采用雷诺平均的Navier-Stokes方程,对接网格技术和TRIP（TRI sonic Platform）软件,数值模拟了CT-1标模大迎角静态气动特性。来流马赫数0.5,迎角0°～100°,侧滑角0°和5°,在与1.2 m跨声速风洞试验结果对比的基础上,...采用雷诺平均的Navier-Stokes方程,对接网格技术和TRIP（TRI sonic Platform）软件,数值模拟了CT-1标模大迎角静态气动特性。来流马赫数0.5,迎角0°～100°,侧滑角0°和5°,在与1.2 m跨声速风洞试验结果对比的基础上,重点讨论了对流项离散方法、湍流模型、远场距离和不同尾部处理形式对CT-1标模大迎角静态气动特性影响。研究结果表明,不同尾部处理形式对大迎角静态气动特性数值模拟结果影响显著,模拟试验的尾部支杆是对比大迎角静态测力试验结果与计算结果的基本要求。展开更多
The coordination correctness of Nuclear power plant current transformer (CT)/ voltage transformer (PT) polarity and relay protection is often verified through the dynamic test on the unit no load / load operating cond...The coordination correctness of Nuclear power plant current transformer (CT)/ voltage transformer (PT) polarity and relay protection is often verified through the dynamic test on the unit no load / load operating conditions. This paper proposes a test method to prevent and circumvent the failure of the dynamic test abnormality caused by the static power test before the plant power is applied and the whole group is started. Reduce the dynamic test workload and test difficulty, to ensure that the dynamic test safety risk control and control in the state.展开更多
The construction of modern livable cities faces challenges in karst areas,including ground collapse and engineering problems.Wuhan,with a population of 13.74×10^(6) and approximately 1161 km^(2)of soluble rocks i...The construction of modern livable cities faces challenges in karst areas,including ground collapse and engineering problems.Wuhan,with a population of 13.74×10^(6) and approximately 1161 km^(2)of soluble rocks in the urban area of 8569.15 km^(2),predominantly consists of concealed karst areas where occasional ground collapse events occur,posing significant threats to underground engineering projects.To address these challenges,a comprehensive geological survey was conducted in Wuhan,focusing on major karstrelated issues.Geophysical methods offer advantages over drilling in detecting concealed karst areas due to their efficiency,non-destructiveness,and flexibility.This paper reviewed the karst geological characteristics in Wuhan and the geophysical exploration methods for karst,selected eight effective geophysical methods for field experimentation,evaluated their suitability,and proposed method combinations for different karst scenarios.The results show that different geophysical methods have varying applicability for karst detection in Wuhan,and combining multiple methods enhances detection effectiveness.The specific recommendations for method combinations provided in this study serve as a valuable reference for karst detection in Wuhan.展开更多
文摘采用雷诺平均的Navier-Stokes方程,对接网格技术和TRIP（TRI sonic Platform）软件,数值模拟了CT-1标模大迎角静态气动特性。来流马赫数0.5,迎角0°～100°,侧滑角0°和5°,在与1.2 m跨声速风洞试验结果对比的基础上,重点讨论了对流项离散方法、湍流模型、远场距离和不同尾部处理形式对CT-1标模大迎角静态气动特性影响。研究结果表明,不同尾部处理形式对大迎角静态气动特性数值模拟结果影响显著,模拟试验的尾部支杆是对比大迎角静态测力试验结果与计算结果的基本要求。
文摘The coordination correctness of Nuclear power plant current transformer (CT)/ voltage transformer (PT) polarity and relay protection is often verified through the dynamic test on the unit no load / load operating conditions. This paper proposes a test method to prevent and circumvent the failure of the dynamic test abnormality caused by the static power test before the plant power is applied and the whole group is started. Reduce the dynamic test workload and test difficulty, to ensure that the dynamic test safety risk control and control in the state.
基金jointly supported by the project of Chinese National Natural Science Foundation(42107485)National Key R&D Program(2020YFC1512400,2018YFC800804)China Geological Survey(DD20190282,DD20221734,and DD20230323)。
文摘The construction of modern livable cities faces challenges in karst areas,including ground collapse and engineering problems.Wuhan,with a population of 13.74×10^(6) and approximately 1161 km^(2)of soluble rocks in the urban area of 8569.15 km^(2),predominantly consists of concealed karst areas where occasional ground collapse events occur,posing significant threats to underground engineering projects.To address these challenges,a comprehensive geological survey was conducted in Wuhan,focusing on major karstrelated issues.Geophysical methods offer advantages over drilling in detecting concealed karst areas due to their efficiency,non-destructiveness,and flexibility.This paper reviewed the karst geological characteristics in Wuhan and the geophysical exploration methods for karst,selected eight effective geophysical methods for field experimentation,evaluated their suitability,and proposed method combinations for different karst scenarios.The results show that different geophysical methods have varying applicability for karst detection in Wuhan,and combining multiple methods enhances detection effectiveness.The specific recommendations for method combinations provided in this study serve as a valuable reference for karst detection in Wuhan.
文摘介绍了碳纳米管(Carbon Nano Tube, CNT)冷阴极X射线源及分布式X射线源的概念、构成和发展历史,总结了CNT冷阴极的3个特点:(1)结构简单、体积小,易于高密度集成;(2)常温工作、控制简单且无热管理问题;(3)阴极电流和工作寿命达到应用需求。详细介绍了国内外冷阴极分布式X射线源的研究进展情况。国外多个单位的CNT冷阴极分布式X射线源、医疗静态三维成像系统及静态安检CT;国内的研究和应用已处于领先地位,实现了焦点数量从7个增加到256个,阳极工作电流从7 mA提高到50 mA,阳极电压最高200 kV。工作寿命达数万小时的CNT冷阴极分布式X射线源已产品化,且已在安检、工业和医疗领域取得了积极的应用:安检静态CT检测通道尺寸超过1 m,检测速度已经达到1.5 m/s,通过中国民航和欧洲民航会议(European Civil Aviation Conference, ECAC)最高等级3.1的认证,已投入运行近百套;高速工业CT可实现10 f/s的高速成像,在高速流场分析、烧蚀过程分析及运动疲劳分析等过程分析中发挥重要作用;牙科3D成像设备获得美国食品药物管理局(Food and Drug Administration, FDA)认证并销售近百套;移动式胸部层析成像在北美放射学年会(Radiological Society of North America, RSNA)获得较高关注度。随着CNT冷阴极分布式X射线源的技术特性日益清晰,静态三维成像系统技术的优势得到验证,国际知名企业纷纷加入研究队伍,标志着该项技术及应用即将步入快速发展阶段。
