Performance analysis of a ductless Archimedes screw turbine array for deep-sea power supply

Abstract

This study proposes the use of ductless Archimedes screw turbine (DAST) arrays to provide power to deep-ocean observation platforms. The primary objective is to expand the deployment range and reduce the environmental effects associated with deep-ocean observations. An experimentally validated numerical model was developed to assess the efficiency and self-starting capability of the DAST arrays considering different configurations, rotation directions, and flow orientations. To address the limitations of fixed rotational speeds and phase angle differences, a variable step-length optimal rotational speed tracking algorithm was incorporated into the numerical model. The findings illustrate that the optimal triangular DAST array, in comparison with an isolated DAST, can enhance the maximum power coefficient by 8%, reaching a value of 0.37. Moreover, this array can maintain high performance for more than one-third of the incoming flow directions without the need for a yaw device. Furthermore, a novel full-process simulation platform was devised to evaluate the power generation capacity of DAST arrays with varying dimensions under different flow velocity conditions. The results suggest that in typical deep ocean current scenarios, an optimal DAST array with a turbine radius of 500 mm can generate an excess of 25 Wh of daily power supply, which is adequate to support the periodic operations of miniature autonomous underwater vehicles such as ZF-01.