The thermodynamic properties of humid air at high pressure and temperature

A computer program for calculating the thermodynamic properties of humid air at high pressure and temperature taking into account the imperfect properties of components (an ideal mixture) is presented. Information is given on the equations used for the components of humid air and on the effect the consideration of imperfect properties of components has on the limiting partial pressures of steam and on the density and enthalpy of humid air.     

Carrier mobility in ethylene-vinylacetate copolymer estimated bytransient space charge

Carrier mobility in an ethylene vinyl acetate (EVA) copolymer film was measured by a new technique. The time-dependent charge distribution was monitored by the pulsed-electroacoustic method when a pulse voltage was superposed on a dc bias voltage. A positive charge packet was injected from the anode soon after the pulse application, and moved towards the cathode. It was suggested from the movement of the charge packet that the mobility of the positive carrier at 10 to 60 MV/m was in the order of 10^-13 m²/Vs at room temperature. When the pulse voltage was very high, a charge packet appeared within the bulk, suggesting that carrier dissociation takes place     

高温高压蒸汽管道应变测量及应力分析

火力发电厂蒸汽管道是一个庞大复杂的结构体系,运行数年后,由于高温引起的安装应力使管道支吊架松驰,管道结构发生变形,导致非计划性停机检修,影响电网经济和安全运行。为找出管道的最大应力及应力分布,提出了用高温应变测量分析方法,对高温压力下的蒸汽管道进行现场应力测试,通过重新合理调整支吊架,大幅降低了管道结构应力并达到延寿的目的,实际验证表明该方法具有良好的降应力效果。     

注CO2对高温高压条件下油-地层水体系界面张力的影响

目前对于CO2-原油界面张力特征研究较多,但是对于原油-CO2地层水体系相界面作用特征的研究较少.本文采用轴对称悬滴形状分析技术分析了不同CO2饱和度对原油-地层水平衡界面张力的影响,以及原油-饱和CO2地层水与原油-地层水平衡界面张力的变化.同时,对CO2通过油-水界面从油滴中提取轻烃组分的现象,进行了研究和分析.结...     

高温高压水化学环境T22材质均匀腐蚀行为研究

本文在模拟高温气冷堆二回路的高温高压水化学环境下,研究了蒸汽发生器T22材质传热管在不同水化学环境中的均匀腐蚀行为。结果表明:提高溶液pH值、降低联氨质量浓度能够在一定程度上抑制T22材质的均匀腐蚀;随着反应温度升高,T22材质传热管均匀腐蚀速率加快;在高温高压水化学环境中,T22材质表面生成Fe3O4氧化膜,并随着反应时间的延长,Fe3O4晶粒尺寸逐渐长大,氧化膜致密性显著增加,导致T22材质均匀腐蚀速率显著降低,反应768 h后的T22材质均匀腐蚀速率降至0.016 g/(m2·h)。     

INCONEL 617 合金的高温时效析出相

INCONEL 617合金（简称617合金）具有较好的高温强度、塑性以及良好的抗氧化、抗腐蚀性能,故可作为超超临界机组耐高温候选材料。为进一步了解617合金长期高温时效后的析出相及其组织结构,在760 ℃下对该合金进行长达10 000 h的时效试验,借助扫描电镜和透射电镜等分析设备研究 617合金高温时效处理（简称时效）后的析出相。结果表明：在760 ℃时效10 000 h过程中, 617合金析出面心立方结构的M₂₃C₆、M₆C碳化物和面心立方有序结构的γ′相,γ′相分布于晶内,M₂₃C₆和M₆C碳化物在晶界和晶内均有析出;整个时效过程晶内析出相基本稳定;时效300~3 000 h过程中,晶界析出相均呈不连续分布,时效至5 000 h,晶界碳化物聚集且连续分布,晶界M₆C碳化物数量明显增多;时效300 h后硬度明显升高,时效1 000 h后硬度达到最大值,时效5 000 h后硬度有一定幅度降低。     

磷酸铁锂常温常压环境下时效性能研究

对常温常压环境下保存1、30、180、360、720、1 080天的磷酸铁锂进行了研究。采用比色法比较不同时效样品Fe3+含量,化学滴定法测定不同时效样品LiOH、Li2CO3含量变化,并对不同时效样品进行了电化学性能测试。随保存时间的延长,Fe3+含量、LiOH和Li2CO3含量急剧增加,充/放电比容量降低,而且充电比容量降低得更多。     

高压加热器出品给水温度偏低原因分析

针对国电宁夏石嘴山发电有限公司3号机组（330Mw）6号、7号高压加热器给水温度偏低问题,从加热器的结构、受热特性、运行和维护方式等方面进行分析,提出了相应的解决措施。分析结果表明：高压加热器给水温度偏低的主要原因是分水隔板制作工艺不合理及密封垫片安装方法不正确。     

MEMS接触电容式高温压力传感器的温度效应

介绍了一种基于SOI／硅片键合技术制作的接触电容式高温压力传感器结构,并对传感器的测试装置、测试方法进行详细的介绍后,对传感器进行压力测试和温度特性测试。压力测试结果表明,传感器线性工作区压力为110～280kPa,灵敏度约为0．14pF／kPa;温度特性测试结果表明,传感器具有正温度效应,在30～300％,传感器输出误差约为0．5％。文中还分析了热胀冷缩及介电常数温度系数对传感器温度效应的影响,以及设计了参考电容及运算放大器式传感器测量电路来消除温度效应。     

高背压供热机组供热温度特性与?分析

高背压供热具有大幅减少冷源损失及扩大机组供热能力的优势,而针对高背压供热机组供热温度特性及?分析未见报道。本文采用自主研发的热力系统集成优化软件,搭建热力系统仿真模型,建立了热电联产机组?分析模型,研究了不同供热期高背压机组供热温度特性。为了避免低供热负荷对机组供电负荷的限制,提出了高背压凝汽器供热-新风加热方法。结果表明:采用高背压凝汽器供热-新风加热方法,解决了低供热负荷对机组供电负荷的限制,实现了供热初末期热电解耦;相同主蒸汽流量工况,热电厂总?效率大小顺序为严寒期＞寒冷期＞次寒期。本文研究结果可为热电联产运行优化提供借鉴。     

High-field dissipation current waveform in e-beam-irradiated XLPEfilm at high temperature

We developed a detection method of ac dissipation current waveforms combined with a fast rising ac ramp voltage application as a new technique to evaluate the high-field dielectric properties and the dissipation current waveform over a very short time range. This measurement was carried out on electron beam irradiated crosslinked polyethylene film. At high temperature the high field tan δ and ac dissipation current show nonlinear electric field dependence and the dissipation current during decreasing field becomes larger than that during increasing field, suggesting the contribution of carrier injection from electrodes. The dissipation current waveforms in the high temperature region show the peak in the first part of each half cycle of a full waveform, and fast decrease in the latter part. This result is probably due to the hetero and home space charge formation caused by the injected carriers from the electrode     

Characteristics of laminated tape insulation in high vacuum at cryogenic temperature

A composite insulation system of laminated tape and high vacuum is newly proposed for a superconducting bus-line cable operated at relatively low voltage. Its breakdown characteristics were investigated using model cable specimens with different kinds of laminated tapes such as semisynthetic paper, polypropylene film, and kraft paper of insulation thickness less than 1 mm. First, ±dc, ac, and —Imp breakdown stresses of the semisynthetic papers were investigated. +dc breakdown stress was 21.7 kV/mm for a specimen of insulation thickness 1 mm and −dc breakdown stress was 41.5 kB/mm, so that the remarkable polar effect was observed. ac breakdown stress was 18 kV/mm. Also, the ratio of −Imp breakdown stress was about 3. Furthermore, ac breakdown stresses of other tapes were investigated, but remarkable differences among their stresses were not observed. Most of the specimens were broken from the “butt gap” between tapes. To understand this cause, measurements of the partial discharge were carried out. It was found that the inception stress of partial discharge of butt gap located just on the conductor was about 20 kV/mm, not dependent on the kind of tape. This value is much lower than the breakdown stress of the same length of vacuum gap. Therefore, it is considered that the trigger of the breakdown of this insulation system is the surface discharge along the edge of the butt gap. © 1998 Scripta Technica, Inc. Electr Eng Jpn, 121(3): 20–26, 1997     

聚合物共混提高聚乙烯高温电性能的研究

论文研究了聚乙烯及聚乙烯——丙烯共聚物的共混物的冲击电压击穿强度和高次结构 ,发现通过共混可以改善高温下的冲击电压击穿强度 ,分析了样品的高次结构 ,发现共混可以减小聚乙烯的球晶尺寸 ,并提高样品沿拉伸方向的取向度。高次结构的这一变化被认为是导致冲击电压击穿强度改善的原因。     

SOI高温压力传感器专用集成电路设计

针对压力传感系统高温条件下无法稳定工作、性能下降等问题,设计了一种基于SOI CMOS高温工艺的压力传感器专用集成电路(ASIC),主要由零温度系数恒流源、仪表运算放大器(由恒定跨导运放组成)和零温度系数电压基准组成,具有为压力传感器供电、放大输出信号及调节零点的功能,重点介绍了零温度系数恒流源、仪表运放及组成仪表运放的运算放大器等相关电路。仿真结果表明,-55~225℃温度范围内,恒流源温度系数为109ppm/℃,运算放大器输入MOS管跨导几乎与温度无关,仪表运放输入输出电压成正比且共模抑制比高达125 d B。测试结果显示该压力传感器专用集成电路可在225℃下正常工作。     

On PD mechanisms at high temperature in voids included in an epoxyresin

In this paper the effects of temperature on partial discharge (PD) activity taking place inside a spherical void in epoxy resin system are studied. Indeed, some experimental tests previously performed on specimens, having different void shapes, under multi-stress condition of temperature and voltage, have shown very different PD amplitude distributions at temperatures higher than ambient. However, this phenomenon cannot be explained only by taking into account the different thermobaric conditions of the enclosed gas. In consequence of the general physical inaccessibility of such voids, a study is here performed using a numerical model based on an evolutionary optimization algorithm. This is used to evaluate the range values for the physical parameters of the insulating system influencing the observed changes in PD activity. Finally, comments are presented about the adopted criteria by which the comparison between the experimental data and the simulated ones is performed, and about the interpretation of the dependence on temperature of the experimental PD     

The optical properties of microbulb alumina ceramics at high temperature

The normal spectral emissivity of two types of high-temperature ceramics made of alumina microbulbs as a function of the wavelength and temperature was investigated experimentally for the first time. Data for samples of various thicknesses (2–8 mm) at wavelengths of 1.0–5.0 μm and temperatures of 1073–1873 K were obtained. The ceramics optical properties in the forms of an effective absorption factor and a radiation diffusion factor were calculated in the wavelength band from 3.2 to 4.6 μm using the dependence of emissivity on thickness. The effect the porosity of ceramics has on its optical properties was analyzed.     

大型超高压循环流化床锅炉高温热烟气烘炉实践研究

针对大型超高压循环流化床锅炉采用明火烘炉、局部烘炉不能有效控制烘炉过程、温度分布不均匀等问题,阐述了义马锦江矸石电厂DG-440/13.7-Ⅱ2型循环流化床锅炉炉衬材料的分布情况和养护要求,采用了高温热烟气整体烘炉法,能够对烘炉的全过程进行有效的控制,节省了烘炉时间和烘炉费用,保证了烘炉质量.     

高温高速气流温度测量方法的研究

本文提及的测量方法是针对高温高速气流在温度测量过程中存在着气流温度本身在变化与温度传感器有一定响应时间这2个难点而设计.它是通过启动弹射装置,把热电偶测量端射入气流中,经过一规定时间后,将其自动收回,测出热电偶测量端的瞬时温度,进而就可推算出被测气流的真实温度值.通过此方法测量后,可确定热电偶的时间常数,而当测量时间大于3倍热电偶的时间常数时,动态响应误差可以减到最小.另外,热电偶的测量端体积要尽可能小,这样不仅能提高响应时间,把动态响应误差可以减少到最小,而且还能克服滞后带来的影响.     

Partial discharge endurance life of polymer insulating materials at high temperature

This paper describes the partial discharge (PD) characteristics and V‐t characteristics of several insulating materials, such as liquid crystal polymer, epoxy resins, polyimide, and polyethylene‐terephthalate (PET) with a needle‐plane electrode system at elevated temperature. The life index n for an applied electric field less than 20 kV/mm is found to be about 9 and that for more than 20 kV/mm is found to be less than 4. The PD characteristics of the insulating materials varied. These V‐t characteristics due to PD degradation were similar to those at room temperature except for the absolute life time. © 1998 Scripta Technica, Electr Eng Jpn, 126(1): 15–22, 1999