Environmental Engineering Reference
In-Depth Information
conclude with discussions of future directions on distributed ice sensing and
thermal actuation for the next generation of de-icing systems on wind turbines.
Keywords Active de-icing
Distributed actuation
Localized heating
Optical
ice sensing
Optical frequency domain reflectometry
Nomenclature
AoA
Angle of attack
c
Chord length of the blade
ds
Transform-limited time resolution of an optical measurement
e
j
(t)
Error
signal
j
between
desired
blade
temperature
and
actual
blade
temperature
h
Natural convective heat transfer coefficient of air
J
Performance cost function
K
d
Derivative gain of a PID controller
K
g
Gain of the op-amp circuit
K
i
Integral gain of a PID controller
K
p
Proportional gain of a PID controller
K
Thermal conductivity
k
air
Thermal conductivity of air
Nu
x
Local Nusselt number on the airfoil
n
Total number of thermal resistors in the network
P
Rated power produced by the wind turbine
P
total
Total average power consumption for the distributed thermal resistor
network
q
Input heat flux to the thermal resistor
q
conv
Convective loss heat flux
q
max
Maximum resistor heat flux at maximum applied voltage
R
i
Resistance of heater element i
R
tip
Span-wise radius of the blade tip
r
Span-wise distance from the blade hub
T
a
i
ð
t
Þ
Current temperature on the blade for channel i at time t
T
amb
Ambient temperature
T
d
Maximum desired blade temperature
T
max
b
Maximum
global
temperature
applied
to
the
blade
structure
during
de-icing
t
Time after switching on the resistor network
t
di
De-icing time
u
w
Wind speed
V
ice
Volume of ice residue
V
T[T0
Volume of the blade experiencing temperature higher than T
d
v
Input voltage to the resistors
v
i
Applied voltage to resistor i
v
max
DC input voltage to the resistor at maximum power
