Computational Fluid Dynamics Based Optimal Design of Vertical Axis Marine Current Turbines

Marine turbines are being increasingly used to harness kinetic energy of water and convert it into other useful forms of energy. Widespread commercial acceptability of these machines depends upon their efficiency. This largely depends upon the geometric features of the marine turbines such as number of blades, shape of blades etc. Researchers have been using experimental facilities to optimise these machines for maximum power generation. With the advent of advanced computational techniques, it has now become possible to numerically simulate the flow of water in the vicinity of marine turbines and monitor their performance output. In this work Computational Fluid Dynamics (CFD) based techniques have been used to analyse the effects of number of blades within the stator and rotor, of an in-house built Vertical Axis Marine Current Turbine (VAMCT), on the performance output of the turbine. Furthermore, an effort has been put forward towards better understanding of the flow structure in the vicinity of the blades during transient interaction between rotor and stator blades. This study provides vital information with regards to the flow sensors' requirements and placements in order to monitor various blade configurations of a VAMCT in real world. The results of this study show that the torque output from a VAMCT is a strong function of blade configurations and there is a significant degradation in the performance output of marine turbines as the inequality between the number of rotor and stator blades increases. Hence, CFD has the potential to optimise the design of marine turbines and can be used as a potential modelling tool in the near future for on-line health monitoring of such systems.