Environmental Engineering Reference
In-Depth Information
Fig. 8.16 Experimental
input voltage to the resistive
heaters
14
measured data
least-squares curve
12
10
8
6
4
2
0
0
100
200
300
400
500
600
Time (sec)
upper and lower surfaces of the blade, we simulated the temperature variation on
the blade at the location of the temperature sensor for both h = 6 W/(m
2
C) and
h = 7 W/(m
2
C), and with a composite blade thermal conductivity of
K = 0.3 W/(m
C). Figure
8.17
shows the temperature comparison between our
recorded experimental data and the simulated values in ANSYS, showing a rea-
sonably close match between the numerical simulations and the experimental data.
8.9 Optimizing the Layout of Distributed Heaters
In this section, we explore several heater geometries and layouts (Fig.
8.18
) and
show that there are de-icing efficiency advantages to circular heaters in a staggered
layout. Circular heaters generate uniform heat flux in all radial directions, and
square heaters generate uniform heat flux along their two axes of symmetry.
Figure
8.18
shows different heater layouts modeled for ANSYS computational
analysis. For the created staggered layouts, only heaters in the second row are
shifted in the y
b
direction shown in Fig.
8.11
. For the staggered alignments, in
order to keep the geometry symmetric about the axis that connects the midpoint
leading edge to the midpoint trailing edge, two half-area resistors are used at each
end in the second row of resistors (Fig.
8.18
b, d). The total heating area and total
input heat flux are equal for all of the resistor shapes and layouts considered in
Fig.
8.18
and in the results that will be discussed in Sect.
8.9.2
.
We also investigated other heater geometries. It was observed that the de-icing
performance of other regular polygon-shaped heaters (pentagon, hexagon, etc.) is
between square and circular heaters. Therefore, the performance of only square
and circular heaters will be discussed in Sect.
8.9.2
as the lower and upper bound
of the de-icing performance.
