Abstract:
The research on marine renewable energy technologies is underway around the globe due to the compelling reasons such as environment friendly nature, renewable, intermittent but predictable, security and diversity of supply, and limited social and environmental impacts. However, in Pakistan there is little awareness and appreciation of the potential of these technologies. Owing to grave energy crisis, these renewable energy resources are inevitable for Pakistan.
The hydrokinetic turbine utilizes the kinetic energy of flowing water for the power generation. The horizontal axis hydro-kinetic turbine (HAHT) is probably one of the most promising marine renewable energy technologies due to high-power output and economic viability. Since the power produced by the tidal turbine is directly proportional to the cube of incoming velocity, a small increase in the velocity will increase the power output significantly. Therefore, the power output of a conventional bare turbine can be further improved by enclosing it within a diffuser and accelerating the incoming flow.
The aim of this project is the design and optimization of a diffuser for horizontal axis hydrokinetic turbine application. The two-dimensional flat plate airfoil is used as benchmark and flow around the airfoil is simulated using the commercial CFD software Ansys Fluent16. Later, CFD analyses are carried out for baseline diffuser generated from the flat plate airfoil. The performance of this diffuser was optimized by achieving an optimum curved profile at the internal surface of the diffuser. Bezier curves parameterization and design of experiment (DOE) techniques are used for this purpose. The Response Surface Methodology (RSM) is used as a tool for optimization. It is observed that by finding the optimum set of input parameters, maximum velocity (at the diffuser throat) that can be achieved is 3.68 m/s. This means that an augmentation of 34.3% in the velocity can be achieved with an optimum diffuser in comparison to baseline diffuser.
