新型应变筒式光纤Bragg光栅压力传感器

设计并制作了一种基于弹性应变筒式光纤布拉格光栅压力传感器,通过对传统结构进行优化,即弧形筒身设计,避免了应力梯度的存在,使筒身受力均匀,同时增大了应力响应范围.使用参考光栅进行温度补偿,解决了交叉敏感问题带来的影响.通过对应变筒几何尺寸和材料的改变,达到具体测量所需传感头的参数.实验以普通不锈钢材料为基体,测量范围0～30 MPa,压力灵敏度达到0.033 nm/MPa.使用该结构可用于液体和气体的高压测量.     

涡街流量传感器压力损失系数的试验研究与计算

在天津大学电气与自动化工程学院流量实验室的气体流量试验装置上,通过改变管道内气体的压力,对涡街流量传感器的压力损失系数进行试验研究。对大量试验数据进行处理后发现,涡街流量传感器的压力损失系数会随着管道内气体压力的变化而有所变化。当管道内气体压力在0.1～1.1 Mpa的范围内变化时,压力损失系数会随着气体压力的增大而减小,变化幅度最大达到了7%。对压力损失系数随气体压力变化的规律进行分析,并给出压力损失系数随管道内气体压力变化的计算公式。     

基于MEMS压力传感器的研究

提出了一种新型高精度高温压力传感器,此压力传感器以硅片为弹性片,敏感材料为Ni-Cr合金,利用溅射合金薄膜压力敏感元件和先进的加工工艺技术制作而成。对溅射薄膜压力传感器弹性膜应变进行理论和三维有限元分析,再用先进的软件ANSYS模拟弹性膜片的应变分布,研究应变与膜的大小、厚度的关系。最后确定敏感电阻的最佳布置区域,提高了传感器的灵敏度。     

基于SnO2-CuO掺杂的CO2气体敏感特性研究

以氧化物半导体SnO2为基体材料加入40％的活性CuO材料,制备出了对CO2具有敏感性的气体敏感材料,其检测浓度范围为0 ～5％.实验结果表明,在SnO2 - CuO敏感材料的基础上掺杂适量CeO2、Ag2O、Bi2O3等氧化物,不仅提高了其对CO2气体的灵敏度,而且可以提高其稳定性,从而改善了其对CO2的敏感特性.在试验结果的基础上,分析并讨论了该系列材料对CO2气体的敏感机制.基于这种敏感材料的CO2气体传感器具有结构简单、容易制备、使用方便和价格低廉等优点.     

车用新型陶瓷电容式压力传感器

压力传感器是车辆电子控制装置获得压力信息的主要元件之一,文章通过对电容式压力传感器基本原理的分析,阐述在电容敏感材料变为陶瓷时,其性能、特点、精度及相应的信号处理,使其在低成本的基础上,广泛地应用于社会的各个领域     

气动系统换向冲击压电俘能特性

为充分利用气动系统管路产生的压力冲击,提出了一种基于压电材料的正压电效应压电俘能器,搭建了基于该俘能器的实验测试系统,研究了气体压力、换向时间对该俘能器俘能特性的影响。结果表明,在气体动载荷激励下,压电俘能器内的压电片产生了弯曲形变,俘能电压与形变变化密切相关;气体压力值增大时,峰值电压、峰值功率升高;而随着换向时间的改变,峰值电压、峰值功率未有显著变化。     

阀门防汽蚀新型结构的设计

一、前言 在高压差工况下,当液态介质通过阀门时,入口压力p1在阀芯节流部位的压力降低到液体的饱和蒸汽压力p1以下直到pvc,部分液体会变成气体,在液体中形成一个个的气体空腔,然后压力又恢复到液体蒸汽压pv以上,直到出口压力p2,这些气体空腔挤压破裂而恢复成为液体,称为汽蚀。其压力的变化如图1所示。     

基于硅微控阀门的气压控制器的设计

本文针对硅微控阀门的特性,提出了一种新的气体压力控制方法,设计了基于微机电硅微控阀门的气体压力控制系统,对系统的传感器调理电路、控制电路进行了设计,解决了小压力和低流量时的压力精密控制问题.该系统压力输出的范围为0-110kPa,不确定度为0.1%FS,气体压力控制稳定性达到了0.01%.可广泛用于模拟和数字压力计和航空气压仪表的校准检定.     

不同压力腔的气体静压轴承静特性的数值模拟

气体静压轴承以其低摩擦、高精度成功应用于高精密回转运动台,其定位精度已达到纳米级水平,达到了物理极限,因此压力腔形状对气体静压轴承的影响无法忽略。通过CFD数值模拟,研究了不同压力腔形状对气体静压轴承静态性能的影响。针对矩形压力腔、圆形压力腔和锥形压力腔,研究分析了气膜内压力分布、气体质量流量和承载力等静态性能。结果表明:相同的条件下,锥形压力腔承载力较大,且压力腔内部气旋强度较弱,比较适合应用于高压重载的场合。     

气体减压阀动静压差研究

动静压差是气体减压阀一项主要性能指标，分析了一种航天发射领域广泛应用的气体减压阀动静压差产生的原因，通过理论推导得到了基于动态数据计算对应静态压力和动静压差的公式，然后通过该公式研究了进出口压力、气体流量、敏感活塞面积等影响减压阀动静压差的因素，得到了以下结论：动静压差随着出口压力、气体流量的增加而增大，随敏感活塞面积增加呈“U”字形趋势，最后通过试验验证了所得公式的正确性。提出的研究方法也可供其他类型气体减压阀的动静压差分析提供参考。     

掺杂ZnO臭氧敏感特性研究

通过主体材料ＺｎＯ掺入多种掺杂剂对Ｏ３气敏特性影响的研究,得到了对Ｏ３敏感的较佳材料,用该材料制作 成的气敏传感器对Ｏ３具有较高的灵敏度、较低秘较好的响应恢复特性。     

p+p型半导体气体传感器原理

p p型半导体气体传感器是基于气体传感器互补反馈原理的一种新结构半导体气体传感器。该传感器由两种传导类型相同的敏感体A和B构成，A和B都是p型半导体材料。理论分析表明：当敏感体A和B满足一定条件时。该传感器可获得高的选择性和好的热稳定性，同时可减少零点漂移，缩短初期驰豫时间，提高抗湿干扰能力。文中在理论上给出了实现上述特性的条件。该传感器原理是通用的理论，对各种具有不同气敏特性的材料组合均适用。     

High resolution gas volume change sensor

Changes of gas quantity in a system can be measured either by measuring pressure changes or by measuring volume changes. As sensitive pressure sensors are readily available, pressure change is the commonly used technique. In many physiologic systems, however, buildup of pressure influences the gas exchange mechanisms, thus changing the gas quantity change rate. If one wants to study the gas flow in or out of a biological gas pocket, measurements need to be done at constant pressure. In this article we present a highly sensitive sensor for quantitative measurements of gas volume change at constant pressure. The sensor is based on optical detection of the movement of a droplet of fluid enclosed in a capillary. The device is easy to use and delivers gas volume data at a rate of more than 15 measurements/s and a resolution better than 0.06 microl. At the onset of a gas quantity change the sensor shows a small pressure artifact of less than 15 Pa, and at constant change rates the pressure artifact is smaller than 10 Pa or 0.01% of ambient pressure.     

高压储气罐的有限元应力分析

传统的储气罐设计采用理论计算与类比方法.随着新材料的应用以及储存气体压力越来越大,传统计算方法,难免带来意想不到的后果.采用理论计算方法和有限元方法对储气罐进行应力分析计算,此方法为进一步设计制造储存压力更大、体积更大的储气罐做出基础性研究,使之成为设计依据之一.     

半导体一氧化碳敏感材料研究进展

金属氧化物半导体由于具有耐热、耐腐蚀、成本低廉等特点，常用于制作气体传感器的敏感元件。本文简要介绍了SnO2半导体材料、TiO2半导体材料作为一氧化碳敏感材料的最新研究进展。     

Slip-line field modeling of orthogonal machining pressure sensitive materials

The slip-line field methods are widely used in solving cutting problem; however, most of which were focused on the pressure-independent materials. In this work, a new slip-line field model for orthogonal cutting of pressure sensitive materials is developed. Analytical characterization for orthogonal cutting process is obtained, which can give the explicit expressions for the shear angle, cutting force, and chip thickness in terms of the tool geometry, the friction coefficients on the tool flat, and the internal friction angle of the materials. To investigate the effect of the material and cutting parameters on cutting process, the finite element simulation is performed as well. The comparisons between the shear angle and cutting force predicted by the theoretical model with those obtained from finite element model simulation are made. The good agreement of the predicted results with the numerical results clearly reveals that the proposed slip-line field model can satisfactorily characterize the orthogonal cutting behavior of the pressure sensitive materials. Further analysis has demonstrated that the pressure sensitivity of materials has a significant influence on cutting process.     

Flow rate measurements of a fibrous material using a pressure drop technique

The measurement of flow rates of solids in gas–solid flows is a challenging task. Fibrous materials are known to change in character as they flow and, as such, can compound the difficulty of measurement of such flow rates over that of powders and granular materials in the transport condition. The principle of measuring the pressure loss experienced by a gas–solid flow in a straight section of piping was used here to test a metering device for fibrous solid flow which has been shown to work for a wide range of powders and granular materials in our laboratories. The flow rates obtained for the fibrous material had a high degree of reproducibility suggesting the possibility of widespread industrial application of the pressure drop flow-metering device.     

Creating a high temperature environment at high pressure in a gas piston cylinder apparatus

An internal heater capable of 1400 K has been developed for use with a gas piston cylinder apparatus capable of achieving in excess of 3 GPa with an argon pressure medium. The heated gas piston cylinder produces a truly hydrostatic environment for samples up to 3 mm in diameter and 8 mm in length. The apparatus can be used to study systems that are sensitive to stress or samples that cannot withstand shear tractions. The gas piston cylinder apparatus was developed in an effort to reduce experimental uncertainty in the pressure scale and has been used to improve understanding of the Bi I-II transition at 298 K. We estimate that the pressure during a high temperature soak in the gas piston cylinder can be known to within ±0.01 GPa.     

车用压缩天然气全复合材料气瓶缺陷分析

在对车用压缩天然气全复合材料气瓶进行定期检验过程中,发现气瓶内胆出现鼓包和裂纹等缺陷。为了确定缺陷产生的原因,对复合气瓶内胆材质进行力学性能、微观分析、缠绕层和内胆材料线膨胀系数测试。在此基础上,采用工业CT方法分析了气瓶内压与缺陷产生的关系。分析认为,缠绕层与内胆材料线膨胀系数不同是复合气瓶产生鼓包和裂纹的根本原因,同时,充放气过程中的内压和温度的低周循环也是气瓶产生缺陷的重要因素。