Method for preventing acing of aircraft wings with the use of laser anti-icing system

The invention relates to aviation, specifically to anti-icing systems of aircraft.

Icing the wings of aircraft (LA) in flight occurs on the frontal surfaces in a collision with supercooled water droplets of clouds and precipitation and their subsequent freezing.

The most vulnerable are the wing surfaces at the leading edge.

To ensure the ability to perform flights, prevention is used to prevent the formation and removal of ice on its surface using anti-icing systems (PIC), based mainly on the following methods:

- mechanical-dynamic, which consists in the destruction of the formed ice with the help of a force effect and the removal of its fragments by an incident stream.

The disadvantages of the method are the possibility of irreversible deformation of the structure, as well as a change in the aerodynamics of the flow around the air flow;

- physico-chemical, consisting in the use of anti-icing fluids that dissolve water and lower the freezing point of the resulting mixture.

The disadvantage of this method is the need for constant availability of liquid on board, which increases the take-off weight and fuel consumption in flight;

- heat, which consists in heating the protected surface to prevent the formation of ice or periodically melting the ice build-up and dropping it under the action of the velocity head, while the heat of the engine gases or electric heaters can be used for heating.

The disadvantages of the method are the need to use complex structures to supply the amount of heat to the extended areas, additional requirements for electrical heat resistance to the heated surfaces, as well as the formation of barrier ice during its use. [1]. [2].

At present, to prevent icing of the wing of the aircraft, it is supposed to use laser anti-icing systems, in which it generates a beam of laser beams directed at the outer edges of the airframe, mainly in the area of ​​the leading edge of the wing (patent documents DE 102011102804 A1, IPC: B64D 15/00, publ - 12.06.2012, DE 102010045450 MPK: B64D 15/00, published April 19, 2012).

The disadvantage of use is the possible violation of the physical properties of the skin of the wing in places of contact with a beam of laser beams.

The closest to the present invention is a technical solution of an aircraft integrated laser system for removing ice using a beam of laser beams (patent US 6206325 B1, IPC: B64D 15/00, publ. 27.03.2001), containing an optical quantum laser flow generator radiation, connected through a fiber-optic cable by waveguides with collimators-emitters.

Removal or prevention of ice formation using an integrated device occurs in a way that generates a stream of laser radiation, which is collimated into a beam of laser beams and scans, directing the laser beam to the outer surfaces of the wing with the direct creation of irradiation zones on them and then moving the coating area. When using the method, water particles or formed ice are heated due to the transfer of energy from the beam of generated rays.

The disadvantage of the prototype is a possible violation of the physical properties of the skin of the wing during irradiation, especially in the case of using composite materials, as well as burning is possible, which limits the installation capacity and the choice of structural material. In addition, a complex control system is required for the directional movement of the laser beam during scanning.

The technical task of the invention was to develop a method for preventing icing of an aircraft wing using a laser de-icing system (POS), which eliminates the possible deformation of the wing surface caused by heating the surface of the skin when a laser beam hits it and simplifies the design of the laser system.

The task is solved by a method of preventing icing of the wing of the aircraft, in which it generates a directional beam of laser beams, while the beams of the laser beam are directed parallel to the leading edge of the wing profile or in the direction at which the beams form an acute angle with it, without irradiating the outer rim of the casing.

The technical result achieved with the use of the invention is to prevent icing of the surfaces of the wing of the aircraft without deforming the surface and also to simplify the design of the PIC.

In private cases, the implementation of the method:

- the angle of the direction of the rays of the laser beam is determined in the process of design study of the placement of the elements of the PIC on the glider of the aircraft;

- generation of a laser beam is produced automatically, during the passage of atmospheric cloud fronts of layered and cumulus clouds, as well as in take-off and landing modes;

- the power of the laser beam is set directly proportional to the water content of the surrounding atmosphere and the length of the leading edge of the wing profile.

- the wavelength of the rays of the laser beam is chosen in the infrared range.

To clarify the essence of the claimed invention, the following graphic materials are used:

FIG. 1 is a block diagram of a laser pic.

FIG. 2 is a functional diagram of the use of PIC in accordance with the claimed method.

FIG. 3 is a diagram of the effect of laser beams on water droplets during the passage of a laser beam.

FIG. 4 is a diagram of the interaction of vapor particles with an incoming flow while preventing icing of the aircraft wing.

The claimed invention is carried out using an anti-icing system installed on an aircraft (POS) generating a directional laser beam (Fig. 1) and containing an energy source (1), such as gas-discharge flash lamps or continuous burning lamps, in the case of a solid-state laser or microwave generator using a gas, optical quantum generator (2) of laser beams, collimators (3) of a beam of laser beams (8), for example focusing heads (FG) or radiating mirrors, connecting cables (4) and the waveguide (5).

The power source is powered from the standard power supply system (6) of the aircraft (7).

The equipment of the anti-icing system is located inside the body of the airframe, while the collimators can be located on the outer surface of the airframe (both the fuselage and the wing) or be hidden in them, with the possibility of being extended during operation, to reduce aerodynamic drag. The positioning of collimators enables the direction of the laser beams in accordance with the present invention.

The angle (17) is determined in the process of design study of the collimator (emitter) placement on the airframe.

When turned on, the POS functions as follows (Fig. 2), the energy source (1) models and pumps the pump energy into the working medium of the optical quantum generator (2), which generates a stream of laser radiation transmitted through waveguides (5)

to the collimator (3), converts the radiation into a beam (9) of laser beams (8) and directs the generated beam (9) parallel to the leading edge (10) of the profile of an airplane wing or at an acute angle (17) to it, for example, in the case of using variable the geometry of the wing, or the impossibility of positioning the collimator with the possibility of obtaining a beam strictly parallel to the leading edge (10), without irradiating the outer edges of the skin. The angle (17) is made sharp, for the laser beam (9) as close as possible to the edge (10) - the main surface to be protected, in case it is impossible to ensure the required distance, between the beam and the front edge of the wing when they are parallel. The required distance to prevent icing using the invention is determined experimentally,

The initiation of a beam of laser beams with a specific wavelength creates a directional perturbation of the electromagnetic field propagating in space (Fig. 3), characterized by the power and wavelength of the laser beams (8)

In the case of a collision of a laser beam (8) with a water drop (11), explosive evaporation of water occurs with the formation of vapor particles (12), which are picked up by the incident flow (13) in the direction of the leading edge (10). At the same time, heat transfer from the formed vapor to other supercooled drops occurs, increasing their temperature (entropy) and excluding the possibility of participation in ice formation (Fig. 3, 4). In addition, smaller vapor particles (14), scattering as a result of explosive evaporation towards the front edge trapping zone (10), due to the air flow near the wing surfaces (15, 16) will tend to deviate towards the skin (Coanda effect) and interacting with frost, they form drops of non-supercooled water, blown away by the oncoming flow.

Thus, as a result of the application of the invention, it is possible not only to prevent the formation of ice on the surface of the wing, but also to remove it if it is formed during a temporarily inactive PIC.

The angle of the direction of the rays of the laser beam is determined in the process of design study of the placement of the elements of the PIC on the glider of the aircraft.

The most intense icing of the wing during take-off and landing flight modes and, at the same time, icing most often occurs during the passage of atmospheric cloud fronts of stratus and cumulus clouds.

In general, the diameter of the settling supercooled droplets is in the range from 5 to 75 microns,

The diameter of the droplet clouds is from 3 to 20 microns, the average water content is 0.18 g / m³.

The diameter of droplets of cumulus clouds is from 3 to 12 microns, the average water content is 0.36 g / m³. Therefore, for the maximum possible prevention of icing when calculating the required power of the laser beam (9) is set directly proportional water content of the surrounding atmosphere and the length of the leading edge of the wing.

Specific power values ​​are calculated according to the laws of fluid dynamics, using the probability theory, or determined experimentally.

To prevent diffraction of the laser beam relative to water droplets, laser radiation should be selected from the wavelength range from 3 to 12 μm., Which corresponds to the infrared range, in this case the interference will be commensurate with the wavelength and increase the efficiency of the transfer of the entropy of the electromagnetic field to supercooled drops, with this, even at a wavelength of 12 μm and a sufficient amplitude of the power of the beam, the kinetic energy of the beam will be enough to heat the supercooled emulsion as a result of heat transfer to the state sklyuchayuschego icing.

In analogs, usually, [1]. [2] PIC is turned on depending on the readings of the icing sensors.

To avoid the formation of ice, in the event of malfunctioning of the icing sensors or preventing its formation, it is advisable to automatically switch on the PIC during the passage of atmospheric cloud fronts of layered and cumulus clouds, as well as during takeoff and landing modes.

Since the beam of laser beams does not hit the surface of the wing, deformation of the surface of the wing is prevented without limiting the radiation power and simplifying the design of the laser system.

Since, in the implementation of the method does not change the direction of the laser beam, the scanning mechanism is not required, simplifies the design of the laser installation, thereby increasing the reliability.

Changes and modifications to the disclosed embodiment may be obvious to those skilled in the art and are within the scope of the claimed formula.

References

1. Fundamentals of aviation technology S.M. Eger, AM Matveenko, I.A. Shatalov. M., Publishing house of MAI, 1999

2. Aircraft equipment systems; AM Matveenko, V.I. Bekasova, M., Mechanical Engineering, 2005