Aerodynamics of a wind turbine

Author: Kosmacheva Anna

Supervisor: Jari Hämäläinen

Lappeenranta University of Technology

Technomatematics

Introduction

Wind turbine is a device that converts kinetic

energy from the wind into mechanical energy.

The smallest turbines are used for applications such as

battery charging or auxiliary power on sailing boats.

Large grid-connected arrays of turbines are becoming an

increasingly large source of commercial electric power.

Defects of wind turbine blades

There are some types of defects of wind turbine blades:

Influence of defects:

Energy losses

Noise generation

Porosity Wrinkles/Cracks Delamination

Problem statement

Main goal - analysis of the performance of the wind

turbine blades with and without defects

Subject of research – 2D-3D models of wind turbine

blade, 3D wind turbine model

Method – Computational Fluid Dynamics (CFD)

Literature review – 2D case

M. Edon (2010) “Numerical analysis of the Naca airfoils of a wind turbine blade”

J. Leary (2010) “Computational Fluid Dynamics analysis of a low cost wind turbine”

H. Cao (2011) “Aerodynamics analysis of small horizontal axis wind turbine blades by using 2D and 3D CFD modeling”

O. Badran “Two-equation turbulence models for turbulent flow over a NACA 4412 airfoil at angle of attack 15 degree”

I.H. Abbott (1959) “Theory of wind sections. Including a summary of airfoil data”

Literature review – 3D case

S.N. Prasad, S.S. Rao “Analysis of aerofoil blade using

ANSYS for a vehicle mounted micro wind turbine”

S. Guntura, C. Bak “Analysis of 3D stall models for wind

turbine blades using data from the MEXICO experiment”

V. Sajjan, R.A. Savanur (2009) ”CFD analysis of 500 kW

horizontal-axis wind turbine blades: straight and bent

cases”

C. Ghenai, A. Sargsyan “Wind energy”

Literature review - Defects

H. S. Toft, K. Branner “Distribution of defects in wind

turbine blades and reliability assessment of blades

containing defects”

S.N. Ganeriwala, M. Richardson “Modes indicate cracks in

wind turbine blades”

Wind Energy Department, Risø National Laboratory

(2002) “Guidelines for design of wind turbines”

Research plan (1)

CFD analysis of 2D wind turbine blade model with

different design

Simulation of 2D model with some defects

The profile of NREL S809

The profile of DU93-W-210

Research plan (2)

3D modeling of rotating blades without any fixed objects

Research plan (3)

Studying of rotating blades and stationary tower and

some parts of the terrain

NACA 4412

The NACA airfoils are airfoil shapes for aircraft wings

developed by the National Advisory Committee for

Aeronautics (NACA).

Lift, drag and moment coefficients

The lift is the force used to overcome gravity and the higher the

lift the higher the mass that can be lifted off the ground.

In order to maintain a constant speed the drag must be balanced

by a propulsion force delivered from an engine, and the smaller

the drag the smaller the required engine.

Flow in the vicinity of leading edge bubble

Stall angle – NACA 4412

Mesh

ANSYS ICEM

19890 QUAD elements

Computational conditions of aerofoil

simulation

Solver – ANSYS FLUENT 13.0

Simulation Type – Steady Simulation

Fluid Material – Air

Wind Speed – 45.48 m/s

Turbulent models – RNG K-E, Spalart-Allmaras

Boundary condition – velocity inlet, pressure-outlet,

Stationary wall with no slip shear condition

Numerical results – Static pressure

Inviscid, Angle of attack – 2

Khandakar Niaz

Morshed [1]

My results

Numerical results – Velocity Magnitude

My results

Khandakar Niaz

Morshed [1]

Inviscid, Angle of attack – 2

Numerical results – flow separation

Angle of attack

18

Angle of attack

20

Comparison with experiment [2]

2 4 6 8 10 12 14 16 18 200.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Angle of attack

Lift

coeff

icie

nt

Experiment

K-E RNG

Spalart-Allmaras

References

1. Khandakar N. Morshed (2010) “Experimental and

numerical investigations on aerodynamic characteristics

of savonius wind turbine with various overlap ratios”

2. Robert N. Pinkerton “Calculated and measured

pressure distributions over the midspan section of the

NACA 4412 airfoil”

Thank you