Influence of viscosity variation on ferrofluid based long bearing

This paper deals with a theoretical analysis on the effect of viscosity variation on a ferrofluid based long bearing. The model of Tipei considering viscosity variation is deployed here. The magnetic fluid flow is governed by Neuringer-Rosensweig model. The pressure distribution is obtained after solving the associated Reynolds type equation, which gives the load carrying capacity. The computed results indicate that the increased load carrying capacity owing to magnetization gets negligible help from the effect of viscosity variation.

Research on Pressure Measuring Device with Magnetic Fluid

Magnetic fluid is a novel material which could be applied in many fields including sensors, sealings, bilmedicines, and so on. Its super magnetism and fluidity could be used in the sensor as an inducting core. Magnetic fluid and its characteristics were introduced to adapt to the application in the pressure measuring devices. A pressure measuring device with magnetic fluid was proposed and the structure was analyzed and designed according to the characteristics of magnetic fluid. The working principle of pressure measuring device with magnetic fluid was analyzed, and the structure of pressure measuring device was designed and reformed to avoid the overflow and recovery of excessive of magnetic fluid. One arm of the U tube was designed to be a large cylinder to storage large quantities of magnetic fluid. The higher the required precision is, the larger the diameter of one arm should be designed with respect to the other arm of the tube. The measuring range of designed device could also be adjusted as needed. The measuring efficiency of the device could be improved by the designing and reforming work.

Wave instability of a magnetic fluid surface at the boundary with water in an electric field

Свойства межфазной поверхности магнитной жидкости на границе с водой в электрическом поле изучались во многих работах. Были обнаружено изменение отражательной способности межфазной поверхности вода – магнитная жидкость в электрическом поле, что авторами связывается с образованием на межфазной границе слоя плотноупакованных частиц. По оптическим и электрическим измерениям оценена толщина d этого слоя. Интерес к этим эффектам, помимо чисто академического, связан с возможностью управления поведением межфазной границы раздела магнитного коллоида и гомогенной жидкости внешним электрическим полем, что представляет практический интерес, поскольку слой частиц магнетита на межфазной поверхности может быть интерпретирован как жидкая мембрана с особыми свойствами. Задача настоящего исследования – теоретически показать, что образование слоя частиц дисперсной фазы магнитной жидкости в электрическом поле и связанное с этим уменьшение межфазного натяжения является определяющим фактором для развития волновой неустойчивости. A layer of close-packed particles of a dispersed phase (magnetite) with a protective shell of oleic acid is formed on the interface of a weakly conducting magnetic colloid (magnetic fluid) and water in a perpendicular electric field. The formation of a layer leads to a decrease in the interfacial tension. When the magnetic particles come into contact with the electrode surface, the electrochemical interaction of oleic acid molecules surrounding the particle with water occurs. As a result of the reaction, released ions charge the surface layer. After some time, the particles in the layer get recharged and repelled from the interface. This leads to wave instability. This paper considers the mathematical modeling of instability in the form of a boundary value problem – a dispersion equation. The determining factor in the development of wave instability is the action of the electric field, the formation of the near-electrode layer and, as a consequence, a decrease in the interfacial tension.

Asphaltene Management Leading to Significant Reduction of Production Deferment Through New Technology Trial MFC Tool

In Southern Oman, PDO is producing from several high pressure (500-1000 bar), deep (3-5 km) and sour fields (1-10 mol % H2S). Over time, wells from one field (S A3) started having asphaltene deposition in the wellbore. Recently, the impact on production became severe resulting in high deferment, increased HSE exposure with plugging and high intervention costs. Asset team kicked off an asphaltene management project to tackle this problem, with one initiative being a field trial of a new technology, Magnetic Fluid Conditioner (MFC) to avoid/delay asphaltene plugging in the wellbore. This paper discusses the asphaltene management strategy and field trial results from this new tool deployed to prevent/delay asphaltene deposition.

All Fiber Mach–Zehnder Interferometer Based on Intracavity Micro-Waveguide for a Magnetic Field Sensor

A magnetic fluid (MF)-based magnetic field sensor with a filling-splicing fiber structure is proposed. The sensor realizes Mach–Zehnder interference by an optical fiber cascade structure consisting of single mode fiber (SMF), multimode fiber (MMF), and single-hole-dual-core fiber (SHDCF). The core in the cladding and the core in the air hole of SHDCF are used as the reference and sensing light path, respectively, and the air hole of SHDCF is filled with magnetic fluid to realize magnetic field measurement based on magnetic controlled refractive index (RI) characteristics. The theoretical feasibility of the proposed sensing structure is verified by Rsoft simulation, the optimized length of SHDCF is determined by optical fiber light transmission experiment, and the SHDCFs are well fused without collapse through the special parameter setting. The results show that the sensitivity of the sensor is −116.1 pm/Gs under a magnetic field of 0~200 Gs with a good long-term operation stability. The proposed sensor has the advantages of high stability, fast response, simple structure, and low cost, which has development potential in the field of miniaturized magnetic field sensing.