核泵水润滑推力轴承及机械密封性能研究

发布时间：2018-04-08 16:00

本文选题：水润滑　切入点：可倾瓦推力轴承　出处：《大连理工大学》2012年硕士论文

【摘要】：核主泵担负着驱动冷却剂介质在核反应堆一回路中循环的重要作用,被喻为核电站的心脏,在核电站中的重要性不言而喻。可倾瓦推力轴承和机械密封是核主泵和其它核泵中两个最为关键的润滑部件。一方面,轴承和密封系统性能的好坏直接决定了核泵能否安全可靠运行；另一方面,轴承和密封作为核泵中的易损件,其寿命长短又决定了核泵的维修周期,对整个核泵的高效经济运行有重要影响。因此,提高核泵水润滑推力轴承与机械密封性能对于整个核泵的高效、经济与安全运行起着至关重要的作用。新一代核泵用可倾瓦推力轴承和机械密封均选用液态水作为润滑介质。相对一般的润滑油而言,水具有来源广、成本低、污染小、辐射环境下不易变质等优点。水的粘度很低,一方面有利于减小摩擦降低能耗,但另一方面也导致承载能力低下,容易引起水膜破裂等事故,尤其当设计不合理时更是如此。此外,低粘度还往往使核泵水润滑轴承处于复杂的紊流润滑状态,导致计算上存在一定的困难。由于涉及生产厂商的核心利益,国外关于核泵水润滑轴承和机械密封性能相关研究的公开资料不多,我国有关核泵的研究起步较晚,而对核泵水润滑轴承和机械密封性能的研究更少。鉴于此,本文以核泵水润滑推力轴承和机械密封系统为研究对象,基于紊流润滑理论,通过详细的计算分析讨论了各设计参数对其性能的影响。本文共分为四章,主要内容如下：第一章简单介绍了水润滑推力轴承及机械密封的研究发展概况。第二章介绍了润滑基本理论,并基于紊流润滑理论,结合核泵水润滑可倾瓦推力轴承及机械密封的特点,给出了两者的计算方程,并对方程进行了无量纲化、数值离散和求解。第三章以某一典型尺寸的可倾瓦推力轴承作为具体研究对象,通过计算分析研究了支撑位置、旋转速度等对轴承性能的影响。研究发现支撑点位置的改变对轴承性能的影响非常大。此外在高速重载工况下惯性力对轴承性能有重要影响,不能被简单忽略掉。第四章首先对机械密封做了简单介绍,然后通过详细的计算研究了机械密封槽几何尺寸与形状对密封性能(开启力、泄流量、液膜刚度等)的影响,得出了密封结构的具体设计规则。
[Abstract]:Nuclear main pump plays an important role in driving coolant medium in the primary loop of nuclear reactor. It is regarded as the heart of nuclear power station, and the importance of nuclear power station is self-evident.Tilting pad thrust bearing and mechanical seal are the two most important lubricating parts in nuclear main pump and other nuclear pump.On the one hand, the performance of the bearing and sealing system directly determines whether the nuclear pump can operate safely and reliably; on the other hand, the life span of the bearing and seal, as the vulnerable parts of the nuclear pump, determines the maintenance period of the nuclear pump.It has an important effect on the efficient and economical operation of the whole nuclear pump.Therefore, improving the performance of water lubricated thrust bearing and mechanical seal of nuclear pump plays an important role in the efficient, economical and safe operation of the whole nuclear pump.Liquid water is used as lubricating medium for the new generation of tilting pad thrust bearings and mechanical seals for nuclear pumps.Compared with general lubricating oil, water has many advantages, such as wide source, low cost, low pollution and not easy to deteriorate under radiation environment.The viscosity of water is very low, on the one hand, it helps to reduce friction and reduce energy consumption, but on the other hand, it also leads to low bearing capacity, which can easily lead to water film rupture and other accidents, especially when the design is unreasonable.In addition, low viscosity often makes the water lubricated bearing of nuclear pump in complicated turbulent lubrication state, which leads to some difficulties in calculation.Due to the core interests of the manufacturers concerned, there is not much public information about the research on the performance of water lubricated bearings and mechanical seals of nuclear pumps abroad, and the research on nuclear pumps in China started relatively late.Less research is done on the performance of water lubricated bearings and mechanical seals of nuclear pumps.In view of this, this paper takes the water lubricated thrust bearing and the mechanical seal system of the nuclear pump as the research object. Based on the turbulent lubrication theory, the influence of various design parameters on its performance is discussed through detailed calculation and analysis.This paper is divided into four chapters, the main contents are as follows:Chapter 1 introduces the research and development of water-lubricated thrust bearings and mechanical seals.In the second chapter, the basic lubrication theory is introduced, and based on the turbulent lubrication theory, combined with the characteristics of water lubricated tilting pad thrust bearing and mechanical seal of nuclear pump, the calculation equations are given, and the equations are dimensionless, numerical discretized and solved.In the third chapter, a typical tilting pad thrust bearing is taken as the research object, and the influence of support position and rotation speed on the bearing performance is studied by calculation and analysis.It is found that the bearing performance is greatly affected by the change of support point position.In addition, the inertial force has an important effect on the bearing performance under high speed and heavy load conditions, and can not be simply ignored.In the fourth chapter, the mechanical seal is introduced briefly, and then the effects of the geometry and shape of the seal slot on the sealing performance (opening force, discharge rate, film stiffness, etc.) are studied in detail.The specific design rules of sealing structure are obtained.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH133.31

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