Energy dissipation in quasielastic materials during cyclic rolling

The relationship between the density of the energy absorbed by the contact pair during cyclic rolling and the structural-mechanical characteristics of the surface layer on the deformable material is established experimentally and theoretically within the framework of the concept of dislocation nonelasticity as a cause of hysteretic losses in quasielastic materials. It is shown that the energy losses in the subsurface layer in a material with a high yield stress depend on the contact pressure, yield stress point, and dispersion of distribution of dislocations based on the starting stresses.     

Patterned anvils for high pressure measurements at low temperature

Multiprobe high pressure measurements require electrical leads in the sample chamber. Compared to conventional wire-based techniques, metallic tracks patterned onto the anvil surface improve reliability and ease of use, and enable novel and more demanding measurements under high pressure. We have developed new anvil designs based on sputter-deposited tracks on alumina and moissanite anvils. These anvils allow convenient and reliable measurements of electrical transport properties or of the magnetic susceptibility under hydrostatic conditions, as demonstrated by test measurements on Pb and Ca(3)Ru(2)O(7).     

A microfluidic vibrating wire viscometer for operation at high pressure and high temperature

This article discusses a microfluidic vibrating wire viscometer with an internal volume of a few microliters. Accuracy of order ±10% for viscosities ranging from 0.1 to 100 cP is demonstrated for temperatures (10 °C-175 °C) and pressures (10-24,000 psi) suitable for oilfield use by prior calibration in air and toluene. Comparison between multiple data sets indicates that a large fraction of the discrepancy between literature values is systematic, indicating that future refinements may be possible with better interpretation. Confinement effects are evaluated and are not found to play a significant role, which is surprising since the ratio (6.6) of the fluid channel width to the wire diameter is very low.     

Quantitative vapor phase exciplex fluorescence measurements at high ambient temperature and pressure

The exciplex fluorescence technique with the TMPD (tetamethyl-p-phenylene-diamine) / naphthalene dopant system was applied in a combustion-type constant-volume spray chamber. A detailed set of calibration experiments has been performed in order to quantify the TMPD fluorescence signal. It has been demonstrated that the TMPD fluorescence intensity was directly proportional to concentration, was independent of the chamber pressure, and was not sensitive to quenching by either water vapor or carbon dioxide. Using a dual heated-jet experiment, the temperature dependence of TMPD fluorescence up to 1000 K was measured. The temperature field in the spray images was determined using a simple mixing model, and an iterative solution method was used to determine the concentration and temperature field including the additional effects of the laser sheet extinction. The integrated fuel vapor concentration compared favorably with the measured amount of injected fuel when all of the liquid fuel had evaporated.     

Density measurements of noncrystalline materials at high pressure with diamond anvil cell

We describe an x-ray absorption method for in situ density measurement of non-crystalline materials in the diamond anvil cell using a monochromatic synchrotron x-ray microbeam. Sample thickness, which is indispensable in the absorption method, can be determined precisely by extrapolating the thickness profile of the gasket obtained by x-ray absorption and diffraction measurements. Diamond deformation across the sample chamber becomes noticeable at high pressures above 10 GPa, which can be monitored with a precision better than 1%, as demonstrated by measurements on crystalline Ag. We have applied the developed method to measure densities of the classic network-forming GeO(2) glass in octahedral form at pressures up to 56 GPa. The fit to the pressure-volume data with the Birch-Murnaghan equation from 13 to 56 GPa gives parameters of V(0)=23.2+/-0.4 cm(3)mol and K=35.8+/-3.0 GPa, assuming that K(')=4. This method could be applicable for in situ determination of the density of liquids and other noncrystalline materials using a diamond anvil cell up to ultrahigh pressures.     

Lubrication of high temperature ceramic materials

A composite of CaF₂/BaF₂/Ni was shown to be an effective lubricant for a silicon carbide ceramic and a titanium carbide/nickel cermet when tested as like pairs in crossed cylinders geometry at room temperature and at 600°C.     

高温高压电动截止阀支架端部设计

阐述了高温压电动截止阀支架与电动装置连接端的设计原理及盘形弹簧的计算方法，并采用过渡接盘解决了不同电动装置与支架的连接。     

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。     

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.     

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.     

高温高压模拟井筒的设计

根据教育部"石油天然气装备"重点实验室的建设要求,设计了能模拟3000 m井下工况的高温高压模拟井筒.该装置通过泵和电加热器循环加热井筒内的液压油.使其基本达到预期温度;用加压泵循环加压至设定压力,再由循环泵和盘管保持设定温度,实现井下温度和压力环境.根据设计条件采用第三强度理论确定模拟井筒的壁厚,进而确定井筒的结构方案;同时进行了系统热平衡计算,根据循环装置的设计使用要求选定了电加热器的功率.     

耐高温压力传感器的设计研究

借助弹性力学和板壳力学理论,建立了双岛型耐高温压力传感器应变膜的简化力学模型,得到近似应力分布的数学模型.利用有限元分析方法,借助ANSYS仿真软件,对应变膜进行一系列的计算机模拟,探讨简化应力模型的合理性以及温度对应力差分布的影响,为力敏电阻在应变膜上的布置、研发新颖的高温压力传感器芯片提供有力的依据.     

高温阀门的高温等级和主体材料

介绍了高温阀门的高温等级划分方法及各温度等级高温阀门的主体材料。     

套筒式高温高压电磁阀研制

介绍了套筒式高温高压电磁阀的技术参数、工作原理和技术特点,论述了套筒与阀体分离式密封结构、组合式阀瓣及适用于高温的高压差和低压差状态的低泄漏与长寿命刚性阀座密封副等先进结构的设计。     

高温高压井下压力传感器的补偿与校正

潜油电泵、油藏监测、智能井等系统需要对井下压力进行长期在线监测,压力测试装置是其一个重要组成部分,是反映采油井实时状况的一个重要参数。井下温度随着深度的增加变化比较大,选用硅压阻式传感器存在温度漂移和线性误差,因此需要对压力传感器进行温度补偿和线性化校正。由于井下环境比较复杂,井下采集电路没有CPU进行处理,因此采用软件温度补偿与校正不易实现。经分析研究采用MAX1452信号调理芯片对压力传感器进行补偿与校正,能使压力传感器的精度达到0.1%。本文主要分析与研究MAX1452的补偿原理和实现方法,经试验分析得出经补偿校正后的系统在-40~125℃的温度范围内输出电流具有很好的线性度。     

高温高压临氢阀门制造工艺的分析

阐述了石化工业生产中高温高压临氢介质对阀门的要求,介绍了高温高压临氢阀门制造中,承压壳体材料、机械加工、特殊工序和整机检查试验等过程的控制要点。     

MEMS高温接触式电容压力传感器

本文介绍了一种用SOI硅片和硅-硅键合MEMS技术制作的高温接触式电容压力传感器，并给出了详细的工艺制作流程。在对测试装置、测试电路进行了详细地介绍和深入分析后，用此测试电路对制作的传感器器件进行了高温测试。测试结果表明，传感器在小于250kPa的室温条件下工作，传感器的灵敏度为0．54mV／kPa;而在400℃条件下工作，传感器的灵敏度为0．41mV／kPa，传感器的零点飘移为0．1mV／℃。可见这种微传感器可在低于450℃的条件下正常工作，且具有很大的线性工作范围、良好的稳定性和较高的灵敏度。     

A high temperature high pressure cell for quasielastic neutron scattering

We present our recent development of a high temperature high pressure cell for neutron scattering. Combining a water cooled Nb1Zr pressure cell body with an internal heating furnace, the sample environment can reach temperatures of up to 1500 K at a pressure of up to 200 MPa at the sample position, with an available sample volume of about 700 mm(3). The cell material Nb1Zr is specifically chosen due to its reasonable mechanical strength at elevated temperatures and fairly small neutron absorption and incoherent scattering cross sections. With this design, an acceptable signal-to-noise ratio of about 10:1 can be achieved. This opens new possibilities for quasielastic neutron scattering studies on different types of neutron spectrometers under high temperature high pressure conditions, which is particularly interesting for geological research on, e.g., water dynamics in silicate melts.