Pressure Pulsation Analysis of Oscillating Water Column Rotor Eccentricity Based on the Pulsation Tracking Network Method

Document Type : Regular Article


1 College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083, China

2 Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China

3 College of Engineering, China Agricultural University, Beijing 100083, China



An oscillating water column (OWC) is typical of axial rotor turbines, which are used to convert ocean wave energy into electrical energy. This device impacts downstream pressure pulsations when its rotor becomes eccentric. This study compared the details of pressure pulsations downstream of eccentric and non-eccentric rotors under three operating conditions: low flow A, high-efficiency flow B, and high flow C. Computational fluid dynamics (CFD) simulations based on the pulsation tracking network (PTN) method were used for the OWC device to compare the experimental results. The results indicate downstream pressure pulsations were mostly dominated by the blade frequency in non-eccentric low-flow cases. In the other eccentric operating conditions, downstream pressure pulsations were mainly dominated by the 2-, 3.6-, 6-, and 7-times rotation frequencies and the 0.5-times blade frequency. The phase change of downstream pressure pulsations in eccentric and non-eccentric conditions is consistent with the flow direction. The phase change is relatively uniform and steady before eccentricity and becomes turbulent after eccentricity, which affects its steadiness. In this study, the OWC device did not significantly change with or without rotor eccentricity at a 1-time blade frequency intensity; however, at a 1-time rotation frequency, the OWC device showed a significant increase in the pressure pulsation amplitude after rotor eccentricity. The study of the dominant frequency, amplitude, and phase of pressure pulsations in OWC devices with eccentric rotors can help prevent excessive pressure pulsations that can lead to incidents.


Main Subjects

Bao, X. H., Li, F. Y., Fang, Y., et al. (2015). Sub-critical speed vibration of rotors for large submersible motors with mixed eccentricity. Transactions of China Electrotechnical Society, 30(6), 142-149.
Bell, D. L., & He, L. (2000). Three-dimensional unsteady flow for an oscillating turbine blade and the influence of tip leakage. Journal of Turbomachinery-Transactions of the ASME, 122(1), 93-101.
Decaix, J., Dreyer, M., Balarac, G., et al. (2018). RANS computations of a confined cavitating tip-leakage vortex. European Journal of Mechanics B-Fluids, 67, 198-210.
Eric T. D., Shawn S., Reid A. B., & Karen A T. (2022). Evaluating the influence of rotor-casing eccentricity on turbine efficiency including time-resolved flow field measurements. Journal of Turbomachinery-Transactions of the Asme, 144(2).
Falcao, A. F. O., & Henriques, J. C. C. (2016). Oscillating-water-column wave energy converters and air turbines, A review. Renewable Energy, 85, 1391-1424.
Gao, Z., Narzary, D. P., & Han, J. C. (2008). Film cooling on a gas turbine blade pressure side or suction side with axial shaped holes. International Journal of Heat and Mass Transfer, 51(9-10), 2139-2152.
Jin, F. Y., Tao, R., Lu, Z. H., Xiao, R. F. (2021). A spatially distributed network for tracking the pulsation signal of flow field based on CFD simulation. Method and A Case Study. Fractal and Fractional, 5(4), 181.
Kamath, A., Bihs, H., & Arntsen, O. A. (2015). Numerical investigations of the hydrodynamics of an oscillating water column device. Ocean Engineering,102, 10-50.
Li, Y., Wu, Z. C., Tagawa Kotaro; et al. (2018). Numerical simulation on aerodynamic characteristics of vertical axis wind turbine with eccentric rotor structure. Journal of Drainage and Irrigation Machinery Engineering, 36(5), 413-419.
Lu, Z. H., Li, N., Tao, R., Yao, Z. F., Liu, W. C., Xiao, R. F. (2022). Influence of eccentric impeller on pressure pulsation of large-scale vaned-voluted centrifugal pump, Proceedings of The Institution of Mechanical Engineers Part A-Journal of Power and Energy, 237(3),591-601.
Mao, Y. J., Fang, S. Z., Li, T., et al. (2016). Study on the vibration characteristic of turbine rotor eccentricity based on FFT. Proceedings of 2016 7th International Conference on Mechanical and Aerospace Engineering, ICMAE, 239-243.
Miorini, R. L., Wu, H. X., & Katz, J. (2012). The internal structure of the tip leakage vortex within the rotor of an axial waterjet pump. Journal of Turbomachinery-Transactions of the ASME, 134 (3).
Pelc, R., & Fujita, R. M. (2002). Renewable energy from the ocean. Marine Policy, 26 (6), 471-479.
Peters, R., Lundin, U., & Leijon, M. (2007). Saturation effects on unbalanced magnetic pull in a hydroelectric generator with an eccentric rotor. IEEE Transactions on Magnetics, 43(10), 3884-3890.
Rehder, H. J., & Dannhauer, A. (2007). Experimental investigation of turbine leakage flows on the three-dimensional flow field and endwall heat transfer. Journal of Turbomachinery-Transactions of the ASME, 129(3), 608-618.
Setoguchi, T., Takao, M., Santhakumar, S., & Kaneko, K. (2004). Study of an impulse turbine for wave power conversion, effects of Reynolds number and hub-to-tip ratio on performance. Journal of Offshore Mechanics and Arctic Engineering, 126(2), 137-140.
Simshauser, P. (2022). Fuel poverty and the 2022 energy crisis. Australian Economic Review, 55(4), 503-514.
Sinha, B. K. (2002). Trend prediction from steam turbine responses of vibration and eccentricity. Proceedings of the institution of mechanical engineers, part A. Journal of Power and Energy, 216(1), 97-103.
Venter, S. J., & Kroger, D. G. (1992). The effect of tip clearance on the performance of an axial-flow fan. Energy Conversion and Management, 33(2), 89-97.
Volokhovskaya, O. A., & Barmina, O. V. (2016), Effect of initial bending and residual eccentricity of a turbine rotor on its transient vibration amplitudes. Journal of Machinery Manufacture and Reliability, 45(2), 113-121.
Wang, H. M., Wu, Y. Z., Wang, X. H., Hu, Z. L., Lei, X. C., Yang, X. L., Zhu, D., Tao, R., Xiao, R. F. (2022). Influence of runner eccentricity on the hydraulic performance of tubular turbine, a comparative case study. Proceedings of the Institution of Mechanical Engineers Part A-Journal of Power and Energy, 237(4), 819-830.
Wang, J. X., Yang, A. L., Li, G. P., et al, (2014a). Effect of non-uniform tip clearance on the flow exciting force in axial pump. Journal of Engineering Thermophysics, 35(10), 1973-1978.
Wang, X. L., Ge, B. M., Ferreira, FJTE (2014b). Radial force analytic modeling for a novel bearingless switched reluctance motor when considering rotor eccentricity. Electric Power Components and Systems, 42(6), 544-553.
Wang, Y. B. (2004). Shaft mis-alignment induced vibration in high-capacity steam-turbine generator sets. Power Engineering, 24(6), 768-774, 784.
Yu, T., Shuai, Z. J., Jian, J. X. (2022). Numerical study on hydrodynamic characteristics of a centrifugal pump influenced by impeller-eccentric effect. Engineering Failure Analysis, 138.