硅微微压传感器的设计

电容式硅微微压传感器具有灵敏度高、稳定性好、加工复杂程度适中等优点,适用于硅微微压传感器的信号转换.采用ANSYS软件对电容式硅微微压力传感器的核心部件进行有限元模拟,即对周边固支的各种结构类型的应变膜进行均布压力作用下的小挠度和大挠度静力学分析.对比各种结构类型的应变膜的挠度特性发现:圆形带岛波纹薄膜囚其岛部位移的一致性提高了感测电容的灵敏度,其良好的线性降低了后续检测电路的复杂程度,是电容式硅微微压传感器的较好选择.     

电容式差压变送器球形电极的理论分析

球形电极设计使电容式差压变送器以最简单的结构,具有高性能,尤其是“高过压保护”的性能。本文叙述了球形电极设计,包括:应用预张紧膜片作检测压力的主要工具(手段),用球形电极设计具有长期稳定性,无滞迟和突出过压保护性能的高精度“压力——电容”传感器。并指出如何使球形电极的设计合理,导出“电极尺寸——起始电容”关系的方程。最后,讨论了球形电极的一些工作特性。     

铜柱测压器膛压测试产生误差的机理研究

针对同时采用放入式电子测压器和铜柱测压器测量一批弹药的膛压时,出现电子测压器所测压力峰值一致,而铜柱测压器所测的峰值个别出现超差的问题,在分析电子测压器测压和铜柱测压器原理的基础上,建立了铜柱测压器的ANSYS模型,并采用铜柱动态校准数据修正了铜柱JC模型参数。分析了铜柱压力出现偏差时的电子测压器测量的P-t曲线变化率,将电子测压器获得的P-t曲线作用到铜柱模型上仿真得到的变形量与实际测试一致,电子测压器测得的压力曲线更准确地反映了压力的变化过程和压力峰值。研究表明测量一批弹药时,铜柱测压器出现压力峰值偏差大的原因是由膛压上升过程变化率不同导致铜柱的应变率不同造成的。     

火炮膛压的测定方法

火炮最大膛压的测定,是检查火炮强度的重要技术指标.应用最广泛的膛压测定方法是铜柱测压法.本文讲述了膛压测定的原理及实际应用方法.     

新型运载火箭中电容式液位传感器接口专用集成电路

为了提高新型航天运载火箭中电容式液位传感器系统的电容检测性能,设计了一款适用于航天运载火箭中电容式液位传感器的接口专用集成电路(Application Specitic Integrated Circuit,ASIC)芯片。首先,完成了整体电路的系统级设计,实现了对电容式液位传感器输出电容的线性检测,将传感器输出电容量转化为与之呈线性关系的电压量输出。然后,对接口ASIC芯片的线性度、噪声特性和温度环境适应性进行了理论分析与研究。最后,采用0.5μm CMOS工艺完成接口ASIC的流片,并进行了芯片的性能测试。实际测试结果显示,芯片电容检测非线性为0.005%,输出噪声密度3.7aF/Hz~(1/2)(待测电容40pF),电容测量稳定性7.4×10-5 pF(参考电容40pF,待测电容40pF,1σ,1h),输出零位温度系数4.5μV/℃。测试结果证明,该接口ASIC的电容检测性能已经达到国外最高性能的电容式液位传感器液位测量芯片的水准,可以广泛应用到多种电容式检测传感器中。     

圆筒形电容式粮食水分传感器的数学模型与影响因素分析

分析了粮食的介质特性,说明了圆筒形电容式粮食水分传感器的测量原理,得出了传感器电容参数与被测粮食含水量关系的数学模型.运用粮食的导电浴盆效应得出了传感器的等效电路,讨论了影响传感器电容量的因素,为圆筒形电容式粮食水分传感器的设计提供了理论依据.     

基于碳化硅材料的电容式高温压力传感器的研究

针对现有的硅基高温压力传感器不满足更高温度环境(≥500℃)下测试需求的问题,设计并制备了一种基于碳化硅(SiC)材料的电容式高温压力传感器。利用ICP刻蚀工艺和直接键合工艺实现了气密性良好的敏感绝压腔结构,结合金属沉积、金属图形化等MEMS工艺制备了感压敏感芯片。搭建了压力-温度复合测试平台,完成了传感器在0～600℃环境下压力-电容响应特性的测试。测试结果表明,在0～300 kPa内,该传感器灵敏度为4.51×10~(-3) pF/kPa,非线性误差为2.83%;同时测试结果也表明该传感器的温度漂移效应较低,0～600℃环境下电容变化量为8.50～8.65 pF。     

硅微超微压传感器设计

在分析已经商业化的压阻式、电容式、谐振式三类典型的硅微压力传感器各自优缺点和回顾它们微压化进展的基础上,确定了硅微超微压传感器(0～100Pa)的初步结构形式-电容式.针对设计过程中存在的主要难点:超薄平整感压薄膜的制备、高真空压力参考腔的获得与维持、高真空压力参考腔的电极引线以及微弱电容信号的提取,完成了两种差动结构方案的结构与工艺设计,对二者工艺和抗过载能力等方面进行了比较,为下一步的投片工作打下了基础.     

火炮膛压的测定方法

火炮最大膛压的测定,是检查火炮强度的重要技术指标。应用最广泛的膛压测定方法是钢柱测压法。本文讲述了膛压测定的原理及实际应用方法。     

一种双面变极距电容式海水压力传感器的研究

针对传统深度(压力)测量仪器无法满足海洋信息检测对于快速深度测量需求的问题,文中研究并设计了一种基于厚膜工艺制造的双面变极距电容式压力传感器敏感单元。为提高检测灵敏度和满足快速移动测量的需求,采用双面感压电极的芯片式结构设计;基于小挠度薄板设计理论,运用ANSYS对应力、位移进行仿真,对传感器设计的合理性进行理论论证;搭建电容式压力传感器的性能测试系统,分别从线性度、灵敏度、重复性等方面进行性能测试,传感器量程为0～2 MPa,非线性误差小于1%,灵敏度为0. 02 pF/kPa,重复性误差为0. 623%。结果表明该传感器是一种在较浅海域测量线性度好、灵敏度较高、可靠稳定的压力传感器。     

Correlation between runner pressure and cavity pressure within injection mold

The International Journal of Advanced Manufacturing Technology - Cavity pressure in the injection molding process is closely related to the quality of the molded products and is used for process...     

“炮鸣”的产生及其泄压回路

分析了高压大流量系统在完成挤压之后突然卸压时产生"炮鸣"的原因,并介绍了几种不同类型的泄压回路.     

A temperature and pressure controlled calibration system for pressure sensors

A data acquisition and experiment control system has been developed to characterize and calibrate prototype pressure sensors capable of operation in a cryogenic environment. The system consists of: a personal computer for acquisition of sensor output voltage, sensor operating parameters, and data processing including numerically derived corrections for sensor thermal offset, sensitivity variations, and thermal errors; an environmental chamber capable of controlling temperature to within 1 °C over a −184 °C to 220 °C range; a pressure standard capable of generating pressures to within 1 part in 100,000 over a 0 to 344.74 kPa range; and a data logger for recording outputs from system multimeters, precision resistance temperature devices, thermocouples, and power supplies. The system utilizes a modified, commercially available interface board to allow the demultiplexing, digitation, and input of remotely multiplexed, pulse amplitude modulated pressure signals from pressure sensor arrays to the PC bus. System software is discussed and includes: sensor data acquisition, algorithms for numerically derived thermal offset and sensitivity correction, and operation of the environmental chamber and pressure standard.     

Diamond-based pressure sensors

Russian Engineering Research - Instruments for pressure monitoring are widely used today, in fields such as the aerospace industry, machine tools, and automated control systems. The pressure...     

液固两相流压降规律及超声法压降测量

液固两相流广泛存在于能源动力、石油化工等工业过程,两相流压降作为重要的流动参数,有助于流动建模及流态分析。建立液固两相压降测量模型,提出了一种结合超声多普勒及超声透射衰减的液固两相超声压降测量方法。搭建液固两相流动实验平台,对两相压降规律进行研究。两相混合流速和固相体积分数升高时,液固两相压降均逐渐增加。在固相体积分数为0.28%～1.37%,两相混合流速为0.9～1.65 m/s时,根据液固两相压降测量模型及Churchill模型的超声法得到的两相压降与差压传感器测量的压降平均相对误差为4.93%和5.10%,验证了测量模型的准确性。针对非均匀分布的两相流态进行压降测量,进一步拓展了压降测量模型的应用范围。本研究工作为非侵入超声法测量液固两相压降提供了方法基础。     

一种冲裁级进模冲压力及压力中心的自动计算方法

针对冲裁级进模冲压力及压力中心计算效率低、容易出错的问题,运用VBA技术对Auto CAD软件进行了二次开发,实现了任意复杂形状冲裁刃口的冲压力及压力中心的自动计算,显著提高了级进模的设计效率。     

On the propagation pressure of long cylindrical shells under external pressure

Local imperfections induced in long tubes subjected to high external pressures can lead to local collapse, from which a propagating buckle can be initiated. This can result in catastrophic collapse of large sections of the structure. The propagation pressure is the lowest pressure at which such a buckle will propagate. For common structural metal tubes with diameter-to-thickness ratios of less than 100, the propagation pressure is typically half an order of magnitude lower than the collapse pressure of the intact tubes. As a result, the design of several tubular structures with external pressure loading requires that the collapse and propagation pressures be accurately known. This paper deals with the experimental and analytical challenges of establishing the propagation pressure. A special purpose three-dimensional analysis, in combination with experimental observations and results, is used to demonstrate a mechanism of initiation of propagating buckles in long tubes, to study the parametric dependence of the propagation pressure and to illustrate the effect of axial tension on the propagation pressure. Propagation pressures predicted with this analysis are used to evaluate the strengths and weaknesses of simpler models developed in the past.     

Volume ratio and pressure drop on hydraulic dynamic pressure calibration system

The calibration of a pressure transducer that works in dynamic conditions is an unavoidable challenge. To address this challenge, an experimental setup has been designed and developed to simultaneously generate and calibrate the dynamic pressure. The system mainly comprises a pressure chamber that accommodates a step pressure generator and test chamber with a quick open valve and pressure sensor under calibration. Accordingly, an aperiodic type of step pressure generator with a quick open valve is particularly designed. This instrument can generate a positive step pressure with a rise time of up to 11 ms and a negative step pressure with a fall time of up to 12 ms within a working pressure range from the atmospheric pressure to 200 MPa. The volume ratio of the test chamber to the pressure chamber and its effect on pressure drop is critical in such systems. The effect of volume ratio on the dynamic performance parameters, namely, rise/fall time, is explored and inferences for optimizing these parameters are derived. A mathematical model for pressure drop in the test chamber has been developed and validated to precisely determine the magnitude of the step pressure input. Lastly, the experimental study of the effect of volume ratio on pressure drop has been conducted to diminish the pressure drop, thereby minimizing the uncertainty.     

高温高压阀门的带压堵漏

简述了高温高压阀门泄漏对生产的影响，分析了阀门泄漏的原因。通过一起成功的实例。介绍了在不停车条件下对高温高压阀门进行带压堵漏的技巧。