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ITER聚变装置在运行过程中会产生大量的灰尘,当发生事故冷却水进入时,与热的灰尘发生反应产生氢气。氢气聚集后可能会燃烧甚至爆炸,对装置产生破坏。运用CFD的方法对“Wet Bypass”事故后反应产生的氢气风险进行了分析评价,得出在事故的初始阶段氢气达到了燃爆的风险,不同流量的冷却水泄漏进入真空室内会带来不同的氢气风险强度,在冷却水进入量十分大的情况下会惰化灰尘产生的氢气风险。并对注入二氧化碳惰化真空室气体空间的措施进行了分析,在事故发生的初期以较大速率充入二氧化碳能够降低氢气带来的风险。     

空调器焓差实验室节能的实验研究

在焓差实验室的室内侧增加一个热回收装置,利用高温高压制冷剂气体对空气经行加热,减少电加热及电加湿;室外侧采用热气旁通,使蒸发温度控制在一个合适的范围内,减少加湿量,达到节能目的。     

A rapid and simple method for determination of halothane, isoflurane and sevoflurane in blood using gas chromatography

We have developed a technique to determine the concentration of volatile anesthetics (halothane, isoflurane and sevoflurane) in blood that is a modification of a method used for volatile anesthetics in Krebs solution. Methylene chloride was the internal standard and chloroform was used to extract the volatile anesthetic from blood. The congealed blood proteins were separated from the chloroform solvent (containing anesthetic) using a two-compartment vial that filtered out the proteinaceous material during centrifuging. Recovery averaged 102%. Linearity was excellent (r = 0.992-0.999) in the 50-600, 50-300 and 50-300 microg/mL range for halothane, isoflurane and sevoflurane, respectively. Intra-day and inter-day precisions were likewise excellent, with relative standard deviations <5.3 and <7.1%, respectively. Accuracy ranged from 0.8 to 9.5% of the estimated theoretical value. Extracted anesthetic in chloroform solvent was stable over 4-5 days, with <3% variability. The time from obtaining the blood sample to determination of the concentration from the chromatographic peak was 15 min or less.     

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利用有限元仿真软件ANSYS Workbench,结合反应谱法对ITER极向场变流器外旁通设备进行了地震分析。具体分析了在ITER提供的设计地震频谱下,外旁通结构所受的最大等效应力、方向位移以及固定支撑位置的反作用力。分析结果表明,外旁通最大等效应力不超过8.3MPa,最大方向位移不超过2.6mm。以上数据表明,外旁通结构能够满足抗震要求。     

各向异性光折变光开关的原理

提出了利用光折变的各向异性衍射特性在单块LiNbO3 晶体中建立光折变 2× 2开关组件的方案。为减少记录的各光折变全息组件之间的串扰 ,采用局域热固定。基于衍射效率公式 ,分析最佳衍射效率时入射光强比和写入角之间的关系。所建立的光开关具有小型化和垂直的输入 /输出的特点。     

Numerical investigation of hemodynamics at an end‐to‐side junction with a laterally diffused bypass graft

Intimal hyperplasia (IH) at arterial bypass graft is a major factor responsible for graft failure. Several techniques are used to explain IH formation at the end‐to‐side anastomosis junction. Abnormal hemodynamics contributing to the development of disease at the junction is the one of most common theories. This study describes a means of modifying the area of bypass graft at the junction part. This procedure, called the laterally diffused bypass graft (LDBG), is able to alter the hemodynamics in the end‐to‐side anastomosis. The LDBG model, due to an expansion of the outer curvature in the graft, reduces the velocity on the artery bed, side and top junction walls. The recirculation with velocity vectors on the host artery is significantly altered near the heel region on the host artery. Wall shear stress is decreased by up to 34% on the floor of artery centerline at the peak systole and by 61.9% on the top junction of artery during the systole deceleration. Corresponding time‐averaged wall shear stresses are found to decrease by 40.5%. Secondary flow is observed to be decreased significantly at the distal junction. Copyright © 2008 John Wiley & Sons, Ltd.     

大温差离心机组低负荷运行防喘振策略分析

稳态强磁场实验装置水蓄冷系统是国内外具有代表性的大流量大温差水蓄冷系统之一. 系统包含两个3000 m3 的蓄水罐, 为提升蓄冷量双罐均采用了自然分层技术. 由于该技术的特性, 在蓄冷后期, 离心式冷水机组的入口水温会偏低, 这导致系统新增的12 ℃ 大温差机组在试运行阶段多发低负荷喘振故障, 影响了制冷运行的稳定度. 本文首先对离心式冷水机组的喘振机理进行了阐述, 进而分析了在改造前针对该台冷水机组所做的防喘振优化措施; 通过热气旁通改造结合相关参数的合理设置, 避免机组喘振风险; 通过优化 DDC 控制, 优化机组减载能力, 避免了低负荷振动及噪声. 本次改造为系统的安全稳定运行提供了保障.     

自由来流扰动引起的旁路转捩研究进展

本文回顾了自由来流扰动引起的边界层旁路转捩研究进展, 所讨论的自由来流扰动包含高湍流度自由来流和尾迹两大类. 首先介绍旁路转捩的定义、途经及其与规则转捩的区别; 继而讨论高湍流度自由来流引起旁路转捩的路径和机理, 涵盖感受性、瞬态增长、湍流斑、条带稳定性等旁路转捩的主要环节. 在此基础上介绍了尾迹引起旁路转捩的研究现状, 包括对流尾迹和大尺度钝体尾涡两种尾迹形式, 分析了转捩路径及机理, 最后给出研究展望.      

ITER极向场变流器外旁通设备地震分析

利用有限元仿真软件ANSYS Workbench,结合反应谱法对ITER极向场变流器外旁通设备进行了地震分析。具体分析了在ITER提供的设计地震频谱下,外旁通结构所受的最大等效应力、方向位移以及固定支撑位置的反作用力。分析结果表明,外旁通最大等效应力不超过8.3MPa,最大方向位移不超过2.6mm。以上数据表明,外旁通结构能够满足抗震要求。     

涡轮内外涵联立数值模拟

本文对内涵高低压三级涡轮、涡轮出口支板通道、外涵通道以及内外涵混合段流动进行联立计算,给出了流场结构和流动分析。结果表明:联立数值模拟十分必要,是考察多部件匹配特性的有效手段。数值模拟的结果还表明:涡轮与支板的匹配不太理想,但气体通过支板后,仍能够接近轴向出气;混合段内外涵流动掺混作用并不强烈,由于掺混带来的气动损失并不严重。