![]() ![]() In this study, we consider a two-dimensional flow field for the analysis following studies conducted by Dighe et al. High-lift airfoils improve the aerodynamic efficiency ( C L∕ C D), i.e., lift-to-drag ratio, at low Reynolds number by virtue of a high-lift coefficient with minimum drag penalties. The use of high-lift airfoils in wind energy applications has been documented extensively in the literature. The present study uses high-lift airfoils to highlight a simplified simulation pipeline that may assist designers in assessing the suitability of a pool of airfoils while designing DAWTs or other decentralized wind energy generators. Although there is a significant amount of literature employing high-fidelity numerical modeling techniques applied to DAWTs, there is no preliminary analysis that may help potential manufacturers design diffusers with commonly available airfoil geometries. The mass flow rate is thus further increased by this geometric feature. The study showed that flanged diffusers, that is, an additional geometric modification to the shroud, can cause a larger wake expansion due to unsteady flow-separated regions generated by the flange periphery. ( 2008) varied the diffuser open angle by adding a flange around the diffuser exit. This phenomenon is termed as velocity augmentation. Through wind tunnel testing, Igra ( 1981) found that the power coefficient could be improved by 80 % of that of a conventional wind turbine just by placing a diffuser over it. This, in turn, leads to an increase in the mass flow rate of the incoming free-stream air, thereby increasing the efficiency of the system beyond the Betz limit. By enclosing a diffuser around the turbine, the wake of the turbine blades is allowed to expand, resulting in a subsequent rapid drop in pressure aft of the diffuser. Since the early studies, ample research based on empirical, computational, and experimental approaches has been conducted to investigate and optimize the efficiency of DAWT through various means ( Alquraishi et al., 2019). The idea of a DAWT, also commonly referred to as a ducted wind turbine or shrouded turbine, was first explored by Lilley and Rainbird ( 1956). Diffuser-augmented wind turbines (DAWTs) have the ability to increase the power extracted by the wind turbine by virtue of increased mass flow rate through the rotor plane, improved wake mixing with the external flow, and lastly, improved performance even in cases where the flow may not be purely axial in nature. The HAWTs can extract 59.3 % of power available in the wind, in accordance with the Betz limit. While large wind turbines are placed where the wind topology is optimum, smaller wind turbines are locally built to supply power to meet the local energy demands.Ī simplified modeling approach for the wind turbines is carried out, where the conventional horizontal-axis wind turbine (HAWT) is modeled as an actuator disk (AD). This necessitates the transfer of electricity via grids over more considerable distances, increasing the levelized cost of electricity. ![]() Presently, wind turbines are typically installed away from populated areas because of visual and noise regulations ( Pedersen and Persson Waye, 2004). Wind energy is emerging as an alternative renewable source for energy production. ![]() ![]() Global energy demand is expected to more than double by 2050 due to the growth in population and development of economies ( Gielen et al., 2019). ![]()
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