Browsing by Author "Merid, Million"

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    Prediction of Performance Parameters and Determination of Aerodynamic Characteristics of Wind Turbine Airfoil Using CFD Modeling:
    (Addis Ababa University, 2014-08) Merid, Million; Assefa, Abebayehu (PhD)
    In the current situation of global energy crisis, generation of energy derived from renewable energy resource has grown a significant attention. Wind energy is a very interesting due to the fact that fuel is free of cost. The most important aspect of wind energy technology is the wind turbine and its aerodynamic characteristics of the airfoil forming the blade. Thus predicting the performance parameters and determining aerodynamic characteristics of airfoil section are important. However, this requires continued experimental wind tunnel test and validation tools such as computational fluid dynamics (CFD). The primary objective of this study was learning the CFD software and its applications. Secondly, this study was focused on predicting aerodynamic characteristics of an airfoil for varying angles of attack (AOAs). Simulation was done to deduce aerodynamic parameters (lift, drag, lift to drag ratio, contour plot of velocity and pressure distribution over the airfoil section). This can reduce dependence on wind tunnel testing. The simulation was done on airflow over a two – dimensional NACA 63-415 airfoil using FLUENT (version 6.3.26) at various angles of attack varied from -50 to 200 using two turbulence models (S-A and SST k- ω) with the aim of selecting the most suitable model. Domain discretization was carried out using structured quadrilateral grid generated with GAMBIT (version 2.3.16), the fluent pre-processing tool. Comparisons and validation were made with available experimental data for NACA 63-415 airfoil with numerical results. Accordingly, it was found that the two turbulence models achieved a reasonable and a good agreement in predicting the coefficients especially for angle of attacks prior to stall. Among the model, studied the most appropriate turbulence model for the simulations were the SST k- ω two equation models, which had good agreement with the experimental data than S-A one equation model. As a result, it was decided to use the SST k- ω turbulence model for the main analysis with acceptable deviations in results (9.028% for lift and 12.203 % for drag coefficients). This study concluded that CFD simulation provides sufficiently accurate results for a majority of AOAs. The discrepancy in calculating the lift and drag values comes from limitations in the turbulence model behavior. However, the majority of the lift and drag curves match the experimental data. Finally, this study includes simulation results of Adama I wind turbine airfoil section and predicted results was complied.