Numerical Simulation of 2D Model of Diffuser for Tidal Turbines

Abstract

Researchers and engineers around the globe are striving to improve green energy technologies. Among green energy technologies, diffuser augmented tidal turbines are attracting focus due to enormous potential for producing energy. The power output by a tidal turbine is directly proportional to the cube of velocity of incoming fluid flow. Thus, even a minor increase in velocity considerably increases the power output. The diffuser helps accelerate the velocity of incoming fluid flow. Hence, the efficiency of the turbine is significantly increased by using a diffuser. It is challenging to to accelerate the incoming flow by a diffuser due to its shape, geometry and fabrication limitations. The diffuser design requires great deal of innovation and time investment. The research community is investing considerable time and financial resources in this arena. However, limited reserach results are available for diffuser augmented tidal turbines due to their emerging nature, large and costly research & development setup, startup cost and proprietary issues. The purpose of this paper is to present the numerical simulation of 2D model of diffuser for tidal turbine. Numerical simulation results of velocity profile for fifteen models with different mesh sizes is presented in detail. The effect of mesh density on coefficient of velocity is discussed. Predicted results are then compared to experimental results and found in reasonable agreement. The research is essential for utilizing CFD tools for diffuser design for tidal turbine.