An auxiliary power unit lubricating oil cooling system for aircraft

Abstract

This invention discloses an auxiliary power unit (APU) lubricating oil cooling system for aircraft, comprising: an APU compartment, an aircraft air intake duct, an integrated air intake unit, a lubricating oil unit, and an APU body. The APU compartment is installed at the tail of the aircraft. One end of the aircraft air intake duct is connected to the APU compartment; the other end of the aircraft air intake duct is connected to the integrated air intake unit; the integrated air intake unit is connected to the APU body; and the integrated air intake unit is connected to the lubricating oil unit. Compared to fan cooling, this invention eliminates rotating components, reducing power consumption, lowering structural complexity, and enhancing reliability. Compared to exhaust ejector cooling, it eliminates the exhaust ejector, resulting in a more compact structure. The lubricating oil cooler is placed in the cold end region, overcoming the problem of poor cooling effect caused by the cooling air needing to flow through a high-temperature zone for heating.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine technology, and specifically relates to an oil cooling system for an auxiliary power unit of an aircraft. Background Technology

[0002] The primary function of an aircraft's Auxiliary Power Unit (APU) is to provide compressed air and auxiliary / emergency power to the main engine. It is essentially a small air turbine engine, with its own intake, compressor, combustion chamber, turbine, and various accessory systems. It is typically installed in the APU compartment at the tail of the aircraft.

[0003] The APU is designed with an oil cooling system to dissipate heat from the lubricating oil, thereby reducing its temperature and ensuring the normal operation of the auxiliary power unit. Currently, the cooling air for oil cooling is mainly driven by two methods: cooling fans and exhaust ejectors. The cooling fan is a small rotating component that uses a high-speed rotating impeller to "pump" in external cooling air, pressurize the airflow, and then use cooling pipes to impact the oil cooler, thus cooling the lubricating oil. This method inevitably consumes some power due to the rotating component, and it usually requires long cooling airflow pipes before and after the cooling fan, resulting in a bulky, complex structure and relatively poor reliability. The exhaust ejector method involves adding an ejector to the rear of the APU. It uses the high-speed airflow exhausted by the APU to eject the airflow inside the APU compartment. The airflow then flows through the radiator to cool the lubricating oil. This method has several drawbacks. First, it requires an additional ejector, which increases the length and weight of the auxiliary power unit. Second, since the radiator is installed at the end of the APU, while the lubricating oil tank is usually installed at the front, the length of the oil supply and return pipes connecting the oil tank and the radiator is greatly increased, increasing the risk of oil circuit blockage. Furthermore, the cooling airflow must first cool the accessories, inevitably heating up the airflow and reducing the lubricating oil's cooling effect. Summary of the Invention

[0004] To address the aforementioned problems, this invention discloses an auxiliary power unit lubricating oil cooling system for aircraft, comprising: an auxiliary power unit compartment, an aircraft air intake, an integrated air intake unit, a lubricating oil unit, and an auxiliary power unit body;

[0005] The auxiliary power unit nacelle is installed at the tail of the aircraft;

[0006] One end of the aircraft air intake is connected to the auxiliary power unit compartment;

[0007] The other end of the aircraft air intake is connected to an integrated air intake unit;

[0008] The integrated intake unit is connected to the auxiliary power unit body;

[0009] The integrated intake unit is connected to the lubrication unit.

[0010] Furthermore, the outlet cross-section of the aircraft air intake is rectangular, with a length of 350–400 mm and a width of 180–220 mm.

[0011] Furthermore, the integrated intake unit includes an oil cooler and an intake device;

[0012] The lubricating oil radiator is located on the inner wall of the air intake device.

[0013] Furthermore, the air intake device is volute-shaped, comprising an upper part and a lower part, which are connected by bolts.

[0014] The upper part of the air intake device has a rectangular air intake port.

[0015] Furthermore, the oil radiator is an air-oil heat exchanger.

[0016] Furthermore, the length of the oil radiator is 150-200mm and the width is 50-80mm.

[0017] Furthermore, the material of the oil radiator is aluminum alloy.

[0018] Furthermore, the lubricating unit includes an oil supply pipe, an oil return pipe, an oil pump, and an oil tank;

[0019] The lubricating oil tank is connected to the auxiliary power unit body;

[0020] An oil pump is installed on one side of the oil tank;

[0021] The oil outlet of the lubricating oil pump is connected to the oil supply pipe, and the oil inlet of the lubricating oil pump is connected to the oil return pipe.

[0022] The oil supply pipe is connected to one end of the lubricating oil cooler;

[0023] The return oil pipe is connected to the other end of the lubricating oil radiator.

[0024] Furthermore, the auxiliary power unit consists of a compressor, a combustion chamber, a turbine, and a gear transmission unit;

[0025] One end of the gear transmission unit is connected to one end of the air intake device;

[0026] The other end of the air intake device is connected to one end of the air compressor;

[0027] The other end of the compressor is connected to one end of the combustion chamber;

[0028] The other end of the combustion chamber is connected to the turbine.

[0029] Furthermore, it also includes: aircraft exhaust pipes;

[0030] The aircraft exhaust pipe is connected to the auxiliary power unit body by clamps.

[0031] Compared with the prior art, the embodiments of the present invention have at least the following advantages:

[0032] 1) Compared to fan cooling, the elimination of rotating parts reduces power consumption, lowers the complexity of the APU structure, and enhances reliability;

[0033] 2) Compared to the exhaust ejector cooling method, the exhaust ejector is eliminated, making the APU structure more compact;

[0034] 3) At the same time, the lubricating oil radiator is placed in the cold end area of ​​the APU, which overcomes the problem that the cooling air needs to flow through the high temperature area of ​​the APU for heating, resulting in poor cooling effect;

[0035] 4) The length of the lubricating oil supply pipe and return pipe is greatly reduced, which significantly reduces the risk of lubricating oil pipeline blockage.

[0036] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 A schematic diagram of the structure of an aircraft auxiliary power unit lubricating oil cooling system according to an embodiment of the present invention is shown;

[0039] Figure 2 A schematic diagram of the structure of an integral intake unit according to an embodiment of the present invention is shown.

[0040] Reference numerals: 1. Auxiliary power plant compartment; 2. Aircraft air intake; 3. Oil cooler; 4. Air intake device; 4-1. Upper part of air intake device; 4-2. Lower part of air intake device; 5. Oil supply pipe; 6. Oil return pipe; 7. Oil pump; 8. Oil tank; 9. Auxiliary power plant body; 9-1. Compressor; 9-2. Combustion chamber; 9-3. Turbine; 9-4. Gear transmission unit; 10. Aircraft exhaust pipe. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Figure 1 A schematic diagram of an aircraft auxiliary power unit lubricating oil cooling system according to an embodiment of the present invention is shown. Figure 1 As shown, the present invention proposes an auxiliary power unit lubricating oil cooling system for aircraft, comprising: an auxiliary power unit compartment 1, an aircraft air intake duct 2, an integrated air intake unit, a lubricating oil unit, and an auxiliary power unit body 9.

[0043] The auxiliary power unit compartment 1 is installed at the tail of the aircraft;

[0044] One end of the aircraft air intake 2 is connected to the auxiliary power unit compartment 1;

[0045] The other end of the aircraft air intake duct 2 is connected to the integrated air intake unit;

[0046] The integrated intake unit is connected to the auxiliary power unit body 9;

[0047] The integrated intake unit is connected to the lubrication unit.

[0048] The present invention discloses an auxiliary power unit (APU) lubricating oil cooling system for aircraft. Compared with fan cooling, it eliminates rotating parts, reduces power consumption, lowers the complexity of the APU structure, and enhances reliability. Compared with exhaust ejector cooling, it eliminates the exhaust ejector, making the APU structure more compact.

[0049] In some embodiments, the outlet cross-section of the aircraft air intake duct 2 is rectangular, with a length of 350–400 mm and a width of 180–220 mm. Preferably, the length of the cross-section of the aircraft air intake duct 2 is 400 mm and the width is 200 mm.

[0050] like Figure 2 As shown, in some embodiments, the integrated intake unit includes an oil cooler 3 and an intake device 4;

[0051] The lubricating oil radiator 3 is installed on the inner wall of the air intake device 4 and is integrally molded. The integral design reduces the number of parts and makes the structure more compact.

[0052] In some embodiments, the lubricating oil radiator 3 can also be connected to the side wall of the air intake device 4 by welding.

[0053] In some embodiments, the air intake device 4 is volute-shaped and includes two parts: an upper part 4-1 and a lower part 4-2, which are connected by bolts; both sides of the air intake device 4 are provided with circular openings.

[0054] The upper part 4-1 of the air intake device has a rectangular air intake at its top. The size of the rectangular air intake matches that of the aircraft air intake duct 2, and the two are connected by bolts.

[0055] In some embodiments, the lubricating oil radiator 3 is an air-oil heat exchanger, which has the advantages of being lightweight and having high heat dissipation power.

[0056] The air-oil heat exchanger consists of a plate-fin heat dissipation core, inlet and outlet end caps, and oil return end cap.

[0057] In some embodiments, the oil radiator 3 has a length of 150-200 mm and a width of 50-80 mm. Preferably, the oil radiator 3 has a length of 200 mm and a width of 50 mm.

[0058] The size of the lubricating oil radiator 3 can be adjusted according to the actual lubricating oil volume and cooling requirements of the auxiliary power unit.

[0059] In some embodiments, the oil radiator 3 is made of aluminum alloy. Using aluminum alloy improves heat transfer performance and reduces the weight of the equipment, thus reducing the aircraft's load.

[0060] In some embodiments, the lubricating unit includes an oil supply pipe 5, an oil return pipe 6, an oil pump 7, and an oil tank 8;

[0061] The lubricating oil tank 8 is connected to the auxiliary power unit body 9;

[0062] A lubricating oil pump 7 is installed on one side of the lubricating oil tank 8;

[0063] The oil outlet of the lubricating oil pump 7 is connected to the oil supply pipe 5, and the oil inlet of the lubricating oil pump 7 is connected to the oil return pipe 6.

[0064] The oil supply pipe 5 is connected to one end of the lubricating oil radiator 3;

[0065] The return oil pipe 6 is connected to the other end of the lubricating oil radiator 3.

[0066] The auxiliary power unit body 9 consists of a compressor 9-1, a combustion chamber 9-2, a turbine 9-3, and a gear transmission unit 9-4;

[0067] One end of the gear transmission unit 9-4 is connected to one end of the air intake device 4;

[0068] The other end of the air intake device 4 is connected to one end of the air compressor 9-1;

[0069] The other end of the compressor 9-1 is connected to one end of the combustion chamber 9-2;

[0070] The other end of the combustion chamber 9-2 is connected to the turbine 9-3.

[0071] The oil tank 8 and the gear transmission unit 9-4 are integrally molded, and the oil tank 8 is located at the bottom.

[0072] The aircraft auxiliary power unit lubricating oil cooling system also includes: aircraft exhaust pipe 10;

[0073] The aircraft exhaust pipe 10 is connected to the auxiliary power unit body 9 by a clamp.

[0074] The working process of the lubricating oil cooling system for aircraft auxiliary power units is as follows:

[0075] Outside air enters the aircraft intake 4 through the air intake duct 2. Most of the air enters the auxiliary power unit 9 directly, while a small portion flows through the oil cooler 3 before entering the auxiliary power unit 9. Within the auxiliary power unit 9, the air undergoes compression, combustion, and expansion to perform work before entering the aircraft exhaust pipe 10 through the tail nozzle. The lubricating oil stored in the oil tank 8 is pumped by the oil pump 7 through the oil supply pipe 5 into the oil cooler 3 for cooling, and then returns to the oil tank 8 through the oil return pipe 6.

[0076] This invention proposes an auxiliary power unit (APU) lubricating oil cooling system. The lubricating oil cooler 3 and the air intake device 4 are integrated into a single unit. This design reduces excessive power consumption of the APU while ensuring sufficient cooling gas flow to the lubricating oil, resulting in a simpler, more compact APU structure that reduces weight and length, thus increasing reliability. The lubricating oil cooler 3 is positioned in the cold end region of the APU, overcoming the problem of poor cooling performance caused by the cooling air needing to pass through the high-temperature region of the APU. The lengths of the lubricating oil supply pipe 5 and return pipe 6 are significantly reduced, greatly decreasing the risk of lubricating oil pipe blockage and improving the stability and safety of the lubricating oil cooling system.

[0077] In the description of this invention, it should be understood that the terms "upper," "lower," "front," "top," "inner," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and 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 of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0078] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0079] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An auxiliary power unit lubricating oil cooling system for aircraft, characterized in that, include: Auxiliary power plant compartment (1), aircraft air intake (2), integrated air intake unit, lubrication unit and auxiliary power plant body (9). The auxiliary power unit compartment (1) is installed at the tail of the aircraft; One end of the aircraft air intake (2) is connected to the auxiliary power unit compartment (1); The other end of the aircraft air intake (2) is connected to the integrated air intake unit; The integrated intake unit is connected to the auxiliary power unit body (9); The integrated intake unit is connected to the lubrication unit; The integrated intake unit includes an oil radiator (3) and an intake device (4). The lubricating oil radiator (3) is installed on the inner wall of the air intake device (4); The air intake device (4) is volute-shaped and includes two parts: an upper part (4-1) and a lower part (4-2), which are connected by bolts. Among them, a rectangular air inlet is provided at the top of the upper part (4-1) of the air intake device; The auxiliary power unit body (9) consists of a compressor (9-1), a combustion chamber (9-2), a turbine (9-3), and a gear transmission unit (9-4); One end of the gear transmission unit (9-4) is connected to one end of the air intake device (4); The other end of the air intake device (4) is connected to one end of the compressor (9-1); The other end of the compressor (9-1) is connected to one end of the combustion chamber (9-2); The other end of the combustion chamber (9-2) is connected to the turbine (9-3); Outside air enters the air intake device (4) through the aircraft air intake (2). Most of the gas enters the auxiliary power unit body (9) directly, and a small part of the gas flows through the lubricating oil radiator (3) before entering the auxiliary power unit body (9).

2. The aircraft auxiliary power unit lubricating oil cooling system according to claim 1, characterized in that, The outlet section of the aircraft air intake (2) is rectangular, with a length of 350~400mm and a width of 180~220mm.

3. The aircraft auxiliary power unit lubricating oil cooling system according to claim 1, characterized in that, The lubricating oil radiator (3) is an air lubricating oil heat exchanger.

4. The aircraft auxiliary power unit lubricating oil cooling system according to claim 3, characterized in that, The length of the lubricating oil radiator (3) is 150~200mm and the width is 50~80mm.

5. The aircraft auxiliary power unit lubricating oil cooling system according to claim 4, characterized in that, The lubricating oil radiator (3) is made of aluminum alloy.

6. The aircraft auxiliary power unit lubricating oil cooling system according to claim 3, characterized in that, The lubricating unit includes an oil supply pipe (5), an oil return pipe (6), an oil pump (7), and an oil tank (8); The lubricating oil tank (8) is connected to the auxiliary power unit body (9); A lubricating oil pump (7) is provided on one side of the lubricating oil tank (8); The oil outlet of the lubricating oil pump (7) is connected to the oil supply pipe (5), and the oil inlet of the lubricating oil pump (7) is connected to the oil return pipe (6). The oil supply pipe (5) is connected to one end of the lubricating oil radiator (3); The return oil pipe (6) is connected to the other end of the lubricating oil radiator (3).

7. The aircraft auxiliary power unit lubricating oil cooling system according to claim 1, characterized in that, Also includes: Aircraft exhaust pipe (10); The aircraft exhaust pipe (10) is connected to the auxiliary power unit body (9) by a clamp.

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