【作者】 胡敏；

【导师】 何湘宁；

【作者基本信息】 浙江大学 ， 电力电子与电力传动， 2008， 博士

【摘要】 随着科学技术的不断发展,各个学科的交叉研究变得尤为重要。二十一世纪,生物学与生物工程、材料学与材料工程、环境学与环境工程等三大学科的发展对人类的生存和发展、科技的进步及创新等都具有重要的意义。目前,环境问题日益突出,污水处理的研究变得迫切;同时,由于应用领域的扩展以及对材料各类性质的要求在不断提升,材料的表面改性也成为目前研究的热点。污水处理和材料表面改性这两个方向都涉及多个学科,研究难度较大。采用脉冲电凝聚法进行污水处理,以及针对阀金属进行脉冲微弧氧化处理,两者遵循的基本原理都属于电化学理论范畴,使用的设备方法是电力电子研究的领域,因而,两个方向都属于典型的交叉学科研究。本文针对脉冲电絮凝法印染污水处理和脉冲微弧氧化等两个特定的应用场合,在深入分析电解槽负载的基础上,得出电解槽负载的等效电路,自制了分别用于污水处理和微弧氧化场合的特种形变脉冲电源,在此基础上,进行了大量的实验研究,得出了一些有意义的结论。主要内容包括:(1)形变功率脉冲电源的设计和调试针对脉冲电絮凝法印染污水处理和脉冲微弧氧化等两个特定的应用,根据要求分别设计了脉冲电源。电源样机可以输出特定的电压波形,而且输出脉冲电压的幅值、频率和占空比等参数可以实现可编程数字调节。实验表明,电源样机可以满足污水处理及微弧氧化等实验的具体要求。通过功率脉冲电源的研制,为脉冲电凝聚法印染污水处理以及镁合金微弧氧化的实验研究奠定了基础。类似的形变功率电源在相关文献报道中并不多见,本文所设计的脉冲电源输出波形种类多,可以调节的参数多,参数调节方便,是这类形变电源的改进和提高。(2)电解槽负载特性的分析本文从电化学理论入手,分析了电凝聚过程中与负载工作特性相关的化学反应过程,在直流作用下的电解槽负载特性分析的基础上,对脉冲电源作用下的负载特性进行了分析。通过电化学领域使用的电化学阻抗谱(Electrochemicalimpedance spectroscopy,简称EIS)研究方法,对电解槽进行建模,得出定性和定量的模型,通过实验测量电压、电流曲线,进行参数拟合的方法,得出实际应用时负载的定量模型。深入分析了等效电路各个参数的具体意义,得出双电层电容等参数和污水处理效果的关系。通过改变电解槽的电极配置来实现改变等效电路各电容、电阻等参数的值,从而改变电解槽电流,最后得出了等效电路参数和电极配置的关系。本文针对电解槽负载特性进行定性、定量分析,得出其等效电路模型,并采用该模型解释、解决具体的问题,得出相关结论,这样的研究方法在文献中未见报道。该方法采用了EIS理论,并将电解槽的模型作为电化学电极反应和电路分析的桥梁。(3)脉冲电絮凝法污水处理的实验研究本文针对印染污水,利用自制电源进行了一系列污水处理实验和结果分析。得出了脉冲参数和净化效果、电能净化效率的关系。这些结论为脉冲电凝聚法印染污水处理中,脉冲形式和脉冲参数的选择提供了实验验证,具有借鉴意义。在负载特性分析的基础上,分别讨论了电压幅值、电解槽单元数目、极板间距、脉冲的频率及占空比等因素与视在功率、有功功率、电流有效值、电流峰值等因素的关系,分析了脉冲电凝聚法污水处理的功耗,得出功耗和脉冲参数的关系,这些结论及详细理论推导对于本方法的工程应用具有重要参考意义。在此基础上,讨论了污水处理中影响功耗的主要因素,通过计算和外推得出实际工业应用中该方法的能耗状况,为该方法的大规模推广应用提供参考。(4)脉冲微弧氧化的研究本文针对镁合金AZ91D,进行了脉冲微弧氧化的研究。本文首次从实验现象,极化曲线、X射线衍射图谱(XRD)、扫描电镜(SEM)结果等等方面全面分析比较了采用脉冲和传统的正弦交流进行微弧氧化的异同,通过分析,得出了脉冲微弧氧化可以改善膜层的结论。利用自制电源,改变脉冲参数,在不同条件下进行微弧氧化实验,通过分析,研究了脉冲参数对微弧氧化膜层的影响,得到了一些有意义的结论。这些分析和结论对脉冲微弧氧化的深入研究和推广应用都有重要意义。更多还原

【Abstract】 With the development of science and technology, the study based on multiple subjects becomes especially important. Nowadays, wastewater treatment attracts lots of researchers due to the crisis of environment pollution. At the same time, surface modification of materials also becomes research hot point. However, both of them consist of several subjects and are hard to carry out. Water treatment using electrocoagulation and formation of coatings on valve metals by microarc oxidation (MAO) are typical multiple subjects studies. The main theory included in the two fields is electrochemistry and the equipments are pulse power supplies which belong to the field of power electronics technology.The research work in this paper consists of wastewater treatment and MAO using a pulse power. Based on the analysis of the electrolytic bath, the equivalent circuit model is got. Meanwhile, two pulse power supplies are implemented for the experiments of wastewater treatment and MAO. Lots of experiments are carried out and a series of conclusions are obtained.The research contents of this paper include four aspects:1. The design and debugging of the pulse power supply.The model machines are designed based on the experimental demand. The power supplies can output several kinds of pulses and the parameters of the pulse (such as voltage amplitude, frequency and duty cycle) could be set independently. The waveforms and the parameters are set by an accessorial keyboard and displayed by LEDs. The method of the design is discussed in detail.2. Load characterristics of electrobath.On the basis of the electrochemical theory, academic and the equivalent circuit models of electrobath are obtained by the methods of electrochemical impedance spectroscopy (EIS). Quantitative analysis is carried out through measuring and curve fitting. Further more, the existence and effects of the double layer capacitor in the equivalent circuit are analysed. The relationships between the double layer capacitor and the parameters of the voltage pulse are investigated. In the application of wastewater treatment using a pulse power supply, the basic principle is got on how to choose the appropriate power parameters. Based on the equivalent circuit model, the relationships between the equivalent model of electrobath in wastewater treatment and arrangement of the electrodes are disscused. Statistical theory is used to verify the relationships obtained above. At the same time, some reasonable explanations are proposed to describe the mechanism of such relationships.3. The pulse power supply is practically used in the water treatment.Dye wastewater purified by electrocoagulation with pulse power supply is carried out. Some relationships are got between the parameters and the result of the water treatment. The basic principle is discussed on how to choose the appropriate power parameters. Furthermore, based on the equivalent circuit of electrobath, the power consumption is discussed. The relationships between the power consumption and the parameters and between the power consumption and the arrangement of electrodes are investigated at the same time. Some conclusions are got based on the experimental results and analysis.4. The pulse power supply is practically used in the MAO.Ceramic coatings are fabricated on AZ91D magnesium alloy in alkaline borate solution by MAO using pulse and AC power supply. The results show: when the pulse power is selected, the anode dissolving can be restrained effectively, the performance of corrosion resistance may be improved and at the same time, the pulse MAO process is good for forming coating.A series of MAO experiments are carried out using the pulse power with different parameters, such as amplitude, frequency and duty cycle, etc. The relationship between the parameters and the performance of the coatings are discussed and some meaningful conclusions are obtained at last.更多还原