大型水泵机组寿命预测与改善研究

Large pump units are complex electromechanical systems, whose reliability and durability are of crucial importance in drought resistance, flood drainage and water transfer. Because of various influence factors and complicated mechanisms, the service life prediction is difficult and the service life is short, which has affected the application of large pump units. The damageable parts of pump units would be selected out, and their failure modes and standards would be determined in the project. The factors influencing the part lifetime would be analyzed from aspects of structure forms, material properties, assembly quality, load characteristics, operating environment and maintenance modes, etc. The calculation method of the part damage rate under the action of single certain factor would be established through theoretical analyses of operation and test data. The possible range and probability density of each influence factor would be analyzed and determined. It would be calculated that the damage rate based on probability of the part under the action of single random factor. The mathematical models would be established, by which the damage rate based on probability of the part under the action of multiple random factors would be synthesized and solved; and the relationship between the part reliability and the time would be established. The relationship between typical large pump unit reliability composed of multi-components and the time would be synthesized, solved and established, and the results would be verified by investigative information, thus, the life prediction theory based on reliability of large pump units would have been established. The high contribution rate influence factors would be studied and determined. Aimed at longer target service life, the approaches improving the pump unit life would be put forward by solving inverse problems of the mathematical models and improving the factors with high contribution rates to the reliability lifetimes. The project could enrich life prediction theory and lengthen service life of complex systems, therefore, has great theoretical significance and application value.

大型水泵机组为复杂机电系统，要在抗旱排涝和调水中充分发挥作用，可靠耐久性至关重要。但因影响因素多、机理复杂，导致寿命预测难、寿命短，影响功能发挥。 本项目遴选机组易损部件，确定失效模式和标准。从结构形式、材料性能、装配质量、荷载特性、运行环境和维护方式等方面，分析部件寿命影响因素。通过对运行和试验资料理论分析，建立单确定因素作用时部件破坏速率计算方法。确定各因素范围和概率密度，计算单随机因素作用时部件基于概率的破坏速率。建立数学模型，合成求解多随机因素作用时部件基于概率的破坏速率，建立部件可靠度与时间的关系，合成求解多部件组成的典型水泵机组可靠度与时间的关系，用调研资料验证一致，从而建立基于可靠度的寿命预测理论。研究确定机组寿命高贡献率影响因素，针对更长的目标寿命，反问题求解模型，提出贡献率因素的改善途径和方法。 本项目能够丰富寿命预测理论，延长复杂系统寿命，具有重要的理论意义和应用价值。

大型水泵机组广泛应用于抗旱排涝、长距离调水、城市供排水、舰船等工程。但因影响因素多、机理复杂，水泵机组可靠耐久性预测难、寿命短，影响功能发挥。.通过广泛调研，遴选出机组关键易损部件，确定失效模式和标准。分析归纳影响可靠耐久性的因素，确定各影响因素的随机变化范围和概率密度。建立单确定因素作用时部件破坏速率计算方法，建立数学模型，合成求解多因素作用时部件可靠度和寿命，研究提出改善水泵机组可靠耐久性的途径和方法。.关键易损部件: 水泵导轴承、叶轮叶片、电机定子、电机推力轴承；主要失效模式: 水泵导轴承磨损，叶片断裂、汽蚀，电机定子绝缘老化和推力轴承烧损。确定各易损部件主要失效模式的失效判别标准。例如，考虑制造和安装多个因素，确定叶片与外壳不相碰的导轴承最大单边磨损量计算公式；确定叶片间隙汽蚀，以叶片间隙增大到叶轮直径的0.25%、水泵效率下降5%为失效。. 应用CFD方法，计算分析了水泵水润滑导轴承和电机滑动推力轴承的润滑与受力情况、叶顶间隙形式对漩涡空化的影响。提出了水泵叶片疲劳寿命、非金属导轴承基于可靠度的寿命预测方法，提出了延长水泵叶片疲劳寿命的方法，结果与实际一致；计算了水泵叶片调节机构调节力与调角误差。以减小调节力为目标，提出了基于水泵全运行工况的叶片轴位置优化方法，结果表明，平均调节力减小60%左右，平均调角误差由0.15°减小到0.04°，分离推力轴承工作面压力减小68%，寿命大大延长。考虑到大型水泵机组电机运行温度多影响因素的不确定性，建立了电机温升可靠度预测模型，预测了电机温升可靠度；提出了电机基于可靠度的绝缘寿命预测方法。研发了高可靠度智能拦污清污成套设备，并应用于泵站。 . 本项目能够丰富可靠度与寿命预测理论，延长大型水泵机组等设备的寿命，具有重要的理论意义和应用价值。