Aircraft fuel tank inlet device and aircraft

Abstract

The present invention relates to an aircraft fuel tank inlet arrangement for communicating an aircraft fuel tank to an external environment, and comprising: an inlet located at a lower surface of a wing of the aircraft; an outlet located at an interior of the aircraft fuel tank; an inlet passage communicating between the inlet and the outlet; and a flow regulating section provided in the inlet passage and comprising a portion having a cross-section that varies along a direction of travel of the airflow to regulate airflow fluctuations through the flow regulating section. In this way, the flow rate or velocity of ram air flowing through the inlet passage is regulated by the cross-sectional variation of the flow regulating section, thereby attenuating airflow fluctuations and in turn reducing the impact of the airflow on downstream components. Additionally, the present invention also relates to an aircraft comprising such an aircraft fuel tank inlet arrangement.

Description

Technical Field

[0001] This invention belongs to the field of aircraft aerodynamic design, and relates to the design of an air inlet for an aircraft's fuel tank, and more specifically to an aircraft fuel tank air inlet device. Furthermore, this invention also relates to an aircraft including such an aircraft fuel tank air inlet device. Background Technology

[0002] The venting system of the fuel tank of aircraft such as airplanes is connected to the external environment through the NACA air intake (hereinafter referred to as the air intake or air intake device), thereby allowing outside air to be introduced to pressurize the fuel tank.

[0003] Because the air inlet of an aircraft's ventilator fuel tank forms a nearly enclosed space downstream, it can cause significant pressure fluctuations under certain flight conditions. This can lead to structural vibrations, increased drag, and other problems, and may also adversely affect the operation of downstream components. For example, in a flame suppressor with an integrated pressure relief valve, this can result in unintended and frequent opening and closing of the valve, thus reducing its lifespan.

[0004] To avoid the effects of pressure fluctuations, existing aircraft generally avoid integrating pressure relief valves into the flame suppressors downstream of the air intake in their ventilated fuel tanks. However, this requires adding extra openings / holes to the fuel tank and wings, or using a more complex pressure relief valve design, which may increase the aircraft's weight or make its structure more complex.

[0005] Therefore, there is an urgent need to optimize the structure of the aircraft fuel tank air intake device / inlet in order to provide an improved aircraft fuel tank air intake device that can overcome one or more of the disadvantages of the prior art. Summary of the Invention

[0006] The purpose of this invention is to provide an air intake device for an aircraft fuel tank. This structure can significantly reduce the pressure fluctuation at the air intake, while also having a pressure-boosting and drag-reducing effect, and is low in cost and effort.

[0007] According to one aspect of the present invention, an aircraft fuel tank air intake device is provided, which can be used to connect the aircraft fuel tank to the external environment, and may include: Imports can be located on the lower surface of the aircraft's wings; The exit can be located inside the aircraft's fuel tank. The intake passage, which is fluidly connected between the inlet and outlet; and An airflow regulating section is provided in the air intake channel and includes a portion whose cross-section varies along the direction of airflow to regulate airflow fluctuations passing through the airflow regulating section.

[0008] In this way, by changing the cross-section of the airflow regulating section, the flow rate or velocity of the ram air flowing through the intake channel is adjusted, thereby reducing airflow fluctuations and thus reducing the airflow impact on downstream components.

[0009] According to the above aspects of the present invention, preferably, the airflow regulating section may include a first cross-section reduction section, a first tapering section and a second tapering section. The first tapering section may be disposed between the inlet and the first cross-section reduction section, and the cross-section decreases toward the cross-section reduction section. The second tapering section may be disposed between the outlet and the first cross-section reduction section, and the cross-section decreases toward the first cross-section reduction section.

[0010] By using the first section reduction section, in the event of a sudden increase in ram air pressure at the inlet, the flow rate or velocity of air passing through the first section reduction section can be limited. This prevents the downstream duct section from being impacted by such air pressure, or minimizes such impact. This structure allows for the integration of a pressure relief valve into the flame suppressor downstream of the air inlet without unnecessarily complicating the valve's structure, thereby reducing aircraft weight and the complexity of corresponding structural components.

[0011] According to the above aspects of the present invention, in order to further obtain a better pressure boosting and drag reduction effect, preferably, the airflow regulating section may further include a second section decreasing in cross-section, a third section decreasing in cross-section, and a fourth section decreasing in cross-section, which are disposed downstream of the first section decreasing in cross-section. The third section decreasing in cross-section may be disposed between the second section decreasing in cross-section and the second section decreasing in cross-section, and the cross-section decreasing in cross-section is directed toward the second section decreasing in cross-section. The fourth section decreasing in cross-section may be disposed between the outlet and the second section decreasing in cross-section, and the cross-section decreasing in cross-section is directed toward the second section decreasing in cross-section.

[0012] According to the above aspects of the present invention, preferably, the airflow regulating section can be a detachable, independent module that can fit snugly into the inner surface of the intake passage. This allows for direct modification of existing intake passages without replacing the entire intake passage, thereby reducing modification or upgrade costs and installation complexity.

[0013] According to the above aspects of the present invention, preferably, the airflow regulating section can be fixed to the inner surface of the air intake channel by fasteners or welding.

[0014] According to the above aspects of the present invention, preferably, the intake passage may include a first pipe section and a second pipe section arranged at an angle to each other, the first pipe section being disposed upstream of the second pipe section, and the airflow regulating section being disposed on the second pipe section near the first pipe section, thereby obtaining a better pressure boosting and drag reduction effect.

[0015] According to the above aspects of the present invention, preferably, the airflow regulating section is located upstream of the flame suppressor. This arrangement avoids large fluctuations in the airflow pressure through the pressure relief valve of the flame suppressor, thereby preventing frequent opening and closing of the pressure relief valve and extending its service life.

[0016] According to the above aspects of the present invention, in order to obtain a better pressure boosting and drag reduction effect, preferably, the inner surface of the airflow regulating section may be provided with a recess and / or a protrusion.

[0017] According to another aspect of the invention, an aircraft is proposed that may include an aircraft fuel tank air intake device according to the above aspects.

[0018] The aircraft fuel tank air intake device according to the present invention can significantly reduce the pressure fluctuation of the air intake, while also having the effect of increasing pressure and reducing drag, and is low in cost and inexpensive.

[0019] Therefore, the aircraft fuel tank air intake device of the present invention can meet the usage requirements, overcome the shortcomings of the prior art, and achieve the intended purpose. Attached Figure Description

[0020] To further describe the aircraft fuel tank air intake device according to the present invention clearly, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, in which: Figure 1 This is a schematic perspective view of an aircraft fuel tank air intake device according to a first non-limiting embodiment of the present invention; Figure 2 yes Figure 1 A schematic cross-sectional view of the aircraft's fuel tank air intake device; Figure 3 This is a schematic perspective view of an aircraft fuel tank air intake device according to a second non-limiting embodiment of the present invention; Figure 4 This is a schematic cross-sectional view of an aircraft fuel tank air intake device according to a third non-limiting embodiment of the present invention; and Figure 5 This is a schematic diagram comparing the pressure fluctuation of an existing aircraft fuel tank air intake device with that of the aircraft fuel tank air intake device according to the present invention.

[0021] The above figures are for illustrative purposes only and are not drawn to scale.

[0022] The reference numerals in the figures are listed in the figures and embodiments: 100 - Aircraft fuel tank air intake device, including: 10 - Imports; 11 – First end; 12 – Second end; 20 - Exports; 30 - Intake passage, including: 31 – First pipe section; 32 – Second pipe section; 40 – Airflow regulation section, including: 41 – The first section with reduced cross-section; 42 – First tapering section; 43 – Second tapering section; 44 – The section with reduced cross-section; 45 – Third tapering section; 46 – Fourth tapering segment; 47 - Protrusion. Detailed Implementation

[0023] It should be understood that, unless explicitly stated otherwise, the invention may employ various alternative orientations and sequences of steps. It should also be understood that the specific apparatus shown in the drawings and described in the specification are merely exemplary embodiments of the inventive concept disclosed and defined herein. Therefore, unless expressly stated otherwise, the specific orientations, directions, or other physical features involved in the various disclosed embodiments should not be considered limiting.

[0024] The venting system of fuel tanks in aircraft, such as airplanes, connects to the external environment through air inlets or intake devices, allowing outside air to be introduced and pressurized into the fuel tank. For example, the venting system connects the aircraft's fuel tank to the external environment through an air intake channel.

[0025] This allows outside air to be introduced to pressurize the fuel tank. Normally, during flight, as fuel in the aircraft's fuel tank is consumed, outside air enters the vent tank along the path of the air intake, thus maintaining the pressure inside the fuel tank within a certain range.

[0026] Figure 1 This is a schematic perspective view of an aircraft fuel tank air intake device 100 according to a first non-limiting embodiment of the present invention; and Figure 2 yes Figure 1 A schematic cross-sectional view of the aircraft fuel tank air intake device 100 shown.

[0027] As shown in the figure and as a non-limiting embodiment, the aircraft fuel tank air intake device 100 may include an inlet 10, an outlet 20, and an air intake passage 30 with fluid communication (e.g., airflow communication) between the inlet 10 and the outlet 20.

[0028] The inlet 10 may be located on the wing of the aircraft, for example, positioned on the lower surface of the wing. The inlet 10 may be an opening with a generally triangular shape, tapering at a first end 11 and widening at the opposite second end 12 and connecting to the air intake passage 30.

[0029] The outlet 20 can be located inside the aircraft fuel tank, that is, open to the inside of the aircraft fuel tank, so that the aircraft fuel tank is connected to the external environment through the air intake channel 30 and the airflow of the inlet 10 and outlet 20, thereby introducing outside air to pressurize the fuel tank.

[0030] The intake passage 30 may extend between the inlet 10 and the outlet 20, and may include a first pipe section 31 and a second pipe section 32 arranged at an angle to each other, wherein the first pipe section 31 is located upstream of the second pipe section 32. Figure 1 As shown, the first pipe section 31 is generally conical and its sidewall forms an inlet 10, while the second pipe section 32 is generally square and has an opening at its upper end, namely an outlet 20.

[0031] In the embodiment shown in the accompanying drawings, the first pipe segment 31 and the second pipe segment 32 are substantially perpendicular, i.e., arranged at right angles to each other, and are connected together at the joint by means of a bend. However, in an alternative embodiment, the first pipe segment 31 and the second pipe segment 32 may form an acute angle of 45-90 degrees or an obtuse angle of 90-135 degrees. Furthermore, those skilled in the art can design the shape of the first pipe segment 31 and the second pipe segment 32 and the included angle between them according to specific structural requirements.

[0032] According to the present invention, an airflow regulating section 40 may be provided in the air intake passage 30. The airflow regulating section 40 may include a portion whose cross-section varies along the direction of airflow, that is, a portion of the air intake passage 30 whose diameter varies along its extension direction, in order to regulate airflow fluctuations passing through the airflow regulating section 40. Typically, the flame suppressor is arranged near the outlet 20; therefore, the airflow regulating section 40 according to the present invention is typically located upstream of the flame suppressor.

[0033] As shown in the figure, the airflow regulating section 40 is located in the second pipe section 32 near the first pipe section 31, and may include a first cross-section reduction section 41, a first tapering section 42, and a second tapering section 43.

[0034] As an example, the first tapering section 42 can be disposed between the inlet 10 and the first section reducing section 41, and the cross-section decreases toward the section reducing section 41, while the second tapering section 43 is disposed between the outlet 20 and the first section reducing section 41, and the cross-section decreases toward the first section reducing section 41.

[0035] like Figure 1 and 2As shown in the figure, the cross-sectional area of ​​the first section reduction segment 41 first smoothly decreases from the upstream end (i.e., the inlet end) to the downstream end (i.e., the outlet end), thus reaching the first section reduction segment 41. Then, it smoothly increases from the upstream end (i.e., the inlet end) to the downstream end (i.e., the outlet end), thereby gradually restoring the normal cross-sectional shape of the intake passage 30. According to an embodiment of the invention, this smooth reduction or increase can be along a predetermined curve or a straight line. In the embodiment shown in the figure, it is a smooth reduction or increase along a predetermined curve to minimize airflow fluctuations.

[0036] Figure 3 This is a schematic perspective view of an aircraft fuel tank air intake device 100 according to a second non-limiting embodiment of the present invention.

[0037] Figure 3 The embodiments shown are similar to Figure 1 and Figure 2 The embodiments in the example are similar, however, Figure 3 In some embodiments, the airflow regulating section 40 further includes a second section decreasing section 44, a third tapering section 45, and a fourth tapering section 46 disposed downstream of the first section decreasing section 41.

[0038] As shown in the figure, the third tapering section 45 can be set between the second tapering section 43 and the second section reducing section 44, and the cross-section decreases towards the second section reducing section 44, while the fourth tapering section 46 is set between the outlet 20 and the second section reducing section 44, and the cross-section decreases towards the second section reducing section 44.

[0039] Although in the embodiment shown in the figures, the third tapering section 45 is arranged immediately downstream of the second tapering section 43, in alternative embodiments, the third tapering section 45 may be spaced apart from the second tapering section 43, for example, there may be a non-tapering section between the third tapering section 45 and the second tapering section 43.

[0040] In addition, although Figure 3 In the illustrated embodiment, the two cross-section reduction segments have similar structures and are shown as having approximately the same reduction in cross-sectional area. However, those skilled in the art can arrange them with different structures or with different degrees of cross-section reduction, and can arrange a greater number of cross-section reduction segments.

[0041] According to a non-limiting embodiment of the present invention, the airflow regulating section 40 may be integrally formed with the air intake channel 30, or it may be a detachable independent module that can be tightly fitted to the inner surface of the air intake channel 30. For example, the airflow regulating section 40 may be fixed to the inner surface of the air intake channel 30 by means of fasteners, adhesive bonding, or welding.

[0042] Figure 4This is a schematic perspective view of an aircraft fuel tank air intake device 100 according to a third non-limiting embodiment of the present invention.

[0043] As shown in the figure and according to another preferred embodiment of the present invention, the inner surface of the airflow regulating section 40 may be provided with a recess and / or a protrusion 47, thereby further reducing the degree of pressure fluctuation at the air inlet.

[0044] Figure 5 This is a schematic diagram comparing the pressure fluctuation of a conventional aircraft fuel tank air intake device with that of the aircraft fuel tank air intake device 100 according to the present invention.

[0045] like Figure 5 As shown in the figure, the vertical axis represents the pressure difference between the inside and outside of the intake passage 30 wall, in units of... PSI The horizontal axis represents time, and the unit is... ms The dashed line shows the pressure fluctuation in the air intake passage of the prior art without an airflow regulation section, while the solid line shows the pressure fluctuation in the aircraft fuel tank air intake device 100 according to the present invention. The aircraft fuel tank air intake device 100 used in this comparative test is... Figure 1 and 2 The aircraft fuel tank air intake device 100 according to a first non-limiting embodiment of the present invention is shown in the figure, wherein the minimum area of ​​the first cross-sectional reduction section 41 is approximately 50% of the cross-sectional area of ​​the original air intake passage.

[0046] Calculations and analyses show that, compared with the prior art, the pressure fluctuation of the aircraft fuel tank air intake device 100 according to the present invention is significantly reduced.

[0047] The terms “upstream” and “downstream” used herein to indicate orientation or direction, and the terms “first” and “second” used to indicate sequence, are merely to enable those skilled in the art to better understand the concept of the invention as illustrated in preferred embodiments, and are not intended to limit the invention. Unless otherwise stated, all sequences, orientations, or directions are used only to distinguish one element / component / structure from another, and do not indicate any particular order, sequence of operations, direction, or orientation unless otherwise stated. For example, in an alternative embodiment, a “first section reduction segment” may be a “second section reduction segment,” and a “first pipe segment” may alternatively refer to a “second pipe segment.”

[0048] In summary, the aircraft fuel tank air intake device 100 according to the embodiments of the present invention overcomes the shortcomings of the prior art and achieves the intended purpose of the invention.

[0049] While the aircraft fuel tank air intake device of the present invention has been described above with reference to preferred embodiments, those skilled in the art should recognize that the above examples are merely illustrative and should not be construed as limiting the invention. Therefore, various modifications and variations can be made to the invention within the spirit and scope of the claims, and all such modifications and variations will fall within the scope claimed by the claims.

Claims

1. An aircraft fuel tank air intake device (100), the aircraft fuel tank air intake device being used to connect the aircraft fuel tank to the external environment, and comprising: Import (10), the import is located on the lower surface of the wing of the aircraft; The outlet (20) is located inside the aircraft's fuel tank; Air intake passage (30), the air intake passage being in fluid communication between the inlet (10) and the outlet (20); and An airflow regulating section (40) is disposed in the air intake channel (30) and includes a portion whose cross-section changes along the direction of airflow to regulate airflow fluctuations passing through the airflow regulating section (40). The airflow regulating section (40) includes a first cross-section reducing section (41), a first tapering section (42), and a second tapering section (43). The first tapering section (42) is disposed between the inlet (10) and the first cross-section reducing section (41), and its cross-section decreases toward the cross-section reducing section (41). The second tapering section (43) is disposed between the outlet (20) and the first cross-section reducing section (41), and its cross-section decreases toward the first cross-section reducing section (41).

2. The aircraft fuel tank air intake device (100) according to claim 1, characterized in that, The airflow regulating section (40) further includes a second section decreasing section (44), a third tapering section (45), and a fourth tapering section (46) disposed downstream of the first section decreasing section (41). The third tapering section (45) is disposed between the second tapering section (43) and the second section decreasing section (44), and its cross-section decreases toward the second section decreasing section (44). The fourth tapering section (46) is disposed between the outlet (20) and the second section decreasing section (44), and its cross-section decreases toward the second section decreasing section (44).

3. The aircraft fuel tank air intake device (100) according to any one of claims 1-2, characterized in that, The airflow regulating section (40) is a detachable independent module and can be tightly fitted to the inner surface of the air intake channel (30).

4. The aircraft fuel tank air intake device (100) according to claim 3, characterized in that, The airflow regulating section (40) is fixed to the inner surface of the air intake channel (30) by fasteners or welding.

5. The aircraft fuel tank air intake device (100) according to any one of claims 1-2, characterized in that, The air intake channel (30) includes a first pipe section (31) and a second pipe section (32) arranged at an angle to each other. The first pipe section (31) is located upstream of the second pipe section (32), and the airflow regulating section (40) is located on the second pipe section (32) near the first pipe section (31).

6. The aircraft fuel tank air intake device (100) according to claim 5, characterized in that, The airflow regulating section (40) is located upstream of the flame suppressor.

7. The aircraft fuel tank air intake device (100) according to any one of claims 1-2, characterized in that, The internal surface of the airflow regulating section (40) is provided with a recess and / or a protrusion (47).

8. An aircraft comprising an aircraft fuel tank air intake device (100) according to any one of claims 1-7.

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