496
B. Arizmendi et al.
Research in the field of de-icing boot system was conducted to characterize the
effects on aircraft performance of the residual and inter-cycle ice [107, 108]. For
instance, Broeren conducted an experimental study based on wind tunnel tests using
airfoils equipped with de-icing boots. The study concluded that the effects of the
inter-cycle ice in the test conditions are more severe in terms of drag increase, lift
decrease, and stall angle reduction than those of the residual ice after operating the
de-icing boots. Plus, the authors observed that a little amount of ice was left on the
airfoil after the inflation and deflation of the boots.
15.4.1.3 Thermo-Electric protection
These systems use the heat generated by an electric current going through a resistive
component. The resistor component can present different schemes such as internal
coil wires, externally wrapping blankets, tapes, conductive films, and heating rods.
This technology has been implemented on the wing of the Boeing 787 [109]. They
can be anti-icing systems if they do not allow the ice to build up or de-icing that
operate when a layer of ice has been formed. De-icing systems break the adhesion
between the surface of the aircraft and the built layer of ice. In a similar manner
as the thermo-pneumatic systems, the electric ice protection systems can run fully
evaporative or wet runback [110]. In the former approach, the impinging water is
rapidly evaporated when impinging on the protected surfaces. In the latter approach,
the ice is melted and the runback water is driven downstream by aerodynamic
forces. The evaporative systems, however, require a larger power consumption. The
resistive components can be mounted inside or outside the protected element or they
can be built into it. This is the preferred method for the protection of rotorcraft [111]
because it presents the best fit to the design, due to the relatively small thickness
of the blades. In addition, electric protection means are implemented in the vast
majority of aircraft to protect probes from icing such as the Pitot tube or the angle of
attack probes [93, 94, 96, 97, 103]. Since the probes are usually small protuberances
from the aircraft surface, they are very susceptible to ice.
Numerical and mathematical models [112, 113] have been developed in order
to increase the understanding of the performance of the protection systems and to
accurately predict the effects. The goal is to forecast possible effects and to help
on the design of more effective ice protection systems. Moreover, some authors
investigated the use of new conductive materials to improve the efficiency of the
systems and the combination of thermal-electrical systems with super-hydrophobic
coatings to decrease the energy consumption [28]. Also, layers of carbon nano-tubes
have been investigated due to their electrical properties such as high current density
and low heat capacity [114].
B. Arizmendi et al.
Research in the field of de-icing boot system was conducted to characterize the
effects on aircraft performance of the residual and inter-cycle ice [107, 108]. For
instance, Broeren conducted an experimental study based on wind tunnel tests using
airfoils equipped with de-icing boots. The study concluded that the effects of the
inter-cycle ice in the test conditions are more severe in terms of drag increase, lift
decrease, and stall angle reduction than those of the residual ice after operating the
de-icing boots. Plus, the authors observed that a little amount of ice was left on the
airfoil after the inflation and deflation of the boots.
15.4.1.3 Thermo-Electric protection
These systems use the heat generated by an electric current going through a resistive
component. The resistor component can present different schemes such as internal
coil wires, externally wrapping blankets, tapes, conductive films, and heating rods.
This technology has been implemented on the wing of the Boeing 787 [109]. They
can be anti-icing systems if they do not allow the ice to build up or de-icing that
operate when a layer of ice has been formed. De-icing systems break the adhesion
between the surface of the aircraft and the built layer of ice. In a similar manner
as the thermo-pneumatic systems, the electric ice protection systems can run fully
evaporative or wet runback [110]. In the former approach, the impinging water is
rapidly evaporated when impinging on the protected surfaces. In the latter approach,
the ice is melted and the runback water is driven downstream by aerodynamic
forces. The evaporative systems, however, require a larger power consumption. The
resistive components can be mounted inside or outside the protected element or they
can be built into it. This is the preferred method for the protection of rotorcraft [111]
because it presents the best fit to the design, due to the relatively small thickness
of the blades. In addition, electric protection means are implemented in the vast
majority of aircraft to protect probes from icing such as the Pitot tube or the angle of
attack probes [93, 94, 96, 97, 103]. Since the probes are usually small protuberances
from the aircraft surface, they are very susceptible to ice.
Numerical and mathematical models [112, 113] have been developed in order
to increase the understanding of the performance of the protection systems and to
accurately predict the effects. The goal is to forecast possible effects and to help
on the design of more effective ice protection systems. Moreover, some authors
investigated the use of new conductive materials to improve the efficiency of the
systems and the combination of thermal-electrical systems with super-hydrophobic
coatings to decrease the energy consumption [28]. Also, layers of carbon nano-tubes
have been investigated due to their electrical properties such as high current density
and low heat capacity [114].