RU2707154C1 - Unmanned aerial vehicle - Google Patents

Abstract

FIELD: aviation.

SUBSTANCE: invention relates to unmanned aerial vehicles and is intended for monitoring large areas of the earth's surface. Unmanned aerial vehicle comprises body-fuselage, power plant, vessel with hydrogen, main tank with hydrogen located outside fuselage housing and connected to series-connected compressor, additional tank with hydrogen and fuel elements installed inside housing. Main container with hydrogen is made with possibility of changing shape and is divided into sections by hydropermeable partitions, each of which is connected to small capacity through compressor.

EFFECT: invention is aimed at increasing the flight duration of the vehicle owing to the use of hydrogen reserve.

3 cl, 2 dwg

Description

The invention relates to unmanned aerial vehicles (UAVs) and is intended to monitor large spaces and the surface of the earth, as well as long systems: gas pipelines, highways, roads, water transport routes, as well as to carry out special missions related to both monitoring and delivery of goods , devices, products, for example, in the provision of humanitarian assistance.

Currently, unmanned aerial vehicles operating either on fossil fuels (internal combustion engines) or electric traction are widely used for these purposes, in which either lithium-ion (lithium-polymer) batteries or solar panels are used as an energy source or fuel cells with hydrogen. Apply their combination. (See, for example, RF patent No. 2462397)

The main criterion for the equality or comparability of other parameters (primarily the weight of the unmanned vehicle) is the duration of its flight. This requires the creation of highly efficient energy conversion systems and compact devices with a high specific energy content, which ensure a longer flight duration.

An analysis of existing developments shows that one of the most promising areas for creating unmanned aerial vehicles is their energy supply systems based on fuel cells with an energy carrier - hydrogen. At present, hydrogen for fuel cells is stored in composite cylinders with a pressure of 300 atm. Cylinders of 700 atm are being developed. A method for the most compact storage of hydrogen in capillary structures with the possibility of creating a hydrogen density in excess of the density of liquid hydrogen is proposed. But all these methods for ensuring the flight of unmanned vehicles have a significant drawback - they constantly spend energy (fuel) regardless of the task performed. Even arriving, for example, at a monitoring site, an unmanned vehicle continues to expend energy to maintain flight and altitude.

The patent of the Russian Federation for PM No. 138371 of November 19, 2013 is known, which describes a compactly designed unmanned aerial vehicle having folding wings and a folding thrust screw. Inside the unmanned aerial vehicle is a can of compressed gas, which is lighter than air. For vertical take-off, light gas from the canister through a special valve located on the surface of the body of an unmanned aerial vehicle inflates a ball that creates lift. The valve, if necessary, can be disconnected both from the unmanned aerial vehicle and from the ball. This patent implements only one function of light gas - the creation of lift.

The closest is patent No. 2600556 05/21/2015, in which an unmanned aerial vehicle with a lift using the force of Archimedes is presented due to a change in the gas density in a special tank inside the UAV. The change in gas density is carried out by heating the air with special heaters, or by filling the tank with a lighter gas. The energy source is a battery or solar panels. The material of a special gas container uses an airtight material, which limits it when using hydrogen or helium, which have high penetration and are removed from the tank due to diffusion.

The disadvantages of this apparatus include heaters for gas heating, consuming electricity. Gas for creating lift is used only for the purpose of creating lift for Archimedes. The capacity to create lift is located inside the UAV, which imposes restrictions on its size and, therefore, on the creation of the magnitude of the lift.

The technical problem solved by the invention is the maximum use of the hydrogen storage capabilities, which will expand both the UAV functionality: vertical take-off and landing, hovering at the required height at the destination, practically without hydrogen consumption, and ensuring the necessary hydrogen content, which does not impair weight characteristics of the aircraft, but vice versa creates lift.

The technical result is to increase the flight duration of the aircraft, as well as the lack of a platform and special devices for its launch and landing.

To achieve a technical result, an unmanned aerial vehicle is proposed comprising at least a fuselage body, a power plant, a hydrogen tank, while it contains a main hydrogen tank located outside the fuselage body and connected to a compressor in series connected with an additional tank with hydrogen and fuel cells installed inside the housing.

Besides,

- the main tank with hydrogen is divided into sections by hydrogen-tight partitions, each of which is connected to a small capacity through a compressor.

- the main container with hydrogen is configured to change shape.

A diagram of such an aircraft is shown in FIG. 1, which shows an embodiment of a UAV with the location of the main tank divided into sections with hydrogen outside the hull-fuselage of the aircraft.

Figure 1 does not show the general layout of the UAV, which, as a standard, contains a rigid fuselage with wings, a control system, an electric motor, and a propeller providing thrust for the aircraft, Fig. 2.

The positions indicated:

1. The body-fuselage of the aircraft.

2. The main tank with hydrogen located outside the hull-fuselage of the aircraft;

3. The compressor.

4. Additional capacity with hydrogen at elevated pressure, with a system for reducing the pressure of hydrogen supplied to the fuel cells;

5. Fuel cells.

The proposed design allows the use of hydrogen stock in an aircraft in three directions. The first - as fuel for fuel cells, the second - as light gas to keep this device at a given height in the monitoring zone, and the third - to provide vertical ascent and descent of the aircraft. This is achieved as follows.

To ensure vertical take-off and lifting force that keeps the aircraft at the required height, it should initially contain the main tank with hydrogen 2 (hereinafter - tank 2).

Capacity 2 with hydrogen holding the UAV at a given height can have either a spherical shape or another with improved aerodynamic characteristics, a “flying wing”, a paraglider, a cigar-shaped balloon, a torus and others.

The shell of the container 2 is made of elastic hydrogen and airtight material, which will allow it to be converted into a form with minimal aerodynamic drag, for example, by pressing the shell against the fuselage.

This allows you to better combine both maintaining the aircraft at a given height, and maneuvering in space due to propeller thrust. Filling and extraction of hydrogen from this tank 2 with its supply to the fuel cells 5 is carried out by the compressor 3.

Capacity 2 can be divided into sealed sections to prevent complete loss of hydrogen in case of damage. In this case, hydrogen is supplied to each section separately.

The figure does not show valves, shut-off and control equipment, a standard hydrogen reducer installed on the connecting lines and selected depending on the design parameters.

This design has the following advantages:

- the aircraft has the ability to take off and land vertically without creating traction using a screw;

- the aircraft does not require a heavy hydrogen accumulator on board; (So the battery on board the aircraft containing 150 kg of hydrogen and with 15% mass of hydrogen in it will weigh 1000 kg. In this case, when you install such a battery, the weight of the aircraft increases by 1000 kg. If we put these 150 kg of hydrogen into container 2, then at an altitude of 10,000 m at atmospheric pressure corresponding to this height, these 150 kg of hydrogen will create a lifting force of at least 1,500 kg. Thus, in the first embodiment, the battery increases the weight of the aircraft, and in the second version with a large capacity of 2 So The same amount of hydrogen does not increase the weight of the aircraft, but on the contrary creates lift. Forces act in opposite directions, the force difference in the effect on the aircraft is 2500 kg. In the second case, the payload (payload that can be taken aboard the aircraft) increases by 2500 kg.

- when filling the tank 2 with hydrogen to provide lifting force, the hydrogen pressure is at the level of one atmosphere or higher. This pressure is especially necessary when using a container 2 made of a multilayer polymer material with layers of aluminum foil as a shell. Aluminum foil does not pass hydrogen. Overpressure is necessary to tension the shell of the vessel 2. When the aircraft is raised to a height of, for example, 1000 m or more, when atmospheric pressure decreases, hydrogen pressure must be reduced to provide greater lifting force while maintaining the shell tension. Therefore, this excess of hydrogen can be used to provide flight to a given target. If this "excess" of hydrogen is large, then part of the hydrogen can be pumped by compressor 3 from the tank with hydrogen 2 into an additional tank 4 (hereinafter, tank 4) and then supplied to the fuel cells 5. In addition, the tank with hydrogen outside the aircraft 2 can be connected to the aircraft 1 by detachable connections (not shown in the figure) and can be disconnected if necessary. In this case, hydrogen is previously pumped from it by compressor 3 to the tank 4. Another option for this solution is not to disconnect the tank with hydrogen 2 from the aircraft, but to convert its shell into a form with minimal aerodynamic drag, for example, by pressing the shell against the fuselage or compactly placing this shell inside the aircraft 1.

The aircraft, having reached its destination, hangs at the required height in the monitoring zone, using the lifting force of the tank with hydrogen outside the aircraft 2. The hydrogen flow in the monitoring zone is required only for correcting the position of the aircraft at a given height, while for aircraft devices without a tank with hydrogen, outside the aircraft, for example, in the option of storing hydrogen in high-pressure cylinders, a constant flow of hydrogen is required to ensure its flight and its retention for a given high altitude. After completing the monitoring process, hydrogen from the tank with hydrogen 2 by the compressor 3 is downloaded and fed into the tank 4, which does not lead to hydrogen losses.

Compressor 3 has two functions:

- supplies hydrogen from tank 4 to tank 2 to control the lifting force,

- feeds hydrogen from tank 2 to tank 4 to control the lifting force and convert the shell of the tank 2 into a mold with minimal aerodynamic drag.

As the material for the shell of the vessel 2 with hydrogen, you can use a multilayer material having both high-strength layers and a layer (or layers) that prevents the penetration of hydrogen through it, for example, aluminum foil (foil materials). The technology for creating multilayer films with aluminum foil is widely used, for example, in the food industry.

Consider an unmanned aerial vehicle weighing 1,500 kg as an example. We calculate the amount of hydrogen needed to maintain the UAV for monitoring at an altitude of 10,000 m. The air density according to the reference data is 0.414 kg / m ³ , the air temperature is -50 ° C, and the pressure is 26500 Pa. In accordance with thermodynamic calculations, the density of hydrogen at these temperatures and pressures is 0.028.56 kg / m ³ . The difference in the densities of air and hydrogen at the indicated pressure and temperature at this altitude is 0.385 kg / m ^3. To maintain the weight of an unmanned aerial vehicle weighing 1500 kg at an altitude of 10,000 m, a volume with hydrogen of 3896 m ³ will be required, the diameter of the main tank made, for example, in the form ball, equal to 19.5 m, almost 20 m (4186.5 m ³ ). These are quite acceptable sizes for an unmanned vehicle with such a weight. Such a "hydrogen accumulator" (with a diameter of 20 m) will contain 120 kg of hydrogen. Such a "hydrogen accumulator" in the form of a "cigar" will have dimensions: diameter - 20 m, length - 13-15 m.

Consider what weighted amount of hydrogen will be contained in 4186.5 m ³ at various refueling temperatures and normal atmospheric pressure - 1 atm, corresponding to different seasons and normal atmospheric pressure - 1 atm. and also what lifting force corresponds to such gas stations.

1. At a temperature of -20 ° C and 1 atm. The density of hydrogen is 94.96 g / m ³ , the weight of hydrogen is 397.55 kg. The weight of air in this volume is 5573 kg. Lifting power - 5175.45 kg.

2. At a temperature of -10 ° C and 1 atm. The density of hydrogen is 91.35 g / m ³ , the weight of hydrogen is 382.445 kg. The weight of air in this volume is 5360 kg. Lifting power - 4977.6 kg.

3. At a temperature of 0 ° C and 1 atm. The density of hydrogen is 88 g / m ³ , the weight of hydrogen is 368.844 kg. The weight of air in this volume is 5163.746 kg. Lifting power - 4795 kg.

By varying, for example, increasing the pressure of hydrogen in the volume, it is possible to increase its content (reserves) while reducing the lifting force. From the calculations presented, it can be seen that, for example, for the first refueling variant, the lifting force, with a hydrogen content of 397.55 kg, is 5175.45 kg, and a little more than 1500 kg is required (the difference in the required force and created 5175.45-1500 = 3675 , 45 kg), it is possible to significantly increase the hydrogen supply by compensating for the lifting force to the required values.

Thus, by changing the pressure of the hydrogen refueling, it is possible to change the hydrogen content in the tank 2 to create the lifting force of the aircraft and increase the duration of the flight.

This design will allow to solve such problems as vertical take-off and landing, increase in lift, increase in hydrogen supply on board, decrease in hydrogen consumption with long-term hovering of the aircraft at a given height at the destination, which improves the flight characteristics of the UAV.

Claims (3)

1. An unmanned aerial vehicle comprising at least a fuselage body, a power plant, a hydrogen tank, characterized in that it contains a main hydrogen tank located outside the body and connected to a compressor, additional hydrogen and fuel tanks connected in series elements installed inside the case. 2. An unmanned aerial vehicle according to claim 1, characterized in that the main vessel with hydrogen is divided into sections by hydrogen-impervious partitions, each of which is connected to a small vessel through a compressor. 3. An unmanned aerial vehicle according to claim 1, characterized in that the main vessel with hydrogen is configured to change shape.

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