Intercooled regenerative water augmented turbofan engine and method of operation

Abstract

The present application belongs to the technical field of aviation turbine engine, and discloses an intercooling regenerative water enhanced turbofan engine, which comprises a Brayton cycle and a supercritical water vapor Rankine cycle in a main flow path, the two cycles are closely related, and are coupled by increasing a steam turbine, a steam generator and a condenser. The steam turbine does work to supply a high-pressure compressor, and liquid water appears at the steam turbine outlet, the liquid water is injected into the high-low pressure compressor for intercooling, the intermediate temperature of the compressor is reduced, the power consumption of the compressor is reduced, the unit working medium thrust is improved, the intercooler is saved, and the application is facilitated, the low-temperature steam at the steam turbine outlet can be injected into the low-pressure turbine inlet for cooling, and the cold air amount can be effectively reduced and the unit working medium thrust can be improved. The present application effectively overcomes the high temperature difference and large loss of the steam generator, compared with the conventional aviation engine, the total efficiency of the engine can be greatly improved, the fuel consumption rate and the pollutant emission are reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of aviation turbine engines, and particularly relates to an inter-cooled regenerative water-enhanced turbofan engine and a working method. BACKGROUND

[0002] As the core power system of modern aircraft, the performance of the aircraft engine is directly related to the flight efficiency, fuel consumption and environmental impact of the aircraft. With the development of aviation technology, although the traditional turbine engine can provide relatively stable thrust, its fuel efficiency is low and the emission problem is increasingly prominent, and a breakthrough in new power technology is urgently needed. In recent years, hybrid aircraft engines with steam cycle systems have begun to attract attention, but the overall layout scheme of such engines is still in the exploratory stage. The water-enhanced turbofan engine proposed in the present application uses Brayton cycle and supercritical water vapor Rankine cycle and other cycle technologies to improve overall thermal efficiency and reduce fuel consumption and emissions. The supercritical water vapor Rankine cycle system uses a steam turbine as a heat recovery and temperature control device, which can significantly improve the thermal efficiency and thrust of the engine while reducing harmful emissions.

[0003] Through the above analysis, the problems and defects of the prior art are:

[0004] Although the traditional turbine engine can provide relatively stable thrust, its fuel efficiency is low and the emission problem is increasingly prominent; the conventional inter-cooled cycle requires a large inter-cooler, which is not conducive to practical application; the steam generator produces a high temperature difference due to phase change, loss is high; the conventional turbine cooling uses compressor bleed air, and the bleed air quantity is high, and the unit working medium thrust is low. SUMMARY

[0005] In view of the problems existing in the prior art, the present application provides an inter-cooled regenerative water-enhanced turbofan engine.

[0006] The present application is implemented as follows: an inter-cooled regenerative water-enhanced turbofan engine comprises:

[0007] The Brayton cycle in the main flow passage is closely related to the supercritical water vapor Rankine cycle and is coupled through the steam turbine, steam generator and condenser. The main flow passage includes the following components: an air inlet, a fan, a booster compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine and an internal containment nozzle, which are arranged and connected in order from front to back. The outer containment passage and the outer containment nozzle are connected in parallel with the internal containment components after the fan. In the supercritical water vapor Rankine cycle, the following components are included: a steam turbine, a steam generator, a condenser, a gas-liquid separator, a water pump motor and a water pump, which are connected in order to form a closed loop and a cycle.

[0008] The main working fluid in the described main stream Brayton cycle includes air and mixed gas. During the operation of the aircraft, air enters the turbofan engine fan through the air inlet. The flow channel behind the fan is divided into an inner channel and an outer channel. Due to the steam injection, the outer channel has a higher bypass ratio, and the flow rate of the outer channel air accounts for a large proportion of the total air flow rate. The outer channel air enters the outer channel nozzle to expand and generate thrust; the inner channel air is compressed by the booster stage and the high-pressure compressor in turn, and the pressurized air enters the combustion chamber to mix and burn with fuel and steam to generate high-temperature and high-pressure gas. Subsequently, the gas expands to do work in the high-pressure turbine and the low-pressure turbine in turn, and the high-temperature gas is cooled by the steam from the outlet of the steam turbine during the process. The high-pressure turbine provides power for the high-pressure compressor through the high-pressure shaft, and the low-pressure turbine provides power for the fan, the booster stage compressor and the water pump through the low-pressure shaft. The gas contains a large amount of water vapor, and the supercritical water vapor Rankine cycle is responsible for recycling the injected water. After the low-pressure turbine, the high-temperature gas still has a large amount of energy and enters the steam generator hot end for heat recovery to heat the cold end high-pressure liquid water to generate supercritical water vapor. The water vapor in the gas at the outlet of the steam generator hot end needs to be further cooled by the condenser hot end, and the cold end of the condenser uses low-temperature air as the cold source. The condensed mixture is separated by a gas-liquid separator, and the condensed water enters the water pump for pressurization. Since the pressure of the condensed water is low, the water pump pressurizes it to the critical pressure, and the water pump is driven by the low-pressure turbine. The remaining gas part generates thrust through the inner channel nozzle; and the high-pressure condensed water enters the steam generator cold end to be heated to generate supercritical water vapor. The supercritical water vapor enters the steam turbine to do work and is cooled. The steam at the outlet of the steam turbine generates part of the liquid water, which is collected and injected between the compressor stages for intercooling, and the cooled steam is further injected into the turbine for cooling.

[0009] Further, the supercritical water vapor Rankine cycle includes a steam turbine expansion process. The inlet of the steam turbine is connected to the outlet of the steam generator cold end, and the outlet is connected to the inlet of the combustion chamber. The water pump pressurizes the liquid water to more than 23 MPa to meet the supercritical state requirement, and the water pump has the performance to meet the working pressure range and is as small as possible. In addition, the steam turbine can effectively reduce the temperature of the supercritical water vapor during the expansion process. The steam generator hot end is connected to the condenser hot end, and the flow channel of the heat exchanger adopts a counter-flow arrangement to improve the heat exchange efficiency.

[0010] Further, the high-pressure components, low-pressure components, combustion chamber and heat exchange components of the aircraft turbine engine, the high-pressure components include a high-pressure turbine, a high-pressure compressor and a high-pressure shaft, the low-pressure components include a low-pressure turbine, a fan, a booster stage compressor and a low-pressure shaft, and the heat exchange components include a steam generator and a condenser.

[0011] Further, the high-pressure condensed water first enters the evaporator, and is heated into supercritical steam in the evaporator. The heated steam enters the steam turbine to expand and do work, and is then injected into the combustion chamber to participate in combustion, or is used for turbine cooling. Finally, the steam is condensed into liquid water by the condenser, so as to realize water circulation.

[0012] Further, the condenser is arranged under the aircraft wing, and is cooled by the aircraft skin, and the condensed water is recovered to improve the circulation efficiency.

[0013] Further, the heat exchanger is a single heat exchanger element or a combination of multiple heat exchanger elements.

[0014] Further, the evaporator in the heat exchange component is used to heat the condensed water into supercritical water steam. After the steam expands through the steam turbine, the steam can be injected into the combustion chamber to mix with the gas, so as to improve the combustion efficiency; or the steam can be injected into the high-pressure turbine and the low-pressure turbine to cool, so as to improve the thrust. The generated liquid water is injected into the high-pressure compressor inlet to cool the inlet air.

[0015] Further, the control module monitors the content of gaseous water and liquid water at the steam turbine outlet in real time through the sensor, and controls the water injection device according to the optimal water injection amount, so as to optimize the engine operation efficiency.

[0016] Further, considering the demand of aviation operation, the water pump should be as small in volume and mass as possible when compressing the supercritical state water. Therefore, the heat exchanger component is made of high-temperature aviation alloy material, so as to realize high-efficiency heat exchange and light weight

[0017] In combination with the above technical scheme and the solved technical problems, the technical scheme to be protected by the present application has the following advantages and positive effects:

[0018] Firstly, the steam circulation system improves the thermal efficiency and thrust in the key links of the engine by means of steam injection technology, injects the water vapor into the combustion chamber or the turbine, injects the liquid water into the compressor stage to effectively reduce the power consumption of the compressor and improve the unit propulsive force of the aircraft. The steam turbine, the steam generator and the condenser work cooperatively, and the heat exchange and water recovery technology is used to improve the thermal energy conversion efficiency and reduce the overall energy consumption and emission of the system. In addition, the integrated design of the water pump and the heat exchanger makes the system more compact and efficient, and higher thrust and fuel efficiency are realized without increasing too much weight. Through optimization of the steam injection amount, steam turbine power regulation and condensate water design, and reasonable layout of the steam turbine and the cooling turbine, the comprehensive performance of the engine is effectively improved, and the demand of the aviation industry for high-efficiency and environmentally-friendly power systems is met.

[0019] The present application overcomes the shortcomings of conventional steam injection aircraft engine layouts and solves the problems of additional weight caused by water carrying and energy loss during cooling in water-enhanced engines. By introducing steam turbines and steam-cooled turbines, combined with the Brayton cycle and supercritical water-steam Rankine cycle, the present application significantly improves thermal efficiency and thrust output while effectively reducing energy consumption and emissions.

[0020] Compared with traditional regenerative aircraft engines, the condenser design of the engine proposed in the present application is located on the wing and fuselage, which uses high-speed and low-temperature air in the high-altitude environment to cool the exhaust gas of the internal-duct engine, which is significantly lower than the internal cooling design temperature of the engine, thereby significantly reducing the requirements of the condenser on heat exchange performance. Through the coupling design of the steam generator, condenser and water pump, the system not only realizes efficient heat exchange and water recovery, but also optimizes the overall performance and effectively reduces the system weight.

[0021] By optimizing the design of the water pump and heat exchanger, efficient operation of the engine under different working conditions is ensured. The present application improves each link of the steam cycle system to provide a more environmentally friendly and efficient aircraft engine solution, meeting the higher requirements of the future aviation industry for power system performance and environmental friendliness.

[0022] (1) By placing the condenser outside the wing and fuselage surface, especially using the high-speed flow and lower temperature of the wing surface air, the requirements of the engine on the heat exchange performance of the condenser are effectively reduced, and the pressure loss generated by designing the condenser in the external duct is avoided.

[0023] (2) By combining the Brayton cycle and supercritical water-steam Rankine cycle, the heat energy recovery and conversion efficiency of the engine is optimized, and the overall thermal efficiency is significantly improved. At the same time, the synergy of the steam cycle system and the gas turbine enhances the thrust output performance of the engine, further improving the overall performance of the power system.

[0024] (3) Liquid water intercooling is injected into the high-pressure compressor inlet, reducing the power consumption of the compressor and effectively improving the unit working medium thrust; steam cooling reduces the thermal load and work of the turbine, improves the internal-duct thrust, and reduces the demand for cold air.

[0025] (4) By optimizing the design of the water pump and heat exchanger, the engine structure is optimized, and the energy efficiency and reliability of the system are improved without increasing excessive weight.

[0026] (5) Compared with conventional steam injection aircraft engine layouts, the cycle components of the present application are relatively independent, the supercritical water-steam cycle system and the core engine system are easy to maintain, and the use and maintenance cost is relatively low.

[0027] Second, the expected income and commercial value of the technical scheme of the present application after transformation are:

[0028] The present application optimizes energy recovery and utilization, combines the Brayton cycle and the supercritical steam Rankine cycle, greatly improves the fuel utilization rate of the engine, and the oil saving rate can reach 15.06%. The technology can be widely applied to commercial passenger aircraft, military transport aircraft and future high-efficiency aviation platforms, creating new market growth points for aviation manufacturing enterprises.

[0029] The technical scheme of the present application overcomes the technical prejudice: in the traditional view, the steam cycle system is considered unsuitable for aviation engines due to the increase in weight and complexity. The present application realizes efficient energy recovery and weight control of the system through the supercritical steam Rankine cycle and efficient lightweight heat exchange design, effectively overcoming the technical prejudice that the steam system is not suitable for aviation engines. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a schematic diagram of the intercooling regenerative water enhanced turbofan engine cycle provided by the embodiment of the present application (steam injection into the combustion chamber);

[0031] Figure 2 is a schematic diagram of the intercooling regenerative water enhanced turbofan engine cycle provided by the embodiment of the present application (steam injection into the turbine);

[0032] Figure 3 is a schematic diagram of the intercooling regenerative water enhanced turbofan engine cycle provided by the embodiment of the present application (steam injection into the turbine);

[0033] Figure 4 is a schematic diagram of the intercooling regenerative water enhanced turbofan engine cycle provided by the embodiment of the present application (steam injection into the turbine);

[0034] Figure 5 is a schematic diagram of the intercooling regenerative water enhanced turbofan engine cycle provided by the embodiment of the present application (steam injection into the turbine);

[0035] Figure 6 is a schematic diagram of the intercooling regenerative water enhanced turbofan engine cycle provided by the embodiment of the present application (steam injection into the turbine);

[0036] Figure 7 is a schematic diagram of the intercooling regenerative water enhanced turbofan engine cycle provided by the embodiment of the present application (steam injection into the turbine);

[0037] Figure 8 is a schematic diagram of the intercooling regenerative water enhanced turbofan engine cycle provided by the embodiment of the present application (steam injection into the turbine); DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application.

[0039] As shown in Figure 1 An inter-cooled regenerative water augmented turbofan engine is provided by the embodiments of the present application, which comprises:

[0040] The Brayton cycle and supercritical water Rankine cycle in the main flow path are tightly coupled, and connected by the steam turbine, steam generator and condenser. The main flow path comprises an air inlet, a fan, a booster compressor, a high pressure compressor, a combustion chamber, a high pressure turbine, a low pressure turbine and an inner bypass nozzle, which are sequentially arranged from front to back. The outer bypass path and the outer bypass nozzle are connected to the rear of the fan in parallel with the inner bypass components. The supercritical water Rankine cycle comprises a steam turbine, a steam generator, a condenser, a gas-liquid separator and a water pump, which are sequentially connected to form a closed cycle.

[0041] In the described main flow Brayton cycle, the circulating working medium mainly comprises air and mixed gas. During the flight of the aircraft, air enters the turbofan engine fan through the air inlet. The flow path behind the fan is divided into an inner bypass path and an outer bypass path. Due to the higher bypass ratio brought by steam injection, the outer bypass air flow accounts for a large part of the total air flow. The outer bypass air enters the outer bypass nozzle to expand and generate thrust; the inner bypass air is sequentially compressed by the booster and the high pressure compressor, and the pressurized air enters the combustion chamber to mix and burn with fuel and steam to generate high temperature and high pressure gas. Subsequently, the gas is sequentially expanded in the high pressure turbine and the low pressure turbine to do work, and the high temperature gas is cooled by the steam from the outlet of the steam turbine during this process. The high pressure turbine provides power for the high pressure compressor through the high pressure shaft, and the low pressure turbine provides power for the fan, the booster compressor and the water pump through the low pressure shaft. The gas contains a large amount of water vapor, and the supercritical water Rankine cycle is responsible for recycling the injected water. After the low pressure turbine, the high temperature gas still has a large amount of energy and enters the hot end of the steam generator for heat recovery to heat the cold end high pressure liquid water to generate supercritical water vapor. The unrecycled water vapor in the gas at the outlet of the hot end of the steam generator needs to be further cooled by the cold end of the condenser, and the cold end of the condenser uses low temperature air as the cold source. The condensed mixture is separated by the gas-liquid separator, and the condensed water enters the water pump for pressurization. Since the pressure of the condensed water is low, the water pump pressurizes it to the critical pressure, and the water pump is driven by the low pressure turbine. The remaining part of the gas generates thrust through the inner bypass nozzle; and the high pressure condensed water enters the cold end of the steam generator to be heated to generate supercritical water vapor. The supercritical water vapor enters the steam turbine to do work and is cooled. The steam at the outlet of the steam turbine produces part of the liquid water, which is collected and injected between the compressor stages for inter-cooling, and the cooled steam is further injected into the turbine for cooling.

[0042] The embodiment of the present application provides the supercritical water vapor Rankine cycle, steam turbine expansion is arranged; the steam turbine inlet is connected with the steam generator cold end outlet, the steam turbine outlet is connected with the combustion chamber inlet; the water pump pressurizes the liquid water to be higher than 23MPa, so as to meet the supercritical state requirement, meanwhile, the water pump has the performance meeting the working pressure range, and the size is miniaturized as far as possible. The steam turbine can reduce the temperature of the supercritical water vapor; the steam generator hot end is connected with the condenser hot end, and the flow channel of the heat exchanger is arranged in a counterflow mode.

[0043] The embodiment of the present application provides the high-pressure component, low-pressure component, combustion chamber and heat exchange component of the aviation turbine engine, the high-pressure component comprises a high-pressure turbine, a high-pressure compressor and a high-pressure shaft, the low-pressure component comprises a low-pressure turbine, a fan, a booster compressor and a low-pressure shaft, and the heat exchange component comprises an evaporator and a condenser.

[0044] The embodiment of the present application provides that the condensed water first enters the evaporator and is heated into high-temperature steam, the steam then enters the steam turbine and expands to do work and is sprayed into the combustion chamber to participate in combustion or perform turbine cooling, finally, the steam is condensed into liquid water by the condenser to realize water circulation.

[0045] The embodiment of the present application provides that the condenser is arranged under the aircraft wing and is cooled by the aircraft skin, and the condensed water is recovered to improve the circulation efficiency.

[0046] The embodiment of the present application provides that the heat exchanger is a single or multiple heat exchanger elements.

[0047] The embodiment of the present application provides that the evaporator in the heat exchange component is used for heating the condensed water into supercritical water vapor, after the supercritical water vapor enters the steam turbine and expands, the steam is sprayed into the combustion chamber to mix with the gas to improve the combustion efficiency or is sprayed into the high-low pressure turbine to perform cooling and improve the thrust.

[0048] The embodiment of the present application provides that the control module monitors the gaseous water and liquid water content at the steam turbine outlet in real time through a sensor, and controls the water spraying device according to the optimal water spraying amount to optimize the engine operation efficiency.

[0049] The embodiment of the present application provides that the water pump compresses the supercritical state water to meet the requirements of small volume and mass as far as possible, the heat exchanger component adopts a high-temperature aviation alloy to meet the requirements of high-efficiency heat exchange and light weight.

[0050] Embodiment: Application of intercooled regenerative water augmented turbofan engine in commercial passenger aircraft

[0051] In a commercial airliner, the intercooled recuperative water augmented turbofan engine of the present invention is employed. The system effectively reduces the exhaust temperature by using the air cooling effect in high-speed flight through the installation of a condenser under the aircraft skin, while recovering the condensed water and heating it into high-temperature steam through an efficient heat exchange device. The heated steam is injected into the combustion chamber to mix and burn with the gas, thereby improving the combustion efficiency and thrust output, or simultaneously injecting the steam into the turbine for cooling.

[0052] This system not only significantly improves the engine's working efficiency, but also effectively reduces emissions, providing a more environmentally friendly and efficient power solution for commercial aviation.

[0053] As shown in Figure 1 The intercooled recuperative water augmented turbofan engine in this embodiment is a double-shaft gas turbine, including a combustion chamber, a high-pressure compressor, a low-pressure compressor, a high-pressure turbine, a low-pressure turbine, a steam turbine, and a recuperator. The main flow path contains components such as an inlet duct, a fan, a booster compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine, and an internal-duct nozzle, which are arranged and connected in order from front to back. The external-duct and external-duct nozzle are connected in parallel with the internal-duct components behind the fan. The supercritical water vapor Rankine cycle includes a steam turbine, a steam generator, a condenser, a gas-liquid separator, and a water pump, which are connected in order and form a loop, forming a cycle. Figure 1 The steam turbine cooling arrangement is shown, and the supercritical water vapor is injected into the combustion chamber after being expanded and cooled to 470K by the steam turbine. The liquid water produced at the outlet of the steam turbine is injected into the high-pressure compressor inlet for mixing and cooling, thereby effectively improving the power-to-weight ratio. Figure 2 The supercritical water vapor is shown to be injected into the low-pressure turbine after being expanded and cooled to 470K by the steam turbine. The liquid water produced at the outlet of the steam turbine is also injected into the high-pressure compressor inlet to help cool the compressor inlet, reduce compressor power consumption, and improve thrust.

[0054] The engine cruise state is selected as the reference state, the bypass ratio of the inter-cooling water enhanced turbofan engine is 32.9, hydrogen is used as fuel, hydrogen combustion can generate enough water to participate in water circulation, the fan internal and external pressure ratio is 1.5, the pressure ratio of the booster stage compressor is 2.33, the pressure ratio of the high-pressure compressor is 12, the total pressure ratio is 41.9, the inlet air flow is 196 kg / s, and the combustion chamber outlet temperature is 1730 K. The original cycle high-pressure compressor inlet temperature is 363.9 K, and the outlet temperature is 767.7 K. After adding the inter-cooling water enhanced high-pressure compressor outlet temperature is reduced to 603.5 K, reduced by 164.1 K, the compressor power consumption is reduced by 20.5%, and when the optimal water injection amount is 23.2%, the engine total efficiency is 45.2%, the thermal efficiency is 58%. The power-to-weight ratio is 3.46 kN / kg, which is 73% higher than the original engine of 2 kN / kg, so it is inferred that the total weight of the engine basically remains unchanged after adding the supercritical water vapor cycle components.

[0055] The high-pressure components include a high-pressure compressor, a high-pressure turbine, and a high-pressure shaft; the low-pressure components include a low-pressure compressor, a low-pressure turbine, an exhaust gas compressor, a water pump, and a low-pressure shaft; and the heat exchanger components include an evaporator and a condenser. Specifically, the high-pressure turbine drives the high-pressure compressor through the high-pressure shaft, and at the same time, the high-pressure shaft outputs power externally; the low-pressure turbine drives the fan, the booster stage compressor, and the water pump through the low-pressure shaft.

[0056] The working principle of the low-pressure part is relatively complex. The low-pressure turbine receives the gas from the high-pressure turbine and drives the low-pressure compressor and the exhaust gas compressor to operate through the low-pressure shaft. The low-pressure compressor further compresses the air and sends it into the combustion chamber. At the same time, the low-pressure turbine also provides power to the water pump through the low-pressure shaft motor, drives the water pump to send the condensed water in the condenser to the evaporator for heating to generate high-temperature steam. The output power of the steam turbine is connected with the low-pressure shaft to jointly drive the system to operate.

[0057] The evaporator plays a key role in the entire system. The condenser recovers the steam generated after combustion and cools it into liquid water, which is then sent to the evaporator to be heated into high-temperature steam. The evaporator is connected with the high-temperature part of the engine through the heat exchanger, and uses the heat generated by combustion to heat the water into high-temperature steam. These steam is then injected into the combustion chamber to mix with the gas, further improving the combustion efficiency and effectively reducing the exhaust gas temperature. The combination of the steam cycle system and the gas turbine not only improves the energy utilization efficiency, but also recovers the waste heat through the regenerator, thereby reducing the overall energy consumption. The supercritical water vapor does work and cools down in the steam turbine, and the liquid water generated at the outlet of the steam turbine is collected and injected into the inter-cooling stage of the compressor to cool down. The steam generated in the steam generator is made of GH4133 material, with an inner diameter of 1.3 meters and an outer diameter of 2.7 meters, which enhances the heat exchange efficiency. The surface of the heat exchanger is covered with a heat transfer enhancement coating, and the heat transfer efficiency reaches 90%.

[0058] According to Figure 3 Example, the water injection amount of the inter-cooled regenerative water augmented turbofan engine (expressed as water air ratio, WAR) varies in the range of 0 to 47.7%. The low pressure turbine outlet pressure is set to 23.2 kPa (i.e. ambient pressure), and the supercritical water is compressed to 25 MPa, and the water vapor temperature in the steam generator is increased to above 650 K. Under this condition, the total efficiency and fuel saving rate of the steam continuously injected aero turbine engine at different water air ratios (WAR) are calculated. Experimental data show that the performance of the engine at different water vapor ratios is significantly improved compared with the conventional geared turbofan engine. The total efficiency of the conventional geared turbofan engine is 36.8%. By optimizing the water vapor ratio WAR and introducing supercritical water vapor injection, the total efficiency and fuel saving rate of the engine are significantly improved, and the specific changes are shown in Figure 3 .

[0059] Air enters the system through inlet 1 and is compressed in stages via booster stage 22 and high pressure compressor 25. The booster stage achieves initial air pressure through an axially mounted fan, while the high pressure compressor further increases the air pressure to ensure that high pressure air is provided for the combustion chamber 31. This process achieves continuous air flow connection through internal passage 24.

[0060] High pressure air enters the combustion chamber 31, mixes with injected fuel and burns to produce high temperature and pressure gas. The combustion chamber is connected to the high pressure turbine 41, which is driven by the high pressure gas to rotate and complete the energy conversion and release part of the shaft power, which is connected to the compressor 25 through the high pressure shaft 3 to achieve a power cycle.

[0061] High pressure gas flows from the high pressure turbine 41 to the low pressure turbine 45. The low pressure turbine is mechanically connected to the water pump, steam turbine and other components through the low pressure shaft 5, and the rotation output of the low pressure turbine provides shaft power for the water pump and steam turbine. In addition, the low pressure turbine is connected to the steam generator 61 through the steam recovery system 63 to utilize the waste heat of the exhaust gas.

[0062] The steam generator 61 in the system converts liquid water into high temperature steam using waste heat, and the steam drives shaft power output through the steam turbine 62, while the steam is separated into gaseous and liquid parts after being treated by the gas-liquid separator 63, and the gaseous steam is recovered and the liquid water is re-injected into the water tank 64 by the water pump to form a complete steam cycle.

[0063] The exhaust gas after combustion enters the cooler 73 through the exhaust pipe 71, and is discharged to the atmosphere after the temperature is reduced by the cooler. The cooler is connected to the main exhaust system through the external cooling pipe 72, and its installation position ensures the smooth flow of exhaust gas and the heat dissipation efficiency.

[0064] The system ensures stable and efficient energy and fluid transfer between modules through precise connection and positioning design. The water pump motor and steam generator employ independent control systems to ensure efficient water circulation and heat recovery. Simultaneously, the coordinated operation of the gas-liquid separator and cooling system, through reliable connections and installation, guarantees that exhaust emissions meet standards and improves the overall system efficiency and safety.

[0065] Figure 4 The arrangement of the condensers in the aircraft wings and fuselage is shown.

[0066] Figure 5 and Figure 6 The results show that the overall efficiency and thermal efficiency increase with the increase of the water-to-vapor ratio, reaching their maximum values ​​at WAR = 23.2% (overall efficiency 45.2% and thermal efficiency 58%, respectively).

[0067] Figure 8 The demonstration showcases the specific form of an aviation steam generator, primarily composed of front and rear water-cooled walls and tube bundles. High-temperature combustion gases directly contact the tube bundles, thereby reheating the working fluid within the water-cooled walls to generate steam. Regarding material selection, key components of the steam generator can utilize high-temperature aerospace alloys, including but not limited to nickel-based alloys and cobalt-based alloys. The specific material selection can be determined based on actual operating conditions and requirements.

[0068] In summary, this invention proposes an indirect-cooled, regenerative water-enhanced turbofan engine. By introducing a supercritical steam Rankine cycle, steam injection technology, and high-efficiency heat exchange technology, this engine significantly improves energy recovery efficiency and combustion efficiency. The condenser is installed under the wing, utilizing high-speed airflow for cooling and recovering exhaust heat. The steam generator heats the condensate into supercritical steam, and steam injection further enhances combustion efficiency and thrust output. Simultaneously, the indirect-cooling design effectively reduces compressor power consumption and improves the power-to-weight ratio. This invention uses hydrogen fuel as the power source, further improving the system's environmental performance and reducing emissions. Experimental results show that this engine exhibits significant advantages in thrust-to-weight ratio, fuel efficiency, and overall efficiency, particularly demonstrating broad application prospects in energy saving and emission reduction.

[0069] Example 1: High-efficiency cyclic control and dual-condition application

[0070] This embodiment provides a specific operating method for an intercooled regenerative water-enhanced turbofan engine, applicable to both high-load and stable cruise operating conditions.

[0071] 1) Structural layout and component operation

[0072] In the main path, air enters the fan through the intake duct and flows to the inner duct and outer bypass duct.

[0073] The inner air enters the booster compressor and the high-pressure compressor. The compressed high-pressure air is mixed with supercritical water vapor and fuel, and then burned in the combustion chamber.

[0074] The high-temperature and high-pressure gas is expanded by the high-pressure turbine and the low-pressure turbine to do work. The high-pressure shaft drives the high-pressure compressor, and the low-pressure shaft drives the fan and the booster compressor.

[0075] 2) Steam cycle and regenerative process

[0076] The high-temperature gas discharged from the turbine enters the steam generator hot end to heat the high-pressure condensed water, generating supercritical water vapor.

[0077] The generated supercritical water vapor enters the steam turbine to expand and do work. Part of the steam is injected into the combustion chamber to participate in combustion, and part is used for high and low pressure turbine cooling.

[0078] The steam at the outlet of the steam turbine is mixed with liquid water, cooled by the condenser hot end, and separated into liquid water by the gas-liquid separator. The liquid water is pressurized by the water pump and returned to the steam generator cold end to realize closed cycle.

[0079] 3) Water injection cooling and thrust augmentation control under special conditions

[0080] In the high-load take-off condition, the steam injection amount to the combustion chamber is increased to improve the combustion efficiency and thrust output.

[0081] In the steady cruise condition, the steam is mainly used for high and low pressure turbine cooling to ensure the stability and fuel economy of the system.

[0082] The steam at the outlet of the steam turbine is cooled to an appropriate temperature and recovered, effectively improving the cycle efficiency.

[0083] Example 2: Double interference assembly and high-precision machining technology

[0084] This embodiment provides a double interference assembly method for an inter-cooled regenerative water-enhanced turbofan engine to solve the precision error and thermal stress problems of dissimilar materials during assembly.

[0085] 1) Assembly steps

[0086] First interference assembly: heating assembly

[0087] Heat the adapter positioning block 2 (aluminum alloy material) to a predetermined temperature, expand it, and then assemble it on the rotor shaft 3 (structural steel material). Through the principle of thermal expansion and cold contraction, a stable interference fit is achieved.

[0088] Second hole machining

[0089] Due to the influence of assembly error, the mounting hole of the limit pin 1 is difficult to completely align, so after the first assembly is completed, a secondary hole is made using a high-precision numerical control machining center. Specific operation:

[0090] Group drilling of pre-made holes with a remaining amount of 0.10.2mm;

[0091] After rough boring, the single-sided allowance is 0.020.05mm;

[0092] The fine boring is to achieve a hole diameter deviation of less than 0.01mm and a surface roughness of less than Ra0.8.

[0093] 2) Second interference assembly: liquid nitrogen cooling assembly

[0094] Cool the limit pin 1 to liquid nitrogen temperature and insert it into the assembly hole after shrinking to avoid the influence of overall heating on the stability of the first assembly structure.

[0095] During the normal temperature recovery process, the limit pin forms a cross double interference structure with the adapter positioning block 2 and the rotor shaft 3, enhancing the stability and anti-centrifugal force capability under high-speed rotating conditions.

[0096] 3) Assembly quality control and detection

[0097] Use sensors to monitor the installation precision of the limit pin to ensure that the circular runout is less than 0.02mm.

[0098] Use a go-no-go gauge to detect the precision of the assembly hole to ensure the high reliability and long life of the overall assembly structure.

[0099] Example 1 focuses on the engine working process and dual-condition operation efficiency, and realizes thrust enhancement and high-efficiency cooling through steam injection and regenerative processes.

[0100] Example 2 focuses on the double interference assembly process, and solves the assembly precision and structural stability problems of dissimilar materials through the combination of heating and liquid nitrogen cooling assembly.

[0101] By Figure 5 and Figure 6 It can be seen that the inter-cooled regenerative water augmented turbofan engine improves the total efficiency by about 7.2% compared to the traditional engine. The introduction of water vapor in the combustion chamber improves the temperature distribution of the combustion process, increasing the combustion efficiency by 3%5%. The peak combustion temperature is reduced by about 100200K, reducing the generation of harmful gases such as nitrogen oxides (NOx) and improving environmental performance.

[0102] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any modification, equivalent replacement and improvement within the technical range disclosed by the present application and within the spirit and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A water-enhanced turbofan engine with indirect cooling and regenerative heating, characterized in that, The engine includes a Brayton cycle and a supercritical steam Rankine cycle in the main circuit, and the two cycles are coupled to each other; The main path includes, in order: intake duct, fan, supercharger compressor, high-pressure compressor, combustion chamber, high-pressure turbine, low-pressure turbine, and internal exhaust nozzle; The outer duct and the inner duct are arranged in parallel, and the outer duct is connected to the outer duct tail nozzle. The supercritical steam Rankine cycle includes: a steam turbine, a steam generator, a condenser, a gas-liquid separator, and a water pump. These components are connected in sequence through flow channels to form a closed loop. The steam at the outlet of the steam turbine is connected to the combustion chamber through a flow channel, and either participates in combustion or is injected into the turbine for cooling. The inlet of the steam turbine is connected to the cold end outlet of the steam generator via a connecting pipe. The outlet of the steam turbine is connected to the combustion chamber or the high-pressure turbine and low-pressure turbine via pipelines; The water pump is connected to the condensate outlet of the liquid water through a pipeline, compressing the liquid water to a supercritical pressure of over 23 MPa, and is powered by a low-pressure shaft motor. The hot end of the steam generator and the hot end of the condenser are connected by a heat exchanger channel arranged in counter-current manner to improve heat exchange efficiency.

2. The intercooled regenerative water-enhanced turbofan engine according to claim 1, characterized in that, High-pressure components include: a high-pressure turbine and a high-pressure compressor connected via a high-pressure shaft; The low-pressure components include a low-pressure turbine and a low-pressure compressor connected by a low-pressure shaft, which is also connected to a low-pressure shaft motor to provide driving force for the water pump. The heat exchange components include a steam generator and a condenser, which convert condensate into supercritical steam through a flow channel and deliver it to the steam turbine.

3. The intercooled regenerative water-enhanced turbofan engine according to claim 1, characterized in that, The condenser is installed under the aircraft wing and is in close contact with the wing skin, cooling by utilizing the natural heat dissipation characteristics of the aircraft skin; Condensate is separated into gas and liquid by a gas-liquid separator installed at the condenser outlet. The liquid water is connected to the water pump inlet through a flow channel and is pressurized and circulated, thereby improving the engine's circulation efficiency.

4. The intercooled regenerative water-enhanced turbofan engine according to claim 1, characterized in that, The control module monitors the content of gaseous and liquid water in real time through sensors installed at the steam turbine outlet; Based on sensor feedback data, the water injection system is controlled to inject precise amounts of steam into the high and low pressure turbines for cooling or into the combustion chamber to optimize combustion efficiency, thereby dynamically optimizing engine performance.

5. The intercooled regenerative water-enhanced turbofan engine according to claim 1, characterized in that, The heat exchanger is made of high-temperature aerospace alloy material, and the arrangement of the heat exchanger flow channels meets the requirements of high-efficiency heat exchange performance. The water pump is integrated with other engine components and its size and weight are optimized to meet the space and weight constraints of aero engines. The water pump is installed at the shaft power transmission position of the low-pressure shaft and is rigidly fixed to other components through a compact bracket, thereby ensuring the compactness of the engine structure and the stability of the system.

6. A method for operating an indirect-cooled regenerative water-enhanced turbofan engine, characterized in that, The method includes the following steps: Step 1: Air compression Outside air enters the turbofan engine through the intake duct, and after being compressed in stages by the fan, the booster compressor, and the high-pressure compressor, it enters the combustion chamber. Step 2: Combustion and Expansion High-pressure air is mixed and burned with fuel and supercritical water vapor in the combustion chamber to produce high-temperature and high-pressure gas, which then enters the high-pressure turbine and the low-pressure turbine to expand and do work. Step 3: Steam Circulation The high-temperature and high-pressure gas enters the hot end inlet of the steam generator from the outlet of the low-pressure turbine, and the high-pressure liquid water pressurized by the water pump enters the evaporator from the cold end inlet to exchange heat with it, thereby generating supercritical water vapor. Step 4: Steam Utilization and Recovery Supercritical steam is cooled by doing work in a steam turbine. Some of the steam is injected into the combustion chamber to participate in combustion or to cool the turbine. The remaining steam is cooled and recovered into liquid water in the condenser. After being pressurized by a water pump, it re-enters the steam generator, forming a closed loop.

7. The operating method of the indirect-cooled regenerative water-enhanced turbofan engine as described in claim 6, characterized in that, The method includes: The assembly process employs a dual approach: heating and liquid nitrogen cooling. Specifically: During the initial assembly, the adapter positioning block and the rotor shaft are joined by a heated interference fit. During the second assembly, the limit pins are cooled with liquid nitrogen to avoid damaging the structure assembled in the first assembly.

8. The operating method of the indirect-cooled regenerative water-enhanced turbofan engine as described in claim 6, characterized in that, The method includes: By monitoring the gaseous and liquid water content at the steam turbine outlet in real time using sensors, the water injection device is controlled to inject steam into the combustion chamber or high and low pressure turbines at the optimal water injection rate, thereby improving engine combustion efficiency and cooling effect.

9. The operating method of the indirect-cooled regenerative water-enhanced turbofan engine as described in claim 6, characterized in that, The method includes: The remaining energy after the high-temperature gas expands in the low-pressure turbine is recovered through a steam generator to heat the condensate and generate supercritical steam. The heat exchange efficiency is optimized by using a counter-flow heat exchanger, while the condenser is arranged under the aircraft wing and uses the skin for heat dissipation, so as to achieve efficient recovery and reuse of condensate.

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