Water removal system and water removal method for aircraft fuel tank

Abstract

An aircraft fuel tank water removal system and method, the water removal system comprising: a fuel tank body (100), the tank wall of the fuel tank body defining an inner cavity (140) for accommodating fuel (400), the tank wall comprising a tank body top wall (110) located at the top when an aircraft is parked on the ground, a tank body bottom wall (120) located at the bottom, and a tank body side wall (130) connected between the tank body top wall and the tank body bottom wall; an inerting gas inlet (200) provided on the fuel tank body (100), the inerting gas inlet being in fluid communication with an inerting system of the aircraft for supplying an inerting gas into the inner cavity, where at least a portion of the inerting gas inlet is arranged on the tank wall of the fuel tank body other than the tank body top wall. By adjusting the position of the inerting gas inlet, the dry inerting gas is in direct contact with free water deposited at the bottom of the fuel tank and suspended water suspended in fuel oil, and the water evaporation efficiency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of aircraft design, specifically to the design of aircraft fuel tanks, and more specifically to an aircraft fuel tank water removal system and a method for removing water from the fuel in an aircraft fuel tank using the water removal system. Background Art

[0002] Aircraft fuel will inevitably dissolve water during the production, transportation, and storage processes. In particular, when the aircraft is parked, water vapor in the atmosphere will continuously enter the fuel tank through the ventilation system. As the aircraft climbs, the temperature gradually decreases, and the solubility of water in the fuel gradually decreases, causing water molecules to continuously precipitate from the fuel to form suspended water and free water.

[0003] This water dissolved in the fuel is often undesirable and needs to be removed.

[0004] Specifically, at extremely low temperatures, suspended water and free water will form ice crystals. In severe cases, such as when the volume is particularly large or the quantity is particularly large, these ice crystals will block the aircraft fuel pipeline, causing the engine to stop and triggering a flight accident. For example, this was the main reason for the crash of British Airways Flight 38 in 2008.

[0005] At the same time, the water in the fuel tank is also prone to breeding undesirable microorganisms, which will corrode the aircraft structure, wiring, and related on-board systems, posing a threat to the safe operation of the aircraft.

[0006] Generally, aircraft operating units will regularly drain the accumulated water in the fuel tank, such as the water that has settled to the bottom of the fuel due to different densities, through the sediment drain valve of the fuel tank.

[0007] Alternatively, the breeding microbial impurities can also be removed from the fuel tank by regularly cleaning the fuel filters on the fuel tank and fuel pump.

[0008] However, the above water removal methods and cleaning methods all involve additional human resource costs.

[0009] Airworthiness regulations also impose restrictions on the upper limit of the water content in the fuel. However, the reality is that it is impossible to completely prevent the accumulation of free water in the fuel tank, and it is also difficult to completely prevent the dissolved water dissolved in the fuel from precipitating from the fuel in extremely cold weather, posing a risk of blocking pipelines and pump valves.

[0010] Since the explosion of the fuel tank of TWA Flight 800 caused the plane to break up, airworthiness regulations have gradually required newly developed aircraft models to be equipped with an on-board inerting system to prevent similar accidents from occurring in high-temperature weather. Currently, mainstream large aircraft such as the Airbus A320, Boeing B737, and Comac C919 have all been equipped with an on-board inerting system. By installing this inerting system, nitrogen can be separated from the engine bleed air and used to fill the expansion space of the aircraft fuel tank, reducing the oxygen concentration to less than 11%. According to the parameters published on the Honeywell website, the relative humidity of the nitrogen at the outlet of the inerting system is less than 10%. The dry inerting gas provides an idea for solving the problem of removing water from the fuel tank.

[0011] However, the current inerting system is still not satisfactory in removing water from the fuel tank, and it is necessary to explore a fuel tank water removal system that makes more full use of the inerting gas to remove water. Summary of the Invention

[0012] Based on the above-mentioned defects of the prior art, the present invention therefore provides an aircraft fuel tank water removal system and a water removal method, and proposes a means for removing suspended water, free water existing in the aircraft fuel tank that may cause damage to the aircraft system or freeze and block the aircraft fuel pipeline at low temperature, resulting in flight accidents and / or breeding microorganisms.

[0013] Specifically, the present invention provides an aircraft fuel tank water removal system, including:

[0014] A fuel tank body, the tank wall of the fuel tank body defines an inner cavity for accommodating fuel, and the tank wall includes a tank top wall at the top when the aircraft is parked on the ground, a tank bottom wall at the bottom, and a tank side wall connecting between the tank top wall and the tank bottom wall;

[0015] An inerting gas inlet, the inerting gas inlet is provided on the fuel tank body, and the inerting gas inlet is in fluid communication with the inerting system of the aircraft for supplying inerting gas into the inner cavity,

[0016] Wherein, at least a part of the inerting gas inlet is arranged on the tank wall of the fuel tank body other than the tank top wall.

[0017] According to a preferred but non-limiting embodiment of the aircraft fuel tank water removal system of the present invention, at least a part of the inerting gas inlet is provided at the tank bottom wall.

[0018] According to a preferred but non-limiting embodiment of the aircraft fuel tank water removal system of the present invention, at least a part of the inerting gas inlet is arranged at the sediment drain valve at the lowest point of the fuel tank body at the tank bottom wall.

[0019] Injecting dry inerting air into the sediment drain valve area at the bottom of the fuel tank can make more full use of the inerting gas to absorb the water mixed in the fuel into water vapor and discharge it into the atmosphere through the ventilation pipeline. More specifically, after the inerting gas is injected into the fuel tank, it directly contacts the free water at the lowest part of the fuel tank and takes the water to the expansion space in the form of water vapor. At the same time, when the inerting gas bubbles float through the fuel, they can also absorb the suspended water and the dissolved water dissolved in the fuel and form water vapor.

[0020] According to a preferred but non-limiting embodiment of the aircraft fuel tank water removal system of the present invention, at least a part of the inerting gas inlet is arranged at the top wall of the box body.

[0021] According to a preferred but non-limiting embodiment of the aircraft fuel tank water removal system of the present invention, a ventilation hole is opened on the top wall of the fuel tank body to communicate the top space of the inner cavity with the external space of the fuel tank body.

[0022] According to a preferred but non-limiting embodiment of the aircraft fuel tank water removal system of the present invention, a one-way valve is arranged at the inerting gas inlet.

[0023] Arranging a one-way valve in the inerting gas pipeline can effectively prevent the fuel from entering the inerting system through the inerting air pipeline due to the siphon phenomenon.

[0024] According to a preferred but non-limiting embodiment of the aircraft fuel tank water removal system of the present invention, the inerting system is connected to the inerting gas inlet through an inerting gas pipeline, and a heat preservation sleeve is wrapped around the outer periphery of the inerting gas pipeline.

[0025] The evaporation of water in a gas environment depends on the saturated vapor pressure of the environment where it is located. The saturated vapor pressure satisfies relevant physical laws. According to the product parameters published by Honeywell, the outlet temperature of the inerting system is about 50 degrees Celsius. At this temperature, the saturated pressure of water vapor is relatively high, that is, the inerting gas has a strong absorption capacity for various forms of water in the fuel. Therefore, as long as it is ensured that the inerting gas has sufficient temperature to ensure its water absorption capacity and an environment for the inerting gas to fully contact is created, a large amount of water in the fuel can be absorbed.

[0026] To ensure the temperature of the inerting gas inlet, a heat preservation sleeve needs to be installed on the inerting gas pipeline. At the same time, the inerting gas pipeline needs to avoid passing directly through the fuel.

[0027] In addition, the present invention also provides a water removal method using the aforementioned aircraft fuel tank water removal system, including the following steps:

[0028] Fill fuel in the inner cavity of the fuel tank body;

[0029] Inerting gas is introduced into the inner cavity at least through at least one inerting gas inlet disposed on the tank wall of the fuel tank other than the top wall of the tank body.

[0030] In a preferred but non-limiting embodiment of the water removal method according to the present invention, inerting gas is introduced into the inner cavity through at least one inerting gas inlet at the water layer under the fuel.

[0031] In a preferred but non-limiting embodiment of the water removal method according to the present invention, inerting gas is introduced into the inner cavity at least through one inerting gas inlet disposed at the bottommost part of the fuel tank body.

[0032] In summary, based on the characteristics of the inerting gas from the inerting system and the three forms of water in the fuel tank, the present invention proposes a method of adjusting the position of the inerting gas inlet so that the dry inerting gas directly contacts the free water precipitated at the bottom of the fuel tank and the suspended water suspended in the fuel, greatly improving the efficiency of water evaporation.

[0033] Compared with the prior art practice of generally disposing the inerting gas inlet at the top of the fuel tank body, the water removal system and method of the present invention can effectively reduce the humidity of the expansion space, and will not, as in the prior art, only absorb a small part of the dissolved water dissolved in the fuel because the dry air in the expansion space only contacts the upper surface of the fuel. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] This document includes drawings to provide further understanding of various embodiments. The drawings are incorporated into and constitute a part of this specification.

[0035] The drawings illustrate various embodiments described herein and, together with the written description, are used to explain the principles and operations of the claimed subject matter.

[0036] For the above purposes, the technical features of the present invention are clearly described hereinafter, and its advantages are obvious from the following detailed description with reference to the drawings, which illustrate the preferred embodiments of the present invention by way of example and do not limit the scope of the present invention.

[0037] In the drawings:

[0038] Figure 1 A schematic cross-sectional view of the aircraft fuel tank water removal system according to the present invention is shown in principle along a cross-sectional plane parallel to the longitudinal symmetry plane of the aircraft.

[0039] LIST OF REFERENCE NUMERALS

[0040] 100 Fuel tank body

[0041] 110 Tank top wall

[0042] 120 Bottom wall of the box

[0043] 130 Side wall of the box

[0044] 140 Inner cavity

[0045] 150 Vent hole

[0046] 200 Inerting gas inlet

[0047] 210 Inerting gas inlet on the bottom wall of the box

[0048] 220 Inerting gas inlet on the top wall of the box

[0049] 300 Precipitation discharge valve

[0050] 400 Fuel oil

[0051] 500 Inerting gas pipeline Detailed implementation manners

[0052] Now, the implementation manners of the present invention will be described in detail. Examples of these implementation manners are shown in the drawings and will be described hereinafter.

[0053] Although the present invention will be described in combination with exemplary embodiments, it should be realized that this specification is not intended to limit the present invention to those exemplified embodiments. On the contrary, the present invention is intended to cover not only these exemplary embodiments, but also various alternative forms, modified forms, equivalent forms and other embodiments that may be included within the spirit and scope of the present invention.

[0054] For the convenience of explanation and precise definition of the technical solution of the present invention, the terms "upper", "lower", "inner" and "outer" are used to describe the features with reference to the positions of the features of the exemplary embodiments shown in the drawings.

[0055] The water removal system of the present invention will be specifically described below with reference to the drawings.

[0056] As Figure 1 shown, a preferred but non-limiting embodiment of the aircraft fuel tank water removal system according to the present invention includes: a fuel tank body 100 and an inerting gas inlet 200.

[0057] The wall of the fuel tank body 100 defines an inner cavity 140 for accommodating the fuel oil 400. The wall includes a top wall 110 of the box ( Figure 1 the uppermost one when the aircraft is parked on the ground), a bottom wall 120 of the box ( Figure 1 the lowermost one), and a connection between the top wall 110 and the bottom wall 120 of the box ( Figure 1The side wall 130 of the fuel tank body on the left, middle, and right sides. It should be noted here that those skilled in the art can understand that the specific shape of the aircraft fuel tank can be mainly determined by the airfoil of the aircraft wing. Therefore, Figure 1 Only a possible cross-sectional form of the fuel tank is schematically shown in the figure. Those skilled in the art can select other forms of cross-sections according to the actual situation. For example, the top wall 110 and the bottom wall 120 of the fuel tank body can have different profile curves, and the cross-sectional shapes at different cross-sections of the fuel tank body 100 in the transverse direction can also be different. Figure 1 Only a possible form of the fuel tank body is schematically shown in the figure for better reflecting the principle of the present invention, and the shape of the tank wall therein does not constitute any limitation to the present invention.

[0058] The inert gas inlet 200 is provided on the fuel tank body 100. For example, Figure 1 Two inert gas inlets 200 are schematically shown in the figure, labeled as 210 and 220 respectively. These inert gas inlets 200 are in fluid communication with the inerting system of the aircraft ( Figure 1 not shown in the figure) and are used to supply the inert gas from the inerting system to the inner cavity 140.

[0059] It should be noted here that Figure 1 The positions and quantities of the above-mentioned inert gas inlets 200 shown in the figure are only schematic. As long as it conforms to the inventive concept of the present invention with the following specific limitations, those skilled in the art can also set more similar inert gas inlets 200 on the fuel tank body 100 based on the idea of the present invention.

[0060] According to the concept of the present invention, at least a part of the above-mentioned inert gas inlets 200 is arranged on the tank wall of the fuel tank body 100 other than the top wall 110 of the tank body. In other words, at least one inert gas inlet 200 is arranged on the bottom wall 120 or the side wall 130 of the tank body.

[0061] For example, as Figure 1 shown in the figure, at least a part of the inert gas inlets 200 is arranged at the bottom wall 120 of the tank body. The inert gas inlet 210 arranged at the bottom wall 120 of the tank body can supply the inert gas upward from the bottom wall 120 of the tank body so that the supplied inert gas passes through the fuel 400 in the fuel tank to form bubbles passing through the free water and the fuel.

[0062] Based on the above basic inventive concept, more preferably, at least a part of the inert gas inlets 200 can be arranged at the sediment drain valve 300 located at the lowest point of the fuel tank body 100 at the bottom wall 120 of the tank body. It should be noted here that Figure 1The specific position of the sediment drain valve 300 shown in [the figure] is only illustrative. The lowest point of the bottom wall 120 of the fuel tank 100 can also be located at other positions, and there can also be more than one lowest point. In this case, corresponding sediment drain valves 300 can be provided at the corresponding lowest points or at each lowest point. At this time, one or more inert gas inlets 200 can be arranged around each sediment drain valve 300.

[0063] And, although Figure 1 not shown in [the figure], those skilled in the art can also consider setting at least one of the inert gas inlets 200 on the side wall 130 of the fuel tank.

[0064] It should be noted here that the basic concept of the present invention is to provide the inert gas inlet 200 on the tank wall outside the top wall 110 of the fuel tank, without excluding the setting of the inert gas inlet 200 on the top wall 110 of the fuel tank. For example, as Figure 1 shown in [the figure], preferably, those skilled in the art of the present invention can also additionally set at least a part of the inert gas inlets 200 at the top wall 110 of the fuel tank. Figure 1 The inert gas inlet provided at the top wall 110 of the fuel tank is identified by the reference numeral 220 in [the figure]. It is easy to understand that, under the working conditions shown in Figure 1 [the figure], the inert gas inlet 220 provided at the top wall 110 of the fuel tank introduces the inert gas from the inerting system into the top space of the inner cavity of the fuel tank 100. However, in different flight stages of the aircraft (such as different pitch angles of the aircraft), the inert gas inlet 220 provided at the top wall 110 of the fuel tank can also directly introduce the inert gas from the inerting system into the fuel in the fuel tank 100.

[0065] In addition, a ventilation hole 150 is provided on the top wall 110 of the fuel tank 100 for communicating the top space of the inner cavity 140 with the external space of the fuel tank 100. In this way, the inert gas introduced into the inner cavity 140 of the fuel tank 100 can leave the inner cavity 140 of the fuel tank 100 through this ventilation hole 150.

[0066] Although Figure 1 not shown in detail in [the figure], preferably, a check valve can be provided at the inert gas inlet 200. The setting of the check valve can prevent the fuel 140 from flowing back towards the inerting system through the inert gas inlet 200, causing unnecessary trouble and danger.

[0067] Continuing to refer to Figure 1 [the figure], preferably, the inerting system is connected to the inert gas inlet 200 through an inert gas pipeline 500, and more preferably, a heat-insulating sleeve can be provided around the outer periphery of the inert gas pipeline 500. It should be noted that Figure 1The specific arrangement and size of the inert gas pipeline 500 are for illustration only, and those skilled in the art can select a suitable inert gas pipeline 500 according to actual needs to pass the inert gas from the inertization system into the inert gas inlet 200 .

[0068] The following briefly describes a method of using the aforementioned system. According to the concept of the present invention, a method of removing water from an aircraft fuel tank using the aircraft fuel tank dewatering system of the present invention comprises the following steps:

[0069] 1) Fill the inner cavity 140 of the fuel tank 100 with fuel 400. Those skilled in the art will appreciate that the filled fuel 400 itself may contain moisture that needs to be removed, and as analyzed in the background technology section of this specification, during the operation of the aircraft, moisture may be further introduced into the filled fuel 400.

[0070] 2) Inerting the inner cavity 140 with inert gas through at least one inert gas inlet 200 arranged on the tank wall of the fuel tank 100 except the tank top wall 110. Those skilled in the art can select a suitable inert gas source on an aircraft equipped with an inerting system to meet the above requirements.

[0071] More preferably, the inert gas can be inlet 200 (i.e. Figure 1 An inertizing gas is injected into the inner cavity 140 through an inertizing inlet 210 .

[0072] Further preferably, at least one inert gas inlet (i.e. Figure 1 An inertizing inlet 210) is used to inject inert gas into the inner cavity.

[0073] Preferred embodiments of the present invention have been described above in detail, but it should be understood that aspects of the embodiments can be modified, if necessary, to employ aspects, features and concepts of the various patents, applications and publications to provide further embodiments.

[0074] Various changes can be readily appreciated in light of the above detailed description, and can be made to the embodiments described herein.

[0075] In general, in the claims, the terms used should not be considered limited to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which the claims are entitled.

Claims

1. An aircraft fuel tank water removal system, It is characterized in that include: A fuel tank (100), wherein the tank wall of the fuel tank (100) defines an inner cavity (140) for accommodating fuel (400), and the tank wall comprises a tank top wall (110) located at the top when the aircraft is parked on the ground, a tank bottom wall (120) located at the bottom, and a tank side wall (130) connected between the tank top wall (110) and the tank bottom wall (120); an inert gas inlet (200), the inert gas inlet (200) being arranged on the fuel tank (100), the inert gas inlet (200) being in fluid communication with an inerting system of the aircraft and being used for supplying inert gas into the inner cavity (140), Wherein, at least a portion of the inert gas inlet (200) is arranged on a box wall of the fuel box (100) except the box top wall (110).

2. The aircraft fuel tank water removal system according to claim 1, It is characterized in that At least a portion of the inert gas inlet (200) is disposed on the bottom wall (120) of the box.

3. The aircraft fuel tank water removal system according to claim 2, It is characterized in that At least a portion of the inert gas inlet (200) is arranged at the bottom wall (120) of the tank body at a settling valve (300) located at the lowest point of the fuel tank body (100).

4. The aircraft fuel tank water removal system according to claim 1, It is characterized in that At least a portion of the inert gas inlet (200) is disposed on the top wall (110) of the box body.

5. The aircraft fuel tank water removal system according to claim 1, It is characterized in that A vent hole (150) is provided on the top wall (110) of the fuel tank (100) for connecting the top space of the inner cavity (140) with the external space of the fuel tank (100).

6. The aircraft fuel tank water removal system according to claim 1, It is characterized in that A one-way valve is provided at the inert gas inlet (200).

7. The aircraft fuel tank water removal system according to claim 1, It is characterized in that The inerting system is connected to the inerting gas inlet (200) via an inerting gas pipeline (500), and the outer periphery of the inerting gas pipeline (500) is provided with a thermal insulation jacket.

8. A method for removing water from an aircraft fuel tank using the aircraft fuel tank water removal system according to any one of claims 1 to 7, It is characterized in that The following steps are involved: Filling the inner cavity (140) of the fuel tank (100) with fuel (400); Inert gas is injected into the inner cavity (140) through at least one inert gas inlet (200) arranged on the tank wall of the fuel tank (100) except the tank top wall (110).

9. The water removal method according to claim 8, It is characterized in that Inerting gas is injected into the inner cavity (140) through at least one inerting gas inlet (200) at the water layer below the fuel (400).

10. The water removal method according to claim 8, It is characterized in that Inert gas is poured into the inner cavity through at least one inert gas inlet arranged at the bottom of the fuel tank body (100).

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