The effect of tidal flow directionality on tidal turbine performance characteristics

Abstract

a b s t r a c tWith many Tidal Energy Conversion (TEC) devices at full scale prototype stage there are two distinct design groups for Horizontal Axis Tidal Turbines (HATTs). Devices with a yaw mechanism allowing the turbine to always face into the flow, and devices with blades that can rotate through 180 to harness a strongly bi-directional flow. As marine turbine technology verges on the realm of economic viability this paper reveals the performance of Cardiff University's concept tidal turbine with its support structure either upstream or downstream and with various proximities between the rotating plane of the turbine and its support stanchion. Through the use of validated Computational Fluid Dynamics (CFD) modelling this work shows the optimal proximity between rotor plane and stanchion as well as establishing, in the given context, the use of a yaw mechanism to be superior to a bi-directional system from a performance perspective.

Effects of Support Structures in an LES Actuator Line Model of a Tidal Turbine with Contra-Rotating Rotors

“…The lesson here is that care must be used when deploying RANS turbulence schemes to capture transient behaviour in diagnostics. Moreover, the flow direction experiments of Frost et al [68] showed that individual blade thrusts varied considerably with blade angle upstream, whereas net rotor thrust and power output did not. It must be noted that their turbine configuration differs somewhat from our model, having three blades with one central monopile, versus our dual two-bladed, crossbeam-mounted arrangement.…”

Effects of Support Structures in an LES Actuator Line Model of a Tidal Turbine with Contra-rotating Rotors

“…The lesson here is that care must be used when deploying RANS turbulence schemes to capture transient behaviour in diagnostics. Moreover, the flow direction experiments of Frost et al [65] showed that individual blade thrusts varied considerably with blade angle upstream, whereas net rotor thrust and power output did not. It must be noted that their turbine configuration differs somewhat from our model, having 3-blades with one central monopile, versus our dual two-bladed, crossbeam-mounted arrangement.…”

Marine Renewable Energy

“…This is of varying importance, depending on the details of a particular turbine design, but it can be significant Frost et al 2015). This is of varying importance, depending on the details of a particular turbine design, but it can be significant Frost et al 2015).…”