Numerical analysis of the aerodynamic and geometric relationship of a vertical axis wind turbine

Wei Kee Go; Nurfarina Batrisyia Muhammad Hairi; Ahmad Fazlizan; Kok Hoe Wong; Wan Khairul Muzammil.

The demand for wind energy has a high potential as an alternative energy source. Vertical axis wind turbine (VAWT) has good developmental potential for unfavourable wind conditions, especially in urban areas, such as low wind speed. This paper aims to conduct a comprehensive numerical analysis of the two-dimensional H-Darrieus VAWT to understand the VAWT's performance with different solidities. The VAWTs were subjected to low and ultra-low Reynolds number conditions with various tip speed ratio (TSR) values. The numerical investigation was conducted using ANSYS Fluent software using high-fidelity Computational Fluid Dynamics (CFD) technology. Based on previous studies' experiences and data, different computational settings in CFD simulation were employed. The geometric parameters of the study were validated against published simulation and experimental data to ensure the accuracy of the simulation results obtained in this study. The CFD simulation results demonstrated that only a high solidity turbine (σ = 1.20) at a low TSR of 2.0 and a low solidity turbine (σ = 0.60) at a moderately high TSR of 2.5 could generate the optimal quantity of energy since instantaneous moment coefficient lies in the positive region while operating under low Re 75000. In contrast, some turbine configurations produced negative Cm at specific operational TSR ranges when the rotor was subjected to low Re (15000) and ultra-low Re (5000 and 9000). According to the results, the negative instantaneous moment and power coefficients meant that the wind turbine could not be optimally configured due to insufficient power converted from the wind's kinetic energy.

KEYWORDS: H-Darrieus VAWT; wind energy; computational fluid dynamics; wind turbine; on-site energy generation.



Download this PDF file

REFERENCES

1. Castelli, M. R., Englaro, A. & Benini, E. 2011. The Darrieus wind turbine: Proposal for a new performance prediction model based on CFD. Energy, 36(8), 4919-4934.
2. Danao, L.A., Eboibi, I. & Howell, R. 2013. An experimental investigation into the influence of unsteady wind on the performance of a vertical axis wind turbine. Applied Energy, 107, 403-411.
3. De Marco, A., Coiro, D. P., Cucco, D. & Nicolosi, F. 2014. A numerical study on a vertical-axis wind turbine with inclined arms. International Journal of Aerospace Engineering, 2014, Article ID 180498.
4. Hassan, S. M. R., Ali, M. & Islam M. Q. 2016. The effect of solidity on the performance of H-Rotor Darrieus turbine. Proceedings of the 11th International Conference on Mechanical Engineering (ICME 2015). 18-20 December, 2015, Dhaka, Bangladesh. 1754.
5. Kirke, B. K. 1998. Evaluation of self-starting vertical axis wind turbines for stand-alone applications. PhD Thesis, Griffith University, Australia.
6. Li, S. & Li, Y. 2010. Numerical study on the performance effect of solidity on the straight-bladed vertical axis wind turbine. Asia-Pacific Power and Energy Engineering Conference (APPEEC). 28-31 March, 2010, Chengdu, China. pp 1-4.
7. Mohamed, M. H. 2012. Performance investigation of H-rotor Darrieus turbine with new airfoil shapes. Energy, 47(1), 522-530.
8. Rezaeiha, A., Montazeri, H. & Blocken, B. 2018. Towards accurate CFD simulations of vertical axis wind turbines at different tip speed ratios and solidities: Guidelines for azimuthal increment, domain size and convergence. Energy Conversion and Management, 156, 301-316.