Development of a Shrouded Wind Turbine with Various Diffuser Type Structures

Abstract

The Shrouded wind turbine is an innovative mean to increase power generated by wind turbine. By encompassing the rotor with a diffuser structure, it is possible to increase the wind velocity through the turbine up to 1.8 times of free stream velocity. Specifically, this study is numerical simulations that investigate the effect of wind velocity on various diffuser type structures to develop shroud wind turbine. Numerical study was conducted using Computational Fluid Dynamics (CFD) method. A reasonable agreement between the computed results, available experimental data and previous simulation is obtained. The results show that simulation results have good agreement to experimental results. However, Curved diffuser give the best increment of wind velocity (at centreline diffuser) than flat diffuser and others, which is 84.18%, with the maximum velocity was 9.21 m/s. Regarding the velocity contour results, vortex in downstream curved diffuser is bigger than others. Therefore, suction effect on curved diffuser is strongest and can generate positive impact on the wind velocity quality inside the diffuser.

Wind Lens Performance Investigation at Low Wind Speed

“…The early designs of DAWT have never been upgraded to become a commercial product due to the complexity added by the boundary layer controllers and the cost added by the long diffuser. To solve this problem, a group of researchers at Kyushu University had introduced the concept of Wind lens 8,11,17,18) . Wind lens is a compact ducted wind turbine characterized by the following: it has a small length to diameter ratio of less than 0.4, and it has a high vertical flange at its rear.…”

“…A diffuser duct placed in a free flow has been proved to accelerate the airflow at its inlet 7,8) . Many researchers have proved that mating a turbine with a diffuser increases the power significantly to exceed the Betz limit, which is 59.3% 9,10) ; wind turbines shrouded with a diffuser are known as diffuser augmented wind turbine (DAWT) or Wind Lens 11) .…”

Modelling Design Diffuser Horizontal Axis Wind Turbine

“…Putra et al [9] obtained the wind speed profile around the diffuser which earlier changed the diffuser in the form of supplementary inlet and flange curvature. Advance study on wind speed in DAWT was carried out by unpredictable the diffuser types, namely the camber diffuser and the uniform diffuser [10]. Ahmed et al [11] stressed the superiority of this DAWT performance where there are 3 diffuser design parameters that is able to enhance mass flow and wind speed, explicitly the length, height and the diffuser angle.…”

Computational Investigation of a Wind Turbine Shrouded with a Circular Ring

“…A group of researchers in Japan has shown by wind tunnel testing that a diffuser placed in a free flow will accelerate the airspeed [7,8]. The diffuser configuration creates a pressure difference across its length such that the inlet will have a sub-atmospheric pressure, which encourages upstream air to flow through the diffuser.…”

“…The flange acts as a vortex generator; it produces a low-pressure zone at the back of the diffuser, which helps accelerate the flow. Wind-lens designs have been proven practical and efficient, but with the price of a total drag increase [8,10,[15][16][17].…”