In this paper, the reason was analyzed that the aerodynamic efficiency of the traditional vertical axis wind turbine (VAWT) was always low, and a new type of VAWT—Guiding VAWT was introduced. On that basis, a new blade shape called as combined blade for Guiding VAWT was proposed and numerical investigation was complemented on its aerodynamic performance by CFD (Computational Fluid Dynamics) technique. This Guiding VAWT includes two components: guiding impeller and rotating impeller, which are both combined blade in shape. The guiding blade is combined by three sections: inlet radial section, middle arc section and outlet linear section. The wind blade is combined by two sections, inlet arc section and outlet linear section. The combined guiding blade may not only avoid the wind impeller from the direct impact by the coming flow on its convex surface of the blade so as to decrease the drag torque but also improve the effective impact by the coming flow on the concave surface of the blade, both of which contribute the enhancement for the driving torque of the wind turbine. Results indicate: This new type of Guiding VAWT with combined blade has a wider operating range, higher aerodynamic efficiency than the traditional VAWTs. And more, this paper introduced the airfoil blade into this new type of VAWT and numerically validated that even though the flow inside VAWT was a large separated flow with variable attack angles, the aerodynamic advantage of the airfoil blade could still be shown to some extent, which hoped to further enhance the aerodynamic efficiency of the VAWT. Additionally, this new type of VAWT has a two dimensional structure for convenient manufacture, which has the latent energy to be popularized.

The dynamic characteristics of the wall lift and drag of the rigid sphere moving parallel to the single wall surface in the static viscosity laminar flow field are numerically studied, on the basis of the three-dimensional numerical simulation method of the quasi-steady “relativity of motion.” The results show that: (1) The wall surface acts to increase the drag; (2) On the near wall, the lift coefficient decreases as the Reynolds number between the sphere and the wall increase when Re <  100. However, when Re >  100, the lift coefficient increases sharply; (3) On the far wall, there is no wall effect when Re >  10, consistent with the unbounded flow, but the wall effect still exists when Re <  10; and (4) The particle rotation has few influences on drag but slightly increases the lift. And the lift induced by rotation is mainly determined by the surrounding fluid pressure. These results all contribute to the study of the hydrodynamic behavior of particles in the boundary and deepen the understanding of the phenomenon of particle transport in the wall effect layer.

By ‘Radial Equilibrium’ principle, an equation was derived to describe the radial distribution of the throughflow velocity, by which a design approach was proposed for the twisted blade of axial microfan. This approach can take into consideration the influence of the radial gradient for the throughflow velocity at the impeller’s outlet, which is different from the traditional design approach for large fans assuming the throughflow velocity remains radially unchangeable. By this design approach, attempt was made on the design for an axial microfan by choosing different twisted powers so as to obtain different shapes of twisted blades and their respective aerodynamic performance was numerically investigated. Compared to the corresponding straight blade and the twisted blade designed by the traditional approach, this new twisted blade can not only enlarge the stable operating range but also improve the flow pressure, which contributes to the improvement of the blade’s aerodynamic performance.