Turbine engine low-cost efficient heat insulation system for unmanned aerial vehicle

Abstract

The invention discloses a low-cost and high-efficiency heat insulation system for a turbine engine for an unmanned aerial vehicle. The heat insulation system is composed of a metal heat insulation cover matched with the appearance of the engine, aerogel coated with aluminum foils inside and outside, convection air, a steel supporting frame, an aluminum foil adhesive tape, a metal strap and the like. Wherein the appearance of the metal heat shield clings to the outer wall surface of the engine, and smooth air circulation is kept in the middle; the outer edge of the heat shield adopts a turnup design, so that the air inflow is increased; the aerogel with low thermal conductivity and the aluminum foil with high reflectivity are wrapped on the outer surface of the metal heat shield in a staggered manner; the aluminum foil tape is further wound outside the aluminum foil; the metal strap is tightly hooped on the outer surface of the aluminum foil tape; air circulates between the outside of the aluminum foil tape and the inner wall of the aircraft; the heat shield is fixed on the engine by the steel support frame; air mainly comes from a plurality of air inlet grilles arranged on the unmanned aerial vehicle and adjacent to the air inlet position of the heat shield, and external airflow of the aerial vehicle is introduced through the air inlet grilles for heat dissipation.

Description

Technical Field

[0001] The invention relates to the field of unmanned aerial vehicle design, and in particular to a low-cost and high-efficiency thermal insulation system for a turbine engine used in unmanned aerial vehicles. Background Art

[0002] With the continuous changes in the world situation, turbine-powered unmanned aerial vehicles (such as cruise missiles and target drones) have become an important part of the equipment of various countries. In order to meet the increasing demand for flight speed and range, lightweight, miniaturization and low cost have also become the research focus of unmanned aerial vehicles. At present, in the design of mainstream aircraft, lightweight composite materials and electronic components with low heat resistance are widely used. In order to ensure the normal use of the above components, a heat shield is often added to the outside of the hot end components of the engine. However, due to the size limitation of the aircraft, the heat of the heat shield is still at a high temperature when radiated to the body material or electronic components, affecting their normal operation; or expensive heat insulation paint is applied to the hot end components of the engine, but this heat insulation method is more complicated, and during long-term operation, the large amount of heat accumulation generated by the hot end components will also affect the body material and electronic components. Considering the narrow space limitations and low-cost requirements of existing aircraft, conventional heat insulation methods are difficult to meet the use requirements.

[0003] From the above analysis, it can be seen that the improvement work on traditional insulation methods mainly revolves around how to reconcile the contradiction between the thermal control size of the heat insulation cover, efficient insulation and low cost. Summary of the invention

[0004] The purpose of the present invention is to provide a low-cost and high-efficiency thermal insulation system for a turbine engine for an unmanned aerial vehicle in order to solve the above-mentioned problem.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0006] The present invention provides a low-cost and efficient thermal insulation system for a turbine engine for an unmanned aerial vehicle, comprising a support frame, a metal heat insulation cover, aerogel and aluminum foil, aluminum foil tape, and a metal hoop. The metal heat insulation cover is designed to be close to the outer wall of the engine and is connected to it through the support frame, and there is internal convection air between the two. On the outside of the metal heat insulation cover, aerogel and aluminum foil are alternately wrapped on the outside of the metal heat insulation cover. The aluminum foil tape is further wrapped around the outside of the aluminum foil layer to play a fastening role. The metal hoop is tightly clamped on the outer surface of the aluminum foil tape at a certain interval to strengthen the fastening effect. There is external convection air between the outside of the aluminum foil tape and the inner wall of the fuselage. Both the internal convection air and the external convection air come from a plurality of air intake grilles arranged on the aircraft adjacent to the air intake of the heat insulation cover.

[0007] As a preferred embodiment of the present invention, as a connection structure, one end of the steel support frame is welded to the wall surface of the hot end component of the engine, and the other end is connected to the metal heat insulation cover through bolts and support plate self-locking nuts.

[0008] As a preferred embodiment of the present invention, the metal heat shield is designed to fit closely to the engine wall, and holes are opened at places where the engine parts interfere. The holes are covered with hemispherical protective covers as appropriate, and the hemispherical protective cover and the metal heat shield also adopt a similar connection structure.

[0009] As a preferred embodiment of the present invention, there is free-flowing air between the metal heat shield and the wall of the hot end part of the engine; there is free convection air outside the aluminum foil tape; the convection air comes from a plurality of air intake grilles arranged adjacent to the air intake of the heat shield on the aircraft, and the air intake grilles are part of the aircraft body structure to ensure that sufficient air enters the engine compartment for heat dissipation. The air intake grilles are designed with a diamond mesh structure, which increases the air intake volume on the one hand and prevents foreign matter from being inhaled during flight on the other.

[0010] As a preferred embodiment of the present invention, as the supporting part of the heat insulation structure, the outer end of the metal heat insulation cover is sequentially wrapped with aerogel, aluminum foil, aerogel and aluminum foil, and each part is bonded to each other. The aluminum foil is completely wrapped with an aluminum foil tape, and a metal hoop is fastened to the outer periphery of the aluminum foil tape to further strengthen the fastening.

[0011] As a preferred embodiment of the present invention, the steel support frame connecting the metal heat insulation cover and the wall of the hot end component of the engine is fixed to the two by bolt connection and welding respectively, and self-locking nuts are used at the bolt connections to ensure the stable fixation of the metal heat insulation cover, realize the integration of heat insulation and load bearing, and have high reliability and impact resistance.

[0012] As a preferred embodiment of the present invention, the aluminum metal heat insulation cover has a wall thickness of 1 mm, is coaxial with the wall of the engine hot end component and the minimum distance between the two is 2 mm, which reduces weight, ensures uniform heat dissipation from the engine wall and installation space for external components of the insulation system, and maintains a good aerodynamic shape of the aircraft.

[0013] As a preferred embodiment of the present invention, the outer edge air inlet of the aluminum metal heat insulation cover adopts a flange design to increase the internal convection air volume. At the same time, the metal heat insulation cover is provided with waist-shaped holes at the bolt connection with the steel support frame to accommodate possible deviations in the circumferential positioning of the bolts.

[0014] As a preferred embodiment of the present invention, there is internal flowing air between the aluminum metal heat insulation cover and the wall of the hot end component, and there is external convection air between the outer side of the aluminum foil tape and the inner wall of the fuselage, both of which can block the heat emitted from the wall of the hot end component of the engine. When the aircraft flies at high speed, most of the heat is taken away by circulating convection heat exchange of the air, thereby realizing the function of the heat insulation system.

[0015] As a preferred embodiment of the present invention, a metal heat insulation cover, aerogel, aluminum foil, aerogel and aluminum foil structure are adopted, and the layers are tightly bonded. The aerogel with very low thermal conductivity (about 0.02W / (M·K)) effectively blocks the heat conduction of heat, and the aluminum foil with high reflectivity can effectively reflect the heat back, further blocking the transfer of heat, thereby achieving excellent thermal insulation performance.

[0016] As a preferred embodiment of the present invention, the thickness of each aerogel layer is 6 mm, and the thickness of each aluminum foil layer is 0.05 mm. Under the premise of ensuring the thermal insulation effect, the thickness of the aerogel and the aluminum foil can be appropriately reduced to avoid interference with the internal devices of the aircraft.

[0017] The beneficial effects of the present invention are:

[0018] 1. The present invention provides a heat insulation system composed of a metal heat shield, a support frame, aerogel, aluminum foil, flowing air, aluminum foil tape, and a metal hoop, which maintains a good aerodynamic shape of the engine and has efficient heat insulation performance, ensuring the normal operation of composite materials and electrical components in the aircraft;

[0019] 2. The present invention utilizes the air intake grille on the aircraft to ensure a sufficient air source, utilizes the flowing air to take away the heat, reduces the heat radiation borne by the aluminum metal heat shield, and ensures a good working environment for the heat shield;

[0020] 3. The aluminum heat shield used in the present invention is 1mm thick and has a minimum distance of 2mm from the wall of the hot end component, which greatly reduces the load of the support frame and the impact on the internal space of the aircraft, ensuring the installation space of components such as electronic components and the stability and impact resistance of the heat insulation system;

[0021] 4. The thickness of each layer of aerogel used in the present invention is 6 mm, and the thickness of each layer of aluminum foil is 0.05 mm, which reduces the weight of the thermal insulation system and has low production costs and simple processes for each component, thereby ensuring low cost of the thermal insulation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the thermal insulation system;

[0023] Figure 2 The schematic diagram of the air intake grille structure;

[0024] Figure 3 This is a schematic diagram of the metal heat shield appearance design;

[0025] Figure 4 Schematic diagram of the steel support frame assembly structure.

[0026] In the figure: 1 - internal convection air, 2 - support frame, 3 - metal heat shield, 4 - aerogel, 5 - aluminum foil, 6 - aluminum foil tape, 7 - metal hoop, 8 - external convection air. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention clearer, the implementation method of the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0028] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0029] As attached Figure 1-4 As shown, an embodiment of the present invention provides a low-cost and efficient thermal insulation system for a turbine engine for a drone, including a support frame 2, a metal heat insulation cover 3, an aerogel 4, an aluminum foil 5, an aluminum foil tape 6, and a metal hoop 7. The metal heat insulation cover 3 is designed to be close to the outer wall of the engine and is connected to it through the support frame 2, and there is internal convection air 1 between the two. On the outside of the metal heat insulation cover 3, the aerogel 4 and the aluminum foil 5 are alternately wrapped on the outside of the metal heat insulation cover. The aluminum foil tape 6 is further wrapped around the outside of the aluminum foil layer to play a fastening role. The metal hoop 7 is tightly clamped on the outer surface of the aluminum foil tape 6 at a certain interval to strengthen the fastening effect. There is external convection air 8 between the outside of the aluminum foil tape 6 and the inner wall of the fuselage. The internal convection air 1 and the external convection air 8 are both derived from a plurality of air intake grilles arranged on the aircraft adjacent to the air intake of the heat insulation cover.

[0030] The aircraft body structure needs to have multiple air intake grilles adjacent to the heat shield air intake to ensure sufficient air enters the engine compartment. The air intake grille structure diagram is shown in the figure. Figure 2 Remove the components on the engine that interfere with the heat shield, and then fit the processed metal heat shield 3 to the engine wall to ensure the coaxiality of the two. The schematic diagram of the metal heat shield appearance design is shown in Figure 3 shown.

[0031] The steel support frame 2 and the metal heat shield 3 are assembled. The assembly structure diagram of the support frame is as follows: Figure 4 As shown. Then assemble the engine interference components, cover the hemispherical protective cover on the heat shield and tighten the bolts.

[0032] After the heat insulation cover is completely fixed, the outer surface is wrapped with aerogel 4 and a layer of aluminum foil. After being shaped, a layer of aerogel 4 is wrapped on the outside of the aluminum foil and then a layer of aluminum foil is wrapped, and then the aluminum foil tape 6 is completely wrapped around the outside of the aluminum foil, and finally the metal hoop 7 is used to tighten the outside of the aluminum foil tape to further strengthen the fastening and complete the installation of the heat insulation system. There are fixed intervals between the metal hoop 7, which are generally set to three.

[0033] After the engine is started, a large amount of heat radiation is generated on the wall of the hot end components of the engine. Considering the high reflectivity of the aluminum heat shield 3, most of the heat energy will return to the flowing air 1 between the wall and the heat shield, avoiding the influence of this part of the heat energy on the composite materials and electronic components. After entering the heat shield 3, the heat enters the aerogel 4 through heat conduction. Due to the lower thermal conductivity, the aerogel 4 greatly suppresses the further expansion of the heat. When part of the heat enters the aluminum foil 5, the highly reflective aluminum foil will reflect most of the heat and continue to suppress the expansion of the heat. Thereafter, after passing through the second layer of aerogel 4, aluminum foil 5 and aluminum foil tape 6, the heat conduction is further suppressed, and then the air convection heat dissipation outside the aluminum foil tape 6 is affected to achieve an efficient heat insulation effect.

[0034] Tests have shown that when the wall temperature of the hot end components of the engine reaches 600°C, the outer surface temperature of the insulation system (aluminum foil tape) does not exceed 70°C, which is far lower than the allowable operating temperature of electrical components and composite materials, proving the system's efficient thermal insulation performance.

[0035] Although the present invention is described herein with reference to the illustrative embodiments of the present invention, the above embodiments are only preferred embodiments of the present invention, and the embodiments of the present invention are not limited to the above embodiments. It should be understood that those skilled in the art can design many other modifications and embodiments, which will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A low-cost and high-efficiency thermal insulation system for a turbine engine for an unmanned aerial vehicle, characterized in that: The invention comprises a support frame (2), a metal heat insulation cover (3), an aerogel (4), an aluminum foil (5), an aluminum foil tape (6), and a metal hoop (7). The metal heat insulation cover (3) is designed to be close to the outer wall of the engine and is connected to the engine through the support frame (2). Internal convection air (1) exists between the two. On the outside of the metal heat insulation cover (3), the aerogel (4) and the aluminum foil (5) are alternately wrapped around the outside of the metal heat insulation cover. The aluminum foil tape (6) is further wrapped around the outside of the aluminum foil layer to play a tightening role. The metal hoop (7) is tightly clamped on the outer surface of the aluminum foil tape (6). External convection air (8) exists between the outside of the aluminum foil tape (6) and the inner wall of the fuselage. Both the internal convection air (1) and the external convection air (8) are derived from a plurality of air intake grilles (9) arranged at positions adjacent to the air intake of the heat insulation cover on the aircraft.

2. A low-cost and high-efficiency thermal insulation system for a turbine engine for an unmanned aerial vehicle according to claim 1, characterized in that: The metal heat shield (3) is made of aluminum alloy and has a wall thickness of 1 mm, which reduces weight while ensuring sufficient strength. The metal heat shield (3) is designed to match the shape of the engine and is designed to fit closely to the engine wall. At the same time, the metal heat shield (3) is appropriately opened at the position of protruding parts of the engine to avoid interference. At the same time, a hemispherical protective cover is installed at the position of the opening as appropriate to prevent a large amount of heat from dissipating. The edge of the protective cover needs to fit closely to the arc-shaped surface of the heat shield, which is more conducive to bolt assembly. The edge of the metal heat shield (3) at the air inlet adopts a flanged design to increase the air intake volume.

3. A low-cost and high-efficiency thermal insulation system for a turbine engine for an unmanned aerial vehicle according to claim 1 or 2, characterized in that: The support frame (2) is a Z-shaped structure, connecting the metal heat shield (3) and the engine, and is fixed to the metal heat shield (3) by bolt connection, and is fixed to the wall of the hot end component of the engine by welding. A waist-shaped hole is opened at the place where the metal heat shield (3) and the steel support frame (2) are bolted to accommodate the deviation that may occur during the circumferential positioning of the bolt connection.

4. A low-cost and high-efficiency thermal insulation system for a turbine engine for an unmanned aerial vehicle according to claim 3, characterized in that: The steel support frame (2) connects the metal heat shield (3) and the wall surface of the hot end component of the engine, and the two are fixed by bolt connection and welding respectively, and self-locking nuts are used at the bolt connection.

5. A low-cost and high-efficiency thermal insulation system for a turbine engine for a drone according to claim 4, characterized in that: In the flight state, the internal convection air (1) between the metal heat shield (3) and the wall surface of the hot end component of the engine flows freely, and the external convection air (8) between the aluminum foil tape (6) and the inner wall of the fuselage flows freely, and both the internal convection air (1) and the external convection air (8) are derived from a plurality of air intake grilles arranged at positions adjacent to the air intake of the metal heat shield (3) on the aircraft.

6. A low-cost and high-efficiency thermal insulation system for a turbine engine for an unmanned aerial vehicle according to claim 5, characterized in that: The outer end of the metal heat insulation cover (3) is wrapped with aerogel (4), aluminum foil (5), aerogel (4) and aluminum foil (5) in sequence, and the parts are bonded to each other; an aluminum foil tape (6) is used to completely wrap the aluminum foil (5), and a metal hoop (7) is used to tighten the outer periphery of the aluminum foil tape (6) to further strengthen the tightening.

7. A low-cost and high-efficiency thermal insulation system for a turbine engine for an unmanned aerial vehicle according to claim 6, characterized in that: The thermal conductivity of the aerogel (4) at room temperature reaches 0.02 W / (M·K) and the thickness of each layer is 6 mm.

8. A low-cost and high-efficiency thermal insulation system for a turbine engine for a drone according to claim 7, characterized in that: The thickness of each layer of aluminum foil is 0.05 mm.

9. A low-cost and high-efficiency thermal insulation system for a turbine engine for an unmanned aerial vehicle according to claim 8, characterized in that: The number of metal hoops (7) is generally three.

Images