往复压缩机用新型耐高温、高压活塞环

针对高温、高压工况下使用的聚醚醚酮（PEEK）和聚酰亚胺（PI）活塞环。以PEEK和PI两种高分子树脂为基体的复合材料的机械强度、耐温特性、耐摩擦特性、成型加工性能和产品的结构设计方面进行了研究，枇量生产了高温、高压工况下使用的活塞环并被国内主流压缩机厂正式采用。     

Spectrographic temperature measurement of a high power breakdown arc in a high pressure gas switch

A procedure for obtaining an approximate temperature value of conducting plasma generated during self-break closure of a RIMFIRE gas switch is described. The plasma is in the form of a breakdown arc which conducts approximately 12 kJ of energy in 1 μs. A spectrographic analysis of the trigger-section of the 6-MV RIMFIRE laser triggered gas switch used in Sandia National Laboratory's "Z-Machine" has been made. It is assumed that the breakdown plasma has sufficiently approached local thermodynamic equilibrium allowing a black-body temperature model to be applied. This model allows the plasma temperature and radiated power to be approximated. The gas dielectric used in these tests was pressurized SF(6). The electrode gap is set at 4.59 cm for each test. The electrode material is stainless steel and insulator material is poly(methyl methacrylate). A spectrum range from 220 to 550 nanometers has been observed and calibrated using two spectral irradiance lamps and three spectrograph gratings. The approximate plasma temperature is reported.     

Characteristics of pressure and force considering friction in a closed cylinder with a holed piston

A mathematical model for a closed cylinder with a holed piston was established to investigate the operational characteristics of a gas spring. An ideal gas working fluid and an adiabatic process were assumed in the model. Simulation and experimental results for a typical design and operational condition showed good agreement. The model was then used to investigate the effects of the orifice diameter, the filling pressure, and the velocity of the piston on the applied force and operating pressures of two chambers in the gas spring. The results showed that the orifice diameter and the piston velocity had significant effects on the pressure difference between the two chambers. A 0.05-mm reduction in the orifice diameter led to an approximately two-fold increase in the pressure difference. A 10% increase in the piston velocity resulted in an approximately 25% increase in the pressure difference. The orifice diameter and the piston velocity had a greater effect on the chamber with lower pressure than on the chamber with higher pressure. The force applied to the piston also varied with the piston velocity, the orifice diameter, and the filling pressure due to irreversibilities including the throttling process through the orifice and friction between the wall and the piston. The present model and results are expected to supply useful information about a new gas spring design.     

一种高温高压燃气电磁阀的设计与研究

主要介绍一种高温高压燃气电磁阀的功能原理、结构特点以及材料的选取,对重要执行部件——芯轴受力进行分析,同时对其动密封间隙进行改进,将燃气泄漏量降低,提高燃气发生器的工作效率。     

Modified apparatus for low temperature/high pressure Mossbauer absorber studies

A method is described in which a system designed to study Mossbauer sources as a function of pressure and temperature is modified to include absorbers as well. This is accomplished by coupling the Mossbauer source, mounted inside a cryostat, to an external transducer by means of a bellows. In addition, a simple modification has converted an existing helium Dewar to a dynamic gas flow cryostat. Temperature can be continuously varied from 300 to 20 K at pressures up to 200 kilobars.     

Measuring radial pressure distributions of piston rings based on partial-thin-walled cylinder

The measurement of radial pressure distribution of piston rings is very important for minimizing the wastages of lubricating oils and hence the lower gas emissions; for improving the friction status to reduce the gasoline consumption and for the reasonable heat transfer efficiency for the desired accuracy levels. For accurate and efficient measurement of radial pressure distribution of piston rings, a new PC based prototype instrument based on a partial-thin-walled cylinder sensor is designed and developed. The present paper describes the details of the measurement principle, hardware and software of this instrument. The measurement results thus obtained using the proposed instrument during experiments performed on a conical ring of diameter 110 mm and a drum ring of diameter 120 mm, are quite accurate, consistent and repeatable within the desired level of accuracy.     

特种高压无缝气瓶容积残余变形率的测试

本文综合比较了耐压试验中测定气瓶容积残余变形率的内测法和外测法的优缺点,得出外测法具有测试方便,装置可靠,数据准确的特点;通过和试验验证,设计了一套在水压试验的同时测定特种高压无缝气瓶容积残余变形率的外测法试验装置.     

Energy dissipation of materials at high pressure and high temperature

We report an experimental method to study the anelastic properties of materials at high pressure and high temperature. The multianvil high pressure deformation device, used to apply a cyclic loading force onto the sample, can reach 15 GPa and 2000 K. A synchrotron x-ray radiation source provides time resolved images of the sample and reference material. The images yield stress and strain as a function of time; stresses are derived from the reference material, and strains from the sample. This method has been tested by applying a sinusoidal stress at megahertz to hertz frequency on a San Carlos olivine specimen at 5 GPa and up to 2000 K. Strain as small as 10(-5) can be resolved. We have obtained experimental results which exhibit resolvable attenuation factor (Q(-1)) and shear modulus (M) at deep Earth conditions. These results are in quantitative agreement with previously reported lower pressure data and suggest that temperature and grain size have dominating effect on these properties.     

高压环境下温度传感器矫正系统研制及应用

现有的热敏电阻温度传感器在高气压环境下使用时大都会出现温度测试值不准的问题,对同样温度的热源在常压与高压下进行温度测试的结果偏差较大,表明该类温度传感器在高压环境下使用存在较大的偏差。本研究设计了一套高压下使用的温度矫正系统来解决高压下温度测试不准的问题,通过加压舱内设置水银温度计与热敏电阻温度传感器的对比测试,得出测试温度与矫正温度的数据,并通过数据拟合的方式得出矫正公式,为常用温度传感器在高压下的矫正使用提供了合理的技术支持。     

一种力平衡气体活塞压力计原理及不确定度验证

文章介绍了一种新型的、用于微小表压和绝压测量的力平衡式气体活塞压力计的工作原理、压力复现的计算公式以及不确定度等,并在表压状态下,通过与标准比对的方式,对该气体活塞压力计的原理及宣称的不确定度进行了实验验证,实验结果证明了厂商给出的不确定度指标的正确性.     

Calculation of mixed lubrication at piston ring and cylinder liner interface

This paper reports on the theoretical analysis of mixed lubrication for the piston ring. The analytical model is presented by using the average flow and asperity contact model. The cyclic variations of the nominal minimum oil film thickness are obtained by numerical iterative method. The total friction is calculated by using the hydrodynamic and asperity contact theory. The effects of the roughness height, pattern, and engine speed on the nominal minimum film thickness, friction force, and frictional power losses are investigated. As the roughness height increases, the nominal oil film thickness and total friction force increase. Also, the effect of the surface roughness on the boundary friction is dominant at low engine speed and high asperity height. The longitudinal roughness pattern shows lower mean oil film pressure and thinner oil film thickness compared to the case of the isotropic and transverse roughness patterns.     

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).     

发动机活塞捣缸故障的诊断分析

从缸套与缸体的配合精度、散热冷却、活塞组与缸套的装配 ,分析了活塞捣缸故障发生的原因     

Effect of cyclic internal pressure on the temperature distribution in a viscoelastic cylinder

A modified numerical method is introduced to study the interaction between the heat and dynamic response of viscoelastic bodies with temperature-dependent properties. The method is applied to calculate the stress and temperature distributions in a viscoelastic cylinder subjected to cyclic internal pressures. It is found that a large temperature rise may occur due to the interaction, where the value depends upon the thermal and mechanical properties of the material, cylinder size and the frequency of the applied pressure.     

Note: development of fast heating inert gas annealing apparatus operated at atmospheric pressure

Here, we report the development of a simple, small, fast heating, and portable, homemade, inert gas (Ar) atmospheric annealing setup. Instead of using a conventional heating element, a commercial soldering rod having an encapsulated fast heating heater is used here. The sample holder is made of a block of stainless steel. It takes 200 s to reach 700 °C, and 10 min to cool down. The probability of oxidation or surface contamination has been examined by means of x ray photoelectron spectroscopy of virgin Cu sample after annealing at 600 °C. In addition, we compare the annealing of a hydrogenated carbon nitride film (HCN(x)) in both a conventional vacuum and our newly developed ambient Ar atmosphere setup.     

In situ pressure calibration for piston cylinder cells via ruby fluorescence with fiber optics

A fiber-optic measurement technique is developed for estimating the pressure inside a piston cylinder cell up to approximately 4 GPa, based on the pressure-induced R1 fluorescence line shift of ruby (ruby scale). Ruby scale and a conventional technique (calibration on phase transitions of bismuth) were simultaneously applied to the cell filled with a pressure transmitting medium of isopropyl alcohol. The pressure readings of the two methods were consistent with each other, and no pressure gradient was observed. The ruby scale has the advantages of real time estimation and easy installation in a small space. Because of these advantages, three fibers were simultaneously introduced in the sample space at the same time, and pressure distribution was measured for Fluorinert (FC70:FC77=1:1), Daphne oil 7373, and Fomblin oil (YHVAC 13014).     

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.     

Wet gas overreading characteristics of a long-throat Venturi at high pressure based on CFD

Based on the operational conditions of the PetroChina Southwest Oil & Gas well field, this study aims to explore the wet gas flow overreading (OR) characteristics of a nonstandard long-throat Venturi by the means of computational fluid dynamics (CFD) technique. The studied prototype structure size is an inner diameter of 50 mm, a diameter ratio of 0.4 and a throat length of 50 mm. According to the field experiment, the simulation pressure is 3 MPa gauge. Through a comparative study of the multiphase flow models and turbulence models, combined with the analysis of the Baker׳s flow regime and interparticle space under the field conditions, this paper eventually employed DPM model and Eulerian model for wet gas simulation, respectively, and RSM for turbulence model. An equivalent droplet diameter adjustment method was implemented to improve the precision of prediction. During post-processing, the liquid phase distributions and the wall pressure profiles were investigated. The numerical results indicate that the differential pressure in convergent section of long-throat Venturi by using DPM model is less than that by using Eulerian model, and the differential pressures in the divergent section by using the two models are analogous. Afterwards, the OR prediction correlations based on the differential pressure ratio method were proposed, and then compared and validated by the industrial field tests. The root mean square errors (RMSE) and the average relative errors predicted by Eulerian model were 4.24% and 3.78%, 5.69% and 5.01% by using DPM model, respectively. In conclusion, Eulerian model is more suitable for wet gas flow prediction. And some advice on the improvement of the multiphase flow simulation is provided to get a more preferable performance in wet gas flow prediction.     

用于恶劣环境的耐高温压力传感器

为了解决如高温200℃等恶劣环境下的压力测量问题,基于微机电系统(MEMS)和高能氧离子注入(SIMOX)技术,研制了一种量程为0~120 kPa的压阻式压力传感器。该传感器芯片由硅基底、薄层二氧化硅、惠斯登电桥结构的硼离子注入层、氮化硅应力匹配层、钛-铂-金梁式引线层和由湿法刻蚀形成的空腔组成。在氧剂量1.4×10¹⁸/cm²和注入能量200 keV条件下,由高能氧离子注入技术形成厚度为367 nm的埋层二氧化硅层,从而将上部测量电路层和硅基底隔离开,解决了漏电流问题,使得传感器芯片可以在高温200 ℃以上的环境下使用。为了提高传感器在宽温度范围内的稳定性,对温度补偿工艺进行了研究,补偿后的传感器灵敏度温度系数和零位温度系数很容易控制在1×10^-4/℃·FS。实验标定结果表明:在200 ℃下,研发的耐高温压力传感器具有很好的工作性能,其线性度误差达0.12%FS、重复性误差为0.1%FS、迟滞误差为0.12%FS,精度达0.197%FS,满足油井、风洞、汽车和石化工业等现代工业的应用需求。     

Creating a low-cost, ultra-clean environment

This paper describes a way to create a cleanroom environment with a limited budget, which may be useful to organizations requiring small amounts of very high quality surface processing. After a brief review of some general principles, it discusses the design, including practical constraints, and installation of a small facility in the University of Warwick. Based around standard bought-in items, it achieves cleanroom Class 10 000 (ISO Class 7) with local enclosures of better than Class 10 (ISO Class 4) air quality.