Monitoring of Rotor-Stator Interaction in Pump-Turbine Using Vibrations Measured with On-Board Sensors Rotating with Shaft

Current trends in design of pump-turbines have led into higher rotor-stator interaction (RSI) loads over impeller-runner. These dynamic loads are of special interest having produced catastrophic failures in pump-turbines. Determining RSI characteristics facilitates the proposal of actions that will prevent these failures. Pressure measurements all around the perimeter of the impeller-runner are appropriate to monitor and detect RSI characteristics. Unfortunately most installed pump-turbines are not manufactured with in-built pressure sensors in appropriate positions to monitor RSI. For this reason, vibration measurements are the preferred method to monitor RSI in industry. Usually vibrations are measured in two perpendicular radial directions in bearings where valuable information could be lost due to bearing response. In this work, in order to avoid the effect of bearing response on measurement, two vibration sensors are installed rotating with the shaft. The RSI characteristics obtained with pressure measurements were compared to those determined using vibration measurements. The RSI characteristics obtained with pressure measurements were also determined using vibrations measured rotating with shaft. These RSI characteristics were not possible to be determined using the vibrations measured in guide bearing. Finally, it is recommended to measure vibrations rotating with shaft to detect RSI characteristics in installed pump-turbines as a more practical and reliable method to monitor RSI characteristics.

[1]  Christopher E. Brennen,et al.  Rotor-stator interaction in a diffuser pump , 1989 .

[2]  Eduard Egusquiza,et al.  Cavitation Erosion Prediction in Hydro Turbines from Onboard Vibrations , 2004 .

[3]  P. Jiang,et al.  Dynamics of a rotor-bearing system equipped with a hydrodynamic thrust bearing , 1999 .

[4]  Kadir Aydin,et al.  Effect of impeller-diffuser radial gap ratio in a centrifugal pump , 2009 .

[5]  Cristian G. Rodríguez.  Feasibility of on board measurements for predictive maintenance in large hydraulic turbomachinery , 2006 .

[6]  L. G. Wang,et al.  Study on Antiwear and Reducing Friction Additive of Nanometer Aluminum Borate , 2001 .

[7]  Anh Kiet Tieu,et al.  Identification of sixteen force coefficients of two journal bearings from impulse responses , 1997 .

[8]  Christopher E. Brennen,et al.  Some Unsteady Fluid Forces on Pump Impellers , 1992 .

[9]  Shijie Guo,et al.  An Experimental Study on the Fluid Forces Induced by Rotor-Stator Interaction in a Centrifugal Pump , 2003 .

[10]  Christopher E. Brennen,et al.  Experimental Investigation of Rotor-Stator Interaction in a Centrifugal Pump With Several Vaned Diffusers , 1989 .

[11]  Ilmar F. Santos,et al.  Frequencies in the Vibration Induced by the Rotor Stator Interaction in a Centrifugal Pump Turbine , 2007 .

[12]  R. Spence,et al.  A CFD parametric study of geometrical variations on the pressure pulsations and performance characteristics of a centrifugal pump. , 2009 .

[13]  François Avellan,et al.  Pressure Fluctuation Measurements in Hydro Turbine Models , 2002 .

[14]  P. N. Saavedra,et al.  Accurate assessment of computed order tracking , 2006 .

[15]  Lloyd E. Barrett,et al.  Test results for a highly preloaded three-lobe journal bearing : Effect of load orientation on static and dynamic characteristics , 2001 .

[16]  Eduard Egusquiza,et al.  Failure investigation of a large pump-turbine runner , 2012 .

[17]  Bernd Nennemann,et al.  Experience with Rotor-Stator interactions in high head Francis runner , 2008 .