大型贯流泵机组可靠性研究

发布时间：2018-06-17 16:41

本文选题：贯流泵机组 + 结构形式　；参考：《扬州大学》2011年硕士论文

【摘要】：大型贯流泵机组在机、电、水等方面均有可能发生故障,如叶片调节机构失效、绝缘击穿和轴承失效等,影响泵机组可靠性。因此,研究和提高贯流泵机组关键部件可靠性有重要意义。本文在“十一五”国家科技支撑计划重点项目、全国百篇优秀博士学位论文作者专项基金项目等资助下,开展对大型贯流泵机组可靠性的研究。贯流泵机组系统复杂,其可靠性主要由关键易磨易损部件的可靠性决定。本文分析比较了贯流泵机组结构形式、支撑受力特性与水力特性,提出了贯流泵机组支撑的设计原则；研究确定关键部件失效的判断标准；计算了叶轮进口的汽蚀余量并判断了叶片易汽蚀部位,考虑叶片表面粗糙度、材料的抗汽蚀强度及泵机组年运行时间,求出了叶片最易汽蚀部位基于可靠度的汽蚀寿命；计算了闭式齿轮箱的轮齿磨损模糊可靠度；比较了不同轴承特点,采用指数分布失效密度函数计算了单个滚动轴承与轴承系统的可靠度；从起停机特性、可靠性、管理性、经济运行等方面综合比较了泵机组的工况调节方式,根据故障树法计算了液压叶片调节系统的失效概率,求解基于可靠度的液压调节机构寿命。影响贯流泵机组维修性的因素有关键部件安装检修步骤、泵机组结构,本文分析计算了年运行5000h贯流泵机组的故障及相应检修时间,维修度为95%时,15种贯流泵机组大修时间范围为148.67h-203.23h,比较了不同贯流泵机组维修性的优劣。算例贯流泵机组运行3.25a时的可靠性为90.35%,此时轴承系统的可靠度91.04%,修复轴承后泵机组的可靠度提高到99.24%；继续运行3.25a泵机组可靠性为89.7%,此时轴承系统、叶片调节机构、齿轮箱、叶片与电机的可靠性分别为91.04%、98.59%、99.92%、100%、100%,再次修复轴承后泵机组的可靠度提高到98.52%；继续使用1.5a,贯流泵机组的可靠性降为90.35%,叶轮运转9年后可靠性会快速降低,因此机组运行8年时需修复叶轮,修复轴承系统、齿轮箱与叶片后,泵机组的可靠性提高到98.29%。为提高贯流泵机组可用度,提出了提高电机与齿轮箱可靠性的措施、选择泵机组传动方式、导轴承与推力轴承选用、工况调节方式选择原则。由于轴承易失效,应提高其固有可靠性或其结构便于拆装检修。确定了导轴承座安装高程以保证泵机组运行时电机空气间隙与水泵叶片间隙均匀,控制各部件的安装要素以提高泵机组整体安装质量。
[Abstract]:The failure of large tubular pump unit in machine, electricity, water and so on may occur, such as the failure of blade regulating mechanism, insulation breakdown and bearing failure, which affects the reliability of pump unit. Therefore, it is of great significance to study and improve the reliability of key components of tubular pump unit. Under the support of the National Science and Technology support Program of the Eleventh Five-Year Plan and the special fund project for the author of 100 outstanding doctoral dissertation, this paper carries out the research on the reliability of the large through-flow pump unit. The system of tubular pump unit is complex, and its reliability is mainly determined by the reliability of the key wearable and vulnerable parts. This paper analyzes and compares the structural form, bearing force characteristic and hydraulic characteristic of the tubular pump unit, puts forward the design principle of the support for the tubular pump unit, studies and determines the criterion of determining the failure of the key components. The cavitation margin at the inlet of the impeller is calculated and the cavitation position of the blade is judged. Considering the surface roughness of the blade, the cavitation strength of the material and the annual operating time of the pump unit, the cavitation life of the most vulnerable cavitation part of the blade based on reliability is obtained. The fuzzy reliability of gear wear of closed gear box is calculated, the characteristics of different bearings are compared, and the reliability of single rolling bearing and bearing system is calculated by using exponential distribution failure density function. According to the fault tree method, the failure probability of hydraulic vane regulating system is calculated, and the life of hydraulic regulating mechanism based on reliability is solved. The factors affecting the maintainability of the tubular pump unit are the steps of installation and maintenance of the key components, the structure of the pump unit, the analysis and calculation of the failure and the corresponding maintenance time of the 5 000 h annual operation of the tubular pump unit. The repair time range of 15 kinds of tubular pump units is 148.67h-203.23h. the maintainability of different tubular pump units is compared. The reliability of the tubular pump unit is 90.35a, and the reliability of the bearing system is 91.0444.The reliability of the pump unit after repairing the bearing is increased to 99.244.The reliability of the pump unit continues to run 3.25a is 89.7. at this time, the bearing system, the vane regulating mechanism, the gearbox, The reliability of the vane and the motor are respectively 91.04, 98.599.59 and 99.92and 100, and the reliability of the pump unit after the bearing repair has been raised to 98.52.The reliability of the tubular pump unit will be reduced to 90.35 after the continuous use of 1.5a, and the reliability of the impeller will decrease rapidly after nine years of operation. Therefore, the reliability of pump unit should be improved to 98.29 after 8 years of operation, such as repairing impeller, repairing bearing system, gearbox and blade. In order to improve the availability of through-flow pump unit, the measures to improve the reliability of motor and gear box are put forward, the driving mode of pump unit, the selection of guide bearing and thrust bearing, and the selection principle of working condition adjustment mode are proposed. Because bearing is easy to fail, its inherent reliability should be improved or its structure can be easily disassembled and overhauled. The installation height of the guide bearing seat is determined to ensure that the air gap between the motor and the pump blade is uniform when the pump unit is running, and the installation elements of each component are controlled to improve the overall installation quality of the pump unit.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH38

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