Boundary layer ingestion propulsion system, aircraft

Abstract

A boundary layer intake propulsion system and an aircraft are disclosed. The propulsion system includes an open rotor engine and a BLI fan. A portion of the energy from fuel combustion in the open rotor engine is used to drive the rotor of the open fan as propulsion power, while another portion of the fuel's chemical energy is converted into electrical energy and transferred to the BLI fan mounted at the rear of the fuselage. The electrical energy drives the BLI fan to rotate, providing another portion of the propulsion power. The BLI fan includes a fan hub, a motor, and a flow divider ring. The flow divider ring is located upstream of the fan hub and guides a portion of the airflow through the motor to cool it.

Description

Technical Field

[0001] This invention relates to boundary layer intake propulsion systems and aircraft. Background Technology

[0002] The International Civil Aviation Organization (ICAO) and related research institutions are setting increasingly stringent requirements for fuel consumption and environmental performance of future aircraft. According to reports, NASA and the European Union aim to reduce aircraft fuel consumption by 70% by 2035 (N+3 timeframe). Conventional fuel-powered aircraft engines are no longer sufficient to meet this requirement. Therefore, there is a need in this field for a propulsion system for aircraft engines that can further reduce fuel consumption.

[0003] Currently, one solution to reduce fuel consumption is the use of BLI fans, which is a boundary layer ingestion fan installed at the tail of the aircraft. This concept of propulsive fuelselage is currently a hot research topic.

[0004] The basic idea behind this configuration is to add a fan to the tail of a conventional aircraft. This fan is typically directly driven by electricity generated by a conventional gas turbine engine. When the tail fan is operating, it effectively draws in the gas boundary layer that gradually accumulates on the fuselage surface due to viscosity, thereby reducing boundary layer buildup and effectively lowering aircraft drag, ultimately reducing fuel consumption and range. Due to the boundary layer intake effect of the tail fan, it is commonly referred to internationally as a boundary layer ingestion fan (BLI fan), and therefore, it is abbreviated as BLI fan in this application.

[0005] On the other hand, the BLI fan also provides about 20% to 30% of the thrust. Therefore, with the total thrust requirement of the aircraft remaining unchanged, the thrust requirement of the conventional gas turbine engine is reduced, so its fan diameter can also be reduced, making it easier to meet the size constraints under the maximum diameter of the nacelle.

[0006] Because of the boundary layer removal effect of the BLI fan, it is equivalent to indirectly increasing the bypass ratio of the traditional gas turbine engine. However, the fuel consumption reduction effect of the thrust system using the BLI fan needs further improvement.

[0007] In particular, if the BLI fan needs to provide more thrust, a more complex cooling system is required to cool the motor. For example, a more complex cooling airflow piping system is needed to provide sufficient cooling gas flow. However, this will lead to insufficient installation space and make it impossible to install a larger motor. Therefore, the current BLI fan solution is difficult to further improve the effect of reducing fuel consumption.

[0008] In addition, among the current fuel consumption reduction solutions, there is an open rotor engine, which is an engine between turboprop and turbofan. Since it can be regarded as a turbofan engine with ultra-high bypass ratio except for the outer bypass duct, it combines the advantages of high propulsion efficiency and low fuel consumption of turboprop engines with the high flight speed of turbofan engines. It is one of the important research directions for future high-performance engine configurations. However, it has defects such as noise, which makes it difficult to meet the relevant noise requirements of civil aviation. Summary of the Invention

[0009] The purpose of this invention is to provide a boundary layer intake propulsion system.

[0010] The purpose of this invention is to provide an aircraft.

[0011] A boundary layer intake propulsion system according to a first aspect of the present invention includes: an open rotor engine and a BLI fan; wherein, a portion of the energy from fuel combustion in the open rotor engine is used to drive the rotor of the open fan to rotate as propulsion power, and another portion of the fuel chemical energy is converted into electrical energy and transferred to the BLI fan mounted at the rear of the fuselage, the electrical energy driving the BLI fan to rotate to provide another portion of propulsion power; wherein, the BLI fan includes a fan hub, a motor, and a flow divider ring; the flow divider ring is disposed at the upstream end of the fan hub and guides a portion of the airflow through the motor to cool the motor.

[0012] In one embodiment, the motor includes a motor rotor, a motor stator, and motor heat sink fins; wherein, the motor and the flow divider ring are both disposed at the upstream end of the fan hub, the motor rotor is disposed radially inner on the motor stator, the motor rotor is connected to the BLI fan rotor, and drives the BLI fan; the radially inner end of the motor heat sink fins is connected to the motor stator, and the radially outer end is connected to the flow divider ring, so that after the incoming gas flows through the flow divider ring, part of it passes through the fan rotor from the outside of the fan hub, and another part passes through the motor heat sink fins from the inside of the fan hub, and the other part of the airflow is finally discharged through the exhaust port at the rear of the fan hub.

[0013] In one embodiment, the propulsion system further includes a rechargeable battery that supplies power to the BLI fan during takeoff and climb.

[0014] In one embodiment, during cruise and descent conditions, the electrical energy converted from the other portion of the fuel chemical energy is also provided to charge the rechargeable battery.

[0015] In one embodiment, during descent, landing, and taxiing, the open rotor engine is shut down, and the rechargeable battery supplies power to the BLI fan to provide all the power.

[0016] In one embodiment, during landing, the BLI fan reverses to provide at least a portion of the reverse thrust.

[0017] In one embodiment, the open rotor engine has no thrust reverser, and the BLI fan reverses to provide all the thrust.

[0018] In one embodiment, the open rotor engine includes a propulsion or traction structure.

[0019] An aircraft according to a second aspect of the present invention includes one or more boundary layer inhalation propulsion systems as described above.

[0020] In one embodiment, the inlet support plate and BLI fan stator of the BLI fan are mounted on the fuselage of the aircraft to support the nacelle of the BLI fan.

[0021] According to the technical solution of the present invention, the following technical effects can be achieved:

[0022] 1. By adopting the structure of the flow divider ring, the airflow passing through the BLI fan is properly guided to the motor of the BLI fan for motor cooling. Therefore, there is no need to use more complex air ducts and other components. Only a simple heat dissipation fin structure is needed, which can expand the installation space of the fan motor and make it more conducive to heat dissipation and efficient operation.

[0023] 2. By combining the BLI fan and the open rotor engine, a hybrid power system consisting of the BLI fan, the open rotor engine, and the rechargeable battery is constructed. This not only achieves the high propulsion efficiency brought by the high bypass ratio of the open fan and the boundary layer suction effect of the BLI fan, but also significantly reduces the fuel consumption required by the entire propulsion system while generating the same thrust. Furthermore, during descent, landing, and ground taxiing, the BLI fan can be powered solely by the battery, reducing ground noise and combustion chamber pollutant emissions. In addition to reducing fuel consumption, the synergistic effect of the three components achieves noise reduction.

[0024] 3. The reverse thrust function during landing can be achieved by reversing the BLI fan, and the variable pitch function can even be eliminated. The open rotor engine structure is also simpler, easier to repair and maintain, and the overall structural reliability is improved. Attached Figure Description

[0025] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0026] Figure 1 This is an overall diagram of an aircraft and an open rotary engine and BLI fan, as shown in one embodiment.

[0027] Figure 2 This is a schematic diagram of an open rotor engine mounted under the wing of an aircraft.

[0028] Figure 3 This is a two-dimensional cross-sectional structural diagram of the BLI fan of a propulsion system according to one embodiment.

[0029] Figure 4A , Figure 4B These are two-dimensional cross-sectional structural diagrams of propulsion-type and traction-type open rotor engines, respectively. Detailed Implementation

[0030] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0031] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0032] like Figure 1 The diagram shows the overall structure of the aircraft, its open rotor engine, and its BLI fan. An open rotor engine 300 is mounted on each side of the wing of the aircraft 1. A lithium battery pack 4 is installed inside the fuselage of the aircraft 1 as a rechargeable battery. It can be understood that the rechargeable battery is not limited to lithium batteries and can also be other common rechargeable batteries. Additionally, a BLI fan 500 is installed at the rear of the aircraft 1.

[0033] like Figure 1 As shown, the open rotary engines 300 mounted on both sides of the aircraft 1 use conventional fuel (such as aviation kerosene) as fuel, but are not limited to this and can also use other fuels. A portion of the energy from fuel combustion is used to drive the open fan rotor 308 of the open rotary engine to rotate, providing propulsion. The airflow passing through the open fan rotor 308 then flows through the open fan stator 310 for rectification, as shown... Figure 2 As shown, this outputs propulsive power. It can be understood that the open fan stator 310 can also be replaced with rotating counter-rotating blades to output propulsive power.

[0034] like Figure 1As shown, another portion of the fuel's chemical energy is converted into electrical energy, which is transmitted via aircraft cable 2 to the BLI fan 500 mounted at the rear of the fuselage. The electrical energy drives the BLI fan 500 to rotate, providing another portion of the propulsion power. This portion of thrust can account for 10% to 30% of the total thrust of the propulsion system.

[0035] During takeoff, in addition to the open rotary engine 300 providing power to the BLI fan 500, the lithium battery 4 located inside the aircraft 1 can also provide auxiliary power. During cruise and descent, the electrical energy generated by the open rotary engine 300, besides supplying the BLI fan 500, can also charge the lithium battery pack 4, allowing the excess energy to be stored in the lithium battery pack 4 inside the aircraft 1. During descent, landing, and taxiing, the open rotary engine 300 can be shut down, and the lithium battery pack 4 can supply power to the BLI fan 500 to provide all the power for the propulsion system, thereby reducing combustion chamber pollutant emissions and noise.

[0036] The beneficial effect of combining the BLI fan and the open rotor engine to construct a hybrid power system of the BLI fan, open rotor engine and rechargeable battery not only achieves the high propulsion efficiency brought by the high bypass ratio of the open fan and the boundary layer suction effect of the BLI fan, but also significantly reduces the fuel consumption required by the entire propulsion system under the condition of generating the same thrust. Furthermore, during descent, landing and ground taxiing, the BLI fan can be powered solely by the battery, reducing ground noise and combustion chamber pollutant emissions. In addition to reducing fuel consumption, the synergistic effect of the three components achieves the effect of reducing noise.

[0037] During landing, the BLI fan 500 can reverse to provide thrust reversal, shortening the landing distance. It can even replace the thrust reverser in the open rotary engine 300, simplifying the engine structure, reducing weight, and increasing reliability. By reversing the BLI fan, at least part of the thrust reversal function can be achieved during landing, or even the pitch control function (i.e., no thrust reverser is needed) can be eliminated, allowing the BLI fan to perform all thrust reversal functions. This not only simplifies the structure of the open rotary engine in the propulsion system, making repair and maintenance easier, but also improves the overall system reliability.

[0038] like Figure 3As shown, in some embodiments, the structure of the BLI fan 500 may include a fan hub, a motor, and a flow divider ring. The flow divider ring is located upstream of the fan hub and guides part of the airflow through the motor to cool it. Specifically, the structure may have the left side of the body support structure 501 fixed to the body 1, and the right side connected to the motor support structure 503. The motor support structure 503 contains the motor stator 507, thus supporting the motor. The motor stator 507 contains the motor rotor 508, which is connected to the fan shaft 511 and can drive the fan rotor 510 to rotate, generating thrust. The bottom of the motor cooling fins 506 is connected to the motor stator 507, and the top is connected to the flow divider ring 505. That is, both the motor and the flow divider ring 505 are located upstream of the fan hub 514. The motor stator 507 has the motor rotor 508 radially inwardly mounted, and the motor rotor 508 is connected to the fan rotor 510 of the BLI fan, driving the BLI fan. The structure of the flow divider ring 505 is as follows... Figure 3 As shown, it can be a structure that protrudes upstream along the axis, thus diverting and guiding the airflow through a simple structure.

[0039] After the incoming gas flows through the splitter ring 505, part of it passes above the fan rotor 510, and part passes below it. The gas passing below the splitter ring 505 passes through the motor cooling fins 506, which remove the heat generated during motor operation and cool the motor. The gas flowing through the cooling fins 506 passes through the BLI fan hub and is finally discharged into the atmosphere through the tail cone exhaust port 515.

[0040] The lower end of the BLI fan support plate 504 is fixed to the surface of the fan hub 514, and the upper end is fixed to the inner surface of the fan nacelle 509, providing support for it. The lower end of the BLI fan stator 512 is fixed to the surface of the fan hub 514, and the upper end is fixed to the inner surface of the fan nacelle 509. It can rectify the airflow passing through the BLI fan rotor 510, and at the same time, it provides support for the nacelle 509. The BLI fan stator disk 513 is connected to the right end of the load-bearing beam 502, and the left end of the load-bearing beam 502 is connected to the fuselage 1. Therefore, the load-bearing beam 502 can support the BLI fan 500 and transmit force to the fuselage 1.

[0041] The beneficial effect of the above embodiments is that by employing a flow-splitting ring structure, the airflow passing through the BLI fan is appropriately guided to the motor used for the BLI fan for motor cooling. This eliminates the need for complex air ducts and other components, requiring only a simple heat dissipation fin structure. This allows for a larger installation space for the fan motor, improving heat dissipation and efficient operation. Consequently, the propulsion system using the BLI fan architecture can provide greater thrust, further optimizing the thrust system and reducing fuel consumption.

[0042] like Figure 4A as well as Figure 4B The diagram shown is a structural schematic of an open rotary engine 300. Since open fans are divided into two types: propulsion type with fan rotor blades at the rear of the engine and traction type with fan rotor blades at the front, these two types will be explained separately here:

[0043] 1) Propulsion type

[0044] like Figure 4A As shown, the incoming air is compressed by the compressor 301a and enters the combustion chamber 303a to burn with fuel. The combustion gas enters and drives the high-pressure turbine 304a to rotate. The high-pressure turbine 304a is connected to the compressor 301a through the high-pressure shaft 302a, driving the compressor to rotate and compress the air. After passing through the high-pressure turbine 304a, the combustion gas enters the power turbine 305a and drives it to rotate. The power turbine 305a drives the low-pressure shaft 306a. The reducer 307a is connected to the left low-pressure shaft 306a and the right fan disc assembly 309a respectively, driving the open rotor rotor 308a to rotate and provide thrust. The open fan stator 310a is fixed to the open rotor engine tail cone 314a through the mounting assembly 311a. The motor shaft 315a is connected to both the reducer 307a and the motor 313a. The motor 313a is fixed inside the tail cone 314a via a mounting plate 312a and is driven to rotate by the motor shaft 315a, converting a portion of the combustion's chemical energy into electrical energy through mechanical energy. Furthermore, during high-thrust conditions such as takeoff and climb, the motor 313a can also utilize the electrical energy from the battery pack 4a to provide auxiliary energy to the fan rotor 308a to generate thrust.

[0045] 2) Traction type

[0046] like Figure 4BAs shown, the incoming air is compressed by the compressor 306b and enters the combustion chamber 308b to burn with the fuel. The combustion gas enters the high-pressure turbine 309b and drives it to rotate. The high-pressure turbine 309b is connected to the high-pressure compressor 306b through the high-pressure disc shaft / structure 307b, which drives the high-pressure compressor 306b to rotate and compress the air. The combustion gas leaving the high-pressure turbine 309b enters the low-pressure turbine 311b and drives it to rotate. The low-pressure turbine 311b is connected to the low-pressure turbine disc 312b and the low-pressure shaft 310b, which drives the reduction gearbox 304b connected to the left side of the low-pressure shaft 310b. The left side of the reduction gearbox 304b is connected to the fan shaft 303b, and the left side of the fan shaft 303b is connected to the actuation mechanism 302b. The actuation structure 302b mainly supports and drives the fan rotor 301b to rotate. The rotation of the fan rotor 301b generates thrust by compressing the incoming air. The fan stator 305b is installed behind the fan rotor 301b, and its root is connected and fixed to the open fan hub 314b, which can rectify the airflow. Furthermore, a variable pitch adjustment structure can be installed inside the fan hub 314b to change the pitch angle of the fan stator 305, thereby changing the thrust and aerodynamic efficiency of the open fan 300b, or even providing thrust reverse. The motor 313b is installed inside the open fan tail cone, and it, along with the low-pressure turbine 311b, is connected to the low-pressure shaft 310b. Powered by the fuselage battery pack 4b, the motor 313b can provide auxiliary energy to the fan rotor blades 301b during high-thrust flight conditions such as takeoff and climb, thereby reducing fuel consumption and carbon dioxide emissions. During low-thrust conditions such as cruise and descent, the low-pressure turbine 311b can drive the motor 313b to rotate and generate electricity, which is stored in the battery pack 4b.

[0047] In summary, the beneficial effects of using the boundary layer intake propulsion system and aircraft described in the above embodiments include one or a combination of the following:

[0048] 1. By adopting the structure of the flow divider ring, the airflow passing through the BLI fan is properly guided to the motor of the BLI fan for motor cooling. Therefore, there is no need to use more complex air ducts and other components. Only a simple heat dissipation fin structure is needed, which can expand the installation space of the fan motor and make it more conducive to heat dissipation and efficient operation.

[0049] 2. By combining the BLI fan and the open rotor engine, a hybrid power system consisting of the BLI fan, the open rotor engine, and the rechargeable battery is constructed. This not only achieves the high propulsion efficiency brought by the high bypass ratio of the open fan and the boundary layer suction effect of the BLI fan, but also significantly reduces the fuel consumption required by the entire propulsion system while generating the same thrust. Furthermore, during descent, landing, and ground taxiing, the BLI fan can be powered solely by the battery, reducing ground noise and combustion chamber pollutant emissions. In addition to reducing fuel consumption, the synergistic effect of the three components achieves noise reduction.

[0050] 3. The reverse thrust function during landing can be achieved by reversing the BLI fan, and the variable pitch function can even be eliminated. The open rotor engine structure is also simpler, easier to repair and maintain, and the overall structural reliability is improved.

[0051] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A boundary layer intake propulsion system, characterized in that, include: Open rotary engine, and BLI fan; In this context, a portion of the energy from the combustion of fuel in the open rotor engine is used to drive the rotor of the open fan as propulsion power. Another portion of the fuel's chemical energy is converted into electrical energy, which is then transferred to the BLI fan mounted at the rear of the fuselage. The electrical energy drives the BLI fan to rotate, providing another portion of the propulsion power. The BLI fan includes a fan hub, a motor, and a flow divider ring; the flow divider ring is located at the upstream end of the fan hub and guides part of the airflow through the motor to cool the motor. The motor includes a motor rotor, a motor stator, and motor heat sink fins; The motor and the shunt ring are both located at the upstream end of the fan hub. The motor rotor is located on the radially inner side of the motor stator. The motor rotor is connected to the fan rotor of the BLI fan to drive the BLI fan. The inner radial end of the motor heat sink fins is connected to the motor stator, and the outer radial end is connected to the flow divider ring. This allows the incoming gas to pass through the flow divider ring, with one part passing from the outside of the fan hub and through the fan rotor, and the other part passing from the inside of the fan hub and through the motor heat sink fins. The other part of the airflow is finally discharged through the exhaust port at the rear of the fan hub.

2. The propulsion system as described in claim 1, characterized in that, The propulsion system also includes a rechargeable battery, which supplies power to the BLI fan during takeoff and climb.

3. The propulsion system as described in claim 2, characterized in that, During cruise and descent, the electrical energy converted from the chemical energy of the fuel is also used to charge the rechargeable battery.

4. The propulsion system as described in claim 2, characterized in that, During descent, landing, and taxiing, the open rotor engine is shut down, and the rechargeable battery supplies power to the BLI fan to provide all the power.

5. The propulsion system as described in claim 1, characterized in that, During landing, the BLI fan reverses to provide at least part of the reverse thrust.

6. The propulsion system as claimed in claim 1, characterized in that, The open rotor engine has no thrust reverser; the BLI fan reverses to provide all the thrust.

7. The propulsion system as claimed in claim 1, characterized in that, The open rotor engine includes either a propulsion or traction structure.

8. An aircraft, characterized in that, This includes setting up one or more boundary layer inhalation propulsion systems as described in claims 1-7.

9. The aircraft as claimed in claim 8, characterized in that, The inlet support plate and stator of the BLI fan are mounted on the fuselage of the aircraft to support the nacelle of the BLI fan.

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