空气动压润滑无油涡轮增压器的设计与实验研究

发布时间：2018-10-13 17:16

【摘要】：气体箔片轴承是一种自作用式柔性表面动压轴承,可以利用周围环境中的空气(或者其他气体)作为其润滑剂。利用这种气体箔片轴承,可以实现增压器的“无油化”,消除润滑油对工作转速的限制,并彻底地解决漏油问题,同时在最大程度上降低装置的质量、体积和复杂程度,消除一切因润滑系统而产生的损失。然而,国内对于气体箔片轴承的制作、性能测试研究较少,针对气体箔片轴承的应用研究更是凤毛麟角。因此,本文尝试把气体箔片轴承应用到涡轮增压器当中,探索建立无油透平机械的设计和性能测试方法。本文的主要研究工作和结果如下:在天雁某型增压器的基础上,用气体箔片轴承替换原有的浮动环轴承,对增压器的转子、轴承体和涡轮壳重新进行了设计。对径向气体箔片轴承和推力气体箔片轴承进行了详细的结构参数设计,预测了径向气体箔片轴承和推力气体箔片轴承的承载能力以及静态、动态特性,同时对整个转子系统的转子动力学性能做了初步计算。计算结果表明,箔片气体轴承的承载能力足够,设计的转子系统在正常工作转速范围内可以避开临界转速。在径向气体箔片轴承制作方法的基础上,成功探索出了推力气体箔片轴承的制作方法。制作了两个径向气体箔片轴承和两个推力气体箔片轴承,并且在轴承顶箔表面镀了一层固体润滑剂。针对径向气体箔片轴承,搭建了起飞试验台和静态性能试验台来测量其性能。针对推力气体箔片轴承,搭建了静态特性试验台。实验结果表明,径向气体箔片轴承在加速和平稳运行时没有出现大幅温升,其起飞转速约在11,000rpm,因此可以尝试在增压器实验台上进一步验证其性能;推力气体箔片轴承的箔片具有非线性刚度特性,并且具有一定的阻尼特性。搭建了无油涡轮增压器试验台。三次试运行后径向气体箔片轴承全部损坏,推力气体箔片轴承完好。实验结果证明:箔片温度可以作为判断箔片轴承是否正常工作的非常有效的指标;制作的推力气体箔片轴承具有足够的承载能力,足以承受增压器开机、停机和稳定工作时的轴向力。最后对造成轴承损坏的可能原因进行了分析。
[Abstract]:Gas foil bearing is a kind of self-acting flexible surface dynamic bearing which can use air (or other gas) as lubricant. By using this gas foil bearing, the supercharger can be realized without oil, and the limitation of lubricating oil on working speed can be eliminated, and the problem of oil leakage can be solved thoroughly. At the same time, the quality, volume and complexity of the device can be reduced to the greatest extent. Eliminate any damage caused by the lubrication system. However, there are few researches on the performance test of gas foil bearings in China, and few researches on the application of gas foil bearings. Therefore, this paper attempts to apply the gas foil bearing to the turbocharger to explore the design and performance testing method of the oil-free turbine machinery. The main research work and results are as follows: on the basis of Tianyan turbocharger, the rotor, bearing body and turbine housing of the supercharger are redesigned by replacing the original floating ring bearing with the gas foil bearing. The structure parameters of radial gas foil bearing and thrust gas foil bearing are designed in detail. The bearing capacity and static and dynamic characteristics of radial gas foil bearing and thrust gas foil bearing are predicted. At the same time, the rotor dynamic performance of the whole rotor system is preliminarily calculated. The calculation results show that the bearing capacity of foil gas bearing is sufficient and the rotor system designed can avoid the critical speed in the range of normal working speed. Based on the manufacturing method of radial gas foil bearing, the manufacturing method of thrust gas foil bearing is explored successfully. Two radial gas foil bearings and two thrust gas foil bearings were fabricated, and a layer of solid lubricant was deposited on the top foil of the bearing. For radial gas foil bearing, a take-off test bench and a static performance test bench are built to measure its performance. For the thrust gas foil bearing, the static characteristic test bed is built. The experimental results show that the radial gas foil bearing has no significant temperature rise and its take-off speed is about 1100rpm when it is accelerating and running smoothly, so the performance can be further verified on the turbocharger test bench. The foil of thrust gas foil bearing has nonlinear stiffness characteristic and certain damping characteristic. An oil-free turbocharger test rig was built. The radial gas foil bearing is damaged and the thrust gas foil bearing is in good condition. The experimental results show that the chaff temperature can be used as a very effective index to judge whether the foil bearing is working properly, and the thrust gas foil bearing has sufficient bearing capacity to withstand the booster. The axial force during downtime and steady operation. Finally, the possible causes of bearing damage are analyzed.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TH133.3

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