الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 159 |  |  |
| | | from | 159 | | |
Abstract
The main objective of the present study is to make use of the low wind speed that is spread all over the land of Egypt, in order to produce a useful and economical wind power from it. This includes finding a smart method to increase the natural wind velocity that blows over the wind turbines. Therefore, a study has been carried out in order to select and optimize the best geometric shape that generates the highest wind velocity. A comparison has been held between different structural shapes (nozzle, cylinder and diffuser), where this comparison was based on experimental results and data available in the Literature Review. The experimental results proved that the diffuser geometric shape generates the highest wind velocity rather than the other geometric shapes. In addition, the experimental and numerical investigations proved that a diffuser equipped with a flange will generate a higher wind velocity than a bare diffuser. The present study is based on optimizing the geometric shape of the flanged diffuser, in order to extract the highest wind velocity inside the diffuser, which in turn will generate the highest wind power if a wind turbine is installed inside. This optimization study was performed by carrying out numerical investigations for the air flow inside the flanged diffuser using the ANSYS Fluent CFD software that is based on the Finite Volume Method in order to solve the Navier Stokes Equations and the k- ε Turbulent Models. The numerical investigations were performed to study the effect of the small nozzle installed at the beginning of the diffuser and the influence of changing its angle and length, in addition to the study varying the expansion angle of the diffuser and its length. The present study has studied the major role of the flange length and angle in the increase of the wind velocity inside the flanged diffuser. The results of the numerical investigations concluded the best geometric shape of the flanged diffuser, where the results selection was based on the generation of the highest wind velocity inside the flanged diffuser. The results proved that a flanged diffuser equipped with a nozzle angle of 26˚, nozzle length of (0.2)D, flange length of (0.9)D, diffuser angle of 20˚, diffuser length of (1.35)D and a flange angle of 90˚ are the optimum values thereafter, the velocity inside the flanged diffuser began to decrease, where D is the diffuser throat diameter. The best geometric shape of the flanged diffuser generates a wind velocity factored by 1.83, where this factor maximizes the wind turbine output power to nearly five times a bare wind turbine. The present study includes also a study of some geometrical parameters related to the flange (flange inclination angle, opening through the flange and flange opening length and position). These parameters are presented as protection methods for the wind turbines in case of high wind velocities, in order to protect the wind turbines from being damaged due to overspeed.