含尘离心风机叶片磨损机理与减磨途径的研究

发布时间：2018-07-30 08:33

【摘要】：气固两相流离心风机广泛应用于气力输送、煤粉燃烧、环保除尘、航空、航天等各种工况。当含有固体颗粒的气体作为工作介质通过叶轮时,固体颗粒在运动中不可避免地与叶轮发生碰撞、摩擦、反弹、磨损及沉积等问题,从而影响叶轮的动平衡且危及其可靠性和使用寿命。同时气流中的颗粒会与风机叶片表面发生碰撞产生冲蚀,导致叶片磨损失效。根据我国风机行业协会统计,输送气固两相混合物的风机约占年产量40%,因此研究气固两相流风机磨损问题具有重要的应用价值和现实意义。论文首先阐述了气固两相流离心风机叶片磨损机理,然后介绍了目前国内外在离心风机被动防磨和主动防磨方面的相关研究进展和最新研究方法。本文利用光学显微镜、扫描电子显微镜(SEM)、X射线衍射仪(XRD)、涂镀层测厚仪等分析检测手段,通过磨损模拟试验和耐磨性能对比试验,系统研究了含尘离心风机的结构设计、叶片材料选择、微弧氧化工艺优化对叶片磨损行为和叶轮使用寿命的影响,探讨了含尘离心风机叶片的磨损机理与减磨途径,获得了以下具有创新性的研究结果： (1)通过对离心风机结构的综合创新设计,在叶轮高速旋转时产生气体旋流场,通过这个气体旋流场完成能量传递,使大部分的流体不经过叶轮,达到减少能量损失以及固体颗粒对叶轮的碰撞、摩擦、磨损,提高叶轮寿命的目的。试验结果表明新型离心风机叶片上试样的耐磨性约为传统风机的4倍。 (2)通过优选匹配合适的叶片材料和简单的热处理工艺替代现常用的低碳结构钢,以实现提高性能、减少磨损或降低成本的目的。试验结果表明可采用经淬火+回火处理的40Cr钢和45钢来替代现在叶片材料常用的Q235(A3钢)和Q345(16Mn钢),可增加叶片的耐磨性,提高叶轮使用寿命。 (3)以4A01型铝合金为研究对象,通过微弧氧化工艺在铝合金叶片上形成一层致密均匀的陶瓷层,达到提高叶片耐磨、耐蚀性,延长叶轮使用寿命的目的。研究了不同浓度的电解液对起弧电压、陶瓷膜厚度、表面形貌、相组成、耐磨性能的影响,试验结果表明：电解液为主成膜剂]Na2SiO3+添加剂KOH+性能改善剂H3B03+稳定剂甘油,且Na2SiO3浓度为12g/L左右时,陶瓷膜的耐磨性最好。研究了电压、电流密度对陶瓷膜层厚度、表面形貌、相组成、耐磨性能的影响,试验结果表明：正向电压在450V左右,正向电流密度在12A/dm2左右时,陶瓷膜的耐磨性最好。
[Abstract]:Gas-solid two-phase flow centrifugal fan is widely used in pneumatic conveying, pulverized coal combustion, environmental protection dust removal, aviation, aerospace and other conditions. When the gas containing solid particles passes through the impeller as the working medium, the solid particles will inevitably collide with the impeller in motion, such as friction, rebound, wear and deposition, etc. It affects the dynamic balance of impeller and endangers its reliability and service life. At the same time, the particles in the air flow will collide with the fan blade surface, resulting in the blade wear failure. According to the statistics of China Fan Industry Association, the fan conveying gas-solid two-phase mixture accounts for about 40 percent of the annual output, so it is of great value and practical significance to study the wear problem of gas-solid two-phase flow fan. In this paper, the vane wear mechanism of gas-solid two-phase flow centrifugal fan is first expounded, and then the research progress and the latest research methods on passive and active anti-wear of centrifugal fan at home and abroad are introduced. By means of optical microscope, scanning electron microscope (SEM) X-ray diffractometer, (XRD), coating thickness measuring instrument and so on, the structure design of dust-bearing centrifugal fan is systematically studied by means of wear simulation test and wear resistance contrast test. The influence of blade material selection and micro-arc oxidation process optimization on blade wear behavior and service life of impeller is discussed. The wear mechanism and wear reduction method of centrifugal fan blade with dust are discussed. The following innovative results are obtained: (1) through the comprehensive and innovative design of the centrifugal fan structure, the gas swirl field is produced when the impeller rotates at high speed, and the energy transfer is accomplished through the gas swirl field. Most of the fluids do not pass through the impeller to reduce the energy loss and the impact of solid particles on the impeller friction wear and improve the life of the impeller. The test results show that the wear resistance of the new centrifugal fan blade is about 4 times that of the traditional fan. (2) the commonly used low carbon structural steel is replaced by the suitable blade material and simple heat treatment process. To achieve the purpose of improving performance, reducing wear or cost. The test results show that Q235 (A3 steel) and Q345 (16Mn steel), which are commonly used in blade materials, can be replaced by quenched and tempered 40Cr and 45 steels, and the wear resistance of the blades can be increased. (3) taking 4A01 type aluminum alloy as the research object, a dense and uniform ceramic layer was formed on the blade of aluminum alloy by micro-arc oxidation process, so as to improve the wear resistance and corrosion resistance of the blade. The purpose of prolonging the service life of impeller. The effects of different concentrations of electrolyte on arc starting voltage, ceramic film thickness, surface morphology, phase composition and wear resistance were studied. The experimental results show that the electrolyte is the main film forming agent] KOH additive KOH stabilizer glycerol. When the concentration of Na2SiO3 is about 12g/L, the wear resistance of ceramic film is the best. The effects of voltage and current density on the thickness, surface morphology, phase composition and wear resistance of ceramic film were studied. The experimental results show that the wear resistance of ceramic film is the best when the forward voltage is about 450 V and the forward current density is about 12A/dm2.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH432

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