Investigations on the hydrodynamic interference of the multi-rotor vertical axis tidal current turbine

In the development of tidal energy, in order to extract more energy in the limited tidal farm, large-scale deployment of tidal current turbine is needed. In this paper, based on the PimpleDyMFoam solver in Open Source Fluid Dynamics Software (OpenFOAM), an effective numerical method is proposed for the two-dimensional VATCT (Vertical Axis Tidal Current Turbine). Secondly, the symmetrical simplified model is introduced to simulate the multi-rotor VATCT array. The interaction and wake characteristics of each turbine in different array layout schemes are studied in order to enhance the understanding of the interaction between multiple turbines. It is well known that the interaction between multiple turbines improves the overall power conversion efficiency, so it is of great significance to conduct in-depth research. The CFD numerical simulation results of the multi-rotor turbine array are compared in three aspects: blade force, wake flow field and power conversion efficiency. The results show that the power conversion efficiency of multi-rotor turbine array is higher than that of the stand-alone turbine. The smaller the spacing of each turbine in the multi-rotor turbine, the larger the overall output power. The single-row multi-rotor array in the form of opposite-rotation is more advantageous for energy acquisition. The analysis of the multi-rotor array from the aspect of the wake flow field can provide some insights into the reasons for the increased power conversion in the array. In this paper, force characteristics, wake characteristics and the energy efficiency of multi-rotor VATCT under different array layouts are considered comprehensively. The array optimization scheme proposed from the point of view of hydrodynamics will provide technical insights for the industrialization of large-scale VATCT array farm. (C) 2021 Elsevier Ltd. All rights reserved.