Vertical take-off / landing gas turbine engine

Abstract

To solve the challenge to make a single gas turbine engine function as both a turboprop and a turbofan, because, for an aircraft capable of vertical take-off and landing, a turboprop engine is used to enable horizontal flight with good fuel efficiency, and a turbofan engine, which can generate large thrust during vertical take-off and landing, is used for vertical take-off and landing.SOLUTION: A vertical take-off / landing gas turbine engine of the present invention can be configured as a turbofan engine capable of generating large thrust during vertical take-off and landing by opening and closing two valves relative to each other, and as a fuel-efficient turboprop engine during horizontal flight.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to vertical take-off and landing gas turbine engines. [Background technology]

[0002] A gas turbine engine for aircraft capable of vertical take-off and landing. Examples of its use include the U.S. military's Harrier and F-35B fighter jets.

[0003] One thing that all aircraft capable of vertical take-off and landing have in common is that they are fuel-efficient when flying horizontally. For example, helicopters are a representative example of aircraft capable of vertical take-off and landing, but they are fuel-efficient when flying horizontally. The best way to achieve fuel-efficient horizontal flight is to use a turboprop engine. Therefore, the most effective solution is to add vertical take-off and landing capabilities to a turboprop engine. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 11-321794 Public Relations Summary of the Invention [Problem to be solved by the invention]

[0005] One thing that all aircraft capable of vertical take-off and landing have in common is that they are fuel-efficient when flying horizontally. For example, helicopters are a representative example of aircraft capable of vertical take-off and landing, but they are fuel-efficient when flying horizontally. The best way to achieve fuel-efficient horizontal flight is to use a turboprop engine. Therefore, the most effective solution is to add vertical take-off and landing capabilities to a turboprop engine. [Means for solving the problem]

[0006] The most important feature of the present invention is that it functions as a turbofan engine during vertical takeoff and as a turboprop engine during horizontal flight. Effect of the Invention

[0007] The vertical take-off and landing gas turbine engine of the present invention can function as a turbofan engine that generates large thrust during vertical take-off and landing, and as a fuel-efficient turboprop engine during horizontal flight. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of the vertical take-off and landing gas turbine engine of the present invention (embodiment 1), showing the vertical take-off and landing gas turbine engine in horizontal flight under the thrust of a propeller 1. In other words, at this time, the vertical take-off and landing gas turbine engine of the present invention functions as a turboprop engine. At this time, the central butterfly valve 12 is closed, and the forward butterfly valve 14 is open. Also, the central exhaust port 10 is directed rearward. [Diagram 2] 2 is a cross-sectional view of the vertical take-off and landing gas turbine engine of the present invention (embodiment 1), showing the vertical take-off and landing. That is, at this time, the vertical take-off and landing gas turbine engine of the present invention functions as a turbofan engine. At this time, the central butterfly valve 12 is opened, and the forward butterfly valve 14 is closed. Also, the central exhaust port 10 is directed downward. Therefore, the exhaust gas is ejected downward. [Diagram 3] 3 is a cross-sectional view of a vertical take-off and landing gas turbine engine of the present invention (embodiment 2). This is a diagram showing the vertical take-off and landing gas turbine engine in horizontal flight due to the thrust of the propeller 1. In other words, at this time, the vertical take-off and landing gas turbine engine of the present invention functions as a turboprop engine. At this time, the central butterfly valve 12 is closed, and the free turbine front butterfly valve 16 located in front of the free turbine 3 that drives the propeller 1 is opened. Also, the central exhaust port 10 is directed rearward. The exhaust gas after rotating the free turbine 3 that drives the propeller 1 is exhausted from the front exhaust port 13. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention relates to a gas turbine engine used in a vertical / short take-off and landing aircraft. To put it simply, the present invention is a vertical take-off and landing aircraft having a turboprop engine. In other words, the present invention is a turboprop engine to which a vertical take-off and landing function has been added. The present invention is applicable not only to turboprop engines, but also to ducted fan engines and turbofan engines.

[0010] Many vertical take-off and landing aircraft are compatible with not only vertical take-off and landing (VTOL) but also short take-off and landing (STOL), and the vertical / short take-off and landing aircraft of the present invention is no exception. Such aircraft are called vertical / short take-off and landing aircraft.

[0011] A well-known example of a vertical / short take-off and landing aircraft that has already been implemented is the US military's fighter jet, the F-35B. The thrust of a jet engine is proportional to the product of the exhaust jet velocity and its airflow rate. On the other hand, the fuel flow rate of a jet engine increases in proportion to the product of the square of the exhaust jet velocity and its airflow rate. If there is a turbojet engine and a turbofan engine with the same thrust, and the exhaust jet velocity of the turbofan is half that of the turbojet, which is an extreme assumption, the fuel flow rate of the turbofan will be 1 / 4 of that of the turbojet.

[0012] The mechanism by which the tip of a jet engine nozzle narrows is called convergence, and the mechanism by which it widens is called divergence. A jet engine nozzle with a variable cross-sectional area mechanism is called a convergence-divergence nozzle, or con-die nozzle for short. Almost all jet fighter planes have con-die nozzles.

[0013] In a typical jet engine, the air flowing in from the air intake is first increased in a compressor (and secondarily in temperature), and the airflow is then combusted in the combustion chamber. The airflow, which has rapidly become hot and fast, passes through a turbine to provide shaft power to drive the compressor, and is finally discharged from the nozzle, and thrust is generated by the reaction force.

[0014] The thrust obtained at this time is proportional to the pressure and flow speed of the air flow. In other words, the faster the air flow speed from the nozzle, the greater the thrust. The role of the convex-die nozzle is to change the cross-sectional area of ​​the nozzle to change the thrust. The mechanism by which the tip narrows is called convergence, and the mechanism by which it widens is called divergence.

[0015] However, passenger aircraft jet engines are not cone-dye nozzles. Passenger aircraft only exert maximum thrust during takeoff, and maintain almost constant thrust during cruising, which accounts for the majority of the flight. In other words, for passenger aircraft, a fixed convergence (throttle) for cruising is basically sufficient. Although thrust decreases slightly during takeoff, reducing unnecessary variable mechanisms reduces production man-hours, maintenance time, and costs.

[0016] The afterburner on fighter planes is a device that reheats the airflow just before the nozzle, generating a very high-temperature, expanded airflow. The high-temperature airflow from the afterburner pushes back the airflow that travels from the combustion chamber through the turbine to the afterburner, so when the afterburner is in use, it is better to increase the cross-sectional area of ​​the nozzle and quickly exhaust the afterburner airflow. This will allow for greater thrust.

[0017] The U.S. military's fighter jet, the F-35B, is a vectored thrust vertical take-off and landing aircraft that has a convex nozzle and also has an afterburner.

[0018] In the present invention, a vertical / short take-off and landing aircraft, which has a vertical take-off and landing function added to a turboprop engine, can also obtain large thrust by using an afterburner.

[0019] Many vertical take-off and landing aircraft, such as the US military's F-35B fighter jet and the US military's Harrier vertical take-off and landing aircraft, are vectored thrust aircraft. Vectored thrust aircraft use thrust to lift the aircraft directly during take-off and landing, and then switch thrust to the direction of travel during horizontal flight.

[0020] In this type of aircraft, the thrust direction is often changed by rotating the propeller, rotor, or jet direction by about 90 degrees, as in the tilt rotor and Harrier. The US military's F-35B fighter jet can also bend its exhaust duct by about 90 degrees.

[0021] The F-35B is a short take-off, vertical landing (STOVL) aircraft, and is equipped with a lift fan for vertical ascent in the forward position. The lift fan is driven by an extension shaft from the F-35B's turbofan engine and through a clutch attached to the extension shaft.

[0022] In the vertical / short take-off and landing aircraft of the present invention, which adds vertical take-off and landing capabilities to a turboprop engine, driving force can be transmitted or not transmitted to the propeller 1, but this is not achieved by a clutch, and therefore no clutch is required.

[0023] During vertical landing, all of the engine energy is used to generate vertical force. After takeoff, when moving to horizontal flight, flying with the forward propeller 1 rotating is more efficient for propulsion.

[0024] This is because, if we consider a turbojet engine and a turbofan engine with the same thrust, and the turbofan's exhaust jet velocity is half that of the turbojet, then the turbofan's fuel flow rate will be one-quarter of that of the turbojet, which is an extreme assumption.

[0025] In other words, fuel consumption is reduced when using a large diameter propeller such as the propeller 1. This is because, for the same thrust, a large diameter propeller such as the propeller 1 can slow down the exhaust flow velocity.

[0026] The engine for vertical / short take-off and landing aircraft of the present invention, which adds vertical take-off and landing capabilities to a turboprop engine, has a separate two-shaft configuration in which the compressor drive turbine shaft and the propeller drive turbine shaft are not shared, as is the case with many turboprop engines.

[0027] Therefore, it is possible to rotate the propeller 1 without being affected by the rotational speed of the compressor drive turbine 6. By allowing each turbine shaft to rotate at an optimal rotational speed, the energy remaining in the jet exhaust gas from the front exhaust port 13 can be reduced to 10% or less of the total output including the propeller thrust.

[0028] In the figure, the exhaust gas after rotating the free turbine 3 for driving the propeller is discharged downward, but like many turboprop engines, it may be discharged toward the rear from both sides of the engine.

[0029] The vertical / short take-off and landing aircraft of the present invention, which has a vertical take-off and landing function added to a turboprop engine, needs to stabilize the aircraft during vertical take-off and landing, which is achieved by equipping the main wing with four or more ascent propellers. This is the same method of stabilizing the aircraft as drones. EXAMPLES

[0030] Fig. 1 shows an embodiment of a vertical take-off and landing gas turbine engine of the present invention, in a configuration for horizontal flight. Air flowing in through an intake port 7 is compressed by a compressor 8, and becomes high-temperature gas in a combustion chamber 9, which rotates a compressor-driven turbine 6.

[0031] The exhaust gases then enter the afterburner 4, but because the central butterfly valve 12 on the branch pipe 17 is closed and the forward butterfly valve 14 on the forward exhaust port 13 is open, the exhaust gases rotate the free turbine 3 which drives the propeller 1 and exit through the forward exhaust port 13.

[0032] The rotating shaft 15 driven by the free turbine 3 rotates the propeller 1 via the reduction gear 2. In other words, at this time, this vertical take-off and landing gas turbine engine functions as a turboprop engine, enabling horizontal flight with good fuel efficiency.

[0033] Figure 2 shows the same embodiment as Figure 1, but in the configuration for vertical takeoff and landing. In order to take off and land vertically, the central exhaust port 10 faces downward. The central exhaust port 10 can be rotated by rotating the rotating pipe joint 11 to face the exhaust port backward or downward.

[0034] At this time, the central butterfly valve 12 is opened to eject exhaust gas from the central exhaust port 10, and conversely, the front butterfly valve 14 is closed. Because the front butterfly valve 14 is closed, the exhaust gas does not drive the free turbine 3, and therefore the propeller 1 does not rotate. At this time, in order to generate a large thrust, fuel can be blown into the afterburner 4, which can increase the thrust. EXAMPLES

[0035] 3 shows another embodiment of the vertical take-off and landing gas turbine engine of the present invention in a horizontal flight configuration. A butterfly valve 16 before the free turbine is located close to the free turbine 3, and by closing this butterfly valve 16 before the free turbine, the exhaust gas going to the free turbine 3 can be stopped.

[0036] Of course, during horizontal flight as shown in the figure, the free turbine front butterfly valve 16 is open and the central butterfly valve 12 is closed. Therefore, the exhaust gas that has driven the free turbine 3 is exhausted from the front exhaust port 13.

[0037] This front exhaust port 13 does not have to face downward as shown in the figure, but can be installed on both sides of the engine and exhaust toward the rear, as is the case with many turboprop engines today. [Industrial Applicability]

[0038] The fields of application of the vertical / short take-off and landing aircraft of the present invention, which adds vertical take-off and landing capabilities to a turboprop engine, can be used in areas that have previously been covered by drones and helicopters.

[0039] The vertical / short take-off and landing aircraft of the present invention, which is a turboprop engine with vertical take-off and landing capabilities, is faster, more fuel-efficient, and can travel longer distances than a helicopter. Furthermore, it has a simpler structure than a helicopter, so it is less likely to break down.

[0040] The vertical / short take-off and landing aircraft of the present invention, which has a vertical take-off and landing function added to a turboprop engine, can also perform vertical / short take-off and landing using an afterburner 4 that generates a large thrust. However, when the afterburner 4 is used, high-temperature exhaust gas is sprayed onto the runway surface, damaging the runway, and vertical / short take-off and landing using the afterburner 4 is not possible on a normal runway.

[0041] Therefore, it is desirable to make the vertical / short take-off and landing aircraft of the present invention, which is an amphibious aircraft, by adding vertical take-off and landing capability to a turboprop engine, because vertical / short take-off and landing on water or ocean surfaces can be performed without worrying about damaging the runway and afterburners4 can be used.

[0042] However, it is inconvenient that vertical / short-distance takeoff and landing is only possible on the surface of a lake or ocean. Therefore, it would be possible to build pools with a diameter of about 50 m and a depth of about 1.5 m all over the country, and use afterburners 4 there to enable vertical takeoff and landing.

[0043] In addition, it should be avoided for a seaplane to hit the water surface with its propeller as this can cause malfunctions, but in the present invention, there is no need to worry about this because the propeller 1 is stopped during vertical / short takeoff and landing on water.

[0044] Furthermore, there is no need to worry about seawater getting into the engine when landing on the sea surface, because the intakes are located high above the main wings, and the exhaust valves can be closed to prevent seawater from getting in.

[0045] For the above reasons, it is desirable for the vertical / short take-off and landing aircraft of the present invention, which is an aircraft with a turboprop engine and vertical take-off and landing function, to be an amphibious aircraft, because in the event of an emergency, an amphibious aircraft can make an emergency landing on the sea, and furthermore, because this aircraft is capable of vertical take-off and landing on water, it can land safely on water even in rough weather with high waves. [Explanation of symbols]

[0046] 1. Propeller 2.Reducer 3. Free turbine for driving propeller 4. Afterburner 5. Main wing 6. Compressor drive turbine 7. Air Intake 8. Compressor 9. Combustion chamber 10.Central exhaust port 11.Rotating pipe joint 12.Central butterfly valve 13. Front exhaust port 14. Forward butterfly valve 15. Rotation axis 16.Butterfly valve in front of free turbine 17.Branch pipe

Claims

1. A gas turbine engine characterized in that a branch pipe is provided between the compressor driving turbine and the free turbine, a valve is attached to the branch pipe, and lift is generated by the ejection of exhaust gas that passes through the valve.

2. 2. A gas turbine engine according to claim 1, further comprising a valve attached to an exhaust pipe for gases passing through the free turbine.

3. 2. The gas turbine engine according to claim 1, further comprising a valve provided between the branch pipe and the free turbine.

4. 2. The gas turbine engine according to claim 1, wherein the engine body is disposed under a main wing, and the engine intake is disposed above the main wing.

5. 2. The gas turbine engine according to claim 1, wherein a rotary joint is used in the branch pipe, making it possible to change the direction in which exhaust gas is ejected.

Images