This study presents the design and comparative analysis of 3-blade and 4-blade helical Vertical Axis Wind Turbines (VAWTs) for small-scale urban wind energy applications. The turbines, with a rotor height of 1.5 m and diameter of 1.0 m, were modelled in SolidWorks and analysed using ANSYS Fluent and ANSYS Workbench. CFD analysis was conducted at wind speeds of 3–6 m/s to evaluate aerodynamic performance. The 4-blade VAWT achieved a higher maximum power coefficient (Cp = 0.37) than the 3-blade model (Cp = 0.32). Structural analysis showed maximum equivalent stresses of 107.7 MPa and 93.3 MPa for the 3-blade and 4-blade configurations, respectively, with Factors of Safety above 2.6 and 3.0. Modal analysis showed natural frequencies of 18.4–69.2 Hz for the 3-blade model and 21.6–76.9 Hz for the 4-blade model, well above the operating frequency of approximately 3.97 Hz, indicating minimal resonance risk. Overall, the 4-blade helical VAWT demonstrated better aerodynamic efficiency, lower structural stress and deformation, and improved dynamic stability. The results indicate that the 4-blade configuration is more suitable for compact, low-speed urban wind energy applications.

Dr. Suri Srinivas, Boddu Shiva Gopi, "Design, FEA Simulation, and Performance Evaluation of 3-Blade and 4-Blade Vertical Axis Wind Turbines in Low-Speed Urban Wind Conditions" International Journal of Scientific Research and Engineering Development, V9(5): Page(884-892) September - October 2026. ISSN: 2581-7175. www.ijsred.com. Published by Scientific and Academic Research Publishing.