低于高度大于零, 程序执行第二步计算, 可以模拟 two-phase 流。由于虹吸破碎阶段存在水和气流, 因此必须考虑两种流体的物理性质。因此, 在这个计算步骤中考虑了 two-phase 乘数、质量和空隙率的值。特别地, 用空分式值作为第二步计算的结束判据。空隙率可表示为空气流量与空气和水流之和的比值。第二步演算继续, 直到空隙分数 (α) 价值是0.9。当α超过 0.9, 第三步演算收益描述稳定状态。从理论上讲, 虹吸断裂的结束判据是α = 1, 因为此时管道中只有空气存在。然而, 在这个程序中, 虹吸断裂的最终标准是α = 0.9, 以避免在计算过程中出现任何错误。因此, 部分损失的结果是不可避免的, 但这个错误可以忽略不计。
稳定状态计算在用户设置的时间内进行。由于没有进一步的变化, 稳态的特点是计算结果值总是恒定的。如果虹吸断裂是成功的, 最后水平的水在上部坦克将保持在一个特定的值, 而不是零。然而, 如果虹吸断裂没有成功地执行, 冷却剂将几乎丢失, 并且水的最后水平接近零价值。因此, 如果水位值等于零, 则表明给定的设计条件不足以完成虹吸破断。
计算后, 用户可以通过各种方式确认结果。结果表明, 虹吸破碎、虹吸破碎、奇异性等情况。该仿真程序能够对这一现象进行真实的预测和分析, 并有助于虹吸式断路器系统的设计。本文介绍了实验方案、实验结果和仿真程序的应用。

<table>
	<tbody>
		<tr>
			<td>Absolute pressure transducer</td>
			<td>Sensor Technics</td>
			<td>CTE9000</td>
			<td>0.05% full-scale error</td>
		</tr>
		<tr>
			<td>Differential pressure transducer</td>
			<td>Setra</td>
			<td>C230</td>
			<td>0.25% full-scale error</td>
		</tr>
		<tr>
			<td>Ultrasonic flow meter</td>
			<td>Tokyo Keiki</td>
			<td>UFP-20</td>
			<td>Resolution 0.01m^3/h</td>
		</tr>
		<tr>
			<td>Visual Studio 2012</td>
			<td>Microsoft</td>
			<td>Windows 8</td>
			<td>Microsoft Foundation Class</td>
		</tr>
		<tr>
			<td>E.R.W. steel pipe</td>
			<td>Hyundai Hysco</td>
			<td>KS D 3507(SPP)</td>
			<td>400A(out dia.) x 7.9mm(thickness)</td>
		</tr>
	</tbody>
</table>

study of siphon breaker experiment and simulation for a research reactor

在研究堆的设计条件下, 管道破裂引起的虹吸现象会导致水的持续向外流动。为了防止这种外流, 需要一个控制装置。虹吸式断路器是一种安全装置, 可以有效地控制冷却水的损失。
为了分析虹吸破碎的特点, 进行了实际的实验研究。从实验结果中发现, 影响虹吸破碎现象的设计因素有多种。因此, 在各种设计条件下, 有必要建立一个能够预测和分析虹吸断裂现象的理论模型。利用实验数据, 可以建立一个准确预测虹吸破断现象的进展和结果的理论模型。建立的理论模型以流体力学为基础, 采用奇泽姆模型对 two-phase 流进行分析。从伯努利方程出发, 可以求得或计算 two-phase 流的速度、数量、低于高度、水位、压力、摩擦系数和相关因素。此外, 为了利用本研究所建立的模型, 研制了虹吸式断路器分析与设计方案。仿真程序在理论模型的基础上运行, 并以图的形式返回结果。用户可以通过检查图形的形状来确认虹吸断裂的可能性。此外, 整个仿真结果的保存是可行的, 可以作为分析实际虹吸破碎系统的一种资源。
最后, 使用本研究开发的程序, 用户可以确定虹吸式破碎机的状态, 设计虹吸式破碎机系统。

虹吸破碎的全过程由三阶段组成。第一阶段是由于虹吸效应而流出的冷却剂。第二阶段是通过 SBL 来启动空气流入的过程, 以阻止冷却剂的流失, 称为虹吸破碎。在图 3中, 虹吸断裂现象可以看作是绝对压力的急剧增加。在绝对压力急剧增加后, 由于水位下降而逐渐减少。在虹吸结束时, 由于一些残余水回流到上部水箱, 绝对压力再次增加。如果虹吸破碎完成, 没有进一步泄漏的冷却剂和这个状态称为 ' 稳态 '。由于没有进一步的状态变化, 绝对压力也保持恒定。在第一阶段保持高值的流速随着虹吸断裂开始逐渐减小。当虹吸破断成功完成时, 冷却剂泄漏逐渐减少并停止, 如视频 1所示。在图 3中的差压显示, 在虹吸破断开始后, 趋势会稳步增加。
如果在没有虹吸断路器的情况下发生管道破裂, 所有的冷却剂都会因虹吸效应而泄漏。描述无虹吸断路器的实验显示在视频 2中 (XN; 没有虹吸式破碎机)。另一方面,视频 3 (LN; 线型虹吸式断路器) 和视频 4 (孔型虹吸式破碎机) 表明, 虹吸破碎机有效地防止了冷却剂的损失。在这两种情况下, 确认冷却液不会在一定的水位下泄漏。因此, 实验表明, 虹吸断路器可以是一个可行的装置, 以防止损失的冷却剂。
此外, 从实验结果可以确定奇泽姆系数与设计条件之间的关系。首先, 为了反映实验条件, 进行了压损系数微调的过程。在调整压力损失系数后, 通过试验和误差法推导出奇泽姆系数 B。由于在确定奇泽姆系数 B 的值时应考虑空气和水的质量流量, 因此有必要对质量流量进行定量评价。该判据是利用气流流速系数和水的质量流量来推导的。该判据被称为 C 因子, 用于确定与奇泽姆系数 B 的关系。所提出的 C 因子公式由公式 2和空气流速系数是由公式 39,10给出。在下面的公式中, ρ表示密度, 而 K02表示位置0和位置2之间的压力损失系数。由于密度和公式 3中的数字 "2" 是常量, 因此可以消除它们。因此, 简化的空气流速系数类型被称为方程式 2中的 F 因子。还应评估水的质量流量;随着失水面积的增加, 它会增加, 但同时也会增加。因此, 不同失水量大小的质量流量除以面积来求得单位面积的质量流量。这里, 在空气进入管道前计算质量流量值。
<img alt="Equation 2" src="/files/ftp_upload/55972/55972eq2.jpg">(2)
<img alt="Equation 3" src="/files/ftp_upload/55972/55972eq3.jpg">(3)
为了找出奇泽姆系数 B 和 C 因子之间的关系, 采用回归分析法。结果, 可以导出两种类型的相关公式 (指数函数和二次函数), R2值为 0.93 (指数型) 和 0.97 (二次函数)。每个函数都作为公式 4和公式 59提供。公式 4能够很好地预测较大的失水事故, 如12和16的失水事故的大小。另一方面,公式 5能够很好地预测失水事故的相对较小的大小, 如8和10的失水事故的大小。因此, 指数函数用于预测大于11的失水事故的相对较大的大小, 而二次函数用于小于11的。
<img alt="Equation 4" src="/files/ftp_upload/55972/55972eq4.jpg">(4)
<img alt="Equation 5" src="/files/ftp_upload/55972/55972eq5.jpg">(5)
即, 理论模型的建立是有意义的, 因为从设计条件中推导出奇泽姆系数 B 可以预测虹吸断裂现象。因此, 开发一个包含理论模型的仿真程序, 将有助于分析虹吸断路器的现象和设计。
比较模拟和实验结果的图表如图 5所示。考虑到该图, 仿真程序可以预测实际规模实验所得的结果。不仅低于高度的结果, 而且从模拟程序获得的流量数据显示类似于实验所得的模式。图 6是流率图与在 12 in 和16中的失水事故大小相比所用的时间。然而, 在实验和模拟的开始之间有一些差异。实际上, 在初始阶段的实验流量评估是基于可视化视频, 通过计算 5 s 的下水位, 得到了实验的流量数据。这种方法是一种替代方法, 因为超声波流量计不能准确地测量流量, 才能充分发展。实验和模拟结果之间的差异似乎是由于这一点。除起始阶段外, 模拟流速与实验值相似, 程序根据失水事故的大小准确预测趋势。
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/55972/55972fig3.jpg"> 
图3。实验结果.测量的变量包括水位、低于高度、压力和流速。在结果中, 给出了压力和流量数据。考虑到压力的变化, 该现象大致分为三部分;冷却液损失, 虹吸破碎, 稳定状态。压力e, 在冷却剂部分的损失略有变化, 在虹吸破碎段迅速增加。此外, 在稳定状态下, 压力不会改变。还可以看出, 由于虹吸破碎, 流速逐渐减小。<a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55972/55972fig3large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/55972/55972fig4.jpg"> 
图4。仿真程序的算法.该算法被开发为应用理论模型9。为了反映真实现象, 该算法的主要计算过程由三阶段组成。如果给出了反映设计条件的输入参数, 则为给定的条件自动计算每个阶段。<a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55972/55972fig4large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/55972/55972fig5.jpg"> 
图5。有效性的估计.为了评价仿真结果的准确性, 将低于高度与实验结果进行了比较。仿真结果与实验吻合较好。换言之, 该仿真程序对虹吸断裂的分析具有良好的性能。<a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55972/55972fig5large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/55972/55972fig6.jpg"> 
图6。流率图.模拟 (Sim) 流率与实验 (Exp) 值相似。由于模拟计算可以比较准确地估计流量量, 模拟低于高度和水位值与实验值相似。<a href="//ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55972/55972fig6large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Video 1" src="/files/ftp_upload/55972/55972mov1.jpg"> 
视频1。成功的虹吸破断 (失水事故)。此视频是一个带有虹吸断路器的实验。当蝶阀在失水位置打开时, 冷却剂泄漏出来。然而, 由于虹吸式断路器, 冷却剂泄漏逐渐减少和停止。换言之, 这个视频显示, 虹吸断路器可以防止冷却剂泄漏。<a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55972/Video_1(LOCA).mp4" target="_blank">请单击此处查看此视频。(右键单击可下载.</a>
<img alt="Video 2" src="/files/ftp_upload/55972/55972mov2.jpg"> 
视频2。无虹吸断路器 (XN)。在没有虹吸断路器的情况下, 冷却剂继续流出, 最后, 上部水箱的水位变为零。<a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55972/Video_2(XN).mp4" target="_blank">请单击此处查看此视频。(右键单击可下载.</a>
<img alt="Video 3" src="/files/ftp_upload/55972/55972mov3.jpg"> 
视频3。线式虹吸断路器 (LN).虹吸断路器有效地防止了冷却剂的损失。<a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55972/Video_3(LN).mp4" target="_blank">请单击此处查看此视频。(右键单击可下载.</a>
<img alt="Video 4" src="/files/ftp_upload/55972/55972mov4.jpg"> 
视频4。孔型虹吸式断路器.虹吸断路器有效地防止了冷却剂的损失。<a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55972/Video_4(HN).mp4" target="_blank">请单击此处查看此视频。(右键单击可下载.</a>
<img alt="Video 5" src="/files/ftp_upload/55972/55972mov5.jpg"> 
补充视频1。运行模拟程序。模拟程序的初始屏幕由4按钮 (显示参数、运行、手动和退出) 组成。当用户单击 "显示参数" 按钮时, 将打开一个新的命令窗口, 其中包含参数列表。用户可以修改和确认变量的数值。"Run" 按钮通过将输入参数替换为包含的公式来执行计算。"手动" 是用于通知使用和程序版本的按钮, "退出" 是关闭程序的按钮。结果显示在 "显示结果" 窗口中。<a href="https://ecsource-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/55972/Sup_Video_1(Demonstration).mp4" target="_blank">请单击此处查看此视频。(右键单击可下载.</a>

Watch this Scientific Journal Video about Study of Siphon Breaker Experiment and Simulation for a Research Reactor at JoVE.com

Study of Siphon Breaker Experiment and Simulation for a Research Reactor

对虹吸破断现象进行了实验研究, 并提出了理论模型。建立了基于理论模型的仿真程序, 并与实验结果进行了比较。仿真结果与实验结果吻合较好。

研究堆虹吸断路器试验与仿真研究

Under the design conditions of a research reactor, the siphon phenomenon induced by pipe rupture can cause continuous outward flow of water. To prevent ...

study-siphon-breaker-experiment-simulation-for-research

Nanyang Technological University

Research

JoVE Journal

Engineering

8.6K 次观看.  Handong Global University. 对虹吸破断现象进行了实验研究, 并提出了理论模型。建立了基于理论模型的仿真程序, 并与实验结果进行了比较。仿真结果与实验结果吻合较好。

视频: Study of Siphon Breaker Experiment and Simulation for a Research Reactor

Simulation, Fabrication and Characterization of THz Metamaterial Absorbers

Metamaterials (MM), artificial materials engineered to have properties that may not be found in nature, have been widely explored since the first theoretical1 and experimental demonstration2 of their unique properties. MMs can provide a highly controllable electromagnetic response, and to date have been demonstrated in every technologically relevant spectral range including the optical3, near IR4, mid IR5 , THz6 , mm-wave7 , microwave8 and radio9 bands. Applications include perfect lenses10, sensors11, telecommunications12, invisibility cloaks13 and filters14,15. We have recently developed single band16, dual band17 and broadband18 THz metamaterial absorber devices capable of greater than 80% absorption at the resonance peak. The concept of a MM absorber is especially important at THz frequencies where it is difficult to find strong frequency selective THz absorbers19. In our MM absorber the THz radiation is absorbed in a thickness of ~ &lambda;/20, overcoming the thickness limitation of traditional quarter wavelength absorbers. MM absorbers naturally lend themselves to THz detection applications, such as thermal sensors, and if integrated with suitable THz sources (e.g. QCLs), could lead to compact, highly sensitive, low cost, real time THz imaging systems.

This protocol outlines the simulation, fabrication and characterization of THz metamaterial absorbers. Such absorbers, when coupled with an appropriate sensor, have applications in THz imaging and spectroscopy.

模拟，太赫兹超材料吸收器的制备与表征

Metamaterials (MM),  artificial materials engineered to have properties that may not be found in  nature, have been widely explored since the first ...

科研

工程学

Research and Development of High-performance Explosives

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance tests to verify theoretical calculations. For newly developed formulations, the process begins with small-scale mixes, thermal testing, and impact and friction sensitivity. Only then do subsequent larger scale formulations proceed to detonation testing, which will be covered in this paper. Recent advances in characterization techniques have led to unparalleled precision in the characterization of early-time evolution of detonations. The new technique of Photonic Doppler Velocimetry (PDV) for the measurement of detonation pressure will be shared and compared with traditional fiber-optic detonation velocity and plate-dent calculation of detonation pressure. In particular, the role of aluminum in explosive formulations will be discussed. Recent developments led to the development of explosive formulations that result in reaction of aluminum very early in the detonation product expansion. This enhanced reaction leads to changes in the detonation velocity and pressure due to reaction of the aluminum with oxygen in the expanding gas products.

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance tests to verify theoretical calculations. This paper will share typical development tests associated with the measurement of detonation velocity and detonation pressure.

高性能炸药的研究与发展

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance ...

Detection and Recovery of Palladium, Gold and Cobalt Metals from the Urban Mine Using Novel Sensors/Adsorbents Designated with Nanoscale Wagon-wheel-shaped Pores

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in industrialized countries. Here, the development of optical mesosensors/adsorbents (MSAs) for efficient recognition and selective recovery of Pd(II), Au(III), and Co(II) from urban mine was achieved. A simple, general method for preparing MSAs based on using high-order mesoporous monolithic scaffolds was described. Hierarchical cubic Ia3d wagon-wheel-shaped MSAs were fabricated by anchoring chelating agents (colorants) into three-dimensional pores and micrometric particle surfaces of the mesoporous monolithic scaffolds. Findings show, for the first time, evidence of controlled optical recognition of Pd(II), Au(III), and Co(II) ions and a highly selective system for recovery of Pd(II) ions (up to ~95%) in ores and industrial wastes. Furthermore, the controlled assessment processes described herein involve evaluation of intrinsic properties (e.g., visual signal change, long-term stability, adsorption efficiency, extraordinary sensitivity, selectivity, and reusability); thus, expensive, sophisticated instruments are not required. Results show evidence that MSAs will attract worldwide attention as a promising technological means of recovering and recycling palladium, gold and cobalt metals.

Because of the importance and extensive use of palladium, gold and cobalt metals in high-technology equipment, their recovery and recycling constitute an important industrial challenge. The metal recovery system described herein is a simple, low-cost means for the effective detection, removal, and recovery of these metals from the urban mine.

检测和钯的回收，从城市矿山黄金和钴金属使用标有纳米货车车轮形的孔隙新型传感器/吸附剂

Developing low-cost, efficient processes for recovering and recycling palladium, gold and cobalt metals from urban mine remains a significant challenge in ...

Visualizing Hyporheic Flow Through Bedforms Using Dye Experiments and Simulation

Advective exchange between the pore space of sediments and the overlying water column, called hyporheic exchange in fluvial environments, drives solute transport in rivers and many important biogeochemical processes. To improve understanding of these processes through visual demonstration, we created a hyporheic flow simulation in the multi-agent computer modeling platform NetLogo. The simulation shows virtual tracer flowing through a streambed covered with two-dimensional bedforms. Sediment, flow, and bedform characteristics are used as input variables for the model. We illustrate how these simulations match experimental observations from laboratory flume experiments based on measured input parameters. Dye is injected into the flume sediments to visualize the porewater flow. For comparison virtual tracer particles are placed at the same locations in the simulation. This coupled simulation and lab experiment has been used successfully in undergraduate and graduate laboratories to directly visualize river-porewater interactions and show how physically-based flow simulations can reproduce environmental phenomena. Students took photographs of the bed through the transparent flume walls and compared them to shapes of the dye at the same times in the simulation. This resulted in very similar trends, which allowed the students to better understand both the flow patterns and the mathematical model. The simulations also allow the user to quickly visualize the impact of each input parameter by running multiple simulations. This process can also be used in research applications to illustrate basic processes, relate interfacial fluxes and porewater transport, and support quantitative process-based modeling.

This manuscript describes how to create regular bedforms in a flume, visualize flow through the bedforms, and use computer simulations to simulate the hyporheic flow. The computer simulations compare well with the experimental observations. This coupled simulation and experiment is well-suited for both research and educational purposes.

可视化潜流流通过底形用染料试验及仿真

Advective exchange between the pore space of sediments and the overlying water column, called hyporheic exchange in fluvial environments, drives solute ...

Knowledge Based Cloud FE Simulation of Sheet Metal Forming Processes

The use of Finite Element (FE) simulation software to adequately predict the outcome of sheet metal forming processes is crucial to enhancing the efficiency and lowering the development time of such processes, whilst reducing costs involved in trial-and-error prototyping. Recent focus on the substitution of steel components with aluminum alloy alternatives in the automotive and aerospace sectors has increased the need to simulate the forming behavior of such alloys for ever more complex component geometries. However these alloys, and in particular their high strength variants, exhibit limited formability at room temperature, and high temperature manufacturing technologies have been developed to form them. Consequently, advanced constitutive models are required to reflect the associated temperature and strain rate effects. Simulating such behavior is computationally very expensive using conventional FE simulation techniques.
This paper presents a novel Knowledge Based Cloud FE (KBC-FE) simulation technique that combines advanced material and friction models with conventional FE simulations in an efficient manner thus enhancing the capability of commercial simulation software packages. The application of these methods is demonstrated through two example case studies, namely: the prediction of a material's forming limit under hot stamping conditions, and the tool life prediction under multi-cycle loading conditions.

The following paper presents a novel FE simulation technique (KBC-FE), which reduces computational cost by performing simulations on a cloud computing environment, through the application of individual modules. Moreover, it establishes a seamless collaborative network between world leading scientists, enabling the integration of cutting edge knowledge modules into FE simulations.

板料成形过程的知识基于云的有限元模拟

The use of Finite Element (FE) simulation software to adequately predict the outcome of sheet metal forming processes is crucial to enhancing the ...

3D Printing of Biomolecular Models for Research and Pedagogy

The construction of physical three-dimensional (3D) models of biomolecules can uniquely contribute to the study of the structure-function relationship. 3D structures are most often perceived using the two-dimensional and exclusively visual medium of the computer screen. Converting digital 3D molecular data into real objects enables information to be perceived through an expanded range of human senses, including direct stereoscopic vision, touch, and interaction. Such tangible models facilitate new insights, enable hypothesis testing, and serve as psychological or sensory anchors for conceptual information about the functions of biomolecules. Recent advances in consumer 3D printing technology enable, for the first time, the cost-effective fabrication of high-quality and scientifically accurate models of biomolecules in a variety of molecular representations. However, the optimization of the virtual model and its printing parameters is difficult and time consuming without detailed guidance. Here, we provide a guide on the digital design and physical fabrication of biomolecule models for research and pedagogy using open source or low-cost software and low-cost 3D printers that use fused filament fabrication technology.

Physical models of biomolecules can facilitate an understanding of their structure-function for the researcher, aid in communication between researchers, and serve as an educational tool in pedagogical endeavors. Here, we provide detailed guidance for the 3D printing of accurate models of biomolecules using fused filament fabrication desktop 3D printers.

生物分子模型的3D打印技术的研究与教学

The construction of physical three-dimensional (3D) models of biomolecules can uniquely contribute to the study of the structure-function relationship. 3D ...

Processing of Bulk Nanocrystalline Metals at the US Army Research Laboratory

Given their potential for significant property improvements relative to their large grained counterparts, much work has been devoted to the continued development of nanocrystalline metals. Despite these efforts, the transition of these materials from the lab bench to actual applications has been blocked by the inability to produce large scale parts that retain the desired nanocrystalline microstructures. Following the development of a method proven to stabilize the nanosized grain structure to temperatures approaching that of the melting point for the given metal, the US Army Research Laboratory (ARL) has progressed to the next stage in the development of these materials - namely the production of large scale parts suitable for testing and evaluation in a range of relevant test environments. This report provides a broad overview of the ongoing efforts in the processing, characterization, and consolidation of these materials at ARL. In particular, focus is placed on the methodology used for producing the nanocrystalline metal powders, in both small and large-scale amounts, that are at the center of ongoing research efforts.

This paper provides a brief overview of the ongoing efforts at the Army Research Laboratory on the processing of bulk nanocrystalline metals with an emphasis on the methodologies used for the production of the novel metal powders.

美国陆军研究实验室散装纳米晶金属的加工

Given their potential for significant property improvements relative to their large grained counterparts, much work has been devoted to the continued ...

A 100 KW Class Applied-field Magnetoplasmadynamic Thruster

Applied-field magnetoplasmadynamic thrusters (AF-MPD thrusters) are hybrid accelerators in which electromagnetic and gas dynamic processes accelerate plasma to high speed; they have considerable potential for future space applications with the significant advantages of high specific impulse and thrust density. In this paper, we present a series of protocols for designing and manufacturing a 100 kW class of AF-MPD thruster with water-cooling structures, a 130 V maximum discharge voltage, a 800 A maximum discharge current, and a 0.25 T maximum strength of magnetic field. A hollow tantalum tungsten cathode acts as the only propellant inlet to inhibit the radial discharge, and it is positioned axially at the rear of the anode in order to relieve anode starvation. A cylindrical divergent copper anode is employed to decrease anode power deposition, where the length has been reduced to decrease the wall-plasma connecting area. Experiments utilized a vacuum system that can achieve a working vacuum of 0.01 Pa for a total propellant mass flow rate lower than 40 mg/s and a target thrust stand. The thruster tests were carried out to measure the effects of the working parameters such as propellant flow rates, the discharge current, and the strength of applied magnetic field on the performance and to allow appropriate analysis. The thruster could be operated continuously for significant periods of time with little erosion on the hollow cathode surface. The maximum power of the thruster is 100 kW, and the performance of this water-cooled configuration is comparable with that of thrusters reported in the literature.

The goal of this protocol is to introduce the design of a 100 kW class applied-field magnetoplasmadynamic thruster and relevant experimental methods.

一个100千瓦级的应用场磁等离子体动力学推进器

Applied-field magnetoplasmadynamic thrusters (AF-MPD thrusters) are hybrid accelerators in which electromagnetic and gas dynamic processes accelerate ...

Thermocapillary Convection Space Experiment on the SJ-10 Recoverable Satellite

Thermocapillary convection is an important research subject in microgravity fluid physics. The experimental study on surface waves of thermocapillary convection in an annular liquid pool is one of the 19 scientific experimental projects on the SJ-10 recoverable satellite. Presented is a design for a payload for space experimental study on thermocapillary convection that includes the experimental model, measurement system, and control system. The specifics for the construction of an experimental model of an annular liquid pool with variable volume ratios is provided. The fluid temperatures are recorded by six thermocouples with a high sensitivity of 0.05 &#176;C at different points. The temperature distributions on the liquid free surface are captured by means of an infrared thermal camera. The free surface deformation is detected by a displacement sensor with a high accuracy of 1 &#181;m. The experimental process is fully automated. The research is focused on thermocapillary oscillation phenomena on the liquid-free surface and convective pattern transitions through analyses of experimental data and images. This research will be helpful to understand the mechanism of thermocapillary convection and will offer further insights into the nonlinear characteristics, flow instability, and bifurcation transitions of thermocapillary convection.

A protocol for the space payload design, the space experiment on thermocapillary convection, and analyses of experimental data and images are presented in this paper.

SJ-10可回收卫星的热印对流空间实验

Thermocapillary convection is an important research subject in microgravity fluid physics. The experimental study on surface waves of thermocapillary ...

Optimized Sealing Process and Real-Time Monitoring of Glass-to-Metal Seal Structures

Residual stress is an essential factor to keeping the hermeticity and robustness of a glass-to-metal seal structure. The purpose of this report is to demonstrate a novel protocol to characterize and measure residual stress in a glass-to-metal seal structure without destroying the insulation and hermeticity of sealing materials. In this research, a femto-laser inscribed fiber Bragg grating sensor is used. The glass-to-metal seal structure that is measured consists of a metal shell, sealing glass, and Kovar conductor. To make the measurements worthwhile, the specific heat treatment of metal-to-glass seal (MTGS) structure is explored to obtain the model with best hermeticity. Then, the FBG sensor is embedded into the path of sealing glass and becomes well-fused with the glass as the temperature cools to RT. The Bragg wavelength of FBG shifts with the residual stress generated in sealing the glass. To calculate the residual stress, the relationship between Bragg wavelength shift and strain is applied, and the finite element method is also used to make the results reliable. The online monitoring experiments of residual stress in sealing glass are carried out at different loads, such as high temperature and high pressure, to broaden functions of this protocol in harsh environments.

Key procedures to optimize the sealing process and achieve real-time monitoring of the metal-to-glass seal (MTGS) structure are described in detail. The embedded fiber Bragg grating (FBG) sensor is designed to achieve online monitoring of temperature and high-level residual stress in the MTGS with simultaneous environmental pressure monitoring.

玻璃到金属密封结构的优化密封工艺和实时监控

Residual stress is an essential factor to keeping the hermeticity and robustness of a glass-to-metal seal structure. The purpose of this report is to ...