CROSS-REFERENCE TO PRIORITY APPLICATION

This application claims the benefit of, and priority to, German patent application number 102018129898.6, filed Nov. 27, 2018. The content of the referenced application is incorporated by reference herein.

TECHNICAL FIELD

Embodiments of the subject matter described herein relate generally to a device for carrying fuel in an aircraft and spacecraft, and also relate to aircraft and spacecraft.

BACKGROUND

To provide energy for aircraft and spacecraft, fuel cells may be used which however require fuel. Normally, fuel cells require hydrogen and oxygen in order to be able to provide electrical energy. Hydrogen and oxygen are stored in pressurized tanks, i.e. the containers for hydrogen and oxygen in an aircraft and spacecraft must withstand corresponding pressure forces. Furthermore, the water produced by the fuel cell may be captured in a water tank. The aircraft and spacecraft may comprise an electrolyser which, using a further energy source, splits the water into the constituent elements of hydrogen and oxygen and conducts these into the containers provided for them.

Patent document DE 10 2011 116 841 A1 discloses an aircraft which has a fuel cell and a water electrolysis device. Furthermore, it has a tubular gas-tight wing spar in which an oxygen tank or hydrogen tank is arranged and which when filled forms an additional stiffening of the carrier wing in the span width direction. The wing spar may have an inner tube which receives the internal pressure of the hydrogen or oxygen, the tension and compression forces from the wing bending moment, and the wing pressure forces acting on the surface part of the spar. A longitudinally corrugated outer tube is laid around this inner tube and bonded continuously over the full surface along the contact faces. In another variant, the wing spar may be made of a high-strength fiber composite material.

BRIEF SUMMARY

The object of the disclosure is to provide an improved device for carrying fuel in an aircraft and spacecraft.

This object is achieved by the features of the independent claims. Advantageous refinements are the subject of the dependent claims and the description which follows.

According to the disclosure, a device is provided for carrying fuel in an aircraft and spacecraft, wherein the device comprises: a carrier element for the aircraft and spacecraft, wherein the carrier element has a longitudinal axis, at least one tank with a side wall and a chamber, which is at least partially delimited by the side wall, for receiving the fuel; wherein the at least one tank is arranged in the carrier element and wherein the chamber and the side wall extend in a direction along the longitudinal axis; wherein the side wall has a pressure-receiving component, wherein the pressure-receiving component converts a pressure from the chamber on the side wall into a contraction force acting on the side wall along the longitudinal axis, wherein the contraction force compensates for an expansion force resulting from the pressure from the chamber and acting on the side wall along the longitudinal axis.

According to the disclosure therefore, a carrier element for the aircraft and spacecraft is provided, in which at least one tank with the fuel is arranged. The carrier element may in one example be a spar of the aircraft and spacecraft. If hydrogen and oxygen are provided as fuel, the fuel in the respective tank is under pressure. Pressure forces which undergo a change due to the change in fuel quantity in the tank, for example on fuel consumption or leakage, generate a pressure on the walls of the tank. Due to the pressure in the tank, the walls are exposed to forces which pull the walls apart. Therefore expansion forces act on the wall which result from the pressure in the tank. If the tank is formed so as to be cylindrical, the side wall forms the casing of the cylinder. Each of the expansion forces generates transverse contraction forces. In other words, the expansion forces in the circular direction or in the tangential direction of the cylinder casing, resulting from the internal pressure, generate transverse contraction forces in the axial direction, and the expansion forces along the longitudinal axis, resulting from the internal pressure, generate transverse contraction forces in the tangential direction. The transverse contraction forces counter the expansion forces. In the net balance, expansion forces remain in the tangential and axial direction.

The side walls here have a pressure-receiving component. By means of the pressure-receiving component in the side wall of the chamber of the tank, the expansion forces acting in the circular direction are converted into contraction forces of the side wall which constitute an increase in the transverse contraction force of the tangential expansion force. This contraction force is oriented along the longitudinal axis and compensates for the expansion force along the longitudinal axis. In other words, the side wall undergoes no length change along the longitudinal axis from the pressure acting on the side wall, because of the pressure-receiving component.

The orientation along the longitudinal axis here does not necessarily mean that the contraction force is arranged on the longitudinal axis, but also means that the contraction force may be shifted substantially parallel to the longitudinal axis. The same applies to the side wall, which need not extend on the longitudinal axis but also may extend in the same direction next to the longitudinal axis.

The contraction force provided by the pressure-receiving component in the side wall therefore provides a counter-force to the expansion force pulling the side wall apart in the direction of the longitudinal axis. The side wall may be formed largely or completely from the pressure-receiving component. Furthermore, the pressure-receiving component is configured such that the contraction force provided is equal to the expansion force pulling the side wall apart in the direction of the longitudinal axis. The two forces are thus are balanced, so that the side wall is neither shortened nor lengthened when the fuel quantity in the tank changes. This avoids a change in the carrier element in the direction along the longitudinal axis, so that also the dimensions of the structures of the aircraft and spacecraft supported by the carrier element do not change. At the same time, a rotationally rigid carrier element is provided which offers constant flight-mechanical properties for the aircraft and spacecraft. Furthermore, the device is simple to produce. Also, in comparison with the prior art, the device has a lower total mass so that the entire carrier element has a lower total mass. Furthermore, due to integration of the tank in the carrier element, the conduction paths are minimized.

The carrier element may be a wing spar. Furthermore, the carrier element may be part of the frame structure of an aircraft and spacecraft. The carrier element may therefore, alternatively or additionally, be arranged in a fuselage or in another position in the aircraft and spacecraft, or be a tank which is structurally integrated in the wing.

According to one example, the pressure-receiving component is a fiber material which is wound around the longitudinal axis, wherein at least a portion of the fiber material assumes an angle relative to the longitudinal axis of between 1° and 89°, preferably between 10° and 80°, further preferably between 20° and 70°, further preferably between 30° and 60°, further preferably between 40° and 50°, most preferably 45°.

The fiber material provides a lightweight material for the pressure-receiving component and the side wall. The fiber material may be unidirectional. The winding of the fiber material about the longitudinal axis takes place as a component of the side wall. In other words, the fiber material forms part of the side wall which extends around the chamber along the longitudinal axis. The arrangement of the fiber material, wound at least in portions with one of the above-mentioned angles, means that an expansion of the side wall perpendicularly to the longitudinal axis by a pressure from the interior of the chamber increases the circumference of the fiber material about the longitudinal axis. Since the fiber material has a finite length of the side wall, wherein a fiber of the fiber material may, when wound, extend over the entire length of the side wall along the longitudinal axis, an enlargement of the circumference shortens the distance which the wound fiber may cover in the direction along the longitudinal axis. The fiber material, which is wound at least in portions at one of the above-mentioned angles to the longitudinal axis, as a pressure-receiving component, therefore causes a contraction of the side wall when a pressure acts on the side wall.

In a further example, the side wall has a sealing element which extends along the side wall and is arranged between the chamber and the side wall.

In this way, the tightness of the side wall is improved when the tank is filled with hydrogen or oxygen and under pressure. Above all when the side wall comprises a porous material or fiber material, the sealing element avoids over-rapid escape of the tank contents. Therefore a high long-term tightness is provided.

The sealing element may be a coating of the side wall.

The coating may be connected to the surface of the side wall facing the chamber. The term “coating” also includes that a thin tube is connected by its outside to the surface of the side wall facing the chamber. Furthermore, a film may be connected to the surface of the side wall facing the chamber. Also further types of coating are possible, such as for example a plasma or spray coating of the surface of the side wall facing the chamber.

Furthermore, the sealing element may be an electrical conductor.

The sealing element may then for example be made of a metal.

In this way, a need exists for a device for carrying fuel in an aircraft and spacecraft, wherein the device comprises: a carrier element for the aircraft and spacecraft, wherein the carrier element has a longitudinal axis, at least one tank with a side wall and a chamber, which is at least partially delimited by the side wall, for receiving the fuel; wherein the at least one tank is arranged in the carrier element and wherein the chamber and the side wall extend in a direction along the longitudinal axis; wherein the side wall has a sealing element made of metal which extends along the side wall and is arranged between the chamber and the side wall.

In contrast to sealing elements made of plastic which are used in the prior art, a sealing element made of metal offers increased sealing effect, in particular for hydrogen. The sealing element performs a double function and may simultaneously function as a signal line or power line and as a seal. Thus weight may be saved in the aircraft and spacecraft, since no separate electrical line is required.

In a further example, the device may have at least two tanks, wherein the at least two tanks are arranged next to each other and/or centrally in the carrier element.

This is advantageous above all if one of the two tanks contains water and the other oxygen. A fuel cell of the aircraft and spacecraft converts the oxygen into water, using hydrogen, and extracts oxygen from one tank and adds water to the other tank. Two water molecules (molar mass of water 18.01 g/mol) are converted into one oxygen molecule (molar mass of oxygen 32.00 g/mol) and two hydrogen molecules (molar mass of hydrogen 2.02 g/mol). If the aircraft and spacecraft comprises an electrolyser, i.e. an electrolysis device, the electrolyser can split the water in the reverse direction into hydrogen and oxygen using electrical energy. For this, the electrolyser takes water from the one tank and adds oxygen to the other tank. Since two water molecules and one oxygen molecule have a very similar mass, because of the adjacent and/or central arrangement in the carrier element, the center of gravity shifts only minimally on conversion of the two substances into each other. Furthermore, trim stability can be guaranteed in the event of a leak. This improves the flight-mechanical properties of the aircraft and spacecraft.

Furthermore, in a further example, the device may have at least three tanks, wherein a first tank contains hydrogen, a second tank contains water, and a third tank contains oxygen, wherein the at least three tanks are arranged successively along the carrier element, wherein the first, second and third tanks are arranged such that a combined center of gravity of the first tank and of the third tank is arranged on a center of gravity of the second tank.

Thus a need exists for a device for carrying fuel in an aircraft and spacecraft, wherein the device comprises: a carrier element for the aircraft and spacecraft, wherein the carrier element has a longitudinal axis, at least three tanks each with a side wall and a chamber, which is at least partially delimited by the side wall, for receiving the fuel; wherein the at least three tanks are arranged in the carrier element and wherein the chamber and the side wall extend in a direction along the longitudinal axis; wherein a first tank contains hydrogen, a second tank contains water and a third tank contains oxygen, wherein the at least three tanks are arranged successively along the carrier element, wherein the first, second and third tank are arranged such that a combined center of gravity of the first tank and of the third tank is arranged on a center of gravity of the second tank.

On conversion of hydrogen and oxygen into water, the quantity of hydrogen or oxygen in the first tank and third tank respectively decreases, and the water quantity in the second tank increases. Here, the lever force exerted by the first tank and third tank relative to the connected end piece is reduced by the extraction of hydrogen and oxygen. At the same time, the addition of water to the second tank, with respect to the connected end piece, causes an increase in the lever force of the second tank. The increase and reduction in lever forces equal each other out, since the combined center of gravity of the first tank and of the third tank, from which water is taken, is arranged on the center of gravity of the second tank into which mass is added. The reverse case applies when an electrolyser extracts water from the second tank and supplies hydrogen or oxygen to the first tank or third tank respectively. Thus a shift in the center of gravity of the device or carrier element is avoided. Furthermore, a change in the lever force of the carrier element on the connected end piece due to conversion of fuels in the tanks is avoided.

It may furthermore be provided that the at least one tank is connected to a heat source via a heat-conducting element when the at least one tank contains water.

In this way, freezing of the water in the tank can be avoided, and frost-free operation becomes possible. The heat source may for example be the waste heat from an air-conditioning system of the aircraft and spacecraft.

According to the disclosure, an aircraft and spacecraft is provided which comprises a carrier structure system and a device as described above, wherein the device is connected to the carrier structure system by means of the carrier element.

The advantages and effects of the aircraft and spacecraft are similar to the advantages and effects of the device described above. Therefore in this respect, reference is made to the description above.

The carrier element may be arranged in a wing of the aircraft and spacecraft.

Due to the large expanse of the wings, the wings offer a large volume for the arrangement of tanks. Furthermore, the carrier element may then fulfil a double function, and space may be saved in the fuselage of the aircraft and spacecraft. The carrier element may in this case be a wing spar. It is however not excluded that the carrier element is arranged in the fuselage of the aircraft and spacecraft.

Furthermore, the aircraft and spacecraft may have a fuel cell which is connected to the at least one tank via at least one line. The at least one line may also be described as a fuel cell line.

The fuel cell provides electrical energy to the aircraft and spacecraft for driving or operating the internal systems of the aircraft and spacecraft. In this case, at least hydrogen is stored in the at least one tank.

In a further example, the aircraft and spacecraft may comprise an electrolyser which is connected to the at least one tank via at least one further line. The at least one further line may also be described as an electrolyser line.

Thus, with the electrolyser, fuel can be provided for a fuel cell while the aircraft and spacecraft is travelling in air or space. The electrolyser may produce electrical energy from solar panels contained by the aircraft and spacecraft.

In a further example, the combination of fuel cell and electrolyser may provide a circuit for conversion of oxygen and hydrogen into water, or conversion of water into oxygen and hydrogen.

Furthermore, the aircraft and spacecraft may comprise a heat source, wherein the line and/or the further line is connected to the heat source via a heat-conducting element when the line and/or the further line contains water.

Thus, a need exists for an aircraft and spacecraft which comprises a carrier structure system and a device for carrying fuel in an aircraft and spacecraft, wherein the device comprises: a carrier element for the aircraft and spacecraft, wherein the carrier element has a longitudinal axis, at least one tank with a side wall and a chamber, which is at least partially delimited by the side wall, for receiving the fuel; wherein the at least one tank is arranged in the carrier element and wherein the chamber and the side wall extend in a direction along the longitudinal axis; wherein the device is connected to the carrier structure system by means of the carrier element, wherein the aircraft and spacecraft has a fuel cell which is connected to the at least one tank via at least one line, and/or wherein the aircraft and spacecraft has an electrolyser which is connected to the at least one tank via at least one further line, wherein the aircraft and spacecraft comprises a heat source, wherein the line and/or the further line is connected to the heat source via a heat-conducting element when the line and/or the further line contains water.

Lines which carry water may therefore be heated by the heat source so that freezing of the lines is prevented. Thus an efficient frost protection is provided.

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

