Instrumentation & Measurement Magazine 26-4 - 14

instrumentationand
measurementsystems continued
Fig. 2. Block diagram of the Aerosense sensor node. The hardware is composed of five parts, one main board made of a rigid board, three flexible 0.2 mm thin
boards to support MEMS sensors, and a flexible energy harvesting circuit composed by a solar panel.
The digital twin exploits this data to infer critical performance
quantities in operation, such as the local angle of
attack, local airflow condition over airfoil sections, blade surface
damage and structural deformation. Critical phenomena,
such as wear and performance under extreme loads, can be
monitored and deciphered for improving future design and
operation. Aerosense enables continuous automatic diagnostics,
providing early detection and classification of local blade
surface damage or structural deterioration, reducing operating
costs and increasing revenue by supporting decisions on
operation and maintenance. Finally, acoustic measurements
can help improve design and operation to reduce acoustic disturbances.
Aerosense advocates the adoption of advanced
sensors and electronics for blade monitoring, coupled with a
digital twin platform, in support of sustainable and reliable
wind energy solutions.
Aerodynamic and Acoustic Field
Measurements
The increased demand in energy production requires an increase
in the power produced per wind turbine for these
solutions to remain attractive and efficient [8]. The power produced
is computed as:
P C RV
1
2
14
P
23
where P is the instantaneous power produced, ρ is the air density,
Cp is the power coefficient (the efficiency of the power
conversion), R is the radius of the wind turbine rotor, and V is
the free-stream air velocity. For the same size, offshore wind
turbines can produce more power than onshore wind turbines,
as wind speed (V) is more constant and higher at sea. Longer
blades also contribute to more energy production. A wind turbine
with 100 m long blades produces the same power as two
wind turbines with the same efficiency but with 70 m long
blades (the R2
term). For the same amount of power, one larger
wind turbine would therefore use less material, fewer moving
parts (hence more reliability), and fewer turbine installations
than two smaller wind turbines, thereby reducing the construction
and operational cost. Finally, better wind turbine
performance (the CP
term) further requires optimized blade
designs with complex airfoil sections along the blade and increased
structural flexibility.
Engineering such long and flexible blades requires experimental
validation of their performance in the field.
Aerodynamic field measurements are used during the design
and prototyping phases but are also helpful during
operation for monitoring purposes. The increased structural
flexibility of the blades has reignited concerns related to aeroelastic
instabilities. The techniques traditionally used for wind
turbine monitoring are vibration-based or strain-based measurements
installed on the tower or at the root of the blades.
IEEE Instrumentation & Measurement Magazine
June 2023

Instrumentation & Measurement Magazine 26-4

Table of Contents for the Digital Edition of Instrumentation & Measurement Magazine 26-4