PDF《Wind Power Generators》

28 Pa at the inlet. These results are consistent with Venturi and Bernoulli principals. (a) Velocity Field in the x-z plane (b) Pressure Field in the x-z plane Figure

5 Velocity and pressure field in x-z plane at the center of INVELOX The velocity vectors in x-z plan and velocity profile in y-z plane are shown in Figure 6. It is observed that while most of the vectors point toward negative z direction, some of the wind flows out due to the low back pressure on the other side of the inner cone. (a) Velocity vectors in the x-z plane (b) Velocity Profile inside the Venturi in y-z plane Figure

6 Velocity vector and profile Figure

7 shows the influence of including bars supporting the inner cone on the outer cone. It is shown that average wind speed is practically the same (27.8 mph). Figure

7 Velocity field in the x-z plane The influence of a dome on the top of the inner cone is shown in Figure 8. It observed that the maximum velocity increased to 31.4 mph (Figure 8a) while the amount of the wind outflow due to the low back pressure was slightly decreased. In order to increase the wind speed at the Venturi, where the turbine will be mounted, four fins (or partitioned) were placed at

90 degrees apart between the inner and outer cones. Figure

9 shows an omnidirectional INVELOX with four fins placed at

90 degrees apart. The fins are also used as the supporting structures holding the inner cone. (a) Velocity field in the x-z plane Velocity vectors in the x-z plane Figure

8 Influence of a dome top on the velocity fields of INVELOX Figure

9 Omnidirectional INVELOX with four fins distributed

90 degrees apart Figure

10 shows the velocity and pressure profiles at a cross sectional area inside the Venturi. It is noted that the average velocity was raised to more than

45 mph, while the maximum velocity was increased to more than

48 mph, speed ratio of more than 3. In other words, adding the passive fins between the inner and outer cones, increase speed by 6........