Numerical predictions of pressure pulses in a Francis pump turbine with misaligned guide vanes

• Published in: Journal of hydrodynamics. Series B Vol. 26; no. 2; pp. 250 - 256
• Main Author: 肖业祥 王正伟 张瑾 罗永要
• Format: Journal Article
• Language: English
• Published: Singapore Elsevier Ltd 01.04.2014; Springer Singapore
• Subjects: Computational fluid dynamics; Engineering; Engineering Fluid Dynamics; Fluid flow; Guide vanes; Hydrology/Water Resources; misaligned guide vanes; Navier-Stokes equations; Navier-Stokes方程; Numerical and Computational Physics; numerical simulation; pressure pulsation; Pressure pulses; pump turbine; Pump turbines; rotor stator interaction; Simulation; Turbulence; Turbulent flow; 压力脉冲; 导向叶片; 数值预测; 混流式水泵水轮机; 混流式水轮机; 错位; 非定常流; pump turbine; misaligned guide vanes; pressure pulsation; numerical simulation; rotor stator interaction
• ISSN: 1001-6058; 1878-0342
• DOI: 10.1016/S1001-6058(14)60028-7

Previous experimental and numerical analyses of the pressure pulse characteristics in a Francis turbine are extended here by using the unsteady Reynolds-averaged Navier-Stokes equations with the shear stress transport （SST） turbulence model to model the unsteady flow within the entire flow passage of a large Francis pump turbine with misaligned guide vanes at the rated rotational speed. The S-curve characteristics are analyzed by a combined use of the model test and the steady state simulation with the aligned guide vane firstly. Four misaligned guide vanes with two different openings are chosen to analyze the influence of pressure pulses in the turbine. The characteristics of the dominant unsteady flow frequencies in different parts of the pump turbine for various misaligned guide vane openings are investigated in detail. The predicted hydraulic performance and the pressure fluctuations show that the misaligned guide vanes reduce the relative pressure fluctuation amplitudes in the stationary part of the flow passage, but not the runner blades. The misaligned guide vanes have changed the low frequencies in the entire flow passage with the change of the pulse amplitudes mainly due to changes in the rotor-stator interaction and the low frequency vortex rope flow behavior.