Design and Development of a Wind Turbine with Flanged Diffuser Operating in Low Wind Speed Regime

In this paper, the performance characteristics of a fabricated horizontal axis wind turbine with and without flanged diffusers were studied using wind tunnel experiment. Measurements of global parameters (power, torque, rotational speed efficiency, etc.) were carried out at wind speed regime between ۳-۷ m/s. Flanged diffusers of five different inlet-outlet diameter ratios were employed. The results showed minimum mean increments in tip-speed ratios (TSR) of about ۴۵ % with the smallest diffuser and a maximum of ۸۰ % with the largest diffuser. Increments in the torque even at modest wind speed of ۴ m/s were as much as ۶۵, ۷۰ and ۷۶ % for the largest three diffusers and about ۳۳ % for the smaller diffuser. The power output (with and without diffuser) gradually increased from ۳-۷ m/s wind speed, while the power coefficient (Cp) increased from ۳-۵.۵ m/s, and thereafter began to fluctuate as the wind speed approached ۷ m/s. Comparatively, maximum Cp of the turbine without diffuser was ۰.۲۲ for λ=۰.۵۳۴ at a wind speed of ۷ m/s, while the maximum average value of Cp for turbine with flanged diffuser ۳ was ۰.۳۴ for λ=۰.۷۰۶ at the same wind speed. As a result of the flanged diffuser attachment, the maximum Cp increased by ۳۶ %. The results showed mean incremental values of ۵۲ and ۵۷ % with the greater value obtained from the second largest diffuser (Di/Do = ۰.۷۰) and the least value from the largest diffuser (Di/Do = ۰.۸۰), while the first three diffusers achieved near identical increments of ۵۵ %. This consequently implies that increments in the extracted power (i.e., Cp) above ۵ m/s wind speed declined with indications of separation and turbulence in the flows beyond the rotor.

کلیدواژه ها:

fabrication ، Horizontal ، Wind Turbine ، Flanged Diffusers ، Power output and Power Coefficient