Aircraft wing element
An aircraft wing element comprises two temperature sensors that are situated on each side of an electrothermal mat, between a structure portion and a shield of said wing element. A shield temperature can be measured more accurately, and a thermal energy flow that is transferred to the shield can be evaluated.
1. An aircraft wing element comprising a rigid internal structure portion and a shield intended to be exposed to atmosphere during a flight of the aircraft, and also comprising at least three components which are superimposed between a surface of the structure portion and the shield in an order of listing of said three components, starting from the structure portion, each component being in a form of a layer arranged parallel to the surface of the structure portion:
a first temperature sensor, comprising a first support film and at least one first track of a first electrically conductive material with an electrical resistivity value of the first material that varies as a function of a temperature of said first material, said first sensor being rigidly connected to the surface of the structure portion;
an electrothermal mat forming a heating element, rigidly connected to the first sensor; and
an electrically insulating film, rigidly connected to the electrothermal mat by a first face of said insulating film, and connected to the shield by a second face of said insulating film, and capable of transferring heat between said first and second faces of said insulating film,
wherein the wing element also comprises between the electrothermal mat and the insulating film:
a second temperature sensor, comprising a second support film and at least a second track of a second electrically conductive material, with an electrical resistivity value of the second material which varies as a function of a temperature of said second material, said second temperature sensor being rigidly connected to the electrothermal mat by a first face of said second sensor, and to the insulating film by a second face of said second sensor,
and the second track forms meanders on the second support film, and an average rate of surface occupation of the second track on the second support film is at least equal to 50% when evaluated in an area which contains several adjacent meanders of the second track.
2. The aircraft wing element according to claim 1 , forming a leading edge segment of an aeroplane wing or a helicopter blade.
3. The aircraft wing element of claim 1 , wherein, in the second temperature sensor, the second track is situated on a face of the second support film turned towards the shield.
4. The aircraft wing element of claim 1 , wherein, in the second temperature sensor, a thickness of the second support film is between 25 μm and 250 μm, measured perpendicularly to the surface of the structure portion.
5. The aircraft wing element of claim 1 , wherein, in the second temperature sensor, the second support film comprises polyimide.
6. The aircraft wing element of claim 1 , wherein, for the second temperature sensor, the average surface occupation rate of the second track on the second support film, evaluated in the area that contains several adjacent meanders of the second track, is at least equal to 65%, preferably at least equal to 75%.
7. The aircraft wing element of claim 1 , wherein the surface of the structure portion is a thermally insulating material, comprising epoxy resin.
8. Method for protecting an aircraft wing element against ice, said aircraft wing element comprising a rigid internal structure portion and a shield intended to be exposed to atmosphere during a flight of the aircraft, and also comprising at least four components which are superimposed between a surface of the structure portion and the shield in an order of listing of said four components, starting from the structure portion, each component being in a form of a layer arranged parallel to the surface of the structure portion:
a first temperature sensor, comprising a first support film and at least one first track of a first electrically conductive material with an electrical resistivity value of the first material that varies as a function of a temperature of said first material, said first sensor being rigidly connected to the surface of the structure portion;
an electrothermal mat forming a heating element, rigidly connected to the first sensor;
a second temperature sensor, comprising a second support film and at least a second track of a second electrically conductive material, with an electrical resistivity value of the second material which varies as a function of a temperature of said second material, the second track forming meanders on the second support film, and an average rate of surface occupation of the second track on the second support film being at least equal to 50% when evaluated in an area which contains several adjacent meanders of the second track; and
an electrically insulating film, rigidly connected to the electrothermal mat by a first face of said insulating film, and connected to the shield by a second face of said insulating film, and capable of transferring heat between said first and second faces of said insulating film,
said second temperature sensor being rigidly connected to the electrothermal mat by a first face of said second sensor, and to the insulating film by a second face of said second sensor,
the method comprising:
supplying electricity to the electrothermal mat so as to heat the wing element;
measuring two temperatures by using the first temperature sensor for one of said temperatures and the second temperature sensor for the other one of said temperatures; and
based on the two measured temperatures, evaluating a thermal energy flow that is delivered to the shield.