Parametric study and performance analysis of flanged diverging diffusers for small wind turbines

Mangesh R. Mahajan, Sanjay D. Nikhade, Sandip A. Kale

Abstract


Flanged diverging diffusers are advantageous because of higher durability, low mass and cost, better environment friendly design, compared to various diffuser models used to increase the wind velocity at wind turbine rotor plane. Diffuser length, expansion angle and flange height affects the diffuser performance in terms of velocity enhancement and mass. This study has systematically used Design of Experiments (DOE) for these three parameters at five levels. The computational Fluid Dynamics (CFD) simulations are performed for a total twenty five diffuser models obtained using DOE. The results of one selected CFD model are validated with wind tunnel experimentation showing acceptable agreement. CFD results are further examined using multivariate regression analysis, Pareto Charts, main effect plots, 2D interaction contours and 3D surface response plots. The obtained regression equation is delivering the predicted accuracy. Among the parameters, the expansion angle is observed as an important factor which influences the velocity output followed by the diffuser length and flange height. Further, the optimum dimensions of diffuser are found using desirability function analysis which suggests the intermediate value of diffuser length, lower values of expansion angle and flange height provide compromised velocity performance with significantly reduced mass and cost.


Received: 03 November 2025

Accepted: 25 January 2026

Published: 6 April 2026


Keywords


CFD; diffuser augmented wind turbine; small wind turbine; optimization

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DOI: https://dx.doi.org/10.21622/resd.2026.12.1.1765

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Copyright (c) 2026 Mangesh R. Mahajan, Sanjay D. Nikhade, Sandip A. Kale

Renewable Energy and Sustainable Development

E-ISSN: 2356-8569

P-ISSN: 2356-8518

 

Published by:

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Arab Academy for Science, Technology and Maritime Transport (AASTMT)

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