The development of a multiphase flow meter without separation based on sloped open channel dynamics

The online continuous measurement of multiphase flow is one of the most key technologies which influences the development of oil industry in future. A new type of multiphase meter system is developed based on the open channel flow. The test pipe of the meter is slightly slopped to make the flow pattern mainly stratified flow. Based on the study of oil and gas flow dynamics in the open channel test pipe, the liquid metering model and gas metering model are deduced to calculate the gas and the liquid flow rate, the water cut is measured online by the principle of differential pressure. This device can work online without the separation of the production fluid. By the lab test and field application test, the results of the metering system show that the liquid flow rate errors are within ±5%, the gas flow rate errors can be within ±5%, and the water cut absolute error is within ±2%, which can meet the demands of the field flow rate measurement.     

A new visualisation and measurement technology for water continuous multiphase flows

This paper reports the performance of a research prototype of a new multiphase flow instrument to non-invasively measure the phase flow rates, with the capability to rapidly image the flow distributions of two- and three-phase (gas and/or oil in water) flows. The research prototype is based on the novel concepts of combining vector Electrical Impedance Tomography (EIT) sensor (for measuring dispersed-phase velocity and fraction) with an electromagnetic flow metre (EMF, for measuring continuous-phase velocity with the EIT input) and a gradiomanometer flow-mixture density metre (FDM), in addition to on-line water conductivity, temperature and absolute pressure measurements. EIT–EMF–FDM data fusion embedded in the research prototype, including online calibration/compensation of conductivity change due to the change of fluids' temperature or ionic concentration, enables the determination of mean concentration, mean velocity and hence the mean flow rate of each individual phase based on the measurement of dispersed-phase distributions and velocity profiles. Results from first flow-loop experiments conducted at Schlumberger Gould Research (SGR) will be described. The performance of the research prototype in flow-rate measurements are evaluated by comparison with the flow-loop references. The results indicate that optimum performance of the research prototype for three-phase flows is confined within the measuring envelope 45–100% Water-in-Liquid Ratio (WLR) and 0–45% Gas Volume Fraction (GVF). Within the scope of this joint research project funded by the UK Engineering & Physical Sciences Research Council (EPSRC), only vertical flows with a conductive continuous liquid phase will be addressed.     

Influence of microstructure on erosion resistance of steels

Erosive wear due to solid particle impingement is a very intensive degradation process of surface layers of metallic materials. Erosion resistance is influenced by the working conditions (impact angle, impact velocity of solid particles, size, shape, hardness and amount of impinging particles) and the parameters of the worn material like hardness and microstructure. In our experiments some structural and tool steels were tested by slurry with SiO₂ particles at a flow velocity of 20 m/s. The microstructures of the tested steels were modified in a broad range by changing the conditions of their heat treatment. Increasing pearlite share in the structure of annealed carbon and low-alloyed steels has a positive effect on their erosion resistance. The growing carbon content in the tested hardened steels increases their erosion resistance. Maximum erosion resistance was found in hardened chromium ledeburite steel. Hardened high-speed steel HS 11-0-4 in spite of its high hardness has lower erosion resistance than ledeburitic chomium steels. An increasing amount of retained austenite and decreasing carbide and martensite shares with growing quenching temperature of the tested ledeburitic chromium steels leads to the reduction of their erosion resistance.     

Direct numerical simulation of multiphase flow for arbitrary geometry using level contour reconstruction method

Direct numerical simulation of multiphase flow on fixed Eulerian grid became increasingly popular due to its simplicity and robustness. Some of the well-known methods include VOF, Level Set, Phase field, and Front Tracking method. Lately, hybridization of above methods gets its attention to overcome the disadvantages pertaining to each method. One hybrid approach developed by the author is the Level Contour Reconstruction Method (LCRM) which combines characteristics of both Front Tracking and Level Set method. Many engineering problems also contain complex geometry as boundary condition and proper representation of grid structure plays very important role for the successful outcomes. In this paper, an algorithm for handling arbitrary geometry inside fixed Eulerian computational domain with multiphase flow has been presented. Interface reconstruction between liquid and vapor phase has been performed outside of arbitrary solid boundary explicitly along with dynamic contact angle model. Sharp interface technique using ghost fluid point extrapolation method has been utilized for correct implementation of no-slip boundary condition at the wall. This paper was presented at the 7th JSME-KSME Thermal and Fluids Engineering Conference, Sapporo, Japan, October 2008. Seungwon Shin received his B.S. and M.S. degree in Mechanical Engineering from Seoul National University, Korea, in 1995 and 1998, respectively. He then received his Ph.D. degree from Georgia Tech in 2002. Dr. Shin is currently a Professor at the School of Mechanical and System Design Engineering at Hongik University in Seoul, Korea. Dr. Shin’s research interests include computational fluid dynamics, multiphase flow, surface tension effect, phase change process.     

Uncertainty analysis for multiphase flow: A case study for horizontal air-water flow experiments

This work describes the procedure used to define the measurement uncertainties of horizontal two-phase air-water flow experiments conducted to determine influences due to pipe diameter on pressure gradient on such flows. These experiments were performed with 4 different pipe diameters, always using the same test section length, therefore varying the length-to-diameter (L/D) ratio. Several parameters were measured, such as volumetric/mass flow rate, pressures, temperatures and pressure drop; other parameters were calculated, such as the superficial velocities of each fluid, as well as their corresponding properties. The main parameters studied were the flow patterns for different velocity configurations and the two-phase pressure drop to be used for model improvement, thus the importance of uncertainties analysis. The sources of uncertainty were defined, detailed, systematically studied and quantified. Also, the reproducibility capacity of the experimental setups were analysed through the uncertainty analysis and proving them to be able for future similar studies. The flow maps with their uncertainties could help understand the thresholds for each defined flow pattern region, and the plots of two-phase pressure drop variation with diameter confirmed the homogeneous model as a possible approach to calculate pressure drop if the uncertainties are considered.     

Performance analysis of a single-wire capacitance sensor for interface level measurement in stratified multiphase flows

A single-wire capacitance sensor can be used to measure the interface level of a conductive liquid in a stratified multiphase flow. This type of capacitive sensor uses the conducting core in an insulated wire as its first electrode, and the conductive fluid as its second electrode, separated by the wire insulation, producing a coaxial capacitor with a variable electrode length linearly correlated to the liquid level. Therefore in theory, there should be a linear relationship between the liquid level and measured capacitance value. However, at low liquid levels, the authors have observed a noticeable departure from the theoretical correlation in the way of an upward offset. The cause for such a departure is investigated by means of a simplified model geometry and attributed to an additional capacitance between the wire conductor and conductive plane provided by the liquid interface. Analytical and numerical modelling have been carried out to better understand this effect. Recommendations are given on how to correct it.     

Influence of heat and thermochemical treatment on abrasion resistance of structural and tool steels

Abrasive wear is responsible for intensive degradation of machine parts or tools. This process starts as an interaction between hard, mostly mineral, particles and the working surface. Methods of increasing the lifetime are based on application of abrasion resistant materials or creation of hard, wear-resistant surface layers or coatings on the surfaces of machine parts or tools. Carbon and low-alloy steels with different types of thermochemical treatment (case hardening, nitriding) are used in cases of low abrasion. Another method of increasing lifetime is the application of ledeburitic steels. The wear resistance of these steels depends on their chemical composition and heat treatment. The results of laboratory tests of thermochemically treated steels, heat-treated ledeburitic chromium steels and high-speed steels show the effect of the microstructure of these steels on their abrasion resistance. Abrasion resistance of carburized low-alloy steels is on the same level as in high-carbon structural and tool steels. In ledeburitic chromium steel maximum abrasion resistance was achieved by quenching from 1100 °C whilst in ledeburitic chromium–vanadium steel the optimum quenching temperature was 1150 °C. Growing abrasion resistance was caused by increasing amounts of retained austenite.     

Three-way PLS regression and dual energy gamma densitometry for prediction of total volume fractions and enhanced flow regime identification in multiphase flow

Dual energy gamma densitometry and 3-way partial least squares regression were applied to quantify the total volume fractions and improve flow regime identification in multiphase flow. Multiphase flow experiments were carried out with formation water, crude oil and gas from different North Sea gas fields in Statoil׳s High Pressure Multiphase Flow Loop in Porsgrunn, Norway. Four different flow regimes were investigated (stratified wavy, slug, dispersed and annular). A traversable dual energy gamma densitometer was used to measure the fluid densities in the pipe. Partial least squares regression was previously applied to identify multiphase flow regimes and quantify volume fractions of gas, oil and water. That study showed promising results for flow regime identification but the predictions of the total volume fractions were not acceptable. In this study a new method combining gamma densitometry and 3-way partial least squares regression was applied in order to improve the quantitative estimation of the total volume fractions gained in the previous study. The proposed 3-way regression approach allows prediction of the total volume fractions directly using one model instead of multiple models which was reported earlier. The improved quantification of the volume fractions of gas, oil and water was used to improve the flow regime identification plots and increase the interpretability.The new 3-way prediction results for the volume fractions were significantly better than what was found earlier based on individual PLS models. The root mean square error of prediction for gas, oil and water from the 3-way PLS models were 4.1 %, 4.3 % and 4.6% respectively. All models reported were validated based on independent data (test set validation).     

A mesomodel for the numerical simulation of the multiphasic behavior of materials under anisothermal loading (application to two low-carbon steels)

The determination of residual stresses induced by welding or heat treatment operations requires the use of complex models taking into account thermal, metallurgical and mechanical phenomena. In this paper, we propose a mechanical model in which each phase can follow its own constitutive law. This model also takes into account phase transformation plasticity, which is treated independently of the behavior of each phase. This model has been implemented into the French FEM code Castem 2000. The interest of the proposed method is that it allows one to mix any type of nonlinear behavior using Taylor homogenization hypothesis. There is no need to develop a theory to get the equations of the homogenized material law. Two numerical examples demonstrate the efficiency and the flexibility of this approach. The results obtained are compared to experimental values for a typical welding situation and a high-temperature response. This comparison seems to indicate that viscous effects in the materials have a significative influence on the residual stresses produced by welding.     

In-situ heat treatment system for die steels using YAG laser with a machining center

We propose a laser heat treatment system for die steels using a YAG laser on the machine tool table. Optical fiber is used to transmit the laser light from a source to the machine tool table in this system, which makes it possible to perform the cutting processes, the heat treatment and the grinding processes with a machining center. In the present report, the experiments of laser heat treatment were done in order to research suitable die steels for this system. Additionally, the temperatures based on a theoretical model were investigated during the laser irradiation. As a result, it is clear that the martensite start temperature (Ms point) of materials is an important factor to estimate the application of this heat treatment.     

Current tools and techniques for EHL modelling

We describe the construction of genuine black box software to model in detail elastohydrodynamically lubricated contacts. Such models are necessarily built on a basis of sophisticated numerical software, since the operating parameters encountered in engine and machine components (e.g. an automotive valve train) span a very wide range of conditions from the nearly steady and hydrodynamic case to extreme EHD conditions with rapid transients. As transient phenomena are responsible for the non-failure of many machine components under EHD conditions, we regard the ability to model them as critical. The traditional correlations for lubricant oil film thickness (survey functions) do not account for transients. We are therefore using EHD modelling software as the core of several engine component simulation programs.     

ZSY450型硬齿面减速器高速齿轮轴加工工艺的改进

分析高速齿轮轴断裂的原因，提出了改进措施。     

Tool addition strategies for flexible manufacturing systems

The allocation of tools to machines determines potential part routes in flexible manufacturing systems. Given production requirements and a minimum feasible set of tools, the decision of how to fill vacant slots in tool magazines to maximize routing flexibility is shown to be a minimum cost network flow problem for the cases when routing flexibility is a function of the average workload per tool aggregated over tool types, or of the number of possible routes through the system. A linear programming model is then used to plan a set of routes for each part type so as to minimize either the material handling requirement or the maximum workload on any machine. The impact of these tool addition strategies on the material handling and workload equalization is investigated and computational results presented. The advantage of the overall approach is computational simplicity at each step and the ability to react to dynamic changes.This article is based upon work supported by the National Science Foundation under Grants No. DMC 85–44993 and DDM 92–15432.This work was done by the author while visiting the SIE Department of the University of Arizona.     

提高插孔热处理合格率的工艺改进

对某插孔热处理合格率低的原因进行了分析,从而开展了工艺改进试验。结果表明,用专用工装代替原来的钢丝捆扎工艺,并且适当延长热处理保温时间,提高了插孔热处理的合格率。     

差速器壳内端面反车刀柄设计与制造的解决方案

介绍一种特殊的反车刀柄的设计与制作方法、刀柄材料的选定及热处理淬火硬度要求.     

A complete procedure for leak detection and diagnosis in a complex heat exchanger using data-driven fuzzy models

In this paper, an efficient fuzzy model-based leak detection algorithm is designed for a pilot heat exchanger. A dynamic fuzzy model of the physical plant is first derived from input–output measurements using a fuzzy clustering technique. This model is run in parallel to the process for symptom generation. The leak detection mechanism has been tested and validated on the real co-current heat exchanger, and has proven to be efficient in detecting leaks of different magnitudes in the water circulation pipe.     

服务模型语义完备性判定方法与语义增强策略

为准确地表达服务,需要衡量对服务模型的语义表达能力,并对缺失部分进行语义增强.为此,提出一种基于图论的服务模型语义完备性判定方法.通过扩展子图引入超子图概念,给出了可服务模型语义完备性判定定理及证明.通过完备性验证算法及一系列度量指标,验证并度量了服务语义在服务模型表示中的完备程度,并根据验证和度量的结果,给出不同的语义增强策略.最后,在特定的服务语义范围内,对统一建模语言、业务流程建模符号和服务模型驱动的体系结构等三种模型的语义完备性进行了判定和对比分析.     

45钢制车床主轴的热处理工艺分析

根据车床主轴的服役情况,对材料的选用及相应的热处理工艺进行了详尽的分析,并就其操作技巧及质量控制要点提出了自己的观点。     

模具热处理变形的预防措施

通过模具热处理变形的原因分析，提出有关预防措施，以提高冲模寿命。