A method of improving a thermal sink for an aircraft

Abstract

This invention discloses a method for improving the heat sink of an aircraft. The method includes setting cooling channels and oil inlet pipes on the upper wing skin. Hot return oil to be cooled is introduced into the cooling channels through the oil inlet pipes. The upper skin heat sink cools the hot return oil. Oil delivery pipes are installed at the cooling channel outlet and near the lower skin inside the wing fuel tank. The cooled hot return oil is mixed with the original low-temperature fuel in the wing fuel tank and transported together to the fuel collection tank, where it is again used as a heat sink in various cooling systems, forming a cycle. High-temperature fuel exchanges heat extensively with the upper wing skin through the cooling channels. The low-temperature air outside the upper skin cools the high-temperature hot return oil, improving its heat sink capacity. The cooled return oil mixes with the low-temperature fuel in the wing fuel tank and enters the fuel collection tank. The lower wing skin air heat sink further cools the fuel. The aircraft no longer needs to introduce ram air to cool the hot return oil, improving fuel cooling efficiency, aircraft stealth performance, and reducing flight drag.

Description

Technical Field

[0001] This invention relates to a method for improving the heat sink of an aircraft, and particularly to the fields of aircraft thermal management and fuel cooling. Background Technology

[0002] With the increasing number of avionics and improved overall performance of aircraft, the internal heat load and fuel capacity of aircraft have also increased significantly. To ensure effective cooling of avionics and other equipment, fuel needs to be drawn from the aircraft's fuel tank as a heat sink for use in various cooling systems, absorbing heat and becoming high-temperature fuel. A portion of this high-temperature fuel is cooled and returned to the fuel tank (called heat return fuel), while the other portion enters the engine for combustion.

[0003] As aircraft performance improves, the heat dissipation pressure on fuel increases significantly. Excessively high fuel temperatures drastically reduce cooling efficiency and engine lifespan, necessitating the use of alternative heat sinks to cool the high-temperature hot return fuel and enhance its heat absorption capacity. Currently, most research on aircraft fuel thermal management systems involves introducing ram air to cool the hot return fuel. However, under certain flight conditions, this approach suffers from insufficient fuel cooling efficiency, increased drag, and negative impacts on stealth performance. Therefore, finding new cooling media that can be used by the aircraft itself as a heat sink has become an important direction in thermal management research.

[0004] From the perspective of the aircraft's own structure, the wing skin is in direct contact with the external environment and easily exchanges heat with it. When an aircraft flies for a long time at high altitude (≥10000m) and subsonic speed (usually ≤0.8Ma), the external temperature of the aircraft is low, and the aerodynamic heat borne by the wing skin is relatively weak. Therefore, the temperature of the wing skin and the internal environment (fuel and air) of the wing fuel tanks that are in direct contact with it is also low, usually stable below 0°C. It is a heat sink with great potential that the aircraft has built in and can be used to cool the hot fuel return.

[0005] However, the wing fuel tanks are usually half-filled, and the fuel concentrates in the lower part of the wing fuel tank due to gravity, making it difficult to effectively utilize the heat sink of the upper skin. Summary of the Invention

[0006] This invention provides a method for improving the heat sink of an aircraft to overcome the shortcomings of insufficient cooling medium in the prior art during high-altitude, subsonic cruise.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] This invention discloses a method for improving the heat sink of an aircraft, comprising the following steps:

[0009] S1: Cooling channels and oil inlet pipes are installed on the wing skin;

[0010] S2: The hot return oil that has absorbed heat and increased in temperature after passing through the various heat dissipation systems of the aircraft, which serves as a heat sink, is introduced into the cooling channel through the oil inlet pipe. The hot return oil is cooled down by the air heat sink outside the wing skin.

[0011] S3: Connect the oil supply pipe to the outlet of the cooling channel and the outlet of the wing fuel tank near the lower skin of the wing.

[0012] S4: The cooled hot return oil is mixed with the fuel in the wing fuel tank and transported together through the fuel pipe to the fuel collection tank in the fuselage to reduce the temperature of the fuel entering the fuel collection tank and improve the fuel heat sink.

[0013] S5: The fuel in the fuel tank is used as a heat sink and enters the cooling systems again, forming a cycle.

[0014] Furthermore, the cooling channels are located inside the upper skin of the wing.

[0015] Furthermore, the cooling channel has an upper surface and a lower surface, the upper surface being the inner surface of the upper skin of the wing; the lower surface is parallel to the upper surface and forms a sandwich channel.

[0016] Furthermore, the cooling channel is provided with an inlet and an outlet, the inlet being connected to the oil inlet pipe and the outlet being connected to the oil delivery pipe.

[0017] Furthermore, the wing fuel tank has an outlet located inside the wing fuel tank near the fuel collection tank and the lower wing skin.

[0018] Furthermore, the oil supply pipe has two inlets and one outlet. The two inlets of the oil supply pipe are respectively connected to the outlet of the cooling channel and the outlet of the wing fuel tank; the outlet of the oil supply pipe is connected to the oil collection tank.

[0019] The beneficial effects achieved by this invention are as follows: high-temperature fuel makes full contact with the upper wing skin through the cooling channel for heat exchange, effectively utilizing the low-temperature air heat sink outside the upper skin to cool the high-temperature hot return fuel, thereby improving its heat sinking effect; the cooled return fuel mixes with the low-temperature fuel in the wing fuel tank and enters the fuel collection tank, achieving the effect of utilizing the air heat sink of the lower wing skin to cool the fuel again; the aircraft no longer needs to introduce ram air to cool the hot return fuel, thus improving fuel cooling efficiency and aircraft stealth performance, and reducing flight drag. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0021] Figure 1This is a schematic diagram of the wing cross-section structure and external airflow of the present invention;

[0022] Figure 2 This is a schematic diagram of the fuel tank structure and fuel flow path of the present invention;

[0023] Figure 3 This is a schematic diagram illustrating the operating principle of the present invention.

[0024] In the diagram: 1. Upper wing skin; 2. Cooling channel; 3. Oil inlet pipe; 4. Wing fuel tank; 5. Oil transfer pipe; 6. Oil collection tank; 7. Lower wing skin. Detailed Implementation

[0025] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0026] Example 1

[0027] like Figure 1-3 As shown, a method for improving the heat sink of an aircraft includes the following steps:

[0028] S1: Cooling channels 2 and oil inlet pipes 3 are provided on the upper skin 1 of the wing;

[0029] S2: The hot return oil to be cooled, which has absorbed heat and increased in temperature after passing through the various heat dissipation systems of the aircraft, is fed into the cooling channel 2 through the oil inlet pipe 3, and the hot return oil is cooled down by the air heat sink outside the wing skin 1.

[0030] S3: Connect the oil supply pipe 5 to the outlet of the cooling channel 2 and the outlet of the wing fuel tank 4 near the lower skin of the wing 7;

[0031] S4: The cooled hot return oil is mixed with the fuel in the wing fuel tank 4 and transported together through the fuel pipe 5 to the fuel collection tank 6 in the fuselage, in order to reduce the temperature of the fuel entering the fuel collection tank and improve the fuel heat sink.

[0032] S5: The fuel in the fuel tank 6 is used as a heat sink and enters the cooling system again, forming a cycle.

[0033] The cooling channel 2 is located inside the upper skin 1 of the wing.

[0034] The cooling channel 2 has an upper surface and a lower surface. The upper surface is the inner surface of the upper skin 1 of the wing. The lower surface is parallel to the upper surface and forms a sandwich channel.

[0035] The cooling channel 2 has an inlet and an outlet. The inlet is connected to the oil inlet pipe 3, and the outlet is connected to the oil delivery pipe 5.

[0036] The wing fuel tank 4 has an outlet located inside the wing fuel tank 4 near the fuel collection tank 6 and the lower wing skin 7.

[0037] The oil supply pipe 5 has two inlets and one outlet. The two inlets of the oil supply pipe 5 are respectively connected to the outlet of the cooling channel 2 and the outlet of the wing fuel tank 4; the outlet of the oil supply pipe 5 is connected to the oil collection tank 6.

[0038] Working principle:

[0039] When an aircraft flies for an extended period of time under high-altitude (≥10000m) and subsonic (≤0.8Ma) cruise conditions, the external ambient temperature of the aircraft is low, and the aerodynamic heat borne by the upper wing skin 1 and the lower wing skin 7 is also low. Therefore, the internal ambient temperature (fuel and air) of the two and the wing fuel tank 4, which are in direct contact with them, is also low, usually stable below 0℃. They are the aircraft's own heat sinks with great potential.

[0040] Since the fuel in the wing fuel tank 4 is usually concentrated in the lower part due to gravity, and the fuel is at a low temperature due to direct heat exchange with the lower wing skin 7, the air heat sink of the lower wing skin 7 has been utilized. In this invention, a cooling channel 2 is arranged inside the upper wing skin 1, and a suitable distance between the upper and lower surfaces is determined so that the hot return oil fills the cooling channel 2 and performs forced convection heat exchange with the inner surface of the upper wing skin 1, thereby reducing the fuel temperature.

[0041] The high-temperature hot return oil enters the wing cooling channel 2 through the oil inlet pipe 3, and after being cooled by the upper wing skin 1, it mixes with the low-temperature fuel in the oil supply pipe 5 and the wing fuel tank 4, and enters the oil collection tank 6 to achieve cooling again. A total of two cooling processes are completed to further improve the heat sink of the aircraft.

[0042] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The terminology used in the description of this application is only for describing specific embodiments and is not intended to limit the exemplary embodiments according to this application. For ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings indicate similar items, and therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0043] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and are not limited in number; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0044] It should be noted that in the description of this application, the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

Claims

1. A method of improving a thermal sink of an aircraft, characterized in that, The steps include the following: S1: A cooling channel and an oil inlet pipe are provided on the upper skin of the wing; the cooling channel is located inside the upper skin of the wing; the cooling channel has an upper surface and a lower surface, the upper surface is the inner surface of the upper skin of the wing, and the lower surface is parallel to the upper surface and forms a sandwich channel; the cooling channel has an inlet and an outlet, and the inlet is connected to the oil inlet pipe; S2: The hot return oil that has absorbed heat and increased in temperature after passing through the various heat dissipation systems of the aircraft, which serves as a heat sink, is introduced into the cooling channel through the oil inlet pipe. The hot return oil is cooled down by the air heat sink outside the wing skin. S3: Connect the fuel supply pipe to the outlet of the cooling channel and the outlet of the wing fuel tank near the lower wing skin; the outlet of the wing fuel tank is located inside the wing fuel tank near the fuel collection tank and the lower wing skin; the fuel supply pipe has two inlets and one outlet, the two inlets of the fuel supply pipe are respectively connected to the outlet of the cooling channel and the outlet of the wing fuel tank, and the outlet of the fuel supply pipe is connected to the fuel collection tank. S4: The cooled hot return oil is mixed with the fuel in the wing fuel tank and transported together through the fuel pipe to the fuel collection tank in the fuselage to reduce the temperature of the fuel entering the fuel collection tank and improve the fuel heat sink. S5: The fuel in the fuel tank is used as a heat sink and enters the cooling systems again, forming a cycle.

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