Hydrogen aircraft

Abstract

To provide a hydrogen-powered aircraft equipped with a liquid hydrogen supply system that can minimize the impact on the cabin even if a liquid hydrogen leak occurs. [Solution] The hydrogen aircraft 1 includes a fuselage 11, a hydrogen tank 2 located inside the fuselage 11 for storing liquid hydrogen, a cabin 3 located inside the fuselage 11 for accommodating passengers, and a fuel supply pipe 15 connecting the hydrogen tank 2 to an engine 14 which is the source of the liquid hydrogen. The fuel supply pipe 15 is located outside the cabin 3. Specifically, the fuel supply pipe 15 is located below the floor surface 31 of the cabin 3 in a first space R1 next to a stanchion 41.

Description

Technical Field

[0001] The present disclosure relates to a hydrogen aircraft that flies using hydrogen as an energy source.

Background Art

[0002] For example, a hydrogen aircraft that flies using hydrogen as an energy source, as shown in Patent Document 1, is known. In a hydrogen aircraft, it is necessary to mount a hydrogen fuel tank for storing liquid hydrogen on the aircraft body. In an aircraft using ordinary fuel, a fuel tank is disposed on the main wing of the aircraft body. In contrast, in a hydrogen aircraft, due to the structural requirements of the tank, the hydrogen fuel tank is often disposed inside the fuselage of the aircraft body. The hydrogen fuel tank inside the fuselage and the engine of the main wing are connected by a fuel supply pipe, and liquid hydrogen is supplied through the fuel supply pipe.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is difficult to completely protect against all events so that damage or the like does not occur in the fuel supply pipe for transferring liquid hydrogen. Therefore, it is desirable to assume leakage of liquid hydrogen from the fuel supply pipe. In the fuselage of a hydrogen aircraft on which a hydrogen fuel tank is disposed, there is a cabin that accommodates passengers on the hydrogen aircraft, such as a passenger cabin and a cockpit. Even if leakage of liquid hydrogen occurs from the fuel supply pipe, a piping arrangement that does not affect the cabin as much as possible is desirable.

[0005] An object of the present disclosure is to provide a hydrogen aircraft provided with a liquid hydrogen supply system capable of suppressing the influence on the cabin even when leakage of liquid hydrogen occurs. [[ID=四十二]] ​

[0006] A hydrogen aircraft according to one aspect of the present disclosure comprises a fuselage, a hydrogen tank located inside the fuselage for storing liquid hydrogen, a cabin located inside the fuselage for accommodating passengers, and a supply pipe connecting the hydrogen tank to a source of the liquid hydrogen, the supply pipe located outside the cabin. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide a hydrogen aircraft equipped with a liquid hydrogen supply system that can suppress the impact on the cabin even if a liquid hydrogen leak occurs. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view showing a hydrogen aircraft according to an embodiment of this disclosure. [Figure 2] Figure 2 is a cross-sectional view of the fuselage of a hydrogen aircraft according to the first embodiment, and is a cross-sectional view taken along line II-II in Figure 3. [Figure 3] Figure 3 is a schematic plan view of the hydrogen aircraft showing the piping route of the supply piping in the first embodiment. [Figure 4] Figure 4 is a schematic side cross-sectional view along the line IV-IV in Figure 3. [Figure 5] Figure 5 is a cross-sectional view of the fuselage of a hydrogen aircraft according to the second embodiment, and is a cross-sectional view taken along the VV line in Figure 6. [Figure 6] Figure 6 is a schematic plan view of the hydrogen aircraft showing the piping route of the supply piping in the second embodiment. [Figure 7] Figure 7 is a schematic side cross-sectional view along the line VII-VII in Figure 6. [Figure 8] Figure 8 is a cross-sectional view of the fuselage of a hydrogen aircraft according to the third embodiment, and is a cross-sectional view taken along line VIII-VIII in Figure 9. [Figure 9] Figure 9 is a schematic plan view of the hydrogen aircraft showing the piping route of the supply piping in the third embodiment. [Figure 10]Figure 10 is a schematic side cross-sectional view along line XX in Figure 9. [Figure 11] Figure 11 is a cross-sectional view showing various modified examples of the hydrogen aircraft according to the second embodiment. [Figure 12] Figure 12 is a perspective view showing an embodiment of a wall structure equipped with a ventilation system. [Figure 13] Figure 13 shows a modified example of the hydrogen aircraft according to the third embodiment. [Modes for carrying out the invention]

[0009] The following describes in detail various embodiments of the hydrogen aircraft relating to this disclosure. This disclosure includes an airframe comprising a fuselage and wings, and a propulsion system for flight, and is applicable to various aircraft in which the propulsion system uses liquid hydrogen as an energy source. The propulsion system is not limited insofar as it uses liquid hydrogen or vaporized hydrogen as an energy source. Examples of the propulsion system include a hydrogen combustion gas turbine engine, an electric propulsion system consisting of a combination of a fuel cell and an electric motor, or a hybrid propulsion system of the gas turbine engine and the electric propulsion system.

[0010] [Overview of Hydrogen Aircraft] Figure 1 is a perspective view showing a hydrogen aircraft 1 according to one embodiment of the present disclosure. The front, rear, left, and right direction indicators in Figure 1 are aligned with the direction when viewing the hydrogen aircraft 1 from above, with the nose side defined as "forward". The hydrogen aircraft 1 includes an airframe 10 and an engine 14, fuel supply piping 15, a hydrogen fuel tank 2 mounted at the rear of the fuselage 11 of the airframe 10, and a cabin 3 located inside the fuselage 11. Note that the mounting position of the hydrogen fuel tank 2 is not limited to the rear of the fuselage 11, and one or more may be placed at appropriate locations on the fuselage 11.

[0011] The aircraft 10 comprises a fuselage 11, a pair of left and right main wings 12, and a tail wing 13. The fuselage 11 is composed of fuselage panels 11W, as shown in Figure 2 below. The fuselage panels 11W include structural members such as circular frames and stringers, and a cylindrically assembled skin. The pair of main wings 12 include spars and flaps and extend laterally from the fuselage 11. The tail wing 13 is located at the end of the fuselage 11 and consists of a vertical stabilizer and a horizontal stabilizer. The engine 14 is, for example, a hydrogen combustion gas turbine engine that uses liquid hydrogen as fuel. The engine 14 is fixed to each of the pair of main wings 12. The engine 14 is an example of a liquid hydrogen supply destination in this disclosure. Note that an APU (Auxiliary Power Unit) may also be included as a liquid hydrogen supply destination.

[0012] The hydrogen fuel tank 2 is an example of a hydrogen tank according to this disclosure and stores liquid hydrogen LH, which is the fuel for the engine 14. The hydrogen fuel tank 2 is located inside the fuselage 11. As long as it is inside the fuselage 11, there are no restrictions on the location of the hydrogen fuel tank 2. In the example shown in Figure 1, the hydrogen fuel tank 2 is located in a storage compartment provided at the rear end of the fuselage 11. The storage area is a space outside the pressurized area, separated from the cabin 3 by a bulkhead. The hydrogen fuel tank 2 may also be located inside the pressurized area. There are no particular restrictions on the shape of the hydrogen fuel tank 2. In the example shown in Figure 1, the hydrogen fuel tank 2 has a cylindrical shape that is long in the front-rear direction of the fuselage 11. To maintain the coolness of the stored liquid hydrogen, it is desirable to use a hydrogen fuel tank 2 with a multi-shell structure. For example, as the hydrogen fuel tank 2, a tank with a double-shell structure comprising an inner tank and an outer tank, and a vacuum insulation layer between the inner tank and the outer tank can be used.

[0013] The fuel supply pipe 15 connects the hydrogen fuel tank 2 and the left and right engines 14. The fuel supply pipe 15 is an example of the supply pipe of the present disclosure. As the fuel supply pipe 15, in order to suppress the temperature rise of liquid hydrogen LH, for example, a pipe having a heat insulation structure such as a vacuum double pipe can be used. For ensuring redundancy, the fuel supply pipes 15 leading to each engine 14 may be duplicated. A booster pump 16 for sending out liquid hydrogen LH from the hydrogen fuel tank 2 is disposed in the fuel supply pipe 15. The liquid hydrogen LH stored in the hydrogen fuel tank 2 is supplied to each of the engines 14 through the fuel supply pipe 15. Note that the hydrogen tank of the present disclosure may be a tank for storing liquefied hydrogen used for purposes other than the fuel of the engine 14. The supply pipe may also be a pipe for supplying liquid hydrogen to equipment other than the engine 14.

[0014] The cabin 3 is disposed within the fuselage 11. The cabin 3 is a pressurized space for accommodating passengers boarding the hydrogen aircraft 1. The passengers include crew members and passengers. That is, the cabin 3 referred to in this specification is a space within the fuselage 11 where people are assumed to enter and exit during the operation of the hydrogen aircraft 1, such as a passenger cabin, a cockpit, and a crew-only space.

[0015] The hydrogen fuel tank 2 is disposed within the fuselage 11 that encloses the cabin 3. On the other hand, the engine 14 is disposed on the main wing 12. That is, at least a part of the fuel supply pipe 15 needs to be arranged within the fuselage 11. Therefore, when designing the hydrogen aircraft 1, there is a high possibility that the area defined as the route for arranging the fuel supply pipe 15 within the fuselage 11 and the area of the cabin 3 that is originally arranged within the fuselage 11 overlap. The strength and structure of the pipe body and joint parts of the fuel supply pipe 15 are designed to have resistance to assumed impacts and fluctuations in temperature and pressure. However, leakage of liquid hydrogen LH from the fuel supply pipe 15 must also be assumed. If the liquid hydrogen LH leaks, problems such as the liquid hydrogen having extremely low temperature cold heat scattering, the air being cooled by the scattered liquid hydrogen to generate liquefied air, the scattered liquid hydrogen embrittling surrounding members, and the scattered liquid hydrogen vaporizing to generate an environment where ignition can occur will occur. Therefore, in the hydrogen aircraft 1, in the unlikely event that leakage of liquid hydrogen LH occurs from the fuel supply pipe 15, a piping mode that can suppress entry into the cabin 3, that is, a piping mode that does not affect the passengers in the cabin 3, is desirable. Specific examples of such a piping mode are listed below.

[0016] [First Embodiment] FIG. 2 is a cross-sectional view of the fuselage 11 of the hydrogen aircraft 1A according to the first embodiment in the left-right direction. FIG. 3 is a schematic plan view of the hydrogen aircraft 1A showing the piping route of the fuel supply pipe 15 in the first embodiment. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 3. FIG. 4 is a schematic side cross-sectional view taken along line IV-IV of FIG. 3. The left-right direction indications in FIGS. 2 to 4 and the figures described later are in accordance with the direction indications in FIG. 1. The up-down direction indications are based on the direction when the hydrogen aircraft 1A is on the ground. In the first embodiment and the second embodiment described below, an example where the fuel supply pipe 15 is arranged inside the fuselage 11 is shown.

[0017] The upper part of the fuselage 11 is the cabin 3, and the lower part is the cargo compartment 4. The cargo compartment 4 is a space located within the fuselage 11 for storing passenger luggage and cargo. The cabin 3 is partitioned by a floor 31, sides 32, and ceiling 33. The floor 31 is a plane that extends horizontally, located slightly below the vertical center of the fuselage 11. When the hydrogen aircraft 1A is on the ground, the floor 31 is roughly horizontal. Multiple seats 34 for passengers are mounted on the floor 31. Figure 2 shows an example in which three sets of three-seat rows 34 are arranged on either side of an aisle.

[0018] The sides 32 are walls located to the left and right of the floor 31. The ceiling 33 is a wall located above the floor 31. A central luggage compartment 35 is located in the central area of ​​the ceiling 33 in the left-right direction. Side luggage compartments 36 are located to the left and right of the area where the central luggage compartment 35 is located on the ceiling 33. The central luggage compartment 35 and the side luggage compartments 36 include a space for storing passengers' luggage. The central luggage compartment 35 is opened and closed by operating the central hatch 351. The left and right side luggage compartments 36 are opened and closed by operating their respective side hatches 361. There is a back wall 352 at the rear of the central luggage compartment 35. The back wall 352 separates the luggage storage space of the central luggage compartment 35 from the space above it. There is also a back wall 362 at the rear of each side luggage compartment 36. The rear wall 362 separates the luggage storage space of the side luggage box 36 from the space above that space. Because the rear walls 352 and 362 separate the respective spaces, the cabin 3 can maintain a closed space even when the central hatch 351 or the side hatch 361 is opened.

[0019] The cargo compartment 4 is installed using the space within the fuselage 11 located below the floor surface 31. The cargo compartment 4 is equipped with stanchions 41 that extend vertically and a cargo compartment floor 42 that extends horizontally. The stanchions 41 are columnar support members that support the floor surface 31 from below. Luggage and cargo brought into the cargo compartment 4 are placed on the cargo compartment floor 42.

[0020] The fuel supply pipe 15 is located inside the fuselage 11 and outside the cabin 3. In the first embodiment, the fuel supply pipe 15 is located below the floor 31. More specifically, the fuel supply pipe 15 is located below the floor 31 near the right or left side 32, inward in the lateral direction from the fuselage panel 11W, and outward in the lateral direction from the stanchion 41. In other words, the fuel supply pipe 15 passes through a first space R1 partitioned by the floor 31, the stanchion 41, and the fuselage panel 11W of the side 32. Figure 2 shows an example in which the fuel supply pipe 15 is located in the first space R1 set outside the left stanchion 41. The fuel supply pipe 15 may also be located in the space outside the right stanchion 41, or in the space outside both the left and right stanchions 41.

[0021] Referring to Figures 3 and 4, the hydrogen aircraft 1A of the first embodiment includes a first hydrogen fuel tank 2A ​​and a second hydrogen fuel tank 2B as tanks corresponding to the hydrogen fuel tank 2 in Figure 1. The hydrogen aircraft 1A also includes a first supply pipe 15A and a second supply pipe 15B as piping corresponding to the fuel supply pipe 15 in Figure 1. The first hydrogen fuel tank 2A ​​is located in the rear region of the fuselage 11. The second hydrogen fuel tank 2B is located in the front region of the fuselage 11. Liquid hydrogen is supplied as fuel from the first hydrogen fuel tank 2A ​​and the second hydrogen fuel tank 2B to a pair of left and right engines 14 through the first supply pipe 15A and the second supply pipe 15B.

[0022] The first supply pipe 15A connects the first hydrogen fuel tank 2A ​​to the pair of left and right engines 14. The first supply pipe 15A includes a front and rear piping section 151 that runs along the front and rear of the fuselage 11. The front and rear piping section 151 extends linearly in the front-rear direction on the left side of the fuselage 11. Figure 2 shows a cross-section of the front and rear piping section 151 of the first supply pipe 15A. The second supply pipe 15B connects the second hydrogen fuel tank 2B to the pair of left and right engines 14. The second supply pipe 15B also includes a front and rear piping section 152 that runs along the front and rear of the fuselage 11. The front and rear piping section 152 extends linearly in the front-rear direction on the right side of the fuselage 11. The front and rear piping section 152 of the second supply pipe 15B passes through the space partitioned by the right-side stanchion 41, the floor 31, and the fuselage panel 11W.

[0023] In the hydrogen aircraft 1A of the first embodiment, the fuel supply piping 15, including the first supply pipe 15A and the second supply pipe 15B, is located inside the fuselage 11. Therefore, it is not necessary to provide radial protrusions on the outer circumference of the fuselage 11 to accommodate the fuel supply piping 15. In other words, it is unnecessary to provide protrusions on the surface of the fuselage 11 that would worsen the aerodynamic performance of the hydrogen aircraft 1A for the purpose of fuel supply.

[0024] Furthermore, according to the hydrogen aircraft 1A of the first embodiment, the fuel supply piping 15 can be installed by effectively utilizing the dead space within the fuselage 11. Normally, the cross-section of the fuselage 11 is circular due to structural strength and aerodynamic requirements. In contrast, the floor surface 31 of the cabin 3 is generally a substantially horizontal plane. In other words, a floor material that extends horizontally and has a substantially horizontal surface on its upper surface that becomes the floor surface 31 is placed inside the fuselage 11, which is a structure with a circular cross-section. For this reason, dead space tends to occur below the floor surface 31. In the first embodiment, the fuel supply piping 15 is installed by utilizing the first space R1 to the side of the stanchion 41. The first space R1 is a narrow space near the corner below the floor surface 31 and is particularly prone to becoming dead space. In the first embodiment, by installing the fuel supply piping 15 in the first space R1, the dead space can be effectively utilized. The lower surface of the floor material is the surface that partitions the cargo compartment 4 and is a flat surface or an uneven surface to which equipment is attached.

[0025] Furthermore, since the fuel supply piping 15 is located below the floor 31, even if liquid hydrogen leaks from the fuel supply piping 15, the impact on the cabin 3, especially on the passengers, can be minimized. If the fuel supply piping 15 is damaged, the liquid hydrogen inside the fuel supply piping 15 may leak to the outside, and as a byproduct, gaseous hydrogen or liquefied air may be generated. Even in this case, since the fuel supply piping 15 is located below the cabin 3, the possibility of the leaked liquid hydrogen or liquefied air entering the cabin 3 due to gravity is low. In addition, by not only enclosing the cabin 3 with the floor 31, sides 32 and ceiling 33, but also by strengthening the airtightness of the cabin 3, it is possible to suppress the entry of gaseous hydrogen into the cabin 3.

[0026] [Second Embodiment] Figure 5 is a cross-sectional view of the fuselage 11 of the hydrogen aircraft 1B according to the second embodiment, in the left-right direction. Figure 6 is a schematic plan view of the hydrogen aircraft 1B showing the piping route of the fuel supply piping 15 in the second embodiment. Figure 5 is a cross-sectional view taken along line VV in Figure 6. Figure 7 is a schematic side cross-sectional view taken along line VII-VII in Figure 6.

[0027] The cabin 3 and cargo compartment 4 are located inside the fuselage 11. The cross-sectional structure of the fuselage 11 is the same as that of the first embodiment shown in Figure 2, so a detailed explanation is omitted here. In the second embodiment as well, the fuel supply piping 15 is located inside the fuselage 11, outside the cabin 3. In the second embodiment, the fuel supply piping 15 is located above the ceiling surface 33. More specifically, the fuel supply piping 15 is located approximately in the left-right center of the fuselage 11, between the rear wall 352 of the central cargo box 35 and the vertically inward side of the fuselage panel 11W. In other words, the fuel supply piping 15 passes through the second space R2 partitioned by the ceiling surface 33, the rear walls 352 and 362, and the upper shell of the fuselage panel 11W.

[0028] Figure 5 shows an example in which the fuel supply piping 15 is positioned directly above the central luggage box 35 in the second space R2. Alternatively, the fuel supply piping 15 may be positioned above the left side luggage box 36, above the ceiling surface 33 between the left or right rear wall 362 and the central rear wall 352, or above the right side luggage box 36.

[0029] Referring to Figures 6 and 7, the hydrogen aircraft 1B, similar to the first embodiment, includes a first hydrogen fuel tank 2A ​​and a second hydrogen fuel tank 2B, and a first supply pipe 15A and a second supply pipe 15B as fuel supply piping 15. Liquid hydrogen is supplied as fuel from the first hydrogen fuel tank 2A ​​and the second hydrogen fuel tank 2B to a pair of left and right engines 14 through the first supply pipe 15A and the second supply pipe 15B.

[0030] The first supply pipe 15A connects the first hydrogen fuel tank 2A ​​to the pair of left and right engines 14. The first supply pipe 15A includes a front and rear piping section 151 that is routed along the front and rear of the fuselage 11. The front and rear piping section 151 extends linearly in the front-rear direction near the upper end of the left-right center of the fuselage 11. Figure 5 shows a cross-section of the front and rear piping section 151 of the first supply pipe 15A. The second supply pipe 15B connects the second hydrogen fuel tank 2B to the pair of left and right engines 14. The second supply pipe 15B also includes a front and rear piping section 152 that is routed along the front and rear near the upper end of the left-right center of the fuselage 11.

[0031] According to the hydrogen aircraft 1B of the second embodiment, the fuel supply piping 15 can be installed by effectively utilizing the dead space above the ceiling surface 33 of the cabin 3. The space below the floor surface 31 of the cabin 3 is often used as a cargo compartment. The space next to the stanchion 41, which was utilized in the first embodiment, may also be used as part of the cargo compartment or as a place to install equipment. According to the second embodiment, for example, if space for piping cannot be secured below the floor surface 31, the fuel supply piping 15 can be installed by utilizing the space above the ceiling surface 33.

[0032] [Third Embodiment] Figure 8 is a cross-sectional view of the fuselage 11 of the hydrogen aircraft 1C according to the third embodiment, in the left-right direction. Figure 9 is a schematic plan view of the hydrogen aircraft 1C showing the piping route of the fuel supply piping 15 in the third embodiment. Figure 8 is a cross-sectional view taken along line VIII-VIII in Figure 9. Figure 9 is a schematic side cross-sectional view taken along line XX in Figure 8. In the third embodiment, an example is shown in which the fuel supply piping 15 is located outside the fuselage 11.

[0033] The cross-sectional structure of the fuselage 11 is the same as that of the first embodiment shown in Figure 2, so a detailed explanation is omitted here. In the third embodiment, unlike the first and second embodiments, the fuel supply pipe 15 is located outside the cabin 3 and outside the fuselage 11. More specifically, the fuel supply pipe 15 is located outside the side surface 32 of the fuselage 11 and below the floor surface 31 of the cabin 3. The area around the fuel supply pipe 15 is covered by a fairing 37. By locating the fuel supply pipe 15 outside the fuselage 11, a protrusion is formed on the surface of the fuselage 11, but the aerodynamic shape can be maintained by attaching the fairing 37.

[0034] Figure 8 shows an example where the fuel supply pipe 15 is located on the outside of the left side surface 32 of the fuselage 11. There are no particular restrictions on the location of the fuel supply pipe 15 on the outer circumferential surface of the fuselage 11. The fuel supply pipe 15 may be located on the outside of the top surface 33 of the fuselage 11, the outside of the right side surface 32, or the outside of the bottom surface, etc. Furthermore, there may be multiple fuel supply pipes 15 located on the outer circumferential surface of the fuselage 11, as long as the degree of aerodynamic influence due to the shape of the fuselage 11 is not excessive.

[0035] Referring to Figures 9 and 10, the hydrogen aircraft 1C, similar to the first embodiment, includes a first hydrogen fuel tank 2A ​​and a second hydrogen fuel tank 2B, and a first supply pipe 15A and a second supply pipe 15B as fuel supply piping 15. Liquid hydrogen is supplied as fuel from the first hydrogen fuel tank 2A ​​and the second hydrogen fuel tank 2B to a pair of left and right engines 14 through the first supply pipe 15A and the second supply pipe 15B.

[0036] The first supply pipe 15A connects the first hydrogen fuel tank 2A ​​to the pair of left and right engines 14. The first supply pipe 15A includes a front and rear piping section 151 that runs along the front and rear of the fuselage 11. The front and rear piping section 151 extends linearly in the front-rear direction on the outside of the left side of the fuselage 11. Figure 8 shows a cross-section of the front and rear piping section 151 of the first supply pipe 15A. The second supply pipe 15B connects the second hydrogen fuel tank 2B to the pair of left and right engines 14. The second supply pipe 15B includes a front and rear piping section 152 that runs along the front and rear on the outside of the right side of the fuselage 11.

[0037] According to the third embodiment of the hydrogen aircraft 1C, the fuel supply piping 15 is located outside the fuselage 11. Therefore, even if liquid hydrogen leaks from the fuel supply piping 15, at least the fuselage panel 11W of the fuselage 11 is present between the fuel supply piping 15 and the cabin 3. Thus, the entry of liquid or gaseous hydrogen into the cabin 3 can be suppressed.

[0038] [Example 1] Figure 11 is a cross-sectional view showing various modifications of the hydrogen aircraft 1B of the second embodiment. In the hydrogen aircraft 1B, the fuel supply pipe 15 is located in a predetermined piping area PA in the second space R2 located above the ceiling surface 33 of the cabin 3. In the event that liquefied hydrogen leaks from the fuel supply pipe 15, it is assumed that liquid hydrogen will enter the cabin 3 through gaps in the ceiling surface 33, etc. In view of this, it is desirable to place a liquid receiver 51 between the fuel supply pipe 15 and the ceiling surface 33 to receive the liquid leaking from the fuel supply pipe 15.

[0039] The liquid receiver 51 has a trough-shaped cross-section with an open top. The liquid receiver 51 extends below the fuel supply pipe 15, along the direction in which the fuel supply pipe 15 extends. Even if liquid hydrogen leaks from the fuel supply pipe 15, the liquid receiver 51 will receive the leaked liquid hydrogen. Therefore, the scattering of liquid hydrogen and its entry into the cabin 3 can be suppressed. Furthermore, even if the heat insulation structure of the fuel supply pipe 15 is damaged and liquefied air is generated around the fuel supply pipe 15, the liquid receiver 51 will also receive this liquefied air. Therefore, the scattering of liquefied air and its entry into the cabin 3 can also be suppressed. There are no restrictions on the shape of the liquid receiver 51 as long as it can receive and store the liquid hydrogen falling from the fuel supply pipe 15. However, it is desirable that the liquid receiver 51 be made of a material that does not become brittle upon contact with liquid hydrogen.

[0040] Figure 11 shows four specific configuration examples of a piping area PA equipped with a liquid hydrogen receiving function, namely the first configuration example PA1 to the fourth configuration example PA4. In the first configuration example PA1, a flat tray 51A, which serves as a liquid receiver, is positioned below the fuel supply piping 15. The flat tray 51A includes a bottom piece 511 and side pieces 512. The bottom piece 511 is a flat plate located directly below the fuel supply piping 15. The side pieces 512 rise diagonally upward from both sides of the bottom piece 511.

[0041] The height of the upper end of the side piece 512 is set such that the liquid hydrogen stored in the flat tray 51A does not leak out even when the hydrogen aircraft 1B is tilted within the allowable tilt range. Let L1 be a horizontal line passing through the axis of the fuel supply pipe 15, L2 be a line connecting the upper end of the side piece 512 and the circumferential surface of the fuel supply pipe 15, and L3 be a line perpendicular to line L2 and passing through the axis. The angle between lines L1 and L3 is set to the tilt range angle AN, for example 60 degrees, which is defined for the bank attitude of the hydrogen aircraft 1B.

[0042] The second configuration example PA2 is an example in which a U-shaped tray 52, which serves as a liquid receiver, is positioned below the fuel supply pipe 15. The bottom surface of the U-shaped tray 52 facing the fuel supply pipe 15 is a curved surface that is convex downwards. A pair of side pieces 521 of the U-shaped tray 52 sandwich the fuel supply pipe 15. The height of the upper end of the side pieces 521 is higher than the upper end of the fuel supply pipe 15.

[0043] The third configuration example PA3 is an example of a wall structure 6 that covers at least a portion of the outer circumference in the longitudinal direction of the fuel supply pipe 15. The wall structure 6 has a duct-like structure with a rectangular cross-section and forms a substantially sealed internal space R3. The fuel supply pipe 15 is housed in the internal space R3. Even if liquid hydrogen leaks from the fuel supply pipe 15, the leaked liquid hydrogen can be received at the bottom of the wall structure 6. Furthermore, even if the leaked liquid hydrogen vaporizes and gaseous hydrogen is generated, the diffusion of the gaseous hydrogen can be suppressed because the area around the fuel supply pipe 15 is surrounded by the wall structure 6.

[0044] The fourth configuration example PA4 is an example in which the area around the fuel supply piping 15 is filled with an inert gas. In the fourth configuration example PA4, the hydrogen aircraft 1B is equipped with an inert gas supply source 63. The area around the fuel supply piping 15 is covered by a wall structure 6A. The wall structure 6A is equipped with an air inlet 61 and an exhaust port 62. An inert gas, such as nitrogen gas or helium gas, is supplied from the inert gas supply source 63 to the inside of the wall structure 6A through the air inlet 61. This supply fills the internal space R4, which is the space between the inner surface of the wall structure 6A and the outer surface of the fuel supply piping 15, with the inert gas. A portion of the filled inert gas is discharged from the internal space R4 through the exhaust port 62. If the wall structure 6A has high airtightness, the air inlet 61 and exhaust port 62 may be closed after the internal space R4 has been filled with the inert gas. In this case, it is not necessary to permanently install the inert gas supply source 63 on the hydrogen aircraft 1B.

[0045] According to the fourth configuration example PA4, even if liquid hydrogen leaks from the fuel supply pipe 15, the leaked liquid hydrogen can be received at the bottom of the wall structure 6A. Furthermore, since the destination of the liquid hydrogen leak is the internal space R4 where oxygen is absent or scarce, ignition can be suppressed even if gaseous hydrogen is generated. Note that any of the first to fourth configuration examples PA1 to PA4 described above may be applied to the location of the fuel supply pipe 15 in the first embodiment. In this case, instead of the stanchion 41, a wall member that makes the first space R1 a substantially sealed space may be attached to form the wall structure.

[0046] [Differentiation 2] Figure 12 is a perspective view showing a modified example in which a ventilation device is attached to a wall structure covering the fuel supply piping 15. The fuel supply piping 15 includes a portion housed in the internal space R5 of a cylindrical wall structure 6B. An intake duct 64 is located at one end of the wall structure 6B, and an exhaust duct 65 is located at the other end. The intake duct 64 and the exhaust duct 65 are openings that connect the internal space R5 of the wall structure 6B to the outside.

[0047] As a ventilation system, an intake fan 71 is installed in the intake duct 64, and an exhaust fan 72 is installed in the exhaust duct 65. When the intake fan 71 is driven, outside air is drawn into the internal space R5 of the wall structure 6B. When the exhaust fan 72 is driven, the exhaust of gas from the internal space R5 is promoted. In other words, the operation of the intake fan 71 and the exhaust fan 72 ventilates the space between the inner surface of the wall structure 6B and the outer surface of the fuel supply piping 15.

[0048] By performing the ventilation described above, air can be continuously supplied to the internal space R5, either under normal circumstances or in emergencies. Therefore, even if liquid hydrogen leaks from the fuel supply pipe 15, it is possible to prevent the occurrence of a condition where hydrogen and oxygen reach a specific ratio that would cause ignition. The intake fan 71 and exhaust fan 72 may also be applied to the supply and exhaust of inert gas in the fourth configuration example PA4 shown in Figure 11.

[0049] [Difference 3] Figure 13 shows a modified example of the hydrogen aircraft 1C of the third embodiment. In the hydrogen aircraft 1C, the fuel supply piping 15 includes a portion that is routed outside the fuselage 11. For example, the front and rear piping portions 151 of the first supply piping 15A are arranged on the outer circumferential surface of the fuselage 11. Modification 3 shows an example in which an air intake opening 371 and an air outlet opening 372 are provided in the fairing 37A that covers the front and rear piping portions 151. The air intake opening 371 is an opening for taking in air. The air outlet opening 372 is an opening for expelling air. The longitudinal direction of the fairing 37A is along the longitudinal direction of the fuselage 11. The air intake opening 371 is provided on one side of the longitudinal direction of the fairing 37A, and the air outlet opening 372 is provided on the other side.

[0050] The intake opening 371 is an opening at the front end of the fairing 37A. The exhaust opening 372 is an opening at the rear end of the fairing 37A. By having an opening in the fairing 37A, the internal space R6 of the fairing 37A can be ventilated automatically during the flight of the hydrogen aircraft 1C. That is, as indicated by arrow Ar1, air enters the internal space R6 from the intake opening 371. As indicated by arrow Ar2, air is discharged from the internal space R6 from the exhaust opening 372. Therefore, air is constantly supplied to the internal space R6 during flight, and the internal space R6 is ventilated. For this reason, even if liquid hydrogen leaks from the fuel supply pipe 15, ignition can be suppressed.

[0051] [Summary of this disclosure] The specific embodiments described above include disclosures having the following configurations.

[0052] A hydrogen aircraft according to one aspect of the present disclosure comprises a fuselage, a hydrogen tank located inside the fuselage for storing liquid hydrogen, a cabin located inside the fuselage for accommodating passengers, and a supply pipe connecting the hydrogen tank to a source of the liquid hydrogen, the supply pipe located outside the cabin.

[0053] According to the first embodiment, even if liquid hydrogen leaks from the supply pipe, since the supply pipe is located outside the cabin, it is possible to prevent liquid hydrogen or vaporized hydrogen from entering the cabin where the passengers are located. Therefore, it is possible to prevent damage to the cabin from the cryogenic coldness of the leaked liquid hydrogen and the liquefied air generated by that coldness, thereby protecting the passengers.

[0054] In the hydrogen aircraft according to the second embodiment, the supply piping is located inside the fuselage, in the hydrogen aircraft according to the first embodiment.

[0055] According to the second embodiment, it is not necessary to provide radial protrusions on the outer circumference of the fuselage to accommodate the supply piping. In other words, it is not necessary to provide protrusions on the fuselage surface that would worsen the aerodynamic performance of the hydrogen aircraft.

[0056] A hydrogen aircraft according to a third embodiment is a hydrogen aircraft according to the first or second embodiment, wherein the cabin is partitioned by a floor, sides and ceiling, and the supply piping is located below the floor.

[0057] Typically, the fuselage cross-section of an aircraft is circular due to structural strength and aerodynamic requirements. In contrast, the cabin floor is horizontal. Because a planar member extending horizontally is placed inside a circular cross-section structure, dead space tends to be created below the floor. According to the third embodiment, the dead space below the cabin can be utilized to install supply piping. Furthermore, the possibility of leaked liquid hydrogen entering the cabin through the supply piping can be eliminated.

[0058] A hydrogen aircraft according to the fourth embodiment further comprises a cargo compartment located within the fuselage, wherein the hydrogen aircraft according to any of the first to third embodiments is further comprising a cargo compartment located within the fuselage, the cabin being partitioned by a floor, sides, and ceiling, the cargo compartment being located below the floor, and the supply piping being located above the ceiling.

[0059] According to the fourth embodiment, even when the dead space below the cabin floor is used as a cargo area, the dead space above the ceiling can be effectively utilized to install the supply piping.

[0060] A hydrogen aircraft according to the fifth embodiment further comprises a liquid receiver located between the supply piping and the ceiling surface, which is provided for receiving liquid leaking from the supply piping, in addition to the hydrogen aircraft according to any of the first to fourth embodiments.

[0061] According to the fifth embodiment, even if liquid hydrogen leaks from the supply pipe, the leaked liquid hydrogen can be received by the liquid receiver. Therefore, the scattering of liquid hydrogen can be suppressed. Furthermore, even if the insulation structure of the supply pipe is damaged and liquefied air is generated around the supply pipe, this liquefied air can also be received by the liquid receiver, thus suppressing its scattering as well.

[0062] A hydrogen aircraft according to the sixth embodiment further comprises a wall structure covering at least a portion of the outer circumference in the longitudinal direction of the supply piping, in addition to the hydrogen aircraft according to any of the first to fifth embodiments.

[0063] According to the sixth embodiment, even if liquid hydrogen leaks from the supply pipe, at least in the portion of the supply pipe enclosed by the wall structure in the longitudinal direction, the leaked liquid hydrogen can be received at the bottom of the wall structure. Furthermore, even if the leaked liquid hydrogen vaporizes and gaseous hydrogen is generated, the diffusion of the gaseous hydrogen can be suppressed because it is enclosed by the wall structure.

[0064] A hydrogen aircraft according to the seventh embodiment further comprises an inert gas that fills the space between the inner surface of the wall structure and the outer surface of the supply piping, in addition to the hydrogen aircraft according to any of the first to sixth embodiments.

[0065] According to the seventh embodiment, even if liquid hydrogen leaks from the supply piping, the leak destination is an oxygen-free space. Therefore, the risk of ignition can be suppressed.

[0066] The hydrogen aircraft according to the eighth embodiment further comprises a ventilation device for ventilating the space between the inner surface of the wall structure and the outer surface of the supply piping, in addition to the hydrogen aircraft according to any of the first to seventh embodiments.

[0067] According to the eighth aspect, even if liquid hydrogen leaks from the supply piping, the ventilation operation of the ventilation device makes it possible to avoid the hydrogen and oxygen reaching a specific ratio that would cause ignition.

[0068] In the ninth embodiment, the hydrogen aircraft is a hydrogen aircraft of any of the first to eighth embodiments, wherein the supply piping is located outside the fuselage.

[0069] According to the ninth embodiment, even if liquid hydrogen leaks from the supply piping, the fuselage is present between it and the cabin. Therefore, the entry of liquid hydrogen into the cabin can be suppressed.

[0070] A hydrogen aircraft according to the tenth embodiment further comprises a fairing covering the area around the supply piping, wherein the hydrogen aircraft according to any of the first to ninth embodiments further comprises a fairing, the fairing having openings on one longitudinal side and the other side of the fuselage.

[0071] According to the tenth embodiment, by covering the supply piping with a fairing, the aerodynamic shape can be maintained even if the supply piping is located outside the fuselage. In addition, by providing openings, ventilation inside the fairing can be performed naturally during the flight of the hydrogen aircraft. [Explanation of Symbols]

[0072] 1. Hydrogen aircraft 10 aircraft 11 Torso 14. Engine (source of liquid hydrogen supply) 15 Fuel supply piping (supply piping) 15A First supply piping (supply piping) 15B 2nd supply piping (supply piping) 2. Hydrogen fuel tank (hydrogen tank) 2A, 2B: First hydrogen fuel tank, second hydrogen fuel tank (hydrogen tank) 3 Cabins 31 Floor surface 32 Side view 33 Ceiling surface 37, 37A Fairing 371, 372 Inlet opening, outlet opening (opening) 4. Luggage compartment 51. Dish tray (liquid tray) 52 U-shaped tray (liquid tray) 6, 6A, 6B wall structure 71. Intake fan (ventilation device) 72 Exhaust fan (ventilation device) LH Liquid Hydrogen

Claims

1. Torso and, A hydrogen tank for storing liquid hydrogen is located inside the fuselage, A cabin, which is located inside the fuselage and accommodates the passengers, A supply pipe connecting the hydrogen tank and the liquid hydrogen supply destination, the supply pipe being located outside the cabin, A hydrogen-powered aircraft.

2. In the hydrogen aircraft according to claim 1, The aforementioned supply piping is located inside the fuselage of the hydrogen aircraft.

3. In the hydrogen aircraft according to claim 2, The cabin is partitioned by the floor, sides and ceiling, The aforementioned supply piping is located below the floor surface, in a hydrogen aircraft.

4. In the hydrogen aircraft according to claim 2, The fuselage further comprises a cargo compartment located within the aforementioned body, The cabin is partitioned by the floor, sides and ceiling, A hydrogen aircraft in which the cargo compartment is located below the floor and the supply piping is located above the ceiling.

5. In the hydrogen aircraft according to claim 4, A hydrogen aircraft further comprising a liquid receptacle positioned between the supply piping and the ceiling surface to receive liquid leaking from the supply piping.

6. In the hydrogen aircraft according to any one of claims 1 to 4, A hydrogen aircraft further comprising a wall structure covering the outer periphery of at least a portion of the longitudinal direction of the supply piping.

7. In the hydrogen aircraft described in claim 6, A hydrogen aircraft further comprising an inert gas that fills the space between the inner surface of the wall structure and the outer surface of the supply piping.

8. In the hydrogen aircraft described in claim 6, A hydrogen aircraft further comprising a ventilation device for ventilating the space between the inner surface of the wall structure and the outer surface of the supply piping.

9. In the hydrogen aircraft according to claim 1, The aforementioned supply piping is located outside the fuselage of the hydrogen aircraft.

10. In the hydrogen aircraft according to claim 9, The supply piping is further provided with a fairing that covers the surrounding area. The fairing has openings on one and the other sides in the longitudinal direction of the fuselage, in a hydrogen aircraft.

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