Abstract
Most common renewable unconventional energy sources are solar and wind power systems. To improve market penetration these power production systems have to be localized. In the renewable unconventional energy category, wind turbines occupy a larger portion of the market share. Adoptability of wind turbines in large-scale energy generation is higher, when compared to solar energy systems. In the case of small-scale localized systems used in urban areas, performance of localized wind turbines is affected by limitations in size and operating conditions. Although localized wind power systems reduces transmission losses and cost associated with constructing an offsite plant, the characteristics of the wind flow are adverse due to high turbulence and severe wind shear when it is used to drive wind turbines to generate electricity. Velocity of the flow is often reduced by the obstructions caused by buildings and natural resources. To improve the performance of the localized wind turbine the mass flow rate of air through the rotor plane should be increased. This can be achieved by placing the wind turbine in a convergent - divergent duct. The potential and ability of a divergent duct used to improve the performance of a wind turbine have been thoroughly studied. It is believed that that a convergent – divergent duct can further improve the wind power. However, the parameters needed for an optimal convergent v section are not available. This study aims to address the data deficiency for a convergent section. The Fluent module for CFD in ANSYS Workbench is used to run simulations on validated models to obtain various data. An actuator disk model is used to represent an ideal wind turbine in the duct, where a coefficient of thrust can be assigned to find the changes in flow characteristics. Velocity distribution data along the axis of the duct is used to find the velocity amplification achieved, while the coefficient of pressure data is used to understand the wind capturing capacity. The study discusses the effects of adding a constant area region between the convergent and divergent section. This region is necessary to install a wind turbine and to help the flow fully develop before reaching the rotor plane. The optimal position of the wind turbine inside the duct is identified in this thesis to ensure an optimal turbine performance. These improvements can make localized wind turbines a reality and help increase the adoption rate. Main design criteria in this study are the size of the duct, which has to be small enough for practical applications. Finally, there is a necessity to understand the performance characteristics of this wind turbine system in relation to placement on a building as data in the open literature are limited.