Influences of Yaw characteristics on the performance of an Archimedes screw hydrokinetic turbine

A system for in situ power generation that exploits deep-sea current energy has been developed to meet the electricity demands of deep-sea observational equipment. The Archimedes screw hydrokinetic turbine (ASHT) is notable for its self-starting capabilities and energy efficiency, making it well suited for deployment in the low-speed deep-sea environment. This study elucidates two distinctive hydrodynamic characteristics of ASHT and explicates the underlying operational principles for the first time. Specifically, the ASHT is capable of self-yawing without the need for auxiliary yawing mechanisms and, when fixed, can harness ocean currents from a wide array of directions. Based on these hydrodynamic characteristics, passive yaw and fixed installation methods are proposed. A rigorously validated numerical model, supported by water flume tests, is utilized to illuminate the real-time flow mechanisms and assess the effect of different geometric variables on the ASHT yawing performance. An in-house Simulink model evaluates the power supply capabilities of both installation options, revealing that fixed installations are preferable for locations with varied incoming flow angles, whereas passive yaw installations are more appropriate for sites with a restricted range of incoming flow angles.