Hydropower is a key energy conversion technology for stabilizing electrical power. When running at full load, a 3-D cavitation vortex rope develops in Francis turbines that acts as an internal source of energy and instability. 1-D models allow this phenomenon to be predicted and the range of safe operating points to be defined. These models involve three parameters: the mass flow gain factor, the wave speed and the second viscosity that must be calibrated. For the first time, the present work aims at identifying these parameters using 3-D URANS cavitating simulations. Two cavitation test cases are considered: a 2-D Venturi and a reduced scale model of a Francis turbine at full load operating conditions. RANS simulations allow the mass flow gain factor to be determined, whereas URANS simulations coupled with an optimization process allow the determination of the wave speed and the second viscosity. The new methodology shows its ability to identify the three parameters.

水电是稳定电能的关键能量转换技术。在满负荷运行时，混流式涡轮机中会形成 3-D 空化涡旋绳索，作为内部能量来源和不稳定性。一维模型可以预测这种现象并定义安全操作点的范围。这些模型涉及三个参数：质量流量增益因子、波速和必须校准的第二粘度。目前的工作首次旨在使用 3-D URANS 空化模拟来识别这些参数。考虑了两个空化测试案例：一个二维文丘里管和一个在满负荷运行条件下的混流式涡轮机的缩小模型。RANS 模拟允许确定质量流量增益因子，而 URANS 模拟与优化过程相结合可以确定波速和第二粘度。新方法显示了它识别三个参数的能力。