Quantitative analysis of backflow of reversible pump-turbine in generating mode

[摘要] Significant vibration and pressure fluctuations are usually observed when pump- turbine is operated during the off-design conditions, especially turbine brake and runaway. The root cause of these instability phenomena is the abnormal unsteady flow (especially the backflow) inside the pump-turbine. In the present paper, numerical simulation method is adopted to investigate the characteristics of the flow inside the whole passage of pump-turbine with two guide vane openings (6° and 21° respectively) and three kinds of operating conditions (turbine, runaway and turbine braking respectively). A quantitative analysis of backflow is performed in both the axial and radial directions and the generation and development of backflow in the pump turbine are revealed with great details.

[发布机构] Key Laboratory of Condition Monitoring and Control for Power Plant Equipment, Ministry of Education, North China Electric Power University, Beijing; 102206, China^1;China Institute of Water Resources and Hydropower Research, Beijing; 100048, China^2

[效力级别] 工业技术 [学科分类] 工业工程学

[关键词] Generating mode;Guide vane openings;Numerical simulation method;Off design condition;Operating condition;Pressure fluctuation;Radial direction;Reversible pump-turbine