电磁流动成像测井提取流动参量方法研究

电磁流动成像测井可以实时测量油井内油、气、水在流动截面上的分布图像,进一步通过图像分析识别流体的流型,提取流动参量。根据油井内多相流体的流动特征和电磁流动成像测井原理,解析测量重建的流动图像,在分辨流型的基础上得到各相持率,然后通过相关计算获得各相的流动速度,从而获取流体动力学参量。

平行板微管道内的Jeffrey流体的电磁流动

研究了平行板微管道内线性黏弹性流体的电磁流动,其中线性黏弹性流体的本构关系是由Jeffrey流体模型来描述的。利用分离变量法,在无滑移条件和滑移条件下,求解了线性化的非定常柯西动量方程和Jeffrey流体本构方程,给出了黏弹性Jeffrey流体速度的解析表达式。通过数值计算,分析了无量纲雷诺数Re、哈特曼数Ha、弛豫时间λ1ω和滞后时间λ2ω对速度剖面的影响。结果表明,无量纲滑移长度α增大了流体的速度振幅,滑移条件下流体的速度大于无滑移条件下流体的速度。此外,随着哈特曼数Ha的增加,速度先增加后减少;随着弛豫时间λ1ω的增加,速度也变得越来越大;随着雷诺数Re和滞后时间λ2ω的增加,速度变得越来越小。

连铸板坯内部缺陷及结晶器内钢液电磁流动的控制

利用水模实验和流场数值模拟相结合的方法对连铸过程凝固壳俘获气泡和夹杂物的行为以及结晶器内钢液的湍流和气泡对夹杂物的吸附进行了研究。水模实验揭示了湍流的存在，说明液流在水口不同喷口处的流速不同。通过流场数值模拟估计了钢液流动的湍流流速。利用X射线扫描法，研究了与拉坯方向垂直的铸坯模截面的气泡分布。通过扫描电镜（SEM）观察黏附在气泡表面的Al2O3颗粒数量。为防止气泡进入钢液内部，采用流动控制结晶器（FC）和电磁水平稳定器（EMLS）2种类型的电磁流动控制系统来减少射流速度对结晶器窄边的冲击。

电磁流动成像测井识别气-水层流的信号处理方法

针对大斜度或水平气井中最常见的气-水分层流动,研究利用电磁流动成像测井判别分层流和波状流的方法。首先,分析水平或微倾圆形管道内较常见的气-水两相流型在管道截面上的特征,建立流体分布模型;其次,模拟流体分布模型的电磁流动成像测井响应,分析仿真数据特点;再次,提取仿真数据中与流体分布相关的特征参数,该参数不仅用于判定流体分布模型,而且用于计算分层流模型中的水层高度,从而求取持水率;最后,研究水平气-水两相流型在流动截面上流体分布模型的变化规律,实现气-水层流判别。仿真数据研究结果表明,用这种方法可以实现气-水层流判别和持水率求取,避免了图像重建的过程,计算简单速度较快。

多晶硅定向凝固过程中热电磁流动的数值模拟

采用基于有限元分析方法的COMSOL 4.3a多物理场仿真软件,模拟了稳恒磁场作用下,硅熔体在多晶硅定向凝固过程中热电磁流动的变化规律。结果表明,当0≤B<0.4T时,硅熔体流动区域以及平均流速随着磁感应强度的增大而增大,磁场对硅熔体的流动起促进作用;当磁感应强度为0.4T时,平均流速最大值为60.15μm/s,硅熔体流动能力最强;当0.4T<B≤1.0T时,硅熔体的流动区域以及平均流速随着磁场的增大而减小。相比增长阶段,下降幅度较快,磁场对硅熔体的流动抑制作用明显。根据热电磁流体动力学理论阐明了热电磁力和电磁力对热电磁流动的影响。

表面烧蚀对等离子体的影响及其与电磁场相互作用

表面烧蚀显著影响高速流动中等离体子鞘分布及其与电磁场相互作用的特征.考虑高超声速飞行器表面烧蚀引射机制、烧蚀产物参与流场等离子体生成过程、含碱金属的混合电离气体导电机理和电磁动力学机制,通过耦合求解带电磁源项的三维热化学非平衡流动控制方程、电场泊松方程和磁矢量泊松方程,建立了含碱金属烧蚀的高速流动/等离子体/电磁场耦合计算方法,结合常见的碳碳材料和硅基酚醛树脂材料烧蚀热解过程,较为系统地开展了多种条件下表面烧蚀对高超等离子体鞘影响及其与电磁场相互作用的机制与规律研究.研究表明:烧蚀效应对流场等离子体分布的影响受烧蚀质量引射率和碱金属质量占比共同作用,当碱金属含量较高时,碱金属电离反应占主导,电子数密度可增大1—2个数量级;不同材料烧蚀对等离子体的影响存在差别,硅基酚醛树脂的烧蚀质量引射率较大,电离生成CO^(+),C^(+)的摩尔分数接近空气主要电离组分NO^(+),O_(2)^(+),其影响不容忽视;烧蚀材料中碱金属可以显著提升磁流体力学控制效果,随着碱金属占比增大,电磁场耦合作用效果增强,二者呈非线性关系;在速度较低时,纯空气本身的电离度低导致电磁场耦合作用效果弱,通过含碱金属烧蚀来提升电磁作用效果的效率更高.

电磁流体流动对Al－Al_2Cu共晶形态的影响

研究了Ａｌ－３３％Ｃｕ共晶合金在电磁流体流动下的凝固行为．发现增加流速使Ａｌ－Ａｌ_２Ｃｕ共晶由规则层片状向非规则层片状、非规则棒状、直至规则棒状共晶形态转化，同时层片间距λ略有增加．流体流动造成的溶质重新分配是产生非规则层片共晶及其它形态共晶的主要原因．

阵列电磁传感器测量气水层状流持水率实验研究

基于非线性测量的电磁流动成像测井,几乎不受井斜角度的影响,对水平井的流动剖面测量提供全新的方法。研究利用电磁流动成像测井进行持水率计算和气水分层界面位置识别的方法。根据电磁流动成像测井方法原理设计制作阵列式电磁流动成像测井实验仪;研制实验装置,制定实验方案,进行气水两相水平流动模拟电磁成像测井实验;整理分析实验数据,计算持水率和气水分层界面位置。根据模拟流动实验数据计算持水率与实际持水率之间的相对误差小于2%,计算气水分层界面位置与实际层界面位置的相对误差小于3%。

阵列电磁传感器的频率特性测量实验研究

为了考察阵列电磁传感器的频率特性,在模拟实验装置上进行了全空气、全盐水以及50%空气-盐水测量实验。通过实验测量和观察,频率在1～10MHz内,实验测量信号强,基本保持稳定,且不同介质测量信号差异明显。利用实验数据绘制曲线图,通过对测量响应特征对比分析,工作频率为3MHz时,传感器可获得最高的灵敏度。

油井流动成像电磁测量相位场特性

为了探索电磁流动成像测井仪器激发的相位场信号的传播特性,本文根据实际电磁流动成像传感器的阵列电极结构,应用有限元方法进行正演仿真模拟,得到在不同持水率的层流环境下各电极所测量到的电位相位值,以及6种典型的相位敏感场分布.正演仿真结果表明,相位测量值随着持水率的增加而减小,相位敏感场只对靠近接收电极区域的敏感性较强.不同流型下的相位特征区别明显,表明了利用相位场数据进行电磁流动成像是可行的.

Effects of BYHW Decoction and Its Effective Constituents on the Fluidity of the Cell Membrane in a Stroke-Modeled Rat Brain

With in vitro spin labeling electron spin resonance (ESR) spectroscopy, we have studied the effects of Bu Yang Huan Wu (BYHW) decoction and its effective constituents such as astragaloside IV ferulic acid, chuanxiongzine, rutin, chlorogenic acid, 9,10 dimethoxy pterocarpane 7 O β D glucoside, calycosin, formononetin, calycosin 7 O glucoside, paeoniflorin, paeonal and quercein on the cell membrane fluidity of a rat brain which was modeled after the dual cervical arteries were intercepted and released for realizing an ischemia reperfusion injury which was selected as a brain stroke model. Our results indicated that the cell membrane fluidity in the model group decreased approximately 8% compared with the control group, and after brain cells were incubatied with species, the membrane fluidity could be recovered closely to the control level depending on the BYHW decoction and its different constituents. As the membrane fluidity is a very sensitive biological index which reflectsd the cell status, our method will be useful to study the molecular mechanism of tradition Chinese medicine (TCM) and its combination recipe.

Analytical Study of Magnetohydrodynamic Propulsion Stability

In this paper an analytical solution for the stability of the fully developed flow drive in a magneto-hydro-dynamic pump with pulsating transverse Eletro-magnetic fields is presented. To do this, a theoretical model of the flow is developed and the analytical results are obtained for both the cylindrical and Cartesian configurations that are proper to use in the propulsion of marine vessels. The governing parabolic momentum PDEs are transformed into an ordinary differential equation using approximate velocity distribution. The numerical results are obtained and asymptotic analyses are built to discover the mathematical behavior of the solutions. The maximum velocity in a magneto-hydro-dynamic pump versus time for various values of the Stuart number, electro-magnetic interaction number, Reynolds number, aspect ratio, as well as the magnetic and electrical angular frequency and the shift of the phase angle is presented. Results show that for a high Stuart number there is a frequency limit for stability of the fluid flow in a certain direction of the flow. This stability frequency is dependent on the geometric parameters of a channel.

Numerical simulation of busbar configuration in large aluminum electrolysis cell

Various busbar configurations were built and modeled by the custom code based on the commercial package ANSYS for the 500 kA aluminum electrolysis cell.The configuration parameters,such as side riser entry ratio,number of cathode bars connected to each riser,vertical location of side cathode busbar and short side cathode busbar,distance between rows of cells in potline,the number of neighboring cells,ratio of compensation busbar carried passing under cell and its horizontal location under cell along with large magnetohydrodynamic(MHD) computation based on the custom evaluation function were simulated and discussed.The results show that a cell with riser entry ratio of 11:9:8:9:11 and cathode busbar located at the level of aluminum solution,50% upstream cathode current passing under cell for magnetic field compensation,the distance between rows of 50 m is more stable.

Virtual test system for permanent-magnet DC motor

In order to obtain the primary parameters and operating characteristics of a DC motor without directly measuring its torque and rational speed, it is proposed to use a PC and a data acquisition card to acquire both the dynamic and static data of armature current to establish the performance of a DC permanent magnet motor. The accuracy and validity of this virtual test system proposed were verified by comparing the measurements made with the system proposed with the measurements made with conventional torque meters. It is concluded from the results of comparison that from the mathematic model established for the DC permant magnet motors, both major parameters and operating characteristics can be directly established for the DC motors without measuring their torques and rotational speed, a perfect on line measurement and test system has been established for the DC permanent magnet motors using the theory of virtual test system. The system proposed features shorter test time, higher efficiency and lower cost.

Research on hydrokinetics characteristics of rotating pipe fluid in the crossed electric and magnetic field

The rotating pipe fluid in the crossed electric and magnetic field not only suffered the forces in the steady condition, but also suffered Coriolis force, centrifugal force because of rotation and electromagnetic volume force. The motion equation of fluid and the hydrokinetics equations of rotating pipe were described in the Cartesians coordinates. The equations showed that the solutions to hydrokinetics equations of rotating pipe in the crossed electric and magnetic electromagnetic field were highly complicated and numerical calculations were also astronomical. The pressure distribution and temperature distribution of one dimension were solved using the electromagnetic equations set. The results showed that the fluid in rotating pipe was in the asymmetrical pressure field and temperature field because it was in the energy exchange and thermo-electrical coupling course. The primary characteristic of flow course could be expressed using the proposed hydrokinetics equations.

Calculation of optimal current density of double side permanent magnet linear synchronous motor

The use of design method considering a coil temperature to maximize the thrust density of a double side coreless permanent magnet linear synchronous motor(PMLSM) was presented.The optimal current density where the coil temperature reaches an allowable temperature with heat analysis was applied to a magnetic circuit design.Changing optimal current density is verified whenever the design parameters of the motor are altered.The design parameters of the motor were applied to thrust calculation.In this way,the optimal model,which is a reversal of the existing design method,is deduced.The results were compared with the experimental data to verify their validity.When the convection heat transfer coefficient is applied to other models,the results of the analysis and test values show good concordance.The method proposed has some limitations.

Highly Effective Brushless DC Motor in Which Unidirectional Current Flows in

Authors developed a highly effective brushless DC motor with a simple operation principle. If the operation principle of the motor is simple, a drive circuit will also become simple and its production cost will be lower. From the above fact, Minato motor was noticed. In this motor, a unidirectional current flows in the electromagnets. In other words, unidirectional windings are used. In this motor, only strong repulsive force is utilized when a permanent magnet of a rotor and an electromagnet of a stator are adjacent. Hence, torque constant becomes higher and the efficiency of the motor is high. However, an effective value of the electromagnetic current increases because a large current flows in a short period. Therefore, copper loss increases and the efficiency of the motor decreases. In order to solve above defects, a new motor is proposed. From the experiment, it is clarified that the efficiency of the proposed motor is higher than that of the commercial motors.

Corona-Support for the Entirety of High Energetic Disk

Based on results obtained from the study for MHD （magneto-hydrodynamics） of advective accretion disk, which are applied to real source showing typical values for CBS （close binary star-system）, it will investigate on self-structuring in the disk under the impact of the distribution of leading parameters （density, velocity ...）. The paper is considering the problem of development of the corona and will analyze the process of interaction of the plasma with the magnetic field in connection to support for the instabilities.

A new controller for the semi-active suspension system with magnetorheological dampers

A new sliding mode controller for semi-active suspension system with magnetorheological (MR) damper is presented in this paper. In the proposed sliding mode controller, a semi-active suspension based on the skyhook damper system is chosen as the reference model to be followed, and the control law is so determined that the asymptotically stable error dynamics occurs between the controlled state and the reference model state. Numerical simulations are carried out to study the performance of the new sliding mode controller. The results show that the proposed controller yields almost perfect tracking to the reference model and has a high robustness against model parameter uncertainties and disturbances.

Improving Residence Time Distribution in Glass Melting Tanks Using Additionally Generated Lorentz Forces

Continuous glass melting tanks represent thermo-chemical reactors with very complex flow patterns. Controlling the flow patterns within the glass melting tanks with the aim of improving their performance is one of the glass industry primary challenges. The tank performance is basically determined by the RTD （residence time distribution） of the glass melt, which directly impacts the glass quality and energy distribution. In the present work, numerical simulations are carried out on the electromagnetic flow control to investigate how well the flow can be controlled by externally generated electromagnetic （Lorenz） forces that are added to the glass melt. Furthermore, the melting tanks are equipped with supplementary electric heating systems called ＂electric boosters＂. The desired result would be an improved RTD. The electromagnetic flow control is called ＂electromagnetic boosting＂ and can be realized by exposing the glass bath to an external magnetic field generating Lorentz forces on the glass melt as an additional flow component. The numerical simulations of the present study require coupled calculations of electromagnetic field, flow field, and temperature field, because the material properties of glass melt are strongly temperature-dependent. The computational results show that electromagnetic boosting is an excellent way of improving the RTD in glass melting tanks, ultimately resulting in better glass quality and increased productivity. Of course, the glass industry is highly interested in achieving exactly this result.