Characterization of blade throw from a 2.3MW horizontal axis wind turbine upon failure

The present work concerns aerodynamics of thrown objects from a 2.3 MW Horizontal Axis Wind Turbine (HAWT), as a consequence of blade failure. The governing set of ordinary differential equations for the flying objects are derived and numerically solved using a 4th order Runge-Kutta time advancing discretization technique and the sensitivity of the throw distance to the size of fragment, incoming wind velocity, and release tip speed and height are investigated both qualitatively and quantitatively.

Computations suggest that the tip speed, at the release moment, is the most influential parameter for determining the throw distance and it is shown that when the turbine is operating in normal operating conditions (tip speed ratios of about 7 -with hub height velocity of 10m/s, resulting in blade tip speeds of about 70m/s), the fragments thrown from the turbine can reach between 100m and 500m, depending on their size.

Thereafter, throw distance picks up exponentially with the tip speed. By comparing the throw distance calculations with and without dynamic stall model being active, it is concluded that dynamic stall does not play a major role in throw distances.