A Comparative Study on the Performance of a Horizontal Axis Ocean Current Turbine Considering Deflector and Operating Depths

Abstract

Several different designs and prototypes of ocean current turbines have been tested over recent years. For every design test, emphasis is given to achieving an optimum power output from the flow. In this study, the performance of a Horizontal Axis Ocean Current Turbine (HAOCT) has been investigated using three-dimensional Computational Fluid Dynamics (CFD) simulations for three cases, namely, (1) a turbine without a deflector, (2) a turbine with a deflector, and (3) a turbine with a deflector operating at a higher fluid depth. The turbine design was modeled in DesignModeler software and simulations were carried out in commercial CFD software Flow-3D. The Torque Coefficient (Cm) and Power Coefficient (Cp) for the turbine have been investigated for a certain range of Tip-Speed Ratios (TSRs) in a flow velocity of 0.7 m/s. Furthermore, comparisons have been made to demonstrate the effect of the deflector on the performance of the turbine and the influence of a higher fluid pressure on the same. The results from the simulations indicate that the higher value of Cp was achieved for Case 2 as compared to the other two cases. The findings from the study indicate that the use of the deflector enhances the performance of the turbine. Furthermore, a higher fluid pressure acting on the turbine has a significant effect on its performance.

A performance investigation of a multi-staging hydrokinetic turbine for river flow

“…The standard k -ɛ turbulence model is employed for the simulation as it is superior to other available models in Flow-3D. It can be used to solve problems involving fluid flow in the vicinity of complex geometrical structures [36]. The standard k -ɛ turbulence model uses wall functions based on the law of the wall to resolve the complex forces and flow interaction at sharp corners, straight and curved edges, such as those of the turbine blades [37].…”

Understanding the Stability of Passenger Vehicles Exposed to Water Flows through 3D CFD Modelling

“…The k-ε turbulence model with a no-slip wall shear boundary condition was selected to solve the turbulence flow. The k-ε turbulence model is counted as an advanced and more popular model to solve turbulence flow and it can provide reasonable and accurate approximations for a variety of flows [27,28]. The two transport equations of the k-ε turbulence model are (i) the turbulent kinetic energy k T (Equation ( 5)) and (ii) its dissipation ε T (Equation ( 6)) [26].…”

In-Situ Experiment of Cross-Flow Savonius Hydrokinetic Turbine With a Deflector

“…The majority of the maximum value of the Coefficient of Power (CP) ranges from 0.15 to 0.30. Meanwhile, the Tip-Speed Ratio (TSR) ranges from 0.6 to 0.9 [9].…”