基于硅酸镓镧的声表面波高温压力器件的微结构加工制造技术研究

采用硅酸镓镧(Langasite,LGS)压电材料制备声表面波(Surface acoustic wave,SAW)高温压力传感器可解决高温、高压等恶劣环境下温度、压力等参数的实时原位测试的问题,但由于硅酸镓镧是一种高硬度难加工的硬脆性压电材料,因此开展了硅酸镓镧压电材料在高温等恶劣环境下的微结构加工制造技术的研究.通过分析LGS的化学与物理特性,利用湿法腐蚀工艺实现LGS的微纳成形制造和控制;以及利用高温热压直接键合工艺实现密封空腔的制造,研制出一套适用于LGS等硬脆性材料的微纳结构成形制造技术,并探究了微结构加工制造工艺的实用性.利用微结构加工制造技术实现的压力敏感微结构制备了基于LGS的SAW高温压力传感器样机并进行了测试,样机在25～1000℃、20～500 kPa环境下能稳定工作,验证了LGS微纳结构成形制造技术在高温等恶劣环境下应用的可行性.     

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。     

极端温度环境下飞行器液压蓄能器与气瓶特性研究

飞行器在储存、运送和发射飞行过程中,液压元件往往要经过极端低温、极端高温环境过程考核。研究储存状态的极端低温(-40℃)和极端高温( 60℃)条件下液压蓄能器及小气瓶性能,在大温差范围内气体的充气压力特性及充气质量,分析蓄能器的工作排油量及最大充油量特性,取得不同气体的充气压力特性曲线。     

高温压力传感器测试标定系统的研究

高温压力传感器的标定对于传感器的应用和开发具有非常重要的意义。为了适应高温环境下的气体压力传感器标定,设计实现了由压力控制系统和温度控制系统组成的测试标定系统总体方案。结合单片机自动控制系统和LabView上位监控程序,实现了压力3M Pa和高温150℃下的压力传感器标定测试。     

光纤法珀式SiC耐高温压力传感器的制造与测试

针对高温环境下压力参数的原位测试需求,基于碳化硅（SiC）材料优异的耐高温特性,研制了一种光纤法珀式全SiC结构耐高温压力传感器。采用超声振动铣磨的加工方法制备了表面粗糙度Ra约11.9 nm的SiC传感膜片。利用SiC晶片氢氟酸辅助直接键合技术,实现SiC传感膜片与SiC基板的高强度气密性键合。搭建了高温压力测试系统,对制备的SiC耐高温压力传感器样机进行了高温环境下的性能测试。结果表明,该传感器能够实现600 ℃高温环境下 0~4 MPa范围内的压力测量;600 ℃下传感器的压力灵敏度达到104.42 nm/MPa,具有较高的线性度,R2＞0.99。     

光纤珐珀高温压力传感器的设计与性能测试

为了提高传感器在高温恶劣环境下的测试性能,结合单晶蓝宝石优异的特性,研究了一种能在高温恶劣环境下长期稳定工作的全蓝宝石光纤珐珀高温压力传感器,并对其设计、制造工艺及性能测试进行了详细的分析说明。首先,利用光纤珐珀干涉原理及斐索干涉仪的信号解调原理,对传感器进行了结构的设计;其次,采用蓝宝石刻蚀工艺、激光加工工艺及对蓝宝石三层结构的直接键合工艺完成了对传感器的工艺加工;最后,对制造的传感器进行了常温环境下的密封性测试及高温环境下的性能测试,测试结果表明:制造的高温压力传感器具备良好的密封性,且在高温环境下具有良好的线性响应,且温度在900℃时传感器的灵敏度可达3.035 nm/kPa,可以长期在高温环境下稳定工作。     

高温压力传感器标定的实验研究

传感器的灵敏度是一项重要的静态性能指标。采用所设计的标定系统对高温压力传感器进行了标定实验,分析获得了室温和90℃时的传感器灵敏度值。通过对比两种不同温度下的灵敏度,分析温度对压力传感器灵敏度性能指标的影响程度,为高温环境下的压力传感器应用提供数据支持。     

新型高温压力传感器的设计与性能测试

针对高温恶劣环境下对压力参数的测试需求,以单晶蓝宝石为原材料,对无线无源蓝宝石高温压力传感器进行了设计、工艺加工及性能测试.以压力膜片敏感原理为主要根据,结合不同的信号传输与提取方式,首先对LC谐振式的无线无源蓝宝石高温压力传感器进行了设计,然后通过蓝宝石刻蚀、蓝宝石减薄、直接键合等3个关键工艺实现了蓝宝石密封压力腔的...     

面向内燃机腔室压力监测的光纤F-P传感系统

本项目旨在实现内燃机腔室压力的精确监测,构建通过温度补偿,精确测量压力的光纤传感系统。利用串联Fabry-Pérot(F-P)腔结构光纤传感器,在测量压力信号的同时监测腔室内的温度。利用光谱仪采集双F-P腔的干涉光谱后,使用结合Buneman频率估计的FFT算法实现高精度腔长解调,并通过校准程序实现对压力信号的精确解算。项目成果将适用于内燃机腔室等高温、高压、强腐蚀和强电磁干扰环境下的压力监测。     

不同进气温度下增压压力对某柴油车经济性、动力性的影响分析

本文对某柴油车在不同温度下增压压力需求变化对发动机经济性、动力性影响进行了研究,分析了高寒、高温环境下基于经济性、动力性的增压压力优化结果。通过在实车上的测试及运用,表明环境温度影响相同增压压力条件下发动机实际新鲜进气量,通过优化各负荷点下的增压压力需求可以实现更好的整车性能。     

Evaluation of high temperature pressure sensors

It is becoming more important to measure the pressure in high temperature environments in many industrial fields. However, there is no appropriate evaluation system and compensation method for high temperature pressure sensors since most pressure standards have been established at room temperature. In order to evaluate the high temperature pressure sensors used in harsh environments, such as high temperatures above 250 °C, a specialized system has been constructed and evaluated in this study. The pressure standard established at room temperature is connected to a high temperature pressure sensor through a chiller. The sensor can be evaluated in conditions of changing standard pressures at constant temperatures and of changing temperatures at constant pressures. According to the evaluation conditions, two compensation methods are proposed to eliminate deviation due to sensitivity changes and nonlinear behaviors except thermal hysteresis.     

新型两级压缩热泵中高温工况循环性能分析

中高温热泵系统中在工业领域有广泛的应用,但其排气温度偏高。本文从降低压缩机排气温度角度,设计一种双级压缩新型热泵系统。系统由高低级压缩机、分凝器、两个节流机构等组成。以循环性能较好的两种工质R134a和R152a为系统循环工质,理论分析结果表明:在中高温工况下,新系统工质R152a循环性能系数COP优于R134a,在相同工况下工质R152a循环性能COP比R134a高7%⁸%;高温级压缩机排气温度均随中间压比的升高而降低;排气温度与传统单级压缩系统相比有38%;高温级压缩机排气温度均随中间压比的升高而降低;排气温度与传统单级压缩系统相比有3¹2℃的降幅。     

低温压力容器用钢的现状与发展概况

简要介绍了C-Mn，调质高强度和Ni系低温压力容器用钢的现状、分析了各国及各企业相应产品之间主要技术指标的差异，明确了中国在0．5Ni等低温压力容器用钢方面已处于国际领先水平，概述了各类低温压力容器用钢的发展动向。     

DATA ACQUISITION SYSTEM FOR ARC-DRIVEN HF/DF CHEMICAL LASERS

The article focuses on the development of a data acquisition system (DAS) working in a noisy and hostile environment for an arc-operated hydrogen fluoride/deuterium fluoride (HF/DF) chemical laser. PC-based DAS has been configured using Advantech plug and play modules with fiber link connectivity. This article also focuses on implementation of an orifice-based precise gas flow control system. The plasma arc discharge in an arc heater/generator is essentially employed for inducing thermal dissociation of sulfur hexafluoride SF₆ for production of fluorine atoms, and DAS has been used for performance optimization of the composition of the lasing mixture by independently varying the flow rate, pressure, and temperature of its constituents. Since arc load is complex with high voltage transients and electromagnetic noise, an optical fiber link has been implemented for data transmission. This article also discusses digital output interface circuitry for various electro-pneumatic actuators/solenoid valves. The developed DAS has been used for monitoring and performance evaluation of parameters for 50 kW arc tunnel.     

Preparation of W-Ta thin-film thermocouple on diamond anvil cell for in-situ temperature measurement under high pressure

In this paper, a W-Ta thin-film thermocouple has been integrated on a diamond anvil cell by thin-film deposition and photolithography methods. The thermocouple was calibrated and its thermal electromotive force was studied under high pressure. The results indicate that the thermal electromotive force of the thermocouple exhibits a linear relationship with temperature and is not associated with pressure. The resistivity measurement of ZnS powders under high pressure at different temperatures shows that the phase transition pressure decreases as the temperature increases.     

高性能MEMS电容压力传感器的设计及其热分析

为了进一步提高接触式电容压力传感器的性能,设计了一种高性能双凹槽结构的接触式电容压力传感器,并对该传感器在高温环境中的总体性能进行了分析。推导了热传导和热弹性理论,并对影响传感器热分析的各个因素与温度的依赖关系进行了描述;在整个分析过程中,使用ANSYS软件并结合有限元方法对全尺寸传感器的热效应进行模拟。结果表明,在接触工作状态双凹槽接触式电容压力传感器的温度对输入(压力)-输出(电容)特性的影响是线性的,且线性范围内初始压力随温度的升高而降低;当温度载荷为550 K时,双凹槽结构的灵敏度为1.21×10-6pF/Pa,比传统单凹槽的0.8×10-6pF/Pa高出50%,表明该压力传感器有着非常优异的高温特性。     

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.     

新型光纤光栅温度传感系统在电力测温中的应用

介绍一种光纤光栅温度在线监测系统。系统采用新型光纤光栅温度传感器,具有防爆、防燃、抗腐蚀、抗电磁干扰、耐高压及在有害环境中使用安全等特点,可以实现实时、快速、大容量、准分布式测温并定位。不但可以用在电力高压开关柜温度检测中,还可以应用于电力电缆接头,油库油罐等其它需要检测温度的领域。     

Pressure dependence of mass burning rates in diluent premixed flames of H2/O2 at high pressures

Pressure dependence of mass burning of diluted hydrogen premixed flames is studied numerically over a full range of pressure. Mass burning rate is selected to be a parameter for burning capability of flames. First, positive linear dependence of mass burning rate has been confirmed at low pressures and negative pressure dependence has appeared in the medium range of pressure, which complies with the results reported in previous experimental works. And then, when the pressure range is extended more, positive pressure dependence is recovered or shows up again at high pressures. The flame structures of temperature and species profiles in each pressure regime are demonstrated. They show that the latter two dependences of negative and positive can be explained by enhanced recombination reactions producing HO₂ at high pressures and chain re-branching to OH production via H₂O₂, respectively. There are three distinct dependences of mass burning or global chemistry in hydrogen flames. Two onset pressures, at which pressure dependence changes, depend on equivalence ratio, degree of dilution, diluent species, and unburned-gas temperature. Accordingly, the onset pressure can be used as a parameter characterizing burning of premixed flames.     

Thermal modelling of the lemon-bore hydrodynamic bearing

The lemon-bore hydrodynamic lubricated journal bearing is a bearing type which is commonly used in high-speed machinery. This is because the lemon-bore bearing is less susceptible to self-excited vibrations or instability than the plain cylindrical bearing at high speeds, while remaining easy to manufacture. However, the increased viscous shear will result in a higher increase in the temperature in the lubricating film.In this paper a finite element analysis is presented which has been used to calculate the pressure and temperature distribution in the lubricating film of a lemon-bore journal bearing. This thermo-hydrodynamic (THD) model is an inverse model, that is, a model in which the shaft eccentricity and attitude angle are calculated given a certain known and prescribed load and load angle. A novel, simple and fast mass-conserving cavitation algorithm has been used in order to calculate the pressure and mass fraction distribution in the lubricating film, and consequently accurately describes the heat flow in the cavitated areas. Furthermore, care has been taken to accurately model the heat to and from the oil supplies.This model has been used to check the design of the lemon bearings in a specific naval application. The results of this model are compared with those obtained using the bearing manufacturer's design code. The influence of several operating and design parameters is studied, particularly with respect to the maximum temperature. The results of this parameter study have been used to suggest design improvements for this particular application.