A method for recycling radiation heat from tail nozzle of aircraft engine

Abstract

The present application provides a method for recycling radiant heat from an aircraft engine tail nozzle, wherein a heat exchange coil is wound and laid on the outer wall surface of a casing of the aircraft engine to form a partition-type heat exchange structure, the heat exchange coil is wound and covered on the outer wall surface of the tail nozzle, the heat exchange coil protrudes in the injection direction of the tail nozzle and forms a bell-mouth structure; the oil outlet of the fuel pump is connected with the inlet end of the heat exchange coil, and the outlet end of the heat exchange coil is connected with the oil inlet of an atomizing nozzle in a combustion chamber to form a fuel heating pipeline; the heat at the tail nozzle is transferred to the fuel in the heat exchange coil through the partition-type heat exchange structure, so that the temperature at the tail nozzle is reduced, thermal radiation stealth in the air is achieved, thermal deformation and strength reduction of the tail nozzle are prevented, and the fuel in the heat exchange coil is heated and heated, which is conducive to the atomization and combustion of the heated fuel in the combustion chamber, thereby improving the combustion efficiency of the combustion system and achieving heat recovery and reuse.

Description

Technical Field

[0001] The invention belongs to the technical field of waste heat recovery and utilization of an aircraft engine tail nozzle, and in particular relates to a method for recovering and utilizing radiant heat from an aircraft engine tail nozzle. Background Art

[0002] With the rapid development and technological innovation of aerial UAVs in the fields of military reconnaissance, surveillance and rapid strike applications, the development of new high-performance, low-cost and consumable aerial unmanned equipment has put forward higher requirements for the improvement of flight time capability and stealth performance of their power units.

[0003] In the early days, the stealth capability of aerial vehicles was improved mainly by overall painting to reduce the probability of ground detection. After the emergence and popularization of radar technology, reducing radar reflection signals through means such as appearance design and absorbing materials became the main stealth design solution. However, the current form of air combat mostly uses infrared detection and infrared guidance technology, using ground-to-air and air-to-air missiles to carry out precise strikes on aerial vehicles, and aircraft engines are the strongest infrared radiation source and are usually used as detection target sources. Therefore, reducing the infrared radiation of aircraft engines can effectively reduce the probability of being discovered, identified and tracked, and achieve stealth effects.

[0004] An aircraft engine is a highly complex and sophisticated thermal machine, and its structure consists of an air intake, a compressor, a combustion chamber, a turbine, and a tail nozzle. During flight, air first enters the air intake of the aircraft engine for rectification, and the rectified smooth airflow enters the compressor, where high-pressure air is formed under the swirl supercharging of the compressor. After the high-pressure air flows through the combustion chamber, it is mixed with the fuel and burned to form high-temperature and high-pressure combustion gas. This part of the combustion gas drives the compressor to operate continuously through the turbine, and finally is discharged through the tail nozzle and enters the atmosphere, so that the aircraft engine obtains a reaction thrust. In this process, the external radiation energy of the aircraft engine is mainly concentrated on the wall and outlet of the tail nozzle, which is easily detected and captured by infrared detection devices, and the thermal radiation of the tail nozzle will produce a high-temperature zone in the surrounding area, causing damage to the safety of the aircraft body and control circuits. At present, the conventional solution is to wrap a layer of thermal insulation cotton material near the tail nozzle to reduce the intensity of external radiation. However, this solution will result in the inability of radiant heat to be conducted on the surface of the tail nozzle, and the temperature of the tail nozzle will continue to rise until it reaches a thermal equilibrium state. At this time, the surface temperature of the tail nozzle is extremely high, and there is a risk of thermal deformation and strength loss, posing a hidden danger to the thrust performance and operational safety of the aircraft engine.

[0005] During high-altitude flight, the fuel system of an aircraft engine has a low temperature in the fuel tank, pipelines, etc. due to the low ambient temperature of the high-altitude atmosphere, which leads to a decrease in fuel density and an increase in flow resistance. On the other hand, aircraft engines mostly use an evaporator tube design, which heats and atomizes the fuel inside the combustion chamber to form fuel atomized particles, which are then mixed with air to achieve rapid and efficient combustion and generate kinetic energy. Therefore, the temperature of the fuel and the atomization effect will directly affect the utilization efficiency of the fuel. Summary of the invention

[0006] The purpose of the invention is to provide a method for recovering radiation heat from an aircraft engine tail nozzle.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows:

[0008] A method for recycling radiation heat from an aircraft engine tail nozzle, comprising: winding and laying a heat exchange coil on the outer wall surface of an aircraft engine casing to form a partition-type heat exchange structure, wherein the heat exchange coil is wound around and covers the outer wall surface of the tail nozzle, and the heat exchange coil protrudes toward the injection direction of the tail nozzle to form a bell-mouth structure surrounded by circles of the heat exchange coil;

[0009] The oil inlet of the fuel pump of the aircraft engine is connected to the oil outlet of the fuel tank through a pipeline, the oil outlet of the fuel pump is connected to the inlet end of the heat exchange coil through a pipeline, and the outlet end of the heat exchange coil is connected to the oil inlet of the atomizing nozzle in the combustion chamber, forming a fuel heating pipeline;

[0010] The heat at the tail nozzle is transferred to the fuel in the heat exchange coil through the partition wall heat exchange structure, so that the temperature at the tail nozzle is reduced to achieve thermal radiation stealth in the air and prevent thermal deformation and strength reduction of the tail nozzle, and the fuel in the heat exchange coil is heated to facilitate the atomization and combustion of the heated fuel in the combustion chamber, so that the heat at the tail nozzle can be recycled.

[0011] Preferably, the heat exchange coil is a copper tube, and the heat exchange coil is welded and fixed on the outer wall surface of the casing of the aircraft engine;

[0012] The inner diameter of the heat exchange coil is 3-10 mm, the wall thickness of the heat exchange coil is 0.5-2 mm, and the spacing between two adjacent tubes in the heat exchange coil is 0-2 mm.

[0013] Preferably, the temperature of the fuel oil before heating at the inlet end of the heat exchange coil is -25°C to -10°C, and the temperature of the fuel oil after heating at the outlet end of the heat exchange coil is 0-50°C.

[0014] Compared with the prior art, the present invention has the following advantages and technical effects:

[0015] In order to solve the above technical problems, the present invention considers energy recovery and utilization, adds an annular heat exchange coil on the heat radiation surface of the tail nozzle of the aircraft engine, introduces low-temperature fuel into the heat exchange coil, and transfers the radiant heat energy of the tail nozzle to the low-temperature fuel in the heat exchange coil through the partition heat exchange, thereby reducing the temperature of the tail nozzle itself, preventing the tail nozzle from thermal deformation, and ensuring the strength of the parts. At the same time, the radiant heat energy of the tail nozzle is absorbed by the heat exchange coil, the temperature of the heat exchange coil is relatively low, and the infrared radiation is extremely low, which is basically consistent with the radiation state level of other parts of the body, and the thermal radiation stealth effect in the air can be achieved;

[0016] The low-temperature fuel of the fuel system absorbs the radiant heat energy of the tail nozzle, and its temperature rises, and its flow performance improves, which reduces the fuel supply load of the fuel system. At the same time, the low-temperature fuel enters the combustion chamber after being heated by heat exchange, and can evaporate quickly under the same thermal field environment, thereby increasing the atomization speed and reducing the atomization particle size, so that the fuel is fully in contact with the air, and the energy conversion efficiency in the fuel combustion process is improved;

[0017] The present invention combines the radiation characteristics of the aircraft engine and the design of the heat exchange system of the fuel system to develop a solution for utilizing the radiation heat energy of the tail nozzle of the aircraft engine. While effectively reducing the infrared radiation heat energy of the aircraft engine, it improves the combustion efficiency of the combustion system and realizes energy recovery and reuse.

[0018] The present application is also applicable to other combustion chambers other than evaporation tubes. The fuel oil after heat exchange and temperature increase has better flowability and rapid combustion characteristics, which can improve the combustion efficiency of the fuel oil, reduce the emission of incomplete combustion products of the fuel oil such as alkanes and olefins, and reduce the probability of carbon deposition in the combustion chamber.

[0019] In this application, the heat exchange coil should fit the outer wall of the tail nozzle to improve the heat exchange efficiency. When the cost is controllable, 3D printing technology can be considered to make the heat exchange coil and the tail nozzle integrally formed;

[0020] In this application, the outlet of the tail nozzle can adjust the cone angle and the length of the heat exchange coil according to the infrared characteristics of the tail flame of different aircraft engines; after the high-temperature combustion gas generated by the engine is ejected from the tail nozzle, a temperature-affected area is formed that first expands outward and then converges. The cone angle and wiring length of the heat exchange coil should take into account the range of the heat-affected area after diffusion, and fit the regional boundary of the heat-affected area as closely as possible;

[0021] In the present application, copper tubes are preferably used as heat exchange coils, which have higher heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the working principle of a method for recycling radiation heat from an aircraft engine tail nozzle provided in this application;

[0023] Figure 2 A schematic diagram of the installation structure of an aircraft engine and a heat exchange coil in a method for recycling radiation heat from an aircraft engine tail nozzle provided in this application ( Figure 2 In the process, the heat exchange coil is not only wrapped on the tail nozzle, but also on the outer wall of the casing except the compressor casing. Figure 2 In addition to covering the tail nozzle, the heat exchange coil also covers the combustion chamber, turbine and other parts of the aircraft engine);

[0024] In the figure: 1 aircraft engine, 101 tail nozzle, 2 heat exchange coil, 201 heat exchange coil protrudes toward the injection direction of the tail nozzle and forms a trumpet mouth surrounded by circles of heat exchange coils. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention, not all of them. Therefore, based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] like Figure 2 As shown: an aircraft engine 1, a tail nozzle 101, a heat exchange coil 2, the heat exchange coil 2 protrudes toward the injection direction of the tail nozzle 101 and forms a bell mouth 201 surrounded by circles of the heat exchange coil 2.

[0027] The present application provides a method for recycling radiation heat from an aircraft engine tail nozzle, wherein a heat exchange coil 2 is wound and laid on the outer wall surface of the aircraft engine casing to form a partition-type heat exchange structure, wherein the heat exchange coil 2 is wound and covered on the outer wall surface of the tail nozzle 101, and the heat exchange coil 2 protrudes toward the injection direction of the tail nozzle 101 and forms a bell mouth 201 structure surrounded by circles of the heat exchange coil 2;

[0028] The oil inlet of the fuel pump of the aircraft engine is connected to the oil outlet of the fuel tank through a pipeline, the oil outlet of the fuel pump is connected to the inlet end of the heat exchange coil 2 through a pipeline, and the outlet end of the heat exchange coil 2 is connected to the oil inlet of the atomizing nozzle in the combustion chamber, forming a fuel heating pipeline;

[0029] The heat at the tail nozzle 101 is transferred to the fuel in the heat exchange coil 2 through the partition wall heat exchange structure, so that the temperature at the tail nozzle 101 is reduced to achieve thermal radiation stealth in the air and prevent thermal deformation and strength reduction of the tail nozzle 101, and the fuel in the heat exchange coil 2 is heated to facilitate the atomization and combustion of the heated fuel in the combustion chamber, so that the heat at the tail nozzle 101 can be recycled.

[0030] In one embodiment of the present application, the heat exchange coil 2 is a copper tube, and the heat exchange coil 2 is welded and fixed on the outer wall surface of the casing of the aircraft engine;

[0031] The inner diameter of the heat exchange coil 2 is 3-10 mm, the wall thickness of the heat exchange coil 2 is 0.5-2 mm, and the distance between two adjacent tubes in the heat exchange coil 2 is 0-2 mm.

[0032] In one embodiment of the present application, the temperature of the fuel oil before heating at the inlet end of the heat exchange coil 2 is -25°C to -10°C, and the temperature of the fuel oil after heating at the outlet end of the heat exchange coil 2 is 0-50°C.

[0033] Key technical points of this application:

[0034] (1) The heat exchange coil 2 replaces the heat insulation material or the infrared stealth coating material to realize the recycling of the radiant heat energy of the tail nozzle 101, and reduce the infrared radiation characteristics of the aircraft engine to achieve low detectability;

[0035] (2) Introduce the fuel into the heat exchange coil 2 to preheat the fuel and improve the combustion efficiency;

[0036] (3) This solution is a low-cost infrared stealth solution with high economy and strong consumability.

[0037] The methods and devices not described in detail in the present invention are all prior art and will not be described in detail.

[0038] In order to better understand the present invention, the present invention is further specifically described below through the following examples, but it should not be understood as a limitation of the present invention. Some non-essential improvements and adjustments made by technicians in this field based on the above invention content are also considered to fall within the protection scope of the present invention.

[0039] Example 1

[0040] A method for recycling radiation heat from an aircraft engine tail nozzle, wherein a heat exchange coil 2 is wound and laid on the outer wall surface of the aircraft engine casing to form a partition-type heat exchange structure, wherein the heat exchange coil 2 is wound and covered with the outer wall surface of the tail nozzle 101, and the heat exchange coil 2 protrudes toward the injection direction of the tail nozzle 101 and forms a bell-mouth structure surrounded by circles of the heat exchange coil 2;

[0041] The oil inlet of the fuel pump of the aircraft engine is connected to the oil outlet of the fuel tank through a pipeline, the oil outlet of the fuel pump is connected to the inlet end of the heat exchange coil 2 through a pipeline, and the outlet end of the heat exchange coil 2 is connected to the oil inlet of the atomizing nozzle in the combustion chamber, forming a fuel heating pipeline;

[0042] The heat at the tail nozzle 101 is transferred to the fuel in the heat exchange coil 2 through the partition heat exchange structure, so that the temperature at the tail nozzle 101 is reduced to achieve thermal radiation stealth in the air and prevent thermal deformation and strength reduction of the tail nozzle 101, and the fuel in the heat exchange coil 2 is heated to facilitate the atomization and combustion of the heated fuel in the combustion chamber, so that the heat at the tail nozzle 101 can be recycled;

[0043] The heat exchange coil 2 is a copper tube, and the heat exchange coil 2 is welded and fixed on the outer wall surface of the casing of the aircraft engine;

[0044] The inner diameter of the heat exchange coil 2 is 6 mm, the wall thickness of the heat exchange coil 2 is 0.5 mm, and the spacing between two adjacent tubes in the heat exchange coil 2 is 0-0.5 mm;

[0045] The temperature of the fuel oil before heating at the inlet end of the heat exchange coil 2 is -25°C to -10°C, and the temperature of the fuel oil after heating at the outlet end of the heat exchange coil 2 is 5-50°C.

[0046] Example 2

[0047] In Example 2, except for the following, the remaining structures and parameters are the same as those in Example 1;

[0048] The inner diameter of the heat exchange coil 2 is 8 mm, the wall thickness of the heat exchange coil 2 is 1 mm, and the spacing between two adjacent tubes in the heat exchange coil 2 is 0-0.5 mm;

[0049] The temperature of the fuel oil before heating at the inlet end of the heat exchange coil 2 is -25°C to -10°C, and the temperature of the fuel oil after heating at the outlet end of the heat exchange coil 2 is 10-50°C.

[0050] Example 3

[0051] In Example 3, except for the following, the remaining structures and parameters are the same as those in Example 1;

[0052] The inner diameter of the heat exchange coil 2 is 6 mm, the wall thickness of the heat exchange coil 2 is 0.6 mm, and the spacing between two adjacent tubes in the heat exchange coil 2 is 0-0.5 mm;

[0053] The temperature of the fuel oil before heating at the inlet end of the heat exchange coil 2 is -25°C to -10°C, and the temperature of the fuel oil after heating at the outlet end of the heat exchange coil 2 is 10-45°C.

[0054] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for recycling radiation heat from an aircraft engine tail nozzle, characterized in that: A heat exchange coil is wound and laid on the outer wall surface of the casing of the aircraft engine to form a partition-type heat exchange structure, wherein the heat exchange coil is wound and covered with the outer wall surface of the tail nozzle, and the heat exchange coil protrudes toward the injection direction of the tail nozzle to form a bell-mouth structure surrounded by circles of the heat exchange coil; The oil inlet of the fuel pump of the aircraft engine is connected to the oil outlet of the fuel tank through a pipeline, the oil outlet of the fuel pump is connected to the inlet end of the heat exchange coil through a pipeline, and the outlet end of the heat exchange coil is connected to the oil inlet of the atomizing nozzle in the combustion chamber, forming a fuel heating pipeline; The heat at the tail nozzle is transferred to the fuel in the heat exchange coil through the partition wall heat exchange structure, so that the temperature at the tail nozzle is reduced to achieve thermal radiation stealth in the air and prevent thermal deformation and strength reduction of the tail nozzle, and the fuel in the heat exchange coil is heated to facilitate the atomization and combustion of the heated fuel in the combustion chamber, so that the heat at the tail nozzle can be recycled.

2. The method for recycling radiation heat from an aircraft engine tail nozzle according to claim 1, characterized in that: The heat exchange coil is a copper tube, and the heat exchange coil is welded and fixed on the outer wall surface of the casing of the aircraft engine; The inner diameter of the heat exchange coil is 3-10 mm, the wall thickness of the heat exchange coil is 0.5-2 mm, and the spacing between two adjacent tubes in the heat exchange coil is 0-2 mm.

3. The method for recycling radiation heat from an aircraft engine tail nozzle according to claim 1, characterized in that: The temperature of the fuel oil before heating at the inlet end of the heat exchange coil is -25°C to -10°C, and the temperature of the fuel oil after heating at the outlet end of the heat exchange coil is 0-50°C.

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