High power take-off, high efficiency cruise aero turbine engine-generator system

Abstract

High-power take-off, high-efficiency cruise aviation turbine engine-generator system, comprising turbine engine, inter-stage combustion chamber, free turbine, exhaust pipe, generator, cooling pipeline, free turbine shaft, high-speed coupling, generator rotor, liquid ammonia storage tank, No. 1 stop valve, throttle valve, flowmeter, mixing valve, No. 2 stop valve, oil tank;Inter-stage combustion chamber is placed between turbine engine outlet and free turbine, free turbine shaft and generator rotor are connected through high-speed coupling;Cooling pipeline is embedded in generator stator shell, the inlet of cooling pipeline is connected with mixing valve, and the outlet is connected with inter-stage combustion chamber;The outlet of liquid ammonia storage tank is connected with No. 1 stop valve, throttle valve, flowmeter and mixing valve in sequence;Two outlets of oil tank lead to turbine engine and No. 2 stop valve respectively, and No. 2 stop valve is connected with mixing valve;Among them, liquid ammonia flows into cooling pipeline from liquid ammonia storage tank, absorbs generator heat, vaporizes into high-temperature ammonia gas, and then is sent into inter-stage combustion chamber for combustion.

Description

Technical Field

[0001] This invention relates to the field of aviation hybrid power, and more particularly to an aviation turbine engine-generator system with high-power takeoff and high-efficiency cruise. Background Technology

[0002] All-electric aircraft garnered significant attention in their early research stages. However, limited by advancements in battery technology, their energy and power densities are far lower than those of traditional fuel-powered thermal engines, resulting in overall flight performance inferior to pure fuel-powered aircraft. To reconcile environmental protection with technological requirements, hybrid-electric aircraft emerged. These aircraft effectively utilize the high energy density of pure fuel, overcoming the limitations of all-electric range, while also possessing the high efficiency and low pollution characteristics of all-electric aircraft. Hybrid-electric aircraft primarily employ turboshaft engines as prime movers, using the output shaft power to drive a generator to produce electrical power. This system is known as an aero-turbine engine-generator system (abbreviated as: aero-eddy electric system). Currently, research on eddy electric systems mainly focuses on applications in ground-based gas turbine power generation, with limited research on aerospace-specific eddy electric systems.

[0003] Due to the unique nature of aerospace propulsion applications, the integrated design of vortex-electric systems presents greater challenges. On one hand, from an aerospace component design perspective, generators are required to simultaneously possess characteristics such as small size, light weight, high power density, and high reliability. Compared to traditional generators, meeting these requirements necessitates releasing greater heat generation within a smaller and lighter cooling system, as elevated temperatures can significantly negatively impact the generator's power density, reliability, and lifespan, even leading to permanent magnet synchronous generator failure. On the other hand, from a system design perspective, the performance matching between the turbine engine and the generator needs to be addressed. Specifically, as an air-breathing engine, the turbine engine exhibits typical altitude and speed characteristics. Traditional aero-engines are designed for high-power takeoff to meet ground takeoff and acceleration requirements, while operating at their most economical state during cruise flight. Generators, however, lack altitude and speed characteristics; their design point achieves optimal efficiency and power simultaneously. Therefore, to match the high-power takeoff requirements of the turbine engine, the generator must also meet high-power design requirements, resulting in excessive mass and low efficiency during cruise flight.

[0004] Therefore, in order for the generator to operate stably at high power levels or even exceed its power limit when the aircraft requires high power output (takeoff and acceleration phases), an efficient and reliable cooling system is necessary. While natural air cooling is simple and compact, its heat dissipation efficiency is low. Open-ventilation cooling uses air intakes for heat dissipation, which improves efficiency, but dust can easily enter the motor, requiring regular cleaning. Liquid cooling and evaporative cooling strategies require complex cooling systems. The aforementioned traditional cooling strategies struggle to achieve effective pre-cooling, and the cooling equipment is often heavy and bulky, placing a greater burden on the aircraft's weight and size. Summary of the Invention

[0005] The purpose of this invention is to solve the aforementioned problems in the prior art and provide an aero-turbine engine-generator system with high-power takeoff and high-efficiency cruise. Its structure is simple and rational, unlike traditional aero-engines. This system uses the cruise point as the design point to achieve efficient cruise design. Simultaneously, during ground takeoff, liquid ammonia is used to strongly pre-cool the generator, increasing its power output. The cooled ammonia gas is then supplied to the interstage combustion chamber of the turbine engine to further increase output power, achieving high-power matching during vortex-electric takeoff and acceleration. Ultimately, the design goals of high-power takeoff and high-efficiency cruise for the aero-turbine system are achieved.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A high-power takeoff and high-efficiency cruise aircraft turbine engine-generator system, including turbine engine, interstage combustion chamber, free turbine, exhaust pipe, generator, cooling pipes, free turbine shaft, high-speed coupling, generator rotor, liquid ammonia storage tank, No. 1 shut-off valve, throttle valve, flow meter, mixing valve, No. 2 shut-off valve, and fuel tank.

[0008] The interstage combustion chamber is located between the turbine engine outlet and the free turbine, and the free turbine shaft is connected to the generator rotor via a high-speed coupling. The cooling pipes are embedded in the generator stator housing, with the inlet of the cooling pipes connected to a mixing valve and the outlet of the cooling pipes connected to the interstage combustion chamber. The outlet of the liquid ammonia storage tank is sequentially connected to a first shut-off valve, a throttle valve, a flow meter, and a mixing valve. The two outlets of the oil tank are respectively connected to the turbine engine and a second shut-off valve, with the second shut-off valve connected to the mixing valve. Liquid ammonia flows from the liquid ammonia storage tank into the cooling pipes, absorbs heat from the generator, vaporizes into high-temperature ammonia gas, and is then sent to the interstage combustion chamber for combustion.

[0009] The operating method of the high-power takeoff and high-efficiency cruise aircraft turbine engine-generator system includes the following steps:

[0010] 1) During the flight of the aircraft, the high-pressure and high-temperature gas from the turbine engine outlet impacts the free turbine, causing the free turbine to rotate. This converts the kinetic and thermal energy of the gas into the mechanical energy of the free turbine, and outputs shaft power through the free turbine shaft. The free turbine shaft is connected to the generator rotor through a high-speed coupling, thereby driving the generator rotor to cut magnetic lines of force to generate electrical energy.

[0011] 2) When the aircraft is in takeoff acceleration, the turbine engine operates at high power. Liquid ammonia is stored in the liquid ammonia tank. The No. 2 shut-off valve is closed and the No. 1 shut-off valve is opened. The liquid ammonia flow rate is read by the flow meter and the throttle valve is controlled to adjust the liquid ammonia flow rate. After passing through the throttle valve, the No. 1 shut-off valve, the flow meter and the mixing valve, the liquid ammonia flows into the cooling pipe, absorbs the heat generated by the generator, and effectively reduces the generator temperature. After heat exchange, the liquid ammonia temperature rises and is converted into high-temperature ammonia gas. The high-temperature ammonia gas continues to flow into the interstage combustion chamber as fuel. The heat and kinetic energy generated by the combustion of high-temperature ammonia gas impacts the free turbine rotation, increases the output shaft power, and further increases the generator output power.

[0012] 3) When the aircraft is in cruise mode, close the No. 1 shut-off valve and open the No. 2 shut-off valve. This allows the fuel to flow into the cooling pipes after passing through the No. 2 shut-off valve and the mixing valve. This absorbs the energy generated by the generator and reduces the generator temperature to a certain extent. At the same time, the fuel temperature rises. High-temperature fuel has the characteristics of easy ignition and high combustion efficiency. After being injected into the engine, it effectively reduces the fuel consumption rate of the turbine engine.

[0013] In this invention, an interstage combustion chamber is connected after the turbine engine outlet. A set of free turbines is located after the interstage combustion chamber outlet, and these free turbines are connected to a free turbine shaft. The high-temperature, high-pressure exhaust gas from the interstage combustion chamber impacts the free turbines, converting the thermal and kinetic energy of the gas into the mechanical energy of the free turbines, and outputting shaft power through the free turbine shaft. A high-speed coupling connects the free turbine shaft and the generator rotor, driving the generator rotor to rotate and achieving shaft power transmission. The generator rotor generates electrical energy by cutting the stator magnetic field. When the aircraft requires high power output (takeoff phase), the generator operates at high or over-power. By opening the throttle valve to increase the liquid ammonia flow, the generator temperature is reduced to the expected temperature, stabilizing the generator's operating state. Simultaneously, more high-temperature ammonia gas flows into the interstage combustion chamber for combustion, increasing the output shaft power of the free turbine shaft and achieving afterburning in the turbine engine's interstage combustion. Liquid ammonia is first passed through cooling pipes before flowing into the interstage combustion chamber for combustion. This not only provides strong pre-cooling for the generator, rapidly reducing its temperature, but also improves combustion efficiency by allowing the liquid ammonia to absorb heat from the generator before burning in the interstage combustion chamber. If shaft power output is still insufficient, the energy storage and electric systems (energy storage device and electric motor) can be activated simultaneously to output shaft power to meet the aircraft's needs. When the aircraft requires low power output (cruise flight), the turbine engine still operates at maximum capacity, and the generator operates at its most efficient state, extracting some electrical energy for storage in the energy storage device. Furthermore, fuel is first passed through the generator's exterior for oil cooling, improving generator efficiency. The high-temperature fuel, absorbing heat from the generator, is then injected into the turbine engine for combustion, further improving turbine engine combustion efficiency.

[0014] This invention utilizes liquid ammonia as a cooling medium, which meets the high-power output requirements of the generator, enabling it to operate stably at high power and efficiency during takeoff and acceleration. Furthermore, the high-temperature ammonia gas after heat exchange is combusted, further increasing the output shaft power of the free turbine shaft, while simultaneously solving the ammonia gas handling problem. Moreover, using liquid ammonia as a cooling medium reduces generator performance waste, making the generator design more economical and efficient. All of these improvements achieve comprehensive optimization of the entire power system.

[0015] Compared with the prior art, the beneficial effects achieved by the technical solution of this invention are:

[0016] 1. The generator strong precooling system of the present invention can open the No. 1 shut-off valve and increase the opening of the throttle valve when the aircraft needs high power output (take-off phase), so that liquid ammonia can strongly precool the generator, allowing the generator temperature to drop rapidly, enabling the generator to work stably at the maximum state, or even exceed the power limit and achieve over-power operation.

[0017] 2. The interstage combustion chamber of the present invention provides more rotational mechanical energy to the free turbine and improves the takeoff power of the turbine engine by allowing high-temperature ammonia gas after cooling the generator to flow into the interstage combustion chamber for combustion.

[0018] 3. The generator pre-cooling system described in this invention utilizes the heat absorption capacity of liquid ammonia. Compared with heat dissipation systems such as air cooling, liquid cooling, and evaporative cooling, this pre-cooling system has a better heat dissipation effect, improves the generator parameter design requirements, makes the generator more efficient and economical, reduces generator performance waste, and reduces the weight of the aircraft and the volume of the generator heat dissipation system. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention.

[0020] The markings in the diagram are as follows: 1 represents the turbine engine, 2 represents the interstage combustion chamber, 3 represents the free turbine, 4 represents the exhaust pipe, 5 represents the generator, 6 represents the cooling pipe, 7 represents the free turbine shaft, 8 represents the high-speed coupling, 9 represents the generator rotor, 10 represents the liquid ammonia storage tank, 11 represents the first shut-off valve, 12 represents the throttle valve, 13 represents the flow meter, 14 represents the mixing valve, 15 represents the second shut-off valve, 16 represents the fuel tank, and 17 represents the energy storage and electric system; ① represents high-temperature ammonia, ② represents fuel gas, ③ represents liquid ammonia, ④ represents electric power, ⑤ represents high-temperature fuel oil, and ⑥ represents fuel oil. Detailed Implementation

[0021] To make the technical problems, technical solutions and beneficial effects of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0022] This invention relates to a generator cooling system based on liquid ammonia pre-cooling, which has a simple structure and reliable performance. Using ammonia as the cooling medium greatly improves the generator cooling efficiency and ensures the continuous operation of the generator at high power. Using the high-temperature ammonia gas after heat exchange as fuel for the interstage combustion chamber eliminates the pollution of ammonia gas to the aircraft's internal environment and equipment, and solves the problem of ammonia gas emission treatment.

[0023] See Figure 1 The embodiments of the present invention include a turbine engine 1, an interstage combustion chamber 2, a free turbine 3, an exhaust pipe 4, a generator 5, a cooling pipe 6, a free turbine shaft 7, a high-speed coupling 8, a generator rotor 9, a liquid ammonia storage tank 10, a first shut-off valve 11, a throttle valve 12, a flow meter 13, a mixing valve 14, a second shut-off valve 15, an oil tank 16, and an energy storage and electric system 17.

[0024] The interstage combustion chamber 2 is located between the outlet of the turbine engine 1 and the free turbine 3. The free turbine shaft 7 is connected to the generator rotor 9 via a high-speed coupling 8. The cooling pipe 6 is embedded in the generator stator housing. The inlet of the cooling pipe 6 is connected to the mixing valve 14, and the outlet of the cooling pipe 6 is connected to the interstage combustion chamber 2. The outlet of the liquid ammonia storage tank 10 is sequentially connected to the first shut-off valve 11, the throttle valve 12, the flow meter 13, and the mixing valve 14. The two outlets of the oil tank 16 are respectively connected to the turbine engine 1 and the second shut-off valve 15. The second shut-off valve 15 is connected to the mixing valve 14. The exhaust pipe 4 is located on both sides of the free turbine 3, and the outlet direction of the exhaust pipe 4 is set at 90° with the free turbine shaft 7.

[0025] Liquid ammonia flows from the liquid ammonia storage tank into the cooling pipeline at a certain flow rate. After absorbing heat from the generator, it vaporizes into high-temperature ammonia gas, which is then sent into the interstage combustion chamber for combustion.

[0026] Before takeoff, the required amount of liquid ammonia is determined based on the generator's heat output and stored in liquid ammonia storage tank 10. At this time, the first shut-off valve 11 is closed. After takeoff, fuel ⑥ in fuel tank 16 enters the turbine engine 1 for combustion, and the turbine engine 1 begins operation. When strong cooling of generator 5 is required, the first shut-off valve 11 is opened, the liquid ammonia flow rate is read by flow meter 13, and the throttle valve 12 is controlled to adjust the liquid ammonia flow rate. Liquid ammonia ③ flows into cooling pipe 6 after passing through the first shut-off valve 11, throttle valve 12, flow meter 13, and mixing valve 14, where it absorbs the heat generated by generator 5. After heat exchange, liquid ammonia ③ is converted into high-temperature ammonia gas ①, which flows into interstage combustion chamber 2 through the outlet of cooling pipe 6 and completes combustion there. When generator 5 requires normal cooling, the second shut-off valve 15 is opened, and fuel ⑥ in fuel tank 16 flows into cooling pipe 6 after passing through the second shut-off valve 15 and mixing valve 14, where it absorbs the heat generated by generator 5. After heat exchange, fuel ⑥ is converted into high-temperature fuel ⑤, which flows into the turbine engine 1 through the outlet of cooling pipe 6 for combustion. The combustion gas ② generated by the turbine engine 1 and the interstage combustion chamber 2 impacts the free turbine 3, converting the thermal and kinetic energy of the combustion gas ② into the rotational mechanical energy of the free turbine. The shaft power is output by the free turbine shaft 7 and transmitted to the generator rotor 9 through the high-speed coupling 8. The generator rotor 9 drives the generator to cut magnetic lines of force to generate electrical energy. The generator 5 outputs electrical power ④ to the energy storage and electric system 17.

[0027] The operating method of the high-power takeoff and high-efficiency cruise aircraft turbine engine-generator system described in this invention includes the following steps:

[0028] 1) During the flight of the aircraft, the high-pressure and high-temperature gas from the turbine engine outlet impacts the free turbine, causing it to rotate. This converts the kinetic and thermal energy of the gas into the mechanical energy of the free turbine, and outputs shaft power through the free turbine shaft. The free turbine shaft is connected to the generator rotor through a high-speed coupling, enabling the generator rotor to cut magnetic lines of force to generate electricity. The gas after passing through the free turbine is discharged in a lateral exhaust manner. The outlet direction of the exhaust pipe 4 is at a 90° angle to the free turbine shaft. This exhaust method can more effectively disperse heat, avoid damage to the engine and surrounding components due to excessive exhaust temperature, and reduce the burden on the cooling system. In addition, this method can make the system more compact and further shorten the axial length.

[0029] 2) When the aircraft is in takeoff acceleration, the turbine engine operates at high power. Liquid ammonia is stored in the liquid ammonia tank. The No. 2 shut-off valve is closed and the No. 1 shut-off valve is opened. The liquid ammonia flow rate is read by the flow meter and the throttle valve is controlled to adjust the liquid ammonia flow rate. After passing through the throttle valve, the No. 1 shut-off valve, the flow meter and the mixing valve, the liquid ammonia flows into the cooling pipe, absorbs the heat generated by the generator, and effectively reduces the generator temperature. After heat exchange, the liquid ammonia temperature rises and is converted into high-temperature ammonia gas. The high-temperature ammonia gas continues to flow into the interstage combustion chamber as fuel. The heat and kinetic energy generated by the combustion of high-temperature ammonia gas impacts the free turbine rotation, increases the output shaft power, and further increases the generator output power.

[0030] 3) When the aircraft is in cruise mode, close the No. 1 shut-off valve and open the No. 2 shut-off valve. This allows the fuel to flow into the cooling pipes after passing through the No. 2 shut-off valve and the mixing valve. This absorbs the energy generated by the generator and reduces the generator temperature to a certain extent. At the same time, the fuel temperature rises. High-temperature fuel has the characteristics of easy ignition and high combustion efficiency. After being injected into the engine, it effectively reduces the fuel consumption rate of the turbine engine.

[0031] The interstage combustion chamber described in this invention is located between the turbine engine and the free turbine, using high-temperature ammonia gas after absorbing heat from the generator as fuel, thus solving the problem of ammonia gas disposal after heat exchange. Re-combusting the high-temperature ammonia gas after heat exchange improves combustion efficiency and enhances the overall system performance.

[0032] This invention uses liquid ammonia as a precooling medium. When the aircraft requires high power output (takeoff phase, acceleration cruise phase), the strong heat absorption capacity of liquid ammonia is used to precool the generator, improve the generator's working environment, and increase the generator's working efficiency.

[0033] This invention utilizes liquid ammonia as a cooling medium in a generator cooling system, significantly improving cooling efficiency, achieving strong pre-cooling of the generator, and meeting the temperature requirements for high-power operation. Ammonia has a pungent odor and is somewhat toxic; human exposure can be harmful. This invention introduces high-temperature ammonia gas, after heat exchange, into the interstage combustion chamber as fuel, solving not only the ammonia emission problem but also utilizing the heat and kinetic energy generated by ammonia combustion to increase the power output of the free turbine shaft, further enhancing the generator's power output. Furthermore, generators using traditional cooling systems suffer from low heat dissipation efficiency and cannot operate at high power for extended periods. To meet takeoff power requirements, the takeoff phase is often the primary design focus for the generator. By employing strong pre-cooling with liquid ammonia, the cruise phase is made the primary design focus, allowing the aircraft to simultaneously achieve high-power climb and high-efficiency cruise, reducing generator performance waste and improving economic efficiency.

Claims

1. A method for operating an aircraft turbine engine-generator system with high-power takeoff and high-efficiency cruise, characterized in that: The system includes a turbine engine, an interstage combustion chamber, a free turbine, a generator, cooling pipes, a free turbine shaft, a high-speed coupling, a generator rotor, a liquid ammonia storage tank, a first shut-off valve, a throttle valve, a flow meter, a mixing valve, a second shut-off valve, and an oil tank. The interstage combustion chamber is located between the turbine engine outlet and the free turbine, and the free turbine shaft is connected to the generator rotor via a high-speed coupling. The cooling pipes are embedded in the generator stator housing, with the inlet of the cooling pipes connected to a mixing valve and the outlet of the cooling pipes connected to the interstage combustion chamber. The outlet of the liquid ammonia storage tank is sequentially connected to a first shut-off valve, a throttle valve, a flow meter, and a mixing valve. The two outlets of the oil tank are respectively connected to the turbine engine and a second shut-off valve, with the second shut-off valve connected to the mixing valve. Liquid ammonia flows from the liquid ammonia storage tank into the cooling pipes, absorbs heat from the generator, vaporizes into high-temperature ammonia gas, and is then sent to the interstage combustion chamber for combustion. The system operates by including the following steps: 1) During the flight of the aircraft, the high-pressure and high-temperature gas from the turbine engine outlet impacts the free turbine, causing the free turbine to rotate. This converts the kinetic and thermal energy of the gas into the mechanical energy of the free turbine, and outputs shaft power through the free turbine shaft. The free turbine shaft is connected to the generator rotor through a high-speed coupling, thereby driving the generator rotor to cut magnetic lines of force to generate electrical energy. 2) When the aircraft is in takeoff acceleration, the turbine engine operates at high power. Liquid ammonia is stored in the liquid ammonia tank. The No. 2 shut-off valve is closed and the No. 1 shut-off valve is opened. The liquid ammonia flow rate is read by the flow meter and the throttle valve is controlled to adjust the liquid ammonia flow rate. After passing through the throttle valve, the No. 1 shut-off valve, the flow meter and the mixing valve, the liquid ammonia flows into the cooling pipe, absorbs the heat generated by the generator, and effectively reduces the generator temperature. After heat exchange, the liquid ammonia temperature rises and is converted into high-temperature ammonia gas. The high-temperature ammonia gas continues to flow into the interstage combustion chamber as fuel. The heat and kinetic energy generated by the combustion of high-temperature ammonia gas impacts the free turbine rotation, increases the output shaft power, and further increases the generator output power. 3) When the aircraft is in cruise mode, close the No. 1 shut-off valve and open the No. 2 shut-off valve. This allows the fuel to flow into the cooling pipes after passing through the No. 2 shut-off valve and the mixing valve. This absorbs the energy generated by the generator and reduces the generator temperature to a certain extent. At the same time, the fuel temperature rises. High-temperature fuel has the characteristics of easy ignition and high combustion efficiency. After being injected into the engine, it effectively reduces the fuel consumption rate of the turbine engine.

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