磁流体的光学特性及其在光电信息传感领域中的应用

详细介绍了磁流体的光学性质,包括磁流体的热透镜效应、磁光效应.磁流体折射率的可控性以及磁致分色效应.由于磁流体的光学性质具有可调谐性,这为磁流体在新型光子器件与光纤传感器的设计和研究提供了新原理.新材料.论述了应用磁流体设计的多路复用器、光开关、光纤调制器、可调谐磁流体光栅与可调谐滤波器,以及基于磁流体的光纤电流传感器原理和结构.     

磁性流体的制备及在防伪印刷中的应用

描述了磁流体的特性，不同种类磁流体的生产方法及应用状况，并着重阐述了磁流体在防伪印刷油墨中的应用前景，对提高磁性印刷的性能和拓展磁性印刷的应用提出了建议。     

化学共沉淀法制备水基磁流体的研究进展

简单地介绍了水基磁流体的组成、应用和特性,全面阐述了用化学共沉淀法制备水基磁流体的各种制备方法,重点介绍了用表面活性剂对磁性粒子进行二次包覆后,制备水基磁流体,以及该方法中表面活性剂的作用和加入时机。     

磁流体的热力学特性和应用

介绍了磁流体的组成及其所具有的温度、磁热效应，热磙对流和蒸发等热物理性能，以及磁流体膜在强化传热和减小流阻的作用，并详述了磙流体在热力学领域的具体应用，如热管、磁热泵、太阳能系统等，以此来拓宽对磁流体热应用方面的研究和应用思路。     

磁流体技术的发展及其应用

本文就磁流体及其制取技术的新发展,基于磁汉体特性而开发的磁流体应用技术及应用领域进行了全面的论述,文中最后还对我国进一步发展磁流体技术庆解决的一些问题进行了探讨。     

磁流体阻尼器的动态特性研究

通过实验研究了磁流体的阻尼力特性，提出了基于粘性阻尼和回滞阻尼组成的迟滞阻尼力模型，并应用迭代摄动法分析了含有磁流体阻尼器梁结构的特征值谱．结果表明：磁流体阻尼力可以显著地减小系统的振动，迭代摄动法是研究含有磁流体阻尼力非线性方程的有效方法。     

基于磁流体独有特性的各种潜在传感器

详细分析磁流体所具有的磁通门原理、粘度智能性、液体流动性、可浸泡性、磁光效应等各种独有特性,探讨基于上述特性的潜在传感机理及应用方向,将上述特性单独或组合使用,将可以开发出各类新型磁流体传感器,具有用于倾斜、速度、加速度、体积、流量、非磁性体或磁流体密度、磁场以及磁流体磁化强度等传感的潜在可能性,对磁流体传感器研究具有指导意义.     

水基磁流体的制备与性质研究

采用十二烷基硫酸钠进行磁性颗粒的二次改性 ,通过胶溶法制备稳定的水基磁流体。应用X -ray衍射仪、透射电镜对磁性颗粒的结构、粒径、形貌进行了表征 ,并探讨了制备条件对磁流体性质的影响     

磁流体的制备与性质研究

报道了采用十二烷基硫酸钠进行磁性颗粒的二次改性通过胶溶法制备稳定的磁流体。应用X射线衍射、透射电镜对磁性颗粒的结构、粒径、形貌进行了表征,并探讨了制备条件对磁流体性质的影响。     

磁流体太阳能集热器的温度和热流量特性的实验研究

由于磁流体有很好的吸热和传热特性，将其用作磁流体太阳能集热器的介质是很有应用前景的。设计了一个磁流体太阳能集热器用于温度和热流量特性试验，对2种磁流体进行了试验，结果显示：在磁流体静止不动的时候，磁流体太阳能集热器的磁流体温度可达60℃以上，最高的可达97℃；然而，当磁流体以5m的流速流动时，出口的最高温度仍可达65℃，热流量超过600W／m^2。另外，随着磁流体流速的加大，出口温度将会下降，而热流量则会增加，这对于太阳能集热器工作条件的选择（如温度和热流量的选择）有十分重要的意义。     

磁性液体的研究现状及典型应用

本文从理论研究和实验研究两方面，综述了国内外磁性液体的研究现状及发展。根据磁性液体的性质介绍了磁性液体的应用以及最新的应用进展。     

磁流体密封的磁路设计及磁场有限元分析

为了在磁流体密封结构的密封间隙内获得最大的磁能积以及提高磁流体密封的耐压能力,在磁路设计理论和磁流体密封理论的基础上,对一种并联型的磁流体密封结构进行磁路设计,采用有限元法数值计算出磁流体密封结构中的磁场从而计算出磁流体密封耐压能力,并对计算结果进行了分析和讨论。结果表明:极靴与永磁体结合处的漏磁以及中间极靴轴向长度较短,导致中间极靴与两侧极靴下密封间隙内的磁感应强度差成非线性关系,也导致了磁路法低于有限元法计算出的磁流体密封耐压能力;中间极靴下密封间隙内磁感应强度较大导致两侧极靴下密封间隙内的磁感应强度差近似相等。     

干式罗茨真空泵磁流体密封的研究

本文设计了干式罗茨真空泵的磁流体密封 ,对磁流体密封磁场进行了有限元分析 ,针对不同文献中磁流体密封耐压公式的不严密甚至错误 ,作者对磁流体密封耐压公式进行了严密推导 ,在实验台上验证了磁流体真空密封的效果、耐压能力及转速对真空度的影响。本设备近十年的连续运转证明 :在干式罗茨真空泵采用磁流体密封效果良好     

Effect of magnetic field on the heat and mass transfer in a vertical annulus

This paper reports the effect of axial or radial magnetic field on the double-diffusive natural convection in a vertical cylindrical annular cavity. The boundary conditions at the side walls are imposed in such a way that the thermal and solutal buoyancy effects are either cooperating or opposing, resulting in a cooperating gradients or opposing gradients flow configuration. The top and bottom walls are insulated and impermeable. The governing equations of this fluid system are solved by the Alternating Direction Implicit and the Successive Line Over Relaxation methods. Total heat and mass transfer rates across the cavity are calculated by evaluating the average Nusselt and Sherwood numbers. The main objective of the present numerical study is to understand the effect of magnetic field on the double-diffusive convection in the annular cavity. From the numerical results, it is found that the magnetic field suppresses the double-diffusive convection only for small buoyancy ratios. But, for larger buoyancy ratio, the magnetic field is effective in suppressing the thermal convective flow. Further, the magnetic field is effective when it is applied perpendicular to the main flow.     

磁性液体密封试验研究

在磁性流体密封理论的基础上计算了磁性流体密封的耐压能力，并进行了实验研究。结果表明当间隙在０．０５～０．３ｍｍ之间时密封能力较好。讨论了理论和实验结果之间的差异。     

Magnetic carbonyl iron nanoparticle based magnetorheological suspension and its characteristics

Magnetic nano-sized carbonyl iron (CI) particle was prepared and adopted as an additive for micron-sized CI based magnetorheological (MR) fluid, in which the magnetic nanoparticle was fabricated via decomposition of pentacarbonyl iron (Fe(CO)₅). Magnetic property and morphology of the nanoparticle were confirmed via vibration sample magnetometer (VSM) and transmission electron microscopy (TEM), respectively. MR fluids, consisting of micron-sized CI and carrier fluid, were investigated under different external magnetic field strengths via a rotational rheometer. Their flow behaviors at a steady shear mode were examined with and without a nano-sized magnetic additive under magnetic field strength. The MR fluid with magnetic CI nanoparticle added demonstrated slightly higher yield behaviors, suggesting that micron-sized CI and magnetic CI nanoparticle particle were being oriented in magnetic field direction under applied magnetic field and with strengthened structure.     

Thermal behaviour and particle size evaluation of primary clusters in a water-based magnetic fluid

This paper reports the experimental research on thermal behaviour and particle size evaluation of primary clusters of ferromagnetic nano-particles in a water-based magnetic fluid. The magnetic fluids are suspensions of ultra fine particles coated with a molecular layer of dispersant in a liquid carrier such as water or kerosene. The particles are coated with single- or double-layer of surfactant to achieve stable dispersion. Numerous experimental studies have indicated the existence of the primary cluster of ferromagnetic nano-particles in a water-based magnetic fluid. The purpose of this research is to evaluate the particle size of the primary clusters by applying the Einstein’s equation for Brownian motion assuming that the primary cluster has a spherical-shape. The thermal behaviour of ferromagnetic nano-particles in magnetic fluids is investigated through the micro visualization using the optical darkfield microscope system and particle tracking velocimetry data processing system. Real-time visualization of the Brownian motion of primary clusters in a water-based magnetic fluid was carried out. The experimental results clarified that the primary cluster size depends upon the concentration of the ferromagnetic nano-particle in the magnetic fluid.     

Thermal behaviour and particle size evaluation of primary clusters in a water-based magnetic fluid

This paper reports the experimental research on thermal behaviour and particle size evaluation of primary clusters of ferromagnetic nano-particles in a water-based magnetic fluid. The magnetic fluids are suspensions of ultra fine particles coated with a molecular layer of dispersant in a liquid carrier such as water or kerosene. The particles are coated with single- or double-layer of surfactant to achieve stable dispersion. Numerous experimental studies have indicated the existence of the primary cluster of ferromagnetic nano-particles in a water-based magnetic fluid. The purpose of this research is to evaluate the particle size of the primary clusters by applying the Einstein's equation for Brownian motion assuming that the primary cluster has a spherical-shape. The thermal behaviour of ferromagnetic nano-particles in magnetic fluids is investigated through the micro visualization using the optical darkfield microscope system and particle tracking velocimetry data processing system. Real-time visualization of the Brownian motion of primary clusters in a water-based magnetic fluid was carried out. The experimental results clarified that the primary cluster size depends upon the concentration of the ferromagnetic nano-particle in the magnetic fluid.     

磁流变液减振器的磁路设计方法研究

针对传统的磁流变减振器磁场利用率不高的问题,提出了一种基于多级径向流动模式的磁流变减振器。以磁流变液作为控制介质,研究其流变学特性与磁化特性;选择相应的软磁材料,利用多项式描述其磁化特性,并辨识相应的参数。根据动态磁路设计理论,建立磁路分析模型,确定工作间隙内磁感应强度与励磁线圈激励电流的理论关系。为了验证理论推导的正确性,利用有限元分析软件对阻尼调节器内的磁路进行仿真,并按照轨道车辆抗蛇行减振器的技术要求,设计制作了基于多级径向流动模式的磁流变减振器,利用型号为A1322ELHLT-T3的霍尔传感器对其工作间隙的磁感应强度进行检测,与理论结果进行对比分析。     

Review on numerical modeling of active magnetic regenerators for room temperature applications

The active magnetic regenerator (AMR) is an alternative refrigeration cycle with a potential gain of energy efficiency compared to conventional refrigeration techniques. The AMR poses a complex problem of heat transfer, fluid dynamics and magnetic field, which requires detailed and robust modeling. This paper reviews the existing numerical modeling of room temperature AMR to date. The governing equations, implementation of the magnetocaloric effect (MCE), fluid flow and magnetic field profiles, thermal conduction etc. are discussed in detail as is their impact on the AMR cycle. Flow channeling effects, hysteresis, thermal losses and demagnetizing fields are discussed and it is concluded that more detailed modeling of these phenomena is required to obtain a better understanding of the AMR cycle.