Uniform Test Method Optimum Design for Drag-Type Modified Savonius VAWTs by CFD Numerical Simulation

This paper reports the results of optimizing design of the drag-type modified Savonius VAWTs with 4, 5 and 6 blades by using uniform test method. The optimal design is performed in the light of wind energy utilization rate as the goal function and conducted by numerical simulation for drag-type modified Savonius VAWTs with 4, 5 and 6 blades; the FLUENT software, sliding grid technology and PISO algorithm are employed in the process. In the optimization, the blade width, the blade installation angle and the rotation rate of windmill are taken as the basic parameters. The results indicated that the optimal wind energy utilization rate is \({C}_{\mathrm{p}} = 27.140\%\) for the 4-blade turbine at the blade width \(d = 0.882\,\hbox {m}\), blade installation angle \(\theta = 24.895^{\circ }\) and the windmill rotation rate \(\omega =17.206 \,\hbox {r}/\hbox {min}\); the optimal wind energy utilization rate is \({C}_{\mathrm{p}}=28.493\%\) for the 5-blade turbine at \(d = 0.803\,\hbox {m}\), \(\theta =17.425^{\circ }\) and \(\omega =16.265\, \hbox {r}/\hbox {min}\); the optimal wind energy utilization rate is \({C}_{\mathrm{p}}= 30.564\%\) for the 6-blade turbine at \(d = 0.681\,\hbox {m}\), \(\theta = 21.650^{\circ }\), \(\omega = 18.369\, \hbox {r}/\hbox {min}\).