The blade design of small wind turbines is based on the design method of the horizontal axis and the blade element theory. Since the flow of the vertical axis wind turbine is more complex than that of the horizontal axis, it is a typical large separation unsteady flow. 

The momentum blade element theory is widely applied in small wind turbines. However, since the blade element theory ignores the flow interference between blade elements, and omits the airfoil resistance in the blade element theory design, this simplification inevitably leads to inaccurate results. This simplification has little impact on the appearance design of the blades, but has a significant effect on the wind energy utilization rate of the wind turbine. The interference between the turbine blades is also very intense, and the overall flow is very complex. It is impossible to obtain accurate results solely relying on the blade element theory. 

Design features of small wind turbine generators: 

The starting wind speed is low, and the wind energy utilization rate is high; it has a small size and a beautiful appearance. The running vibration is low. 

2. The installation is designed in a user-friendly manner, facilitating the installation, maintenance and repair of the equipment. 

3. The wind turbine blades are made of aluminum alloy. The aerodynamic design and structural design have been optimized, resulting in a high wind energy utilization coefficient and an increase in annual power generation.