车用燃料电池无油高速空压机模拟实验台设计及实验研究

发布时间：2019-05-19 20:44

【摘要】：箔片气体轴承是一种自适应式柔性支承的动压轴承,它具有诸多的优点,能够解决传统油轴承在应用方面的许多限制,实现机械设备的“无油化”。目前在国外已成功在透平旋转机械、微型压缩机系统、空气循环系统等特殊领域得到应用,但是国内对于箔片气体轴承在实际应用方面的研究是比较少。因此本文依托于车用燃料电池用双叶轮空气压缩机的合作项目,探索利用箔片气体轴承技术搭建无油高速空气压缩机模拟实验台,用于研究箔片轴承应用在高速旋转机械领域的可行性。本文主要对以下几个方面进行了研究:(1)在传统旋转透平机械的基础上,使用箔片气体轴承作为转子系统的支承,提出一种无油高速空气压缩机模拟实验台的设计理念。同时还详细论述了实验台转子系统及附属结构的设计过程。(2)对第一代波箔型径向气体轴承和推力气体轴承结构参数的设计过程进行了详细的论述。首先利用经验公式和计算程序对轴承的承载能力和静动态特性分别进行了预测,然后通过建立有限元模型对转子系统的性能进行了分析。计算结果表明:转子系统各阶次临界转速没有在实验台所设计的工作转速范围内,而且在整个设计工作转速范围内转子系统将不会发生失稳的现象,在理论上完全满足设计要求。(3)对所设计的径向和推力箔片轴承进行了加工和简单的磨合实验,同时还搭建了专门用于研究径向箔片气体轴承特性的实验台,在变转速和变载荷的条件下对径向轴承进行了实验研究。其实验结果表明实验轴承的起飞转速一般在1 0,0 0 0 r p m左右,而且随着施加静载荷的增加而增大;实验轴承的摩擦阻力矩和温升也表现出随转速和载荷增加呈增大的趋势。(4)加工和搭建了无油高速空压机模拟实验台和测试系统。在不同的工作转速下对实验台进行多次实验,绘制了轴承温度特性图和转速图,并使用两个时域波形创建出不同实验条件下的轴心轨迹图。实验结果发现:转子系统同步振动量非常大;径向箔片轴承的顶箔表面有磨损痕迹存在,而推力箔片轴承没有出现明显的磨损。最后对转子性能和造成轴承出现磨损的原因进行了分析。
[Abstract]:Foil gas bearing is a kind of dynamic pressure bearing with adaptive flexible support, which has many advantages, can solve many limitations of traditional oil bearing in application, and realize the "oil-free" of mechanical equipment. At present, it has been successfully applied in turbine rotating machinery, micro compressor system, air circulation system and other special fields, but the domestic research on the practical application of foil gas bearings is relatively few. Therefore, based on the cooperative project of double impeller air compressor for vehicle fuel cell, this paper explores the use of foil gas bearing technology to build oil-free high-speed air compressor simulation experimental platform. It is used to study the feasibility of foil bearing in the field of high speed rotating machinery. In this paper, the following aspects are studied: (1) on the basis of traditional rotating turbine machinery, foil gas bearing is used as the support of rotor system, and a design concept of oil-free high-speed air compressor simulation test platform is put forward. At the same time, the design process of rotor system and auxiliary structure of the experimental platform is discussed in detail. (2) the design process of the structural parameters of the first generation wave foil radial gas bearing and thrust gas bearing is discussed in detail. Firstly, the bearing capacity and static and dynamic characteristics of the bearing are predicted by using the empirical formula and the calculation program, and then the performance of the rotor system is analyzed by establishing the finite element model. The calculation results show that the critical speed of each order of the rotor system is not within the working speed range designed by the experimental platform, and the instability of the rotor system will not occur in the whole designed working speed range. In theory, it fully meets the design requirements. (3) the designed radial and thrust foil bearings are machined and simply run-in experiments, and an experimental platform specially used to study the characteristics of radial foil gas bearings is built. The experimental study of radial bearing is carried out under the condition of variable speed and variable load. The experimental results show that the take-off speed of the experimental bearing is about 100 r p m, and increases with the increase of static load. The friction resistance moment and temperature rise of the experimental bearing also increase with the increase of rotating speed and load. (4) the simulation test bench and test system of oil-free high-speed air compressor are machined and built. Many experiments were carried out on the experimental platform at different working speeds, and the bearing temperature characteristic diagram and rotating speed diagram were drawn, and the axial center trajectory diagrams under different experimental conditions were created by using two time domain waveforms. The experimental results show that the synchronous vibration of the rotor system is very large, and there are wear marks on the top foil surface of the radial foil bearing, but there is no obvious wear of the thrust foil bearing. Finally, the performance of the rotor and the causes of bearing wear are analyzed.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U467.523

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