【作者】 韩凌；

【导师】 王萍萍；

【作者基本信息】 哈尔滨工业大学 ， 人机环境工程， 2009， 硕士

【摘要】 在航天航空领域中,飞行器前期的制件环节、组装连接环节、推进剂储藏环节、飞行中监控环节、地球外环境物质探测环节等都需要对物质含水率进行测量和分析。物质中水分含量的定量分析已经被列为各类物质理化分析的基本参数之一,往往会影响到物质本身的一些特殊的性质及性能参数。因此,研制出体积小、便于携带和测量、可以适应多种测量、多种环境及用途,高精度、智能化的物质水分仪是一项亟待解决的科研问题,也有广阔的工程应用前景。本论文“基于微波谐振腔技术的水分仪设计”对采用谐振腔进行物质水分测量所涉及的理论、方法和关键技术进行深入的研究:首先,通过系统分析国内外微波法物料水分测量技术的发展现状,在现有水分测量方法的基础上,指出红外法、中子法、自由空间微波法在水分测量中存在的不足,基于此提出了一种微波同轴谐振腔水分传感器。其次,分析讨论了设计本论文系统所需的相关理论基础。论文从麦克斯韦方程出发,详细论述了微波谐振腔内的电磁场分布、边界条件、微波的网络分析、时域有限差分法等内容,进而说明了本论文系统的各项参数指标的由来及相关条件。再次,从谐振腔微扰原理出发,利用时域有限差分法(FDTD)对谐振腔空间进行网格划分并求解,建立了谐振腔传感器仿真模型。以该模型为基础,分析了传感器和物料作用后的内外电磁场分布,利用CST软件,研究了谐振腔空载、无耗条件、有耗条件下的谐振频率等参数与物质含水率的关系:均近似成线性关系,从而验证了本文所述理论的正确性与模型的可行性。同时,设计了与传感器相关匹配的电路系统。系统分为前端测量模块和后端控制模块,对控制器、微波源、功率检测器、电源等重要电子器件的选区进行了较详细分析与介绍。最后,针对同轴谐振腔水分传感器的稳定性、分辨能力和重复性进行了实验研究,实验结果表明本水分仪已经达到系统设计时提出的标准和要求。更多还原

【Abstract】 In aerospace-field, previous-part-manufacturing of spacecraft, assembly, propellant storage, flight monitoring, space environment detection, all need analysis of materials water cut. Analysis of materials water cut has already regarded as one of basic parameters in physico-chemical analysis, water cut always could effect other properties of materials. Therefore, development of moisture sensor which is high precise, portable,rapid,multipurpose is necessary and has wide application prospect.In this study, some key technologies, related theories and methods on the design of microwave coxial resonant moisture sensor, are adopted and researched. The main research works are as follows:Firstly, high precise and rapid moisture content measurements have become the main problem that some industries face. On the base of analyzing existing moisture content measurement techniques, some disadvantages about infrared and free space microwave are presented. So, coaxial resonant cavity as moisture content sensor are presented.Secondly, this study systematical analizes theories which related the system, benging with Maxwell Formulation, detailed descripts distribution of electromagnetic field in microwave coxial resonant, boundary conditions, net, FDTD. Because of those, origin and requirements of moisture csensor parameters are presented.On perturation theory resonant cavity model is built by FDTD dividing grids of resonant cavity space and solving them. On the base of the model, electromagnetic fields distribution inside and outside of resonant cavity; state of no-load and lossy are studied by CST, that is relationship of parameters and water cut.Meanwhile, a circuit system which matches the sensor is designed.This system includes 2 parts: front-end measuring module and back-end concrol module.Choises of improtent componets have been presented in detail.Last, samples prepared for experiment are introduced. Experiments of stability, resolution and repeatability on open-ended resonant cavity sensor are researched. Results of experiments show that: this moisture csensor meets the qualification.更多还原