水电机组推力轴承镜板泵及油循环冷却系统的水力优化设计

Hydraulic optimization design of runner-pump and oil circulating and cooling system for thrust bearing of hydroelectric units

针对水电机组推力轴承镜板泵流体动力设计过程中孔的布置形式以及集油槽的断面形状、面积和出口管路直径等几何参数优化问题,提出适合镜板泵流道设计的镜板泵性能预测及优化设计方法。通过不同几何参数组合,采用基于多工况数值模拟的性能预测方法来分析镜板泵的主要过流部件的关键尺寸、形状等对其性能的影响,并在此基础上提出一种基于整个循环系统协同的镜板泵水力优化设计方法,可提高自循环系统设计中流体动力系统的性能及可靠性。对比试验表明,在原试验循环系统参数不变的条件下,某大型水电机组推力轴承镜板泵在优化设计后平均扬程提高4 m,平均效率提高5.5%,且H-Q曲线能更好保证变工况运行时系统的稳定性。

In order to optimize the layout and number of holes and geometric parameters such as the section shape, area, and outlet pipe diameter of the oil bath in hydrodynamic design of a runner-pump for the thrust bearing of hydroelectric units, a method for performance prediction and optimization design suitable for the flow passages of the runner-pump is presented in this paper. Through combination of different geometric parameters, the influence of the size and shape of the main flow passage components on hydrodynamic performance of the runner-pump was analyzed using the performance prediction method based on multi-condition numerical simulations. In this way, a hydrodynamic optimization design method for the runner-pump based on cooperation throughout the circulation system, which can improve the performance and reliability of the hydrodynamic system for self-circulating system design, is proposed. The results show that, compared with the original runner-pump, the average head is increased by 4m, the average efficiency is increased by 5. 5%, and the H-Q curve can guarantee better stability of the system under varying condition operation for the optimized runner-pump under the same test conditions.