Wind Energ. Sci., 3, 221-229, 2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research articles
25 Apr 2018
Ducted wind turbine optimization and sensitivity to rotor position
Nojan Bagheri-Sadeghi, Brian T. Helenbrook, and Kenneth D. Visser Mechanical and Aeronautical Engineering Department, Clarkson University, Potsdam, NY 13699-5725, USA
Abstract. The design of a ducted wind turbine modeled using an actuator disc was studied using Reynolds-averaged Navier–Stokes (RANS) computational fluid dynamics (CFD) simulations. The design variables included the rotor thrust coefficient, the angle of attack of the duct cross section, the radial gap between the rotor and the duct, and the axial location of the rotor in the duct. Two different power coefficients, the rotor power coefficient (based on the rotor swept area) and the total power coefficient (based on the exit area of the duct), were used as optimization objectives. The optimal value of thrust coefficients for all designs was nearly constant, having a value between 0.9 and 1. The rotor power coefficient was sensitive to rotor gap but was insensitive to the rotor's axial location for positions ranging from upstream of the throat to nearly half the distance down the duct. Compared to the design that maximized rotor power coefficient, the design for maximal total power coefficient was characterized by a smaller angle of attack, a smaller rotor gap, and a downstream placement of the rotor. The insensitivity of power output to the rotor position implies that a rotor placed further downstream in the duct could produce the same power with a considerably smaller duct exit area and thus a greater total power coefficient. The design for that maximized total power coefficient exceeded Betz's limit with a total power coefficient of 0.67.
Citation: Bagheri-Sadeghi, N., Helenbrook, B. T., and Visser, K. D.: Ducted wind turbine optimization and sensitivity to rotor position, Wind Energ. Sci., 3, 221-229,, 2018.
Publications Copernicus
Short summary
Simulations were used to design ducted wind turbines with the objective of either maximizing power per rotor area (PPRA) or maximizing power per duct exit area (PPDA). When PPRA is maximized, any rotor position within the first half of the duct produces approximately the same PPRA. When PPDA is maximized, the optimal position of the rotor is at the rear of duct. In this case, the PPDA exceeds the theoretical power per unit area that can be produced by an open rotor.
Simulations were used to design ducted wind turbines with the objective of either maximizing...