翅片管气化器管内相变传热流动数值模拟

采用Fluent多相流混合物模型,通过用户自定义程序(UDF)实现了液氮相变模拟,模拟了不同进口流速对翅片管气化器管内流体换热量、压力降、含气率及汽化体积的影响,并分析了各参数随进口流速改变而变化的原因。由数值模拟可知,翅片管内流体进出口焓差、含气率及单位质量汽化体积随进口流速的增加而减少,而压力降和总换热量随进口流速的增加而增大,其中压力降增大的主要原因是由加速压降引起。     

一种新的恶二唑衍生物在金刚石对顶砧中的电阻率随压力和温度的变化关系

利用金刚石对顶砧测量了恶二唑衍生物微晶, 1,4-bis[(4-methyloxyphenyl)-1,3,4-oxadiazolyl]- 2,5-bisheptyloxyphenylene (OXD-2), 电阻随压力和温度的变化关系，并利用有限元分析方法计算了样品的电阻率。实验中，测量压力和温度达到了16 GPa和150℃。样品的电阻率随着温度的升高而降低，说明样品表现出半导体传导特性。在90-100 ℃之间，样品的电阻率有一明显的下降，说明这时发生了温度诱导的相变。随着压力的增加，样品的电阻率在6GPa左右达到最大值，此后随着压力的增加而下降。结合原位x光数据，在6GPa左右的电阻突变应该是由于样品在压力的诱导下发生了无序化的相变。     

天然气水合物相变测试用光纤传感器

介绍了一种用于海洋天然气水合物状态变化模拟实验中天然气水合物相变测试的光透射比光纤传感器.利用该传感器探测水合物状态变化过程中光透射比的变化，来测定水合物的相态变化.为了提高光纤传感器的测量准确度减小测量误差，在所研制的光纤传感器中采用了双光路结构，在测量透射光强的同时，测量参考光强以补偿光源光强的波动.另外，在光电转换电路中采用双探测器结构来消除光电探测器暗电流的影响.     

Boiling-up of liquid nitrogen jet in water

The hydrodynamic processes occurring at injection of cryogenic liquid into water pool were studied experimentally. Processes accompanying the phase transitions were registered. Data testify the developing pressure burst with an amplitude sufficient for possible formation of gas hydrates when methane is injected as a cryogenic fluid.     

InSe的高压电输运性质研究

高压下对InSe样品进行原位电阻率和霍尔效应测量. 电阻率测量结果显示, 样品在5–6 GPa区间呈现金属特性, 在12 GPa 的压力下发生由斜六方体层状结构到立方岩盐矿的结构相变, 且具有金属特性. 霍尔效应测量结果显示, 样品在6.6 GPa由p型半导体转变成n型半导体, 电阻率随着压力的升高而逐渐下降是由于载流子浓度升高引起的. 关键词： InSe 高压 电阻率 霍尔效应     

A transient method for measuring the gas volume fraction in a mixed gas-liquid flow using acoustic resonance spectroscopy

In this paper, the feasibility of measuring the gas volume fraction in a mixed gas-liquid flow by using an acoustic resonant spectroscopy (ARS) method in a transient way is studied theoretically and experimentally. Firstly, the effects of sizes and locations of a single air bubble in a cylindrical cavity with two open ends on resonant frequencies are investigated numerically. Then, a transient measurement system for ARS is established, and the trends of the resonant frequencies (RFs) and resonant amplitudes (RAs) in the cylindrical cavity with gas flux inside are investigated experimentally. The measurement results by the proposed transient method are compared with those by steady-state ones and numerical ones. The numerical results show that the RFs of the cavity are highly sensitive to the volume of the single air bubble. A tiny bubble volume perturbation may cause a prominent RF shift even though the volume of the air bubble is smaller than 0.1% of that of the cavity. When the small air bubble moves, the RF shift will change and reach its maximum value as it is located at the middle of the cavity. As the gas volume fraction of the two-phase flow is low, both the RFs and RAs from the measurement results decrease dramatically with the increasing gas volume, and this decreasing trend gradually becomes even as the gas volume fraction increases further. These experimental results agree with the theoretical ones qualitatively. In addition, the transient method for ARS is more suitable for measuring the gas volume fraction with randomness and instantaneity than the steady-state one, because the latter could not reflect the random and instant characteristics of the mixed fluid due to the time consumption for frequency sweeping. This study will play a very important role in the quantitative measurement of the gas volume fraction of multiphase flows.     

致冷剂简单气体水合物相平衡计算

本文从统计热力学理论出发,结合ｖａｎｄｅｒＷａａｌｓ－Ｐｌａｔｔｅｅｕｗ理想固溶休假设。给出ＨＦＣ１５２ａ和ＨＣＦＣ１４１ｂ简单气体水合物相平衡计算模型,并进行计算。计算结果与实验数据进行比较,很好吻合,正确反映了简单致冷剂水合物的相平衡规律。本研究为进一步混合气体水合物相平衡计算打下基础。     

螺旋管内气液固三相流颗粒相分布规律

为了深入认识螺旋管多相流相分离现象,并为新型螺旋管除砂器设计提供指导,本文应用马尔文粒度仪,测量了螺旋管气水砂三相流底部水平段液膜中的颗粒浓度和粒度分布。研究表明:在泡状流和分层流条件下,螺旋管底部水平段可形成稳定的连续液膜流动;在宽广的气速范围内,液膜中的颗粒浓度分布规律均为内弯侧较低、外弯侧较高,说明螺旋管除砂器对于实际生产中流动工况的变化具有良好的适应性;泡状流中提高气速有利于分离;分层流中在中等气速条件下外弯侧颗粒浓度最大,中等气速是相分离的最佳操作工况。     

金刚石对顶砧中四点探针法精确测量样品电阻率的电极因素

 为了解金刚石对顶砧上电阻率高压原位测量中的电极效应,使用有限元分析方法,对样品中的稳恒电流场进行了模拟计算,发现电极的几何尺寸以及电极与样品电阻率的差别都会对测量误差产生影响。结果发现：电极的尺寸越大,误差越大;电极与样品电阻率数值差越大,误差越大。由此给出了减小电极效应以及减小测量误差的方法。     

天然流体包裹体中甲烷水合物生成条件原位变温拉曼光谱研究

准确获取流体包裹体中气体水合物的生成条件一直是传统包裹体分析方法面临的一个难题。文章采用原位拉曼光谱技术分析了天然流体包裹体中甲烷水合物的生成条件。并由常温拉曼光谱分析表明,研究流体包裹体的流体组成为CH4-H2O体系。通过三种方法控制实验温度的变化,在第三种方法实验条件下获得了-170 ℃时甲烷水合物与冰的拉曼光谱,逐渐升温原位观测甲烷水合物的消失温度。原位拉曼光谱检测结果表明,研究包裹体中甲烷水合物的生成温度为7.5 ℃。结合CH4-H2O体系水合物形成条件相平衡计算,得到包裹体中甲烷水合物生成时的压力为5.587 3 MPa。研究结果表明,原位拉曼光谱技术是准确获取流体包裹体种气体水合物生成条件的一种有效方法。     

Theoretical investigation of structures and compositions of double neon-methane clathrate hydrates,depending on gas phase composition and pressure

The region of existence of neon clathrate hydrates is an actual problem of hydrate chemistry. The current work presents theoretical study of the equilibrium formation conditions of pure neon clathrate hydrates and double clathrate hydrates of neon-methane mixture. The structures and properties of double clathrate hydrates were described within the scope of the previously developed molecular clathrate hydrate model that takes into account the influence of guest molecules on the host lattice, interaction of guest molecules between themselves, and the possibility of multiple filling of host lattice cages by guest molecules. The model makes it possible to find an equilibrium state and thermodynamic properties of clathrate hydrates at given values of p and T. In the present work, we considered the properties of double clathrate hydrates in the range of pressures from 0 to 4 kbar at 250 K. The results of modeling have shown that the mass fraction of neon in double clathrate hydrate of Ne and CH₄ mixture of cubic structure I (sI) can reach 26%, and 22.5% in double hydrate of cubic structure II (sII) even at a low methane concentration (1%) in gas phase, at high pressure. It is shown that in double clathrate hydrates of the Ne and CH₄ mixture at high pressures, phase transition sII-sI can occur.     

螺旋轴流式多相泵外特性实验研究

本文在建立多相混输泵实验装置的基础上,以自行设计的螺旋轴流式多相泵原理机为实验研究对象,分别以纯水、空气—水为实验介质,系统地研究了多相泵的泵轴转速、进口压力、混合物特性等对多相输送性能的影响,为多相泵的进一步开发研制及完善设计提供了试验资料。     

三维感应成像测井仪设计与实现*

砂泥岩薄互层电阻率准确测量是提高泥质砂岩储层计算的一项重要工作。为了解决薄互层电阻率准确测量问题,该文提出一种三维感应成像测井仪的设计与实现方法。首先,基于感应电磁测量方法,设计由1个三轴发射器、4个单轴接收阵列和3个三轴的接收阵列组成的三维探测器。在此基础上,通过三维线圈系参数与结构创新设计、多频循环发射、高精度多道同步采集、高性能发射接收一体化集成等技术实现,在每一个深度点可获取78个电导率测量值。最后,利用数据校正与处理技术来消除各种环境影响,经过理论模型和实际资料的处理结果均证实,该仪器处理得到5条不同径向探测深度的水平电阻率与垂向电阻率、地层倾角等曲线,实现了对薄互层电阻率的准确测量。     

二氧化碳-甲烷混合气体水合物四相区实验研究

以水合物的形式封存CO₂和置换海底的天然气（CH₄）水合物需要对CO₂-CH₄混合水合物的四相平衡状态及数据有清楚的了解。本文通过实验和模型计算对不同组分的CO₂-CH₄混合水合物的较高四相区（Q2）相平衡进行了测定和表述。实验温度范围为273.16～297 15 K,压力范围分为0～10 MPa。四相区的温度压力范围分别是283.51到287.04 K和4.74到8.37 MPa,甲烷的摩尔组份为0～0.225。结果揭示了相平衡温度和压力随着甲烷组分而变化情况以及四相区的范围和临界点,同时还给出了CO₂-CH₄混合气体水合物在四相状态下的融化开始和融化结束点。实验结果与热力学模型计算得出的CO₂-CH₄混合气体水合物相平衡结果进行比较,两者很好吻合,四相平衡区域的存在范围得以明确。     

An experimental study on the acoustic absorption of sand panels

Potentially sand panels could be used as novel sound absorbing materials that are fire resistant, environmentally friendly, mechanically strong and have good durability. However, the performance of sand panels as sound absorbers has not yet been studied. Results of measurements in a reverberation chamber of the random-incidence absorption coefficients of 13 different sand panel compositions and configurations with air gaps are reported. Also the flow resistivities and bulk densities have been measured. The results prove that sand panels could offer effective and wide-band acoustic absorption. As is the case with conventional sound absorbing materials, adding an air space is found to be the most effective way to widen the absorption bands and improve the overall absorption. Comparisons of the measured sand panel absorption data with predictions of the Delany and Bazley and Voronina models reveal that, while neither model is very accurate, the former gives more accurate predictions especially for sand panels with lower flow resistivity and smaller thickness.     

High pressure behaviour of liquid caesium

This paper deals with the anomalous behaviour of liquid caesium at high pressures. A model for the phenomenon of electron collapse in the liquid phase, based on the anomalous density variation of liquid caesium with pressure has been proposed. The process of 6s→5d electron collapse is pictured as the formation of a virtual bound state and the tunnelling process accounts for the 6s⇌5d dynamic conversion. The same model together with the Friedel sum rule has been used to explain the resistivity variation of liquid caesium with pressure. The resistivity minimum observed in most of the liquid alkali metals in the low pressure region has been explained. The agreement with the experimental curve is good in the low pressure region whereas a large discrepancy exists at higher pressures. This may be due to the breakdown of the Ziman’s resistivity formula under conditions of resonance scattering.     

Monitoring the presence of water and water–sand droplets in a horizontal pipe with Acoustic Emission technology

Monitoring of multiphase flow is a process that has been established over several decades. This paper demonstrates the use of Acoustic Emission (AE) technology to detect and monitor moving water and water–sand droplets in a horizontal pipe. The experimental investigation considered two types of droplets, water and water–sand with average droplet volumes ranging from 1 ml to 5 ml. The experimental findings show good correlation between AE energy, droplet volume and the superficial gas velocity (V_SG).     

Decreasing electrical resistivity of silver along the melting boundary up to 5 GPa

The electrical resistivity of Ag was experimentally measured at high pressures up to 5?GPa and at temperatures up to ～300?K above melting. The resistivity decreased as a function of pressure and increased as a function of temperature as expected and is in very good agreement with 1 atm data. Observed melting temperatures at high pressures also agree well with previous experimental and theoretical studies. The main finding of this study is that resistivity of Ag decreases along the pressure- and temperature-dependent melting boundary, in conflict with prediction of resistivity invariance. This result is discussed in terms of the dominant contribution of the increasing energy separation between the Fermi level and 4d-band as a function of pressure. Calculated from the resistivity using the Wiedemann–Franz law, the electronic thermal conductivity increased as a function of pressure and decreased as a function of temperature as expected. The decrease in the high pressure thermal conductivity in the liquid phase as a function of temperature contrasts with the behavior of the 1 atm data.     

稠密可压缩气粒两相流动中的等熵声速计算建模及物理规律

气体相与颗粒相混合流场的声速研究, 由于具有重要的基础理论价值与广泛的工程应用背景, 逐渐受到人们重视. 针对稠密可压缩气粒两相流动, 综合考虑颗粒相所占空间体积以及颗粒间相互作用, 推导给出了新的等熵声速计算公式; 新公式包含了已有的纯气体、稀疏气粒两相流情形的计算公式作为其特例, 一方面验证了公式推导的正确性, 另一方面说明新公式更具有通用性; 分析了不同颗粒质量分数条件下的声速变化规律, 相应结果与普朗特的理论分析符合, 特别对于稠密气粒两相流动工况得到了一些新的物理认识; 开展了颗粒间相互作用建模参数的物理分析, 揭示了其对气粒两相流动声速的影响机理. 本文取得的成果为稠密可压缩气粒两相流动研究以及相关工程应用提供理论支撑.     

Electrical resistivity of fluid methane multiply shock compressed to 147 GPa

Shock wave experiments were carried out to measure the electrical resistivity of fluid methane. The pressure range of 89–147?GPa and the temperature range from 1800 to 2600?K were achieved with a two-stage light-gas gun. We obtained a minimum electrical resistivity value of 4.5?×?10^?2?Ω?cm at pressure and temperature of 147?GPa and 2600?K, which is two orders of magnitude higher than that of hydrogen under similar conditions. The data are interpreted in terms of a continuous transition from insulator to semiconductor state. One possibility reason is chemical decomposition of methane in the shock compression process. Along density and temperature increase with Hugoniot pressure, dissociation of fluid methane increases continuously to form a H₂-rich fluid.