Auxiliary power unit exhaust pipe fireproof mounting assembly and aircraft

Abstract

The application relates to an auxiliary power unit (APU) exhaust pipe fireproof mounting assembly and an airplane. The APU exhaust pipe fireproof mounting assembly is mounted at a firewall behind an APU cabin and comprises a connecting piece, a bellows, an APU exhaust pipe front support and an APU exhaust pipe. The connecting piece is used for sealing connection between an APU body exhaust ejector and the bellows. The bellows is connected between an outlet of the APU body exhaust ejector and the APU exhaust pipe front support. The APU exhaust pipe front support is used for connecting the bellows, the APU exhaust pipe and the firewall respectively. The APU exhaust pipe is connected with the APU exhaust pipe front support at a front end and communicates with the outside atmosphere at a rear end to discharge high-temperature exhaust gas of the APU body. According to the above technical scheme, the application has the following beneficial technical effects: simple layout, easy installation, light overall weight and meeting the fireproof requirement.

Description

Technical Field

[0001] This invention relates to a fireproof mounting assembly for an auxiliary power unit exhaust pipe and an aircraft. Background Technology

[0002] The auxiliary power unit (hereinafter referred to as "APU") of civil aircraft is usually installed in the APU bay and tail cone at the rear of the fuselage. The high-temperature exhaust generated by the APU during operation is discharged into the outside atmosphere through the APU exhaust pipe, the APU bay, and the tail cone. In addition, since the APU bay is a designated fire zone, a sealed firewall structure must be installed around the APU bay to prevent flames from spreading from any possible gaps.

[0003] When designing the APU exhaust installation structure, it's crucial to consider that the APU exhaust pipe inevitably passes through the firewall aft of the APU compartment when discharging the high-temperature exhaust generated by the APU itself. Therefore, fireproofing is essential at the interface where the pipe crosses the firewall to prevent the spread of flames through component gaps. In particular, as the APU exhaust pipe is a high-temperature component, gaps may form at its interface with the firewall and other components due to thermal expansion and contraction. Thus, the fireproofing design of the APU exhaust pipe crossing the firewall is especially critical.

[0004] Existing APU exhaust fireproof installation structures typically include two schemes depending on the APU exhaust ejection method: 1) The firewall behind the APU compartment is shaped to match the APU exhaust port to form an ejection structure, and protrudes rearward in a tubular shape to form the APU exhaust flow channel. This design requires a high-quality appearance and is difficult to manufacture and install because the firewall must be shaped to match the APU exhaust port to effectively eject the ventilation and cooling airflow within the APU compartment. 2) The high-temperature exhaust from the APU body is mixed with the cooling airflow from the APU compartment in a separately arranged ejector before being discharged. This design does not require a specific shape to match the ejection flow field, but it does require a fireproof seal at the interface where the APU exhaust pipe passes through the firewall. Due to the high temperature of the APU exhaust, a heat insulation structure needs to be added to the portion of the APU exhaust pipe inside the APU compartment to prevent excessively high temperatures, increasing the weight of the APU exhaust installation structure. Summary of the Invention

[0005] One object of the present invention is to provide a fireproof installation assembly for the exhaust pipe of an auxiliary power unit, which overcomes at least some of the defects of the prior art, has a simple layout, is easy to install, is lightweight, and can meet fire protection requirements.

[0006] The above-mentioned objective of the present invention is achieved by an auxiliary power unit exhaust pipe fireproof mounting assembly, which is installed at the firewall behind the APU compartment and includes a connector, a corrugated pipe, an APU exhaust pipe front support, and an APU exhaust pipe.

[0007] The connector is used for a sealed connection between the APU body exhaust ejector and the bellows. The bellows is connected between the outlet of the APU body exhaust ejector and the front support of the APU exhaust pipe. The front support of the APU exhaust pipe is used to connect the bellows, the APU exhaust pipe and the firewall respectively. The front end of the APU exhaust pipe is connected to the front support of the APU exhaust pipe, and the rear end is connected to the outside atmosphere to discharge the high-temperature exhaust of the APU body.

[0008] According to the above technical solution, the auxiliary power device exhaust pipe fireproof installation component of the present invention can achieve the following beneficial technical effects: simple layout, easy installation, light overall weight, and can meet fireproof requirements.

[0009] Preferably, the auxiliary power unit exhaust pipe fireproof mounting assembly further includes a reinforcing member sandwiched between the flange of the APU exhaust pipe front support and the firewall.

[0010] Preferably, the APU exhaust pipe front support includes a hemispherical protrusion.

[0011] Preferably, when the front end of the APU exhaust pipe front support is connected to the bellows, the middle interface is connected to the front end of the APU exhaust pipe, and the rear end is connected to the firewall.

[0012] Preferably, when the front end of the APU exhaust pipe front support is connected to the firewall, the middle interface is connected to the bellows, and the rear end is connected to the front end of the APU exhaust pipe.

[0013] Preferably, the connector is a ring clamp.

[0014] Preferably, the corrugation height of the corrugated pipe is 16-19 mm.

[0015] Preferably, the thickness and bolt hole spacing of the APU exhaust pipe front support are designed to ensure that no gaps that could lead to the spread of flames will be created when the component warps due to thermal expansion and contraction.

[0016] Preferably, the reinforcing member is an annular plate-shaped reinforcing member.

[0017] The above-mentioned objectives of the present invention are also achieved by an aircraft comprising an auxiliary power unit exhaust pipe fireproof mounting assembly as described in any of the above aspects.

[0018] According to the above technical solution, the aircraft of the present invention can achieve the following beneficial technical effects: the auxiliary power unit exhaust pipe fireproof installation component has a simple layout, is easy to install, is lightweight, and can meet fireproof requirements. Attached Figure Description

[0019] Figure 1A This is a schematic diagram of an auxiliary power unit exhaust pipe fireproof mounting assembly (forward-protruding APU exhaust pipe front support) according to an embodiment of the present invention.

[0020] Figure 1B This is a schematic diagram of an auxiliary power unit exhaust pipe fireproof mounting assembly (rear-protruding APU exhaust pipe front support) according to another embodiment of the present invention.

[0021] Figure 2A This is an exploded view of an auxiliary power unit exhaust pipe fireproof mounting assembly (front support component for protruding APU exhaust pipe) according to an embodiment of the present invention.

[0022] Figure 2B This is an exploded view of the auxiliary power unit exhaust pipe fireproof mounting assembly (rear-protruding APU exhaust pipe front support) according to another embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the corrugated pipe in the fireproof installation assembly of the auxiliary power unit exhaust pipe of the present invention.

[0024] Figure 4A This is a cross-sectional view of the installation of the front support component of the protruding APU exhaust pipe.

[0025] Figure 4B This is a cross-sectional view of the installation of the front support component of the rear-protruding APU exhaust pipe.

[0026] Figure 5A This is a cross-sectional view of the through-wall installation of the front support component of the protruding APU exhaust pipe.

[0027] Figure 5B This is a cross-sectional view of the through-wall installation of the front support component of the rear-protruding APU exhaust pipe.

[0028] List of reference numerals

[0029] 1: Connector;

[0030] 2: Corrugated pipe;

[0031] 3: APU exhaust pipe front support component;

[0032] 4: Reinforcing components;

[0033] 5: Firewall;

[0034] 6: APU exhaust pipe;

[0035] 10: APU body exhaust ejector;

[0036] 21: Air-film cavity. Detailed Implementation

[0037] The following describes specific embodiments of the present invention. It should be noted that, in order to provide a concise description, this specification cannot exhaustively describe all features of the actual embodiments. It should be understood that, in the actual implementation of any embodiment, just as in any engineering or design project, various specific decisions are often made to achieve the developer's specific goals and to meet system-related or business-related constraints, and this can change from one embodiment to another. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, some design, manufacturing, or production modifications based on the technical content disclosed herein are merely conventional technical means and should not be construed as insufficient content of this disclosure.

[0038] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in the patent application description and claims of this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising" or "including" and similar terms mean that the element or object preceding "comprising" or "including" encompasses the element or object listed following "comprising" or "including" and its equivalents, and do not exclude other elements or objects. The terms "connected" or "linked" and similar terms are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections.

[0039] In the following description, in order to clearly demonstrate the structure and operation of the present invention, a number of directional terms will be used. However, terms such as "front," "rear," "left," "right," "outer," "inner," "outward," "inward," "upward," and "downward" should be understood as convenient terms and not as limiting terms. In particular, it should be noted that "front" and "rear" are determined according to the exhaust direction of the auxiliary power unit's exhaust pipe.

[0040] Figure 1A This is a schematic diagram of an auxiliary power unit exhaust pipe fireproof mounting assembly (forward-protruding APU exhaust pipe front support) according to an embodiment of the present invention. Figure 1B This is a schematic diagram of an auxiliary power unit exhaust pipe fireproof mounting assembly (rear-protruding APU exhaust pipe front support) according to another embodiment of the present invention. Figure 2A This is an exploded view of an auxiliary power unit exhaust pipe fireproof mounting assembly (front support component for protruding APU exhaust pipe) according to an embodiment of the present invention. Figure 2B This is an exploded view of the auxiliary power unit exhaust pipe fireproof mounting assembly (rear-protruding APU exhaust pipe front support) according to another embodiment of the present invention.

[0041] like Figure 1A - Figure 2B As shown, in one embodiment of the present invention, the auxiliary power unit exhaust pipe fireproof installation assembly is installed at the firewall 5 behind the APU compartment, and includes a connector 1, a corrugated pipe 2, an APU exhaust pipe front support 3, and an APU exhaust pipe 6.

[0042] Among them, connector 1 is used for sealing connection between APU body exhaust ejector 10 and bellows 2. Bellows 2 is connected between the outlet of APU body exhaust ejector 10 and APU exhaust pipe front support 3. APU exhaust pipe front support 3 is used to connect bellows 2, APU exhaust pipe 6 and firewall 5 respectively. APU exhaust pipe 6 is connected to APU exhaust pipe front support 3 at its front end and connected to the outside atmosphere at its rear end to discharge the high temperature exhaust of APU body.

[0043] According to the above technical solution, the auxiliary power device exhaust pipe fireproof installation component of the present invention can achieve the following beneficial technical effects: simple layout, easy installation, light overall weight, and can meet fireproof requirements.

[0044] Specifically, such as Figure 1A - Figure 2B As shown, connector 1 is preferably an annular clamp made of stainless steel, used for a sealing connection between the APU body exhaust ejector 10 and the bellows 2. Bellows 2 is preferably made of stainless steel, with its two ends connected to the outlet of the APU body exhaust ejector 10 and the APU exhaust pipe front support 3, respectively. The APU exhaust pipe front support 3 is preferably made of stainless steel and can be selected as a forward-protruding type (e.g., depending on the APU compartment installation layout and space allowance). Figure 1A (as shown) or rear-protruding type (such as) Figure 1B (As shown). Firewall 5 is preferably made of titanium alloy. APU exhaust pipe 6 is preferably made of stainless steel, with its front end connected to the front support 3 of APU exhaust pipe, and its rear end connected to the outside atmosphere to discharge the high-temperature exhaust from the APU body.

[0045] Figure 3This is a schematic diagram of the corrugated pipe in the fireproof installation assembly for the auxiliary power unit exhaust pipe of the present invention. In some embodiments, the corrugated pipe 2 is made of stainless steel, with its front end connected to the outlet of the APU exhaust ejector 10 via a connector 1, and its rear end connected to the front support 3 of the APU exhaust pipe via bolts. The corrugated structure of the corrugated pipe 2 has a certain degree of flexibility, which can absorb the thermal expansion and contraction of the pipeline caused by the high temperature of the APU exhaust and the axial and radial displacement of the components caused by installation errors, ensuring that the connection will not have gaps due to the above displacement, thereby preventing flames from spreading outward from any possible opening.

[0046] In some embodiments, such as Figure 3 As shown, the high-temperature exhaust gas from the APU body (700℉~1000℉) flows inside the inner wall of the corrugated pipe 2, while the air outside the corrugated outer wall is the air in the APU chamber. Between the inner wall and the corrugated outer wall is a film-film cavity 21 containing air. Because air has a lower thermal conductivity than metal, the presence of this film-film cavity 21 prevents the heat from the high-temperature exhaust gas from the APU body from being directly transferred to the APU chamber through the metal pipe wall, which has a higher thermal conductivity, thus controlling the temperature inside the APU chamber to be below the ignition point of the APU working fluid.

[0047] In some embodiments, such as Figure 3 As shown, the corrugation height of the corrugated pipe 2 is 16-19 mm. The so-called "corrugation height" refers to the distance between the crest and trough of the corrugations in the corrugated pipe 2.

[0048] In some embodiments, such as Figure 1A - Figure 2B As shown, the front support 3 of the APU exhaust pipe is made of stainless steel. Its hemispherical protrusion is used to provide an installation interface between the corrugated pipe 2, the APU exhaust pipe 6 and the firewall 5, so as to avoid direct contact between the high-temperature components and the firewall 5, and to provide a certain shielding effect on the flame; it can also avoid the concentration of thermal stress.

[0049] In some embodiments, such as Figure 1A - Figure 2B As shown, the thickness (i.e., wall thickness) and bolt hole spacing (located on the flange of the APU exhaust pipe front support 3) of the APU exhaust pipe front support 3 are designed to ensure that no gaps that could lead to the spread of flames will be created when the component warps due to thermal expansion and contraction.

[0050] In some embodiments, such as Figure 1A - Figure 2BAs shown, the auxiliary power unit exhaust pipe fireproof mounting assembly also includes a reinforcing member 4, which is sandwiched between the flange of the APU exhaust pipe front support 3 and the firewall 5. The reinforcing member 4 is preferably made of stainless steel and, during installation, is sandwiched between the flange of the APU exhaust pipe front support 3 and the firewall 5 to enhance the sealing of the installation. The reinforcing member 4 is preferably an annular plate-shaped reinforcing member.

[0051] In some embodiments, such as Figure 1A - Figure 2B As shown, the APU exhaust pipe front support 3 includes a hemispherical protrusion, and is designed to be either forward-protruding or rearward-protruding depending on the APU compartment installation layout and space allowance. "Forward-protruding" means that the hemispherical protrusion of the APU exhaust pipe front support 3 protrudes forward; "rearward-protruding" means that the hemispherical protrusion of the APU exhaust pipe front support 3 protrudes rearward.

[0052] Figure 4A This is a cross-sectional view of the installation of the front support component of the protruding APU exhaust pipe. Figure 4B This is a cross-sectional view of the installation of the forward support component for the rear-protruding APU exhaust pipe. When the rear firewall of the aircraft's APU compartment is positioned relatively aft, the APU compartment has greater space margin, while the tail cone has relatively less. In this case, the installation structure of the forward-protruding APU exhaust pipe forward support component 3 can be selected to fill the distance between the front end of the APU exhaust pipe 6 and the firewall 5. In some embodiments, such as... Figure 4A As shown, the front end of the front support 3 of the protruding APU exhaust pipe is connected to the bellows 2 by bolts, the middle interface is riveted to the front end of the APU exhaust pipe 6, and the rear end is connected to the reinforcing member 4 and the firewall 5 by bolts.

[0053] When the rear firewall of the aircraft's APU compartment is positioned relatively forward, the space margin of the APU compartment is relatively small, while the space margin of the tail cone is larger. In this case, a rear-protruding APU exhaust pipe front support structure 3 can be selected to fill the distance between the firewall 5 and the front end of the APU exhaust pipe 6. In some embodiments, such as Figure 4B As shown, the front end of the rear-protruding APU exhaust pipe front support 3 is connected to the reinforcing member 4 and the firewall 5 by bolts, the middle interface is connected to the bellows 2 by bolts, and the rear end is riveted to the front end of the APU exhaust pipe 6.

[0054] Figure 5A This is a cross-sectional view of the through-wall installation of the front support component of the protruding APU exhaust pipe. Figure 5B This is a through-wall installation cross-sectional view of the front support component of the rear-protruding APU exhaust pipe. In some embodiments, such as... Figure 5A As shown, the rear end of the front support component 3 and the reinforcing component 4 of the protruding APU exhaust pipe are connected to the firewall 5 by bolts. The components are arranged in sequence from the front to the rear of the machine: front support component 3 of the APU exhaust pipe, reinforcing component 4, and firewall 5.

[0055] In some embodiments, such as Figure 5B As shown, the front end of the rear-mounted APU exhaust pipe front support 3 and the reinforcing member 4 are connected to the firewall 5 by bolts. The APU exhaust pipe front support 3, the reinforcing member 4, and the firewall 5 are arranged in sequence from the front to the rear of the machine.

[0056] The installation method of the auxiliary power unit exhaust pipe fireproof mounting assembly of the present invention can be as follows:

[0057] For the front support component 3 of the protruding APU exhaust pipe, the front end of the corrugated pipe 2 is connected to the exhaust ejector outlet of the APU body through the connector 1;

[0058] Connect the rear end of the corrugated pipe 2 to the front end of the APU exhaust pipe front support 3 with bolts;

[0059] Rivet the rear end of the APU exhaust pipe front support 3 to the front end of the APU exhaust pipe 6.

[0060] The reinforcement component 4 is embedded into the firewall 5 interface;

[0061] Pass the rear end of the APU exhaust pipe 6 through the interface of the reinforcing member 4 and the firewall 5 along the direction from the front to the rear of the machine.

[0062] The APU exhaust pipe front support 3 middle interface, reinforcement 4, and firewall 5 interface are fixed by bolt connection.

[0063] For the rear-protruding APU exhaust pipe front support 3, the rear end of the APU exhaust pipe front support 3 is riveted to the front end of the APU exhaust pipe 6.

[0064] The reinforcement component 4 is embedded into the firewall 5 interface;

[0065] Pass the front support 3 and the rear end of the APU exhaust pipe 6 through the interface of the reinforcement 4 and the firewall 5 along the direction from the front to the rear of the machine.

[0066] The front end of the APU exhaust pipe front support 3, the reinforcing part 4, and the firewall 5 interface are fixed by bolts;

[0067] Connect the rear end of the corrugated pipe 2 to the middle interface of the front support component 3 of the APU exhaust pipe using bolts;

[0068] Connect the front end of the bellows 2 to the exhaust ejector outlet of the APU body via connector 1.

[0069] The main innovations of the auxiliary power unit exhaust pipe fireproof mounting assembly of the present invention are as follows:

[0070] (1) A fireproof mounting component for APU exhaust pipe that penetrates firewalls is provided, which has a simpler structure and lighter weight while meeting fire protection requirements;

[0071] (2) As a flexible sealing structure, the bellows can absorb the thermal expansion and contraction of the components and the installation offset; the bellows contains a layer of air film cavity, which can block the heat of the high temperature exhaust of the APU body from being transferred to the APU chamber through the pipe wall, thereby controlling the temperature inside the APU chamber to be lower than the ignition point of the APU working liquid.

[0072] (3) The front support of the APU exhaust pipe provides an installation interface between the bellows and the APU exhaust pipe and the firewall, avoiding direct contact between high-temperature components and the firewall, and has a certain shielding effect on the flame; its thickness and bolt hole spacing arrangement ensure that when the components warp due to thermal expansion and contraction, no gaps that may cause the flame to spread will be generated; the forward / rear protrusion type can be adjusted according to the installation layout and space margin in the APU compartment, making the installation layout more flexible.

[0073] According to an embodiment of the present invention, an aircraft includes an auxiliary power unit exhaust pipe fireproof mounting assembly as described in any of the above aspects. Based on the above technical solution, the aircraft of the present invention achieves the following beneficial technical effects: the auxiliary power unit exhaust pipe fireproof mounting assembly has a simple layout, is easy to install, is lightweight, and meets fireproof requirements.

[0074] The specific embodiments of the present invention have been described above. However, those skilled in the art will understand that the above specific embodiments do not constitute a limitation on the present invention. Those skilled in the art can make various modifications based on the above disclosure without exceeding the scope of the present invention.

Claims

1. A fireproof mounting assembly for an auxiliary power unit exhaust pipe, installed at the firewall behind the APU compartment, characterized in that, The auxiliary power unit exhaust pipe fireproof installation assembly includes connectors, corrugated pipes, APU exhaust pipe front support, and APU exhaust pipe; The connector is used for a sealed connection between the APU body exhaust ejector and the bellows. The bellows is connected between the outlet of the APU body exhaust ejector and the front support of the APU exhaust pipe. The front support of the APU exhaust pipe is used to connect the bellows, the APU exhaust pipe and the firewall respectively. The front end of the APU exhaust pipe is connected to the front support of the APU exhaust pipe, and the rear end is connected to the outside atmosphere to discharge the high-temperature exhaust of the APU body. The APU exhaust pipe front support includes a hemispherical protrusion.

2. The auxiliary power unit exhaust pipe fireproof installation assembly as described in claim 1, characterized in that, The auxiliary power unit exhaust pipe fireproof mounting assembly also includes a reinforcing member, which is sandwiched between the flange of the APU exhaust pipe front support and the firewall.

3. The fireproof installation assembly for the exhaust pipe of the auxiliary power unit as described in claim 1, characterized in that, When the front end of the APU exhaust pipe front support is connected to the bellows, the middle interface is connected to the front end of the APU exhaust pipe, and the rear end is connected to the firewall.

4. The fireproof installation assembly for the exhaust pipe of the auxiliary power unit as described in claim 1, characterized in that, When the front end of the APU exhaust pipe front support is connected to the firewall, the middle interface is connected to the bellows, and the rear end is connected to the front end of the APU exhaust pipe.

5. The auxiliary power unit exhaust pipe fireproof installation assembly as described in claim 1, characterized in that, The connector is a ring-shaped clamp.

6. The fireproof installation assembly for the exhaust pipe of the auxiliary power unit as described in claim 1, characterized in that, The corrugation height of the corrugated pipe is 16-19 mm.

7. The fireproof installation assembly for the exhaust pipe of the auxiliary power unit as described in claim 1, characterized in that, The thickness and bolt hole spacing of the APU exhaust pipe front support are designed to ensure that no gaps that could lead to the spread of flames will be created when the component warps due to thermal expansion and contraction.

8. The fireproof installation assembly for the exhaust pipe of the auxiliary power unit as described in claim 2, characterized in that, The reinforcing member is a ring-shaped plate.

9. An aircraft comprising an auxiliary power unit exhaust pipe fireproof mounting assembly as claimed in any one of claims 1-8.

Images