Turbine Type Rotary Wave Energy Converter Performance

Abstract

In this investigation, the utilization of water waves as the fluid medium is explored in the context of turbines, which are mechanical devices that convert fluid motion into rotational motion. The Volume of Fluid (VOF) model in Ansys Fluent is employed to generate regular waves and analyze the turbine's movement in a wave tank. Essential parameters such as force, pressure, momentum, and speed of the turbine are investigated to harvest electrical energy from wave energy. The study aimed to understand how these parameters changed with varying wave characteristics. Results showed that dynamic pressure and moment increase as the wavelength increased. However, the turbine's rotation speed decrease as wavelength increased. The force acting on the blades do not change significantly with wavelength but caused a time delay. The highest force applied to the turbine blades is observed at a wave height of 2 m, reaching 8000 N. Finally, the maximum turbine speed is attained at a wave height of 2 m and wave period of 7 s, reaching 87 mm/s. However, the maximum efficiency of 19.18% is achieved at a wave height of 1m and a wave period of 8.75 seconds. Because as the wave height increases, the power of the wave increases significantly, but the absorption of this power increases at a lower rate. Therefore, this study highlights the need to increase the number of wave energy conversion systems that can operate efficiently for wave forms with high wave heights.

Keywords

• Wave energy
• Dynamic mesh
• VoF method
• Rotating turbine

References

1. [1] Koca, A., Karakose, P., and Yamaç, H., İ., “Offshore Wave Energy Converter Systems”, 1st International Symposium on Graduate Research in Science Focus on Entrepreneurship and Innovation (ISGRS 2018), 73 (özet), (2018).
2. [2] I. Bilgic, “Power optimisation of a wave energy converter system”, Master thesis, Mustafa Kemal University, Hatay, (2011).
3. [3] Zhi, D., and Zhan, J.-m., “Numerical modeling of wave evolution and runup in shallow water”, Journal of Hydrodynamics, 21(6): 731-738, (2009).
4. [4] Finnegan, W., and Goggins, J., “Linear irregular wave generation in a numerical wave tank”, Applied Ocean Research 52, 188-200, (2015).
5. [5] Zhu, Y., Li, Y., Tao, A., and Zhang, J., “Numerical modeling of wave interaction with double curtain-wall breakwater”, Procedia Engineering, 116, 1009-1018, (2015).
6. [6] Ojieh, N., Barltrop, N., and Xu, L., “Rans investigation of the kinematics of an alternative extreme wave”, Ocean engineering, 36(17-18): 1415-1424, (2009).
7. [7] Liu, T.-L., and Lin, C.-C., “Wave-maker stroke design and wave decay methods in numerical wave tank study”, J CCIT, 41, 101-106, (2012).
8. [8] Wu, N.-J., Tsay, T.-K., and Chen, Y.-Y., “Generation of stable solitary waves by a piston-type wave maker”, Wave Motion, 51(2): 240-255, (2014).

9. [9] Saincher, S., and Banerjeea, J., “Design of a numerical wave tank and wave flume for low steepness waves in deep and intermediate water”, Procedia Engineering, 116, 221-228, (2015).
10. [10] Yamaç, H., I., Koca, A., and Yılmaz, T., “Using computational fluid dynamics for wave generation and evaluation of results in numerical wave tank modelling”, Firat University Journal of Experimental and Computational Engineering, 1(1): 31-42, (2022).
11. [11] Yamaç, H., I., and Koca, A., “Numerical analysis of wave energy converting systems in case of using piezoelectric materials for energy harvesting”, Journal of Marine Engineering & Technology, 20(2): 138-149, (2022).
12. [12] Yamac, H., “Modeling and analysis of the wave energy converting systems in case of using piezoelectric materials for harvesting energy”, Master thesis, Firat University, Elazig, (2016).
13. [13] Liu, J.-Q., Fang, H.-B., Xu, Z.-Y., Mao, X.-H., Shen, X.-C., Chen, D., Liao, H., and Cai, B.-C., “A mems-based piezoelectric power generator array for vibration energy harvesting”, Microelectronics Journal, 39(5): 802-806, (2008).
14. [14] Bhinder, M. A., Babarit, A., Gentaz, L., and Ferrant, P., “Potential time domain model with viscous correction and cfd analysis of a generic surging floating wave energy converter”, International Journal of Marine Energy, 10, 70-96, (2015).
15. [15] Yamaç, H., I., Koca, A., and Karakose, P., " Numerical Analysis of Wave Amplitude Effect on Power Output of Oscillating Water Column Device with Coastal Elevation.” 1st Internatıonal Engıneerıng And Technology Symposıum (IETS’18), 208-211, (2018).
16. [16] Koca, A., and Yamaç, H., I., “Oscillating Water Column Analysis in Numerical Wave Tank with Variable Base Geometries”, International Advanced Researches & Engineering Congress 2017 Proceeding Book, (2017).
17. [17] Anbarsooz, M., Faramarzi, A., and Ghasemi, A., “A numerical study on the per¬formance of fixed oscillating water column wave energy converter at steep waves”, in ASME power conference, American Society of Mechanical Engineers, 50213, V001T08A003, (2016).
18. [18] Gomes, M. D. N., Nascimento, C. D. D., Bonafini, B. L., Santos, E. D. D., Isoldi, L. A., and Rocha, L. A. O. “Two-dimensional geometric optimization of an oscillating water column converter in laboratory scale”, Revista de Engenharia Térmica, 11(1-2): 30-36, (2012).
19. [19] Morris, C. E., O'Doherty, D. M., O'Doherty, T., and Mason-Jones, A., “Kinetic energy extraction of a tidal stream turbine and its sensitivity to structural stiffness attenuation”, Renewable Energy 88, 30-39, (2016).
20. [20] Sarma, N., Biswas, A., and Misra, R., “Experimental and computational evaluation of savonius hydrokinetic turbine for low velocity condition with comparison to savonius wind turbine at the same input power”, Energy Conversion and Management, 83, 88-98, (2014).
21. [21] Kumar, A., “R. Saini, Performance analysis of a single-stage modified savonius hydrokinetic turbine having twisted blades”, Renewable Energy, 113, 461-478, (2017).
22. [22] Elbatran, A., Ahmed, Y. M., and Shehata, A. S., “Performance study of ducted nozzle savonius water turbine, comparison with conventional savonius türbine”, Energy, 134, 566-584, (2017).
23. [23] Bai, G., Li, W., Chang, H., and Li, G., “The effect of tidal current directions on the optimal design and hydrodynamic performance of a three-turbine system”, Renewable Energy, 94, 48-54, (2014).
24. [24] McCormick, M. E., “Ocean engineering mechanics: with applications”, Cambridge University Press, (2009).
25. [25] Dalrymple, R. A., and Dean, R. G., “Water wave mechanics for engineers and scientists”, World Scientific Publishing Company, 2, (1991).