CN114852344A

CN114852344A - Brand-new active and passive coupling-based anti-icing and deicing system

Info

Publication number: CN114852344A
Application number: CN202210370611.XA
Authority: CN
Inventors: 刘欣乐; 蔡晋生; 李文丰
Original assignee: Northwestern Polytechnical University
Current assignee: Northwestern Polytechnical University
Priority date: 2022-04-10
Filing date: 2022-04-10
Publication date: 2022-08-05

Abstract

The invention relates to a brand-new active and passive coupling-based anti-icing system/device, belonging to the field of anti-icing. The device mainly comprises an anti-icing and deicing combination layer 2 adhered to the upper surface of an airfoil 1, wherein the anti-icing and deicing combination layer 2 is composed of a super-hydrophobic coating 3, a heat preservation layer 4, a heating element 5, a heat insulation layer 6 and heat conducting wires 7, the heat insulation layer 6 is the bottommost layer and is adhered to the upper surface of the airfoil 1, the upper surface of the heat insulation layer 6 is adhered to the heating element 5, the upper surface of the heating element 5 is adhered to the heat preservation film 4, the heat conducting wires 7 are exposed to the outer portion of the surface of the heat preservation film 4 through holes in the surface of the heat preservation film 4, and the super-hydrophobic coating 3 is sprayed on the upper surface of the heat preservation film 4. The heat conducting wires 7 are arranged in a staggered manner along the spanwise direction and the chord direction, penetrate through the super-hydrophobic coating 3 and the heat insulating layer 4, are connected with the heating element 5 at the lower part and are used for conducting heat generated by the heating element 5, and the tips of the heat conducting wires are exposed to the air. The power supply 9 realizes periodic heating in the process of preventing and removing ice through a lead; the invention relates to a brand-new active and passive coupling deicing method for an aircraft, which is formed by coupling an active deicing method, namely electric heating deicing, and a passive deicing method, namely super-hydrophobic deicing.

Description

Brand-new active and passive coupling-based anti-icing and deicing system

Field of the invention

The invention relates to a brand-new active and passive coupling-based anti-icing system, and belongs to the field of anti-icing.

Background

Accidents caused by the icing problem relate to the fields of aerospace, power systems, ground traffic and the like, and cause inconvenience for production and life of people. In recent years, flight accidents occur, wherein the flight accidents caused by icing of airplanes are many, and the icing problem becomes one of the hidden dangers threatening aviation safety. According to statistics, in 2009-2017, the flight accidents caused by the icing of the airplane only in 8 years account for 28% of all the flight accidents all around the world, and serious loss is caused. The lift-drag characteristics are severely affected by the irregular aerodynamic profile created by icing of the aerodynamic components. Relevant statistics show that: icing can reduce the lift by 30% and increase the resistance by 140%. Icing of the engine not only results in reduced engine efficiency, but even causes engine surge, and more seriously, engine shutdown. Other parts such as a sensor, a windshield and a radome are frozen to influence the processes of aircraft information collection, transmission and the like, so that a pilot can cause wrong operation actions due to wrong judgment on the flight state of the aircraft, and the flight safety is seriously threatened. For civil aircraft, icing phenomena can reduce economic efficiency. The icing of the wind power blade can not only cause errors in measurement of wind speed and wind direction, but also influence pneumatic characteristics and power generation output, and broken ice on the blade falls to threaten personal safety. Therefore, extensive research on the icing problem is required to provide better anti-icing methods.

Since the icing phenomenon seriously threatens the flight safety, the aviation industry has begun to research the icing problem of aircrafts from the last forty years, and various anti-icing and deicing methods such as thermal anti-icing, liquid anti-icing, mechanical anti-icing and the like are proposed and applied. The hot gas ice prevention and deinsectization generally leads air from a compressor of an engine and transfers heat to the surface of an ice prevention and deinsectization component, but the method greatly reduces the efficiency of the engine, has large hot gas ice prevention thermal inertia and has very limited application prospect. The electrothermal ice preventing and removing method has the advantages that heat generated by the heating element is transferred to the ice preventing and removing area, the efficiency of the engine is improved, meanwhile, the consumption of electric quantity is increased, and the method has no substantial effect on energy consumption saving. The method is mainly used for ground anti-icing, the effective load can be reduced by carrying the anti-icing liquid when an aircraft flies, and the anti-icing liquid has damage to surface parts of the aircraft such as skins and has certain pollution to the environment. Mechanical deicing utilizes a mechanical method to destroy the ice layer and the ice layer on the icing surface, reduces the adhesion force of ice, and removes the ice under the action of aerodynamic force, centrifugal force or vibration, for example, the pneumatic appearance of the expansion pipe is destroyed due to the expansion pipe bulge during deicing of the expansion pipe, so that the lift-drag characteristic is influenced. Although the electric pulse deicing reduces the energy consumption, the service life of the skin is greatly reduced due to the high-frequency vibration and the skin riveting process. In addition, some novel anti-icing and deicing methods such as superhydrophobic anti-icing and plasma anti-icing are further developed, the superhydrophobic anti-icing achieves the purpose of delaying icing by utilizing the wetting characteristic of a superhydrophobic material, and the superhydrophobic anti-icing cannot be fundamentally prevented under severe flight conditions. Plasma deicing is realized by using the thermal effect of ionized air, but the method needs a high-voltage power supply to realize the deicing, and has poor applicability on large-scale civil airliners. The above-mentioned novel anti-icing methods are limited in anti-icing effect and conditions of use, and have been studied only. Therefore, there is an urgent need to provide a novel anti-icing method, and to study and apply the method.

The invention content is as follows:

most of the anti-icing methods are already used for aircraft anti-icing and have obvious effects, and some novel anti-icing methods also achieve the aim of anti-icing in the research stage. The technical problem to be solved by the invention is that the energy consumption in the process of preventing and removing ice is too high, the economy is poor, and the aerodynamic characteristics of the aerodynamic parts of the aircraft are seriously damaged.

The invention aims to provide a brand-new aircraft anti-icing method and device with active and passive anti-icing coupling aiming at the defect of economy and practicability of the conventional aircraft anti-icing method. The new method has the advantages of reducing energy consumption, improving economy and the like in the process of preventing and removing ice of the aircraft.

The technical scheme of the invention is as follows: a brand-new active and passive coupling ice preventing and removing system for an aircraft mainly comprises an ice preventing and removing combination layer 2 adhered to the upper surface of an airfoil 1,

the deicing combination layer 2 is composed of a super-hydrophobic coating 3, a heat preservation layer 4, a heating element 5, a heat insulation layer 6 and heat conducting wires 7, the heat insulation layer 6 is the bottommost layer and is bonded with the upper surface of the wing type 1, the upper surface of the heat insulation layer 6 is bonded with the heating element 5, the upper surface of the heating element 5 is bonded with the heat preservation film 4, holes are formed in the surface of the heat preservation film 4, the heat conducting wires 7 are exposed outside the surface of the heat preservation film 4, and the super-hydrophobic coating 3 is sprayed on the upper surface of the heat preservation film 4.

The heat conducting wires 7 are arranged in a staggered manner along the spanwise direction and the chordwise direction, penetrate through the super-hydrophobic coating 3 and the heat insulating layer 4, are connected with the heating element 5 at the lower parts thereof, are used for conducting heat generated by the heating element 5, and have tip ends exposed to the air;

the power supply 9 realizes the periodic heating of the anti-icing process through a lead.

The invention has the following beneficial effects: the invention relates to a brand new active and passive coupling deicing method for an aircraft, which is formed by coupling an active deicing method, namely electric heating deicing, and a passive deicing method, namely superhydrophobic deicing, and is different from the existing superhydrophobic electric heating composite deicing method in the deicing mechanism. The invention optimizes the electric heating anti-icing in the super-hydrophobic electric heating composite anti-icing method to further reduce the anti-icing energy consumption, namely, the surface anti-icing of the electric heating film is optimized into the point anti-icing of the heat conducting wire. The anti-icing mechanism is different from the existing super-hydrophobic electric heating composite anti-icing method, when supercooled water drops collide to the anti-icing surface of an aircraft, the supercooled water drops collide with the super-hydrophobic coating, and due to the hydrophobic effect of the super-hydrophobic coating, the water drops bounce, roll and the like. When the water droplet contacts the heat conduction wire, due to the blocking effect of the heat conduction wire, the rolling action stops, the water droplet gathers at the tip of the heat conduction wire, nucleation and icing are carried out at the tip, fine ice particles are formed, most of heat is conducted to the tip of the heating wire through power supply heating at the moment, the fine ice particles are melted at the tip, and the melted fine ice particles are taken away by airflow under the action of pneumatic force, so that the anti-icing effect is achieved, and the anti-icing phenomenon is not possessed by the existing super-hydrophobic electric-heating composite anti-icing method. In addition, as the heat preservation effect of the heat preservation layer adopts a heating mode of periodic heating, the energy consumption is reduced to the maximum extent;

the invention relates to an aircraft anti-icing and deicing method, and provides a brand-new anti-icing and deicing method, which adopts a point heating and surface heat preservation mode and combines the point heating and surface heat preservation with super-hydrophobic anti-icing, namely, the input heat is used for melting ice at the tip of a heating wire, and the periodic heating of a heat preservation layer is added, so that the method has great advantage in economy.

Drawings

FIG. 1 is a schematic three-dimensional view of a scheme in an embodiment;

FIG. 2 is a three-dimensional schematic diagram of a flexible film assembly layer in an embodiment;

FIG. 3 is a two-dimensional schematic diagram of the arrangement and wiring of layers in the embodiment;

FIG. 4 is a schematic diagram of an anti-icing process in an embodiment;

FIG. 5 is a partial schematic view of the anti-icing principle of the embodiment.

Detailed Description

The brand new active and passive coupling deicing system/device for the aircraft in the embodiment comprises an NACA0012 airfoil 1, an deicing and ice prevention combination layer 2, a super-hydrophobic coating 3, a heat insulation film 4, a heating element 5, a heat insulation layer 6, a heat conduction wire 7, a lead 8 and a power supply 9;

the upper surface of the NACA0012 airfoil 1 is adhered to the lower surface of the ice prevention and control combination layer 2, the ice prevention and control combination layer 2 is composed of a super-hydrophobic coating 3, a heat preservation layer 4, a heating element 5, a heat insulation layer 6 and heat conducting wires 7, the upper surface of the NACA0012 airfoil 1 is adhered to the heat insulation layer 6, the upper surface of the heat insulation layer 6 is adhered to the heating element 5, the upper surface of the heating element 5 is adhered to the heat preservation film 4, the heat conducting wires 7 are exposed to the outside of the surface of the heat preservation film 4 through holes in the surface of the heat preservation film 4, the super-hydrophobic coating 3 is sprayed on the upper surface of the heat preservation film 4, and super-cooled water drops drip on the upper surface of the ice prevention and control combination layer.

The brand new active and passive coupling deicing system/device for the aircraft consists of two deicing systems, namely an active deicing method (electrical heating deicing prevention) and a passive deicing method (super-hydrophobic deicing prevention);

the 1 chord length of the NACA0012 airfoil is 400mm, the spanwise length is 300mm, and the material is aluminum alloy;

the length of the anti-icing and deicing combined layer 2 in the chord direction is 300mm, the length of the anti-icing and deicing combined layer in the span direction is 300mm, and the anti-icing and deicing combined layer is a flexible membrane combined layer and consists of a super-hydrophobic coating 3, a heat insulation layer 4, a heating element 5, a heat insulation layer 6 and heat conducting wires 7;

the length of the super-hydrophobic coating 3 in the chord direction is 300mm, the length of the super-hydrophobic coating in the span direction is 300mm, the thickness of the super-hydrophobic coating is 10-25 mu m, the super-hydrophobic coating is formed by spraying super-hydrophobic materials, and the contact angle theta of super-cooled water drops 10 on the surface of the super-hydrophobic coating 3 is larger than 150 degrees;

the length of the heat-insulating layer 4 in the chord direction is 300mm, the length of the heat-insulating layer 4 in the span direction is 300mm, the lower surface of the heat-insulating layer 4 is bonded with the upper surface of the heating element 5, the heat-insulating layer has a good heat-insulating effect, and heat generated by the heating element 5 is blocked by the heat-insulating layer 4 in a low-temperature environment, so that heat dissipation is slow;

the heating element 5 is 300mm in length along the chord direction, 300mm in length along the span direction and 18 microns in thickness, is arranged between the heat insulation layer 4 and the heat insulation layer 6, is connected with the heat conduction wire 7, generates heat by supplying power through a voltage-stabilizing direct-current power supply, and conducts the generated heat to the tip end through the heat conduction wire 7;

the length of the heat insulation layer 6 in the chord direction is 300mm, the length of the heat insulation layer in the span direction is 300mm, the lower surface of the heat insulation layer is adhered to the anti-icing surface, the upper surface of the heat insulation layer is adhered to the lower surface of the heating element 5, the heat insulation layer 6 is made of high-density heat insulation cotton, the heat conductivity coefficient is low and is less than 0.034W/m & lt k & gt, most of heat generated by the heating element 5 is conducted to the heat conduction wires 7, the use efficiency of energy is improved, and energy consumption is reduced;

the diameter of the heat conducting wires 7 is 0.1mm, the heat conducting wires are arranged in a staggered mode along the spanwise direction and the chordwise direction, the distance between the two heating wires is 10mm, the two heating wires penetrate through the super-hydrophobic coating 3 and the heat preservation layer 4, the lower portions of the two heating wires are connected with the heating element 5 and used for conducting heat generated by the heating element 5, and the tip ends of the two heating wires are exposed to 5mm in the air;

the lead 8 is a copper lead with good conductivity;

the power supply 9 is a programmable direct-current stabilized power supply, the output voltage is 0-50V, the output current is 0-20A, the power required by ice prevention is met, and the periodic heating in the ice prevention and removal process can be realized;

the supercooled water drops are water drops of deionized water in a supercooled state, and the water drops in the cloud layer are usually in the supercooled state under real icing meteorological conditions.

According to the brand-new anti-icing method based on the active and passive coupling aircraft, when the aircraft flies under an icing condition, supercooled water drops in air collide with an anti-icing surface, the supercooled water drops firstly contact with the super-hydrophobic coating, and due to the excellent surface wetting characteristic of the super-hydrophobic coating, the supercooled water drops bounce, roll and other behaviors on the surface of the super-hydrophobic coating. When the supercooled water droplets collide with the heat conductive wire, the rolling is stopped to gather at the tip of the heat wire, and freeze into fine ice particles, where they freeze in the form of dots on the surface. When the power supply is turned on, the heating element generates heat, one part of the heat is quickly transferred to the tip end by the heat-conducting wire to melt the fine ice particles, and the other part of the heat-conducting wire maintains the temperature of the heat-insulating layer. In addition, the heat of the heating element is transferred to the heat-insulating layer, and due to the heat-insulating effect of the heat-insulating layer and the periodic heating mode, the surface temperature is always kept above the freezing point, namely, the surface temperature of the super-hydrophobic coating layer in contact with the upper surface of the heat-insulating layer is also always kept above the freezing point, and supercooled water drops cannot be frozen immediately when impacting the super-hydrophobic surface, but bounce to gather at the tip of the heat-conducting wire to be frozen. And when the ice-free area of the aircraft skin is ice-free, the direct-current stabilized power supply is closed.

Claims

1. A brand new active and passive coupling ice prevention and removal system of an aircraft is characterized by mainly comprising an ice prevention and removal combination layer 2 adhered to the upper surface of an airfoil 1, wherein the ice prevention and removal combination layer 2 consists of a super-hydrophobic coating 3, a heat preservation layer 4, a heating element 5, a heat insulation layer 6 and heat conduction wires 7, the heat insulation layer 6 is the bottommost layer and is adhered to the upper surface of the airfoil 1, the upper surface of the heat insulation layer 6 is adhered to the heating element 5, the upper surface of the heating element 5 is adhered to a heat preservation film 4, holes are formed in the surface of the heat preservation film 4 to expose the heat conduction wires 7 to the outside of the surface of the heat preservation film 4, and the super-hydrophobic coating 3 is sprayed on the upper surface of the heat preservation film 4; the heat conducting wires 7 are arranged in a staggered manner along the spanwise direction and the chordwise direction, penetrate through the super-hydrophobic coating 3 and the heat insulating layer 4, are connected with the heating element 5 at the lower parts thereof, are used for conducting heat generated by the heating element 5, and have tip ends exposed to the air; the power supply 9 realizes the periodic heating of the anti-icing process through a lead.