Numerical and Experimental Study of the Ducted Diffuser Effect on Improving the Aerodynamic Performance of a Micro Horizontal Axis Wind Turbine

Abstract

In the present study, the impact of utilizing an encompassing duct on the aerodynamic performance of a micro horizontal axis wind turbine (HAWT) is numerically and experimentally studied. In the first part of the study, fluid flow through the empty duct is analyzed, numerically and experimentally. Then, by adding a nozzle at the diffuser entrance of the original duct, an improved design is proposed and numerically modelled to achieve higher wind speed at the throat position of the duct. The main innovation of the present work, the modified design is further enhanced via altering the converging and diverging sections angles (ranging from 0 to 90 degrees with the angle increment step of 5 degrees). Moreover, the aerodynamic performance of the micro HAWT is studied in three different conditions: with/without the original duct (numerically and experimentally) and with the improved duct (numerically). The results show that the improved duct increases the inlet wind speed from 5 m/s to 10.7 m/s. Furthermore, the power coefficient of the turbine increases from 0.33 to 1.2 in comparison to the case without duct. Also, employing the improved duct design causes a lower level of the flow turbulence kinetic energy compared to the original duct design.