UA56355C2 - Method for preventing icing of structure elements of an aircraft - Google Patents

Abstract

A method for preventing icing of structure elements of an aircraft is in heating structure elements of the aircraft in the zones with tendency to icing-over to melting temperature of ice. Thermal energy for heating is obtained through transformation of kinetic energy of coming air with directing it to the respective zones of the surface due to accumulation of heat. For this transformation on the front of the face parts of the structure elements of the aircraft acoustic resonators are installed, those are made of material with high heat conductivity. This method makes it possible to exclude additional load for the airborne energy system and to decrease weight of the aircraft.

Description

Description of the invention

The invention relates to aviation technology, in particular to anti-icing systems of aircraft (LA), and 2 can be applied to prevent the formation of ice on the outer surfaces of aircraft wings, inlet devices of gas turbine engines of LA, helicopter propeller blades, propeller blades (thrusters), wind generators etc. That is, in any branch of power engineering, where the high-speed pressure of the surrounding air can be used.

A known method of mechanical destruction of ice on aircraft structures | RF Patent No. 93053570, cl. B64015/16, 70 publ. 1996.06.27|, which provides for the creation of repeated impulse deformations separated by pauses in the cladding being protected and the layer of ice on it. On the outer surface of the cladding to be protected, in areas prone to icing, elastic material with ferromagnetic plates pressed into the latter is fixed and formed by the electropulse method of oscillation of the elastic material when ice forms on it by influencing the ferromagnetic plates with an electromagnetic field of alternating sign, concentrated in 12 areas of the latter.

Disadvantages of the present invention include: - high energy consumption of the method, given the fact that on-board sources of electricity are used to form the electromagnetic pulse; - An increase in the weight of the aircraft due to the need to install additional equipment to create impulse deformations in the skin; - reduction of the flight range of the aircraft and reduction of the distance to the "point of return" in emergency situations due to the additional consumption of fuel for the formation of vibrations of the elastic material of the skin; - reduction of the operational resource of the main engines of the aircraft, associated with additional costs of electricity for the removal of ice; c - the complexity of the design due to the large number of structural elements used in method a (3 namely: elastic cladding elements, ferromagnetic inserts, a distribution device, wires for supplying electricity, etc.; - a decrease in the resource of the cladding due to damage from deformations during the creation of electromagnetic pulses; o - the complexity of the implementation of the method is due to the fact that in the analogue the ice layer that has already formed is destroyed, and not prevented from forming. Therefore, it is necessary to carry out additional operations to activate the operation of devices that generate oscillations.

Known invention "Resistance elements for heating the aerodynamic surface and devices containing such Ge) elements" Patent OB, Mo 5971323, cl. B64815/00, Vb41 01/02, publ. 26.11.1999), which consists in the fact that to remove icing, the aerodynamic surface is heated using several resistance elements, each of which consists of electrically conductive glass fibers and is located in the aerodynamic surface in the immediate close to its front parallel to it. An electric current is applied to the resistance elements, which causes them to heat up due to the Joule effect. The disadvantages of this well-known invention are: "- reduction of the flight range of the aircraft due to the need to spend fuel on heating the aerodynamic C 70 surfaces; c - the complexity of the design due to the need for a large number of resistance elements and c" electrically conductive glass fibers included in their composition; - an increase in the weight of the aircraft as a whole due to an increase in the mass of fuel on board for the generation of electricity needed for heating; - additional load on the power plant of the aircraft due to the withdrawal of electricity from the main engines for the heating of surfaces prone to icing.

Ge") Known method and apparatus for using heated fuels to remove icing from an aircraft (Patent 05, Mo. 5558303, class B64015/02, publ. 09/24/19961. o The method consists in the fact that to remove icing from the aerodynamic surface, it is heated to temperatures c 20 melting ice, using heat from fuel preheated to temperatures high enough to transfer thermal energy through fuel tanks located in the wings to the outer region of the wings. sl The disadvantages of the present invention are: aircraft of different brands, related to the need for the mandatory location of the fuel tank in the wing of the aircraft; 29 - high operating costs due to the need to have special equipment at airfields

HF) for fuel preheating.

The well-known invention "Airplane slat with air heating" (Russian Patent Mo2083441, class B64015/04, published on 07.10.1997), which consists in the fact that an air heating pipe installed in the slat is used to heat structural elements prone to icing of the aerodynamic surface on the support element made in the form of a pad. The pad is fixed to the diaphragm and spring-loaded relative to it by a flat corrugated spring. The air heating pipe is placed in the tip of the front wing and is attached with a clamp to the longitudinal diaphragm, and the clamp is fixed on the side of the front wing tip with the possibility of fixed tension relaxation.

The disadvantages of this invention are: because - an increase in the weight of the aircraft;

- increasing the load on the on-board energy system of the aircraft; - the complexity of the design, the high cost of manufacturing and installing the anti-icing device on board the aircraft; - large overall dimensions of structural elements included in the anti-icing device,

In particular, air heating pipes.

There is a known anti-icing method and microwave anti-icing system of the aircraft (Patent OB, Mo 5615849, class B864015/00, publ. 0О1.04.1997), in which structural elements of the aircraft in areas prone to icing of the surface are heated to the ice melting temperature of 20С"7. Microwave energy , received from the microwave generator, is absorbed by a special heat-absorbing tube contained in the slat /o aerodynamic surface. Then the received microwave energy is converted into heat using the same absorption tube. For more effective conversion of microwave energy into heat, a special coating is applied to the inner surface of the tube a coating with high absorption properties, and an insulating mirror is installed. After that, heat transfer rudders transfer thermal energy to structural elements of the aircraft, for example, to the skin of the front edge of the wing or to another aerodynamic surface, the rotor of the aircraft 7/5, etc. The temperature of these elements is maintained at a constant level so that it is significantly higher than the freezing temperature. Thus, the structural elements of the aircraft are heated, which makes it possible to prevent their icing. The disadvantages of this invention are: 1. Reducing the flight range of the aircraft and reducing the distance to the "point of return" due to the need for additional fuel consumption for heating surfaces prone to icing; 2. A large load on the on-board power system, due to the fact that the flow of microwave energy is obtained with the help of a microwave generator, which uses electricity from the on-board network of the aircraft to create this flow;

C. An increase in the weight of the aircraft due to the fact that the anti-icing system includes a large number of structural elements, namely, a microwave generator, radial transfer rudders, and a heat-absorbing tube. Therefore, together with the installation elements, the anti-icing system is a very complex structure and occupies a significant part of the volume of the internal space of the aerodynamic surface of the aircraft. and)

Disadvantages of the application of this invention also include the high cost of manufacturing structural elements of the anti-icing system due to the fact that expensive equipment and materials are used to manufacture the microwave generator and the absorbing tube. Thus, three main methods are currently used to remove or prevent the formation of ice on the outer surfaces of aircraft, namely: what) 1. By supplying heated gases or liquids through the pipeline; c 2. By electric heating; 3. By mechanical means, for example, vibrating nets or pads attached to the surface of the ise)

LA or built into it. It is obvious that the use of all these known methods leads to the complexity of the design of the aircraft as a whole, requires additional consumption of electricity for heating, and therefore to a decrease in the flight range and to an increase in the weight of the aircraft.

It should also be noted that all the methods and devices discussed above are not used during the entire flight of the aircraft, that is, they are aimed at destroying the layer of ice that has already formed, and not at "preventing" its formation. In the event that it is necessary to carry out these methods or use such devices continuously, the consumption of electricity and, consequently, the consumption of fuel for obtaining this energy will be unacceptable from the point of view of the operating conditions of the aircraft. ;" The invention is based on the task of increasing the flight range of the aircraft, reducing the load on the on-board energy system and, as a result, eliminating additional fuel consumption for heating surfaces prone to icing, as well as reducing the weight of the aircraft. c The problem is solved by the fact that the way to prevent icing of the structural elements of the aircraft is that the structural elements of the aircraft in areas prone to icing of the surface are heated to

Me, the melting temperature of ice is 209. According to the invention, the thermal energy required for heating is obtained

Ge) by converting the kinetic energy of the high-speed head of air approaching with a speed of M 50.4. Then sl 50 the received thermal energy is transferred to the surface zones prone to icing due to heat accumulation.

Acoustic resonators are installed in the frontal parts of the structural elements of the aircraft, for example, in the frontal part of the wing, to convert the kinetic energy of the high-speed pressure of the oncoming air into thermal energy. Then they generate high-frequency shock waves, after which the dead ends of the resonators are heated to accumulate heat.

In some cases, for the most effective use of the energy of the high-speed pressure of the incoming air, acoustic resonators are installed along the front of the frontal parts of the structural elements of the aircraft.

In order to ensure the accumulation of heat for heating the surfaces of structural elements of the aircraft, acoustic i) resonators are made of highly heat-conducting material, after which they are separated from each other by i) separating elements.

In the claimed invention, an increase in the flight range of the aircraft and an increase in the distance to the "point of return" are ensured due to the elimination of the need for additional fuel consumption for heating surfaces prone to icing. This is achieved due to the fact that the surfaces of the structural elements of the aircraft are heated due to the accumulation of heat. That is in acoustic resonators, high-frequency shock waves are generated and the dead ends are heated, and the received thermal energy gradually spreads from the dead end of the resonator throughout the structural element. That is, after the device enters the mode, the temperature along the entire 65 length of the resonator will be constant. Including in the cladding of the structural element it will rise from the temperature of the surrounding environment to the melting temperature of the ice.Thus, the invention achieves the prevention of ice formation in areas prone to icing on the surface of aircraft structural elements.

The invention eliminates the additional load on the on-board power system due to the fact that acoustic resonators are used to prevent icing of structural elements of the aircraft.

The operation of the acoustic resonator, in this case, is based on the transformation of the energy of the surrounding environment, so there is no need to consume electricity from an on-board source.

In the claimed invention, a reduction in the weight of the aircraft is achieved due to the fact that acoustic resonators are installed in the frontal parts of the structural elements of the aircraft. The entire anti-icing system consists of a small number of parts, namely a set of acoustic resonators, which themselves have a 7/0 rather simple design: it is known that the acoustic resonator is a body with a dead end and has small dimensions and weight.

A positive feature of the application of the invention is the reduction of costs for the manufacture of structural elements of the anti-icing device, since the acoustic resonator has a fairly simple design and does not require the presence of special expensive equipment for its manufacture. All design elements /5 Made of available materials, the cost of which is significantly lower than the cost of the materials of the system elements of the closest analogue.

Figure 1 shows a graph of the change in the temperature of the blind end of the resonator with a change in the Mach number M; in Fig. 2 - scheme of thermal energy propagation from the blind end of the resonator to the cladding of the structural element in the zone prone to icing.

The proposed method of preventing icing of structural elements of the aircraft consists in the fact that: - heat energy necessary for heating is obtained by converting the kinetic energy of the high-speed thrust approaching with the speed M". 0.4 air (see Fig. 1); - transfer the received thermal energy to the surface zones prone to icing due to heat accumulation; c - heat the structural elements of the aircraft in the areas of the surface prone to icing to the melting temperature of the ice.

The transformation of the kinetic energy of the high-speed pressure of the incoming air into thermal energy is carried out as follows: - acoustic resonators are installed in the frontal parts of the structural elements of the aircraft, for example, in the frontal part of the wing; oyu - generate high-frequency shock waves in acoustic resonators; - the blind ends of the resonators are heated for heat accumulation. Heating the surfaces of structural elements

LA occurs due to heat accumulation. Thermal energy gradually spreads from the dead end of the resonator throughout the structural element (see Fig. 1):

When the flow of the surrounding medium hits the frontal part of the structural element of the aircraft with a speed of

M » 0.4 the ratio 92 of the temperature of the blind end of the resonator to the temperature at the entrance to the resonator gradually increases. in-

Tek " where: a, - the ratio of the temperature of the blind end of the resonator to the temperature at the entrance to the resonator; o, c Ttk - temperature of the blind end of the resonator; z» Tvh is the temperature at the entrance to the resonator. When M is 0, i.e. in the absence of an onrush of the surrounding medium flow:

Vr

During the flight, the flow of ambient air rushes at a certain speed on the frontal parts (leading edges) on the structural elements of the aircraft with acoustic resonators installed in them. At the same time, high-frequency shock waves are generated in the resonators, which leads to the irreversible transformation of kinetic energy into thermal energy, that is, to the heating of the blind end of the resonator. and The conducted experiments showed that at 0 " M " 0.4 the use of an acoustic resonator is ineffective, g 20 because the increase in the temperature of the blind wall of the resonator is insufficient to heat the surface prone to icing. That is, TC is insignificantly different from the temperature of the surrounding environment. sl At the speed of the oncoming air flow M - 0.4, the increase in the ratio 92 will be sufficient to prevent icing of the structural elements of the aircraft (see Fig. 1).

At the initial moment of time, the temperature at the entrance to the resonator Tvx is equal to the temperature of the surrounding environment T, (see Fig. 2). Gradually due to the accumulation of heat during the time when the device enters the mode

HF) (t4» to.) thermal energy from the blind end of the resonator spreads along its entire length, as well as over the entire frontal part of the cladding of the structural element of the LA.

After the device is switched on, the temperature along the entire length of the resonator will be constant during the entire flight time of the aircraft. Including in the sheathing of the structural element, the temperature will rise from the temperature of the surrounding environment T to the melting temperature of Tobsh ice:

Tovsh liu 7 Tobsha? 2 means 1? Yes

Thus, the invention prevents the formation of ice in areas prone to icing of structural elements of the aircraft. In some cases, for the most effective use of the energy of the high-speed pressure of the incoming air, acoustic resonators are installed along the front of the frontal parts of the structural elements of the aircraft.

In order to ensure the accumulation of heat for heating the surfaces of structural elements of the aircraft, acoustic resonators are made of highly heat-conducting material, and then separated from each other by separating elements.

Application of the method of anti-icing, which is claimed, will make it possible to increase the flight range of the aircraft due to the elimination of the need for additional fuel consumption for heating the surfaces of the aircraft prone to icing.

The invention will make it possible to eliminate additional load on the on-board energy system of the aircraft due to the use of an acoustic resonator, the operation of which does not require the consumption of electricity from the on-board source. In the proposed invention, a reduction in the weight of the aircraft is achieved due to the fact that the entire anti-icing system consists of a small number of parts, namely a set of acoustic resonators, which themselves have a fairly simple design. In addition, it should be noted that this method is universal, that is, it can be applied to any type of aircraft, as it does not require the use of any additional equipment.

Claims (4)

The formula of the invention 1. The method of preventing icing of structural elements of the aircraft, according to which the structural elements of the aircraft in areas prone to icing of the surface are heated to the melting temperature of the ice » 0"C, which differs in that the thermal energy for heating is obtained by converting the kinetic energy of the air, which rushes at a speed corresponding to M 2 04 , and the received thermal energy is transferred to the surface zones prone to icing due to heat accumulation. 2. The method according to claim 1, which differs in that in order to convert the kinetic energy of the incoming air into thermal energy, acoustic resonators are installed in the frontal parts of the structural elements of the aircraft, in which high-frequency shock waves are generated and the blind ends of the resonators are heated to accumulate heat . Q. The method according to claims 1 and 2, which differs in that the acoustic resonators are installed along the front of the frontal parts of the structural elements of the aircraft. 4. The method according to claims 1, 2 and З, which differs in that the acoustic resonators are made of I c) highly thermally conductive material, after which they are separated from each other by separating elements. yu Ge) (Se) IS o) - a 1 (e)) (95) 1 sl ko bo b5