M100D型主泵一号密封结构原理及常见故障分析

M100D型主泵一号密封因其独特的收敛锥角密封面设计,在密封面之间形成具有一定刚度的液膜,维持一号密封静环组件开启力与闭合力平衡,从而实现可控泄漏。对一号密封常见故障进行分析,研究故障产生的原因及影响因素,并制定相应处理措施,从源头上避免M100D型主泵一号密封泄漏量异常缺陷,也可以适用于其他类型的主泵。

泄压阀对乘客舱通风流量和舱内压强影响的评估

评估了汽车乘客舱泄压阀(PRV)设计对舱内通风流量、舱内压强和舒适性的影响。对乘客舱内流场进行数值模拟,根据数值模拟结果拟合泄压阀开口面积、舱内通风流量和舱内压强的相互影响规律,结合舱内流量和压强试验数据建立了可控泄漏和非可控泄漏等效方案和评估流程,根据数值模拟结果分析了舱内气流状态和途径的过程及其对舒适性的影响。结果表明:泄漏开口面积和乘客舱压强、乘客舱压强和通风流量之间按照二次多项式规律变化;结合舱内通风流量、压强试验数据和乘客舱内流场数值模拟,可以获得较准确的可控泄漏和非可控泄漏开口等效方案。从而,本方法可用于泄压阀设计参考以及乘客舱流动状态和舒适性评估。

主泵轴密封系统设计及SBO试验研究

先进三代核电针对全厂断电(SBO)事故工况下,对主泵轴密封系统提出新的技术要求。为了确保主泵轴密封系统的安全可靠性,核主泵供应商采用纵深防御的设计理念,开发了新型的主泵轴密封系统以及非能动热控制阀。简要介绍了轴密封系统的冗余安全设计理念及轴密封系统和非能动热控制阀PTCV在模拟SBO工况下的试验结果,通过研究,表明了主泵轴密封系统及非能动热控制阀PTCV在SBO工况下的安全可靠性,满足三代核电新的技术要求。

Low-leakage diode-triggered silicon controlled rectifier for electrostatic discharge protection in 0.18-μm CMOS process

A diode-triggered silicon controlled rectifier (DTSCR) is being developed as an electrostatic discharge (ESD) pro- tection device for low voltage applications. However, DTSCR leaks high current during normal operation due to the Darlington effect of the triggering-assist diode string. In this study, two types of diode string triggered SCRs are designed for low leakage consideration; the modified diode string and composite polysilicon diode string triggered SCRs (MDTSCR & PDTSCR). Com- pared with the conventional DTSCR (CDTSCR), the MDTSCR has a much lower substrate leakage current with a relatively large silicon cost, and the PDTSCR has a much lower substrate leakage current with similar area and shows good leakage performance at a high temperature. Other DTSCR ESD properties are also investigated, especially regarding their layout, triggering voltage and failure current.