Experimental investigation into the influence of the flanged diffuser on the dynamic behavior of CFRP blade of a shrouded wind turbine

Wind tunnel experiments were conducted to investigate the influence of the flanged diffuser on the dynamic behavior of the blade of a 3kW wind turbine shrouded with a flanged diffuser. The blade was fabricated by the skin of carbon fiber reinforced plastic and solid foam core. Tests were carried out for three wind velocities (6.9m/s to 11.6m/s) and three different yawing angles (0-degree to 30-degree) to investigate the effects of the interactions of the flanged diffuser and the yawing angle on the blade. The rotational speed of the blade and the dynamic strain near the blade root were measured under the conditions with and without the flanged diffuser. Two telemeter systems of transmitter and receiver were used in the measurement of the dynamic strains of the rotating blade. The mechanical tests of the blade and the skin of the blade were also performed to obtain basic data for the estimation of the strength of the blade. Experimental results reveal that the rotational speed and the dynamic strain of the blade of the wind turbine with a flanged diffuser are much higher than those without a flanged diffuser.