【作者】 崔海蓉；

【导师】 李德才；

【作者基本信息】 北京交通大学 ， 机械设计及理论， 2010， 博士

【摘要】 磁性液体水平传感器是一个崭新的研究方向,它是利用磁性液体既具有液体的流动性,又具有可以被外磁场磁化而拥有磁性的特点,将磁性液体作为敏感元件,通过磁性液体随被测物体的姿态相对于水平面的小角度倾斜而发生流动,使感应线圈自感发生变化,将非电量水平倾角转换为可测输出量电压差的装置。磁性液体本身的磁学性质直接影响磁性液体水平传感器的应用特性,而对磁性液体水平传感器工作原理的研究是进行磁性液体的选择与制备、传感器参数设计与确定以及传感器输出信号和灵敏度等特性研究的理论依据和现实基础。本文在分析与磁性液体水平传感器应用相关的磁性液体性能的基础上,选择和制备了适用于磁性液体水平传感器的磁性液体；从理论上研究磁性液体水平传感器的工作原理,建立了磁性液体水平传感器的数学模型,揭示了影响磁性液体水平传感器输出信号与灵敏度的因素及规律；并在此基础上,对磁性液体水平传感器的工作状态进行数值模拟与实验研究,对实验参数、结构参数等做了进一步探讨,提供了磁性液体水平传感器参数设计选择和确定的方法及依据。通过对磁性液体水平传感器工作原理的研究,推导出磁性液体水平传感器输出电压信号与水平倾角的线性关系式,提出了磁性液体水平传感器灵敏度的表达式；选择、制备了三种具有不同磁化性能指标的煤油基磁性液体；设计了磁性液体水平传感器实验模型并进行实验研究；分析了磁性液体的磁化性能,模型结构参数,以及输入电压、频率等实验信号参数对磁性液体水平传感器输出电压和灵敏度的影响规律。当磁性液体水平传感器模型容器内注入一半体积的磁性液体时,输出电压信号最大,即可测一维水平倾角最大。磁性液体水平传感器的最大量程,由容器内径与容器内壁总长之比,即磁性液体水平传感器最大倾角的正切值决定。根据可测最大水平倾角,确定盛装磁性液体的圆柱形容器的结构尺寸；根据灵敏度大小的要求,选择激励线圈与感应线圈的缠绕、布置方式、匝数等结构参数；结构参数确定之后,磁性液体水平传感器的灵敏度正比于磁性液体的磁化系数、激励信号的输入电压有效值、激励信号的输入频率,而与被测倾角大小无关。基于磁性液体水平传感器工作原理的研究与分析,运用ANSYS软件,通过电磁耦合分析,对磁性液体水平传感器模型的工作状态进行数值模拟。提供了在不便获得实物的情况下,对磁性液体水平传感器模型的工作状态及输出结果进行描述与仿真的有效方法；提供了对磁性液体水平传感器输出信号与灵敏度的估算方法；通过对数值模拟结果和实物实验结果的对比与分析,表明数值模拟与实物实验结果相吻合,提出了磁性液体水平传感器设计参数的选择与确定的经验和依据。更多还原

【Abstract】 Magnetic fluid which is characterized by the unique combination of fluidity and the capability of interacting with a magnetic field have been used as a sensitive element of magnetic fluid level sensor which is a novel research field in current. Depending on magnetic fluid is flowing with a small inclination attitude of the measured body, the inclination angles should be transferred into electric signal as output voltage through transition elements by inducing the variation of self-inductance. While the magnetism properties of magnetic fluid impact directly on the application character of magnetic fluid level sensor, the research on the principle of magnetic fluid level sensor is the theoretical laws and the practical foundation for the research of selection and preparation of magnetic fluid, of parameter design, and of the properties of output signal and sensitivity of this level sensor.Based on analysis of magnetism properties of magnetic fluid which is coherent to the application of magnetic fluid level sensor, appropriate magnetic fluid were selected and prepared and the mathematic model for the principle of magnetic fluid level sensor was established. Meanwhile, influencing factors and regularity on the output signal and sensitivity of this level sensor were disclosed. In succession, numerical simulation and experimental research of magnetic fluid level sensor were put up for further analysis of experimental and structural parameters, while the method and laws which the parameter design determined by were proposed.By analysis on the principle of magnetic fluid level sensor, the linearity relationship between output voltage and the level inclination angle was deduced and the expression of sensitivity of this sensor was put forward. After three kinds of kerosene based magnetic fluid with different magnetism properties were prepared, an experimental model was designed for experimental research on this magnetic fluid level sensor. And then, the influence regularity on output voltage and sensitivity of magnetic fluid level sensor caused by magnetism properties of magnetic fluid, by structure parameter of experimental model, and by input voltage and pumping frequency and so on was analyzed. It was known that the measurable level inclination angle of one-dimension magnetic fluid level sensor could reach to the maximum when the half-volume magnetic fluid was filled into the vessel of experimental model. The maximal measuring range of this magnetic fluid level sensor would determined by the ratio between internal diameter and inwall length of the vessel of experimental model, that is to say, it would decided by the tangent of maximal level inclination angle. According to the maximal measurable level inclination angle, the physical dimension of the vessel which contained the magnetic fluid should be settled. In response to sensor sensitivity demand, the structural parameters as well as winding and arranging manner of exciting and inducing coils should be selected. When the structural parameters was defined, the sensitivity of magnetic fluid level sensor was linear to the susceptibility of magnetic fluid, to the effective value of input voltage, and to the pumping frequency of exciting signal, but was independent with the measured inclination angle.In the basement of analysis and research on the principle of magnetic fluid level sensor, the numerical simulation on the working situation of the experimental model was approached by analysis of electromagnetic coupling using ANSYS software. A useful method utilized in the situation without actual test was provided for emulation of working condition and output signals of this sensor. An estimation approach of output signal and sensitivity of this sensor was proposed as well as the experience data was given for parameter design of this magnetic fluid level sensor.更多还原