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WIND TUNNEL MEASUREMENTS OF AERODYNAMIC COEFFICIENTS OF ASYMETRICAL AIRFOIL SECTIONS FOR WIND TURBINE BLADES,EXTENDED TO HIGH ANGLES OF ATTACK.

Objective

THIS WORK IS PART OF A RESEARCH CONTRACT BETWEEN POLITECNICO DI TORINO AND E.N.E.A. (NATIONAL AGENCY OF ALTERNATIVE ENERGIES) WITH A FINANCIAL CONTRIBUTION FROM CEC.
WIND TURBINE BLADES OPERATE VERY FREQUENTLY AT ANGLES OF ATTACK WELL BEYOND THOSE USUAL IN AERONAUTICS. THIS MEANS THAT CONVENTIONAL AIRFOIL DATA USED FOR AIRCRAFT DESIGN AND USUALLY AVAILABLE ARE NOT SUFFICIENT FOR WIND TURBINE APPLICATIONS.
THE AIMS OF THE CONTRACT ARE : 1) TO ENABLE THE NATIONAL FACILITY TO SET UP AN EXPERIMENTAL METHODOLOGY TO DETERMINE THE AERODYNAMIC CHARACTERISTICS (LIFT, DRAG, PITCHING MOMENT COEFICIENTS) OF AIRFOIL SECTIONS UP TO HIGH ANGLES OF ATTACK IN TWO-DIMENSIONAL FLOW; 2) TO DETERMINE THE AERODYNAMIC CHARACTERISTICS AND PRESSURE DISTRIBUTION UP TO HIGH ANGLES OF ATTACK, IN A TWO-DIMENSIONAL FLOW, OF SIX AIRFOIL SECTIONS SELECTED AMONG THOSE MORE SUITABLE FOR WIND TURBINE APPLICATIONS. THE EXPERIMENTAL TESTS ARE PERFORMED AT THE AERONAUTICAL AND SPACE DEPARTMENT OF THE POLITECNICO DI TORINO IN THE LOW SPEED 3 M DIAMETER WIND TUNNEL.
The following results have been achieved:
an experimental methodology has been set up to determine the aerodynamic characteristics (lift, drag, moment coefficients) of airfoil sections up to high angles of attack in 2-dimensional flow;
the aerodynamic characteristics and pressure distribution up to high angles of attack of 6 airfoil sections have been determined in 2-dimensional flow;
Wortmann airfoils have been found to have very good stall characteristics making them suitable for windmills;
NASA low speed airfoils have been found to have a very good performance.
THE NACA 0012 AIRFOIL HAS BEEN TESTED TO VALIDATE THE EXPERIMENTAL METHODOLOGY IN THE MODIFIED WIND TUNNEL AND THEN THE SIX AIRFOIL SECTIONS WERE TESTED AT ANGLES OF ATTACK IN THE RANGE 90 DEGREE TO + 90 DEGREE, FOR TWO REYNOLDS NUMBERS.

THE SIX AIRFOILS ARE : TWO WORTMANN FX AIRFOILS (BECAUSE A WIND TURBINE USING THIS AIRFOIL IS NOW BEING MADE BY AN ITALIAN FIRM); FOR SIMILAR REASONS, THE TWO AIRFOILS OF THE FIVE-DIGIT NACA FAMILY WERE SELECTED FROM THE 230XX SERIES; THE FIFTH AIRFOIL IS THE 23017 AS BUILT AND FINALLY THE SIXTH WAS THE NASA LS-421 BECAUSE ITS SMALL LIFT LOSS AFTER STALL LEADS TO SPECIAL INTEREST FOR WIND TURBINE APPLICATIONS.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Ente per le Nuove Tecnologie, l'Energia e l'Ambiente (ENEA)

Participants (1)

POLITECNICO DI TORINO
Italy
Address
Corso Duca Degli Abruzzi 24
Torino