Hydrogen fuel turbofan engine based on third working medium indirect heat exchange

Abstract

The invention provides a hydrogen fuel turbofan engine based on indirect heat exchange of a third working medium, which relates to the technical field of hydrogen fuel aero-engines and comprises a fan, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine, an exhaust nozzle, a liquid hydrogen tank and a heat exchange system. The heat exchange system comprises a first air heat exchange system, a second air heat exchange system, a hydrogen fuel heat exchange system and a fuel gas heat exchange system. The third working medium indirect heat exchange technology, the cooling air cooling technology and the indirect cooling heat regeneration technology are used for achieving multiple heat management targets such as fuel preheating, air cooling and waste heat utilization of the hydrogen fuel turbofan engine.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen fuel aero-engines, and particularly to a hydrogen fuel turbofan engine based on indirect heat exchange with a third working fluid. Background Art

[0002] The aviation industry has been seeking to reduce its negative impact on the environment and achieve more sustainable development. Aviation flight carbon emissions account for 12% of global warming caused by humans, and among the current carbon emissions in the aviation industry, 79% are generated by the combustion of aviation kerosene. As a clean and renewable energy source, hydrogen fuel has attracted much attention in the global energy field in recent years. It has the characteristics of zero emissions, high energy density, and renewability, making it a powerful tool for reducing carbon emissions and promoting the transformation to green energy. Introducing hydrogen fuel into aero-engines is an effective way to reduce aviation carbon emissions, a potential solution to future climate problems, and can bring greater sustainability to the aviation industry, which will be a disruptive technological change in the aviation field.

[0003] Hydrogen has completely different physical and chemical properties from traditional aviation kerosene. Hydrogen fuel aero-engines face the following thermal management problems: 1) Preheating of liquid hydrogen fuel. The hydrogen on board is stored in liquid form, and the boiling point of liquid hydrogen is extremely low (1 atm, boiling point is 20.37 K), and it needs to absorb heat through a heat exchanger to be completely vaporized before combustion; 2) Efficient utilization of the cryogenic liquid hydrogen heat sink. In order to improve the thermal efficiency of the hydrogen energy aero-engine, it is necessary to efficiently utilize the liquid hydrogen heat sink at multiple levels to cool high-temperature components; 3) Safety risks. Direct heat exchange between hydrogen and high-temperature air poses a risk of hydrogen leakage causing engine fire and explosion. Therefore, safe indirect heat exchange with a third working fluid is required.

[0004] Facing the different thermal management requirements of gas turbine engines, numerous thermal management technologies have been proposed in the academic community. The third - working - fluid indirect heat - exchange technology has been widely applied to hypersonic precooled combined - cycle engines. Using helium as the third working fluid to achieve the indirect transfer of energy between airborne cryogenic fuel and high - temperature air has received the favor of domestic and foreign researchers. To improve the cooling air quality of the turbine cooling air in aero - engines and thus increase the turbine inlet temperature, researchers have proposed the aero - engine cooling air technology, which has also been successfully applied to turbofan engines, such as the AL - 31F engine. In addition, the intercooling and recuperation technology has also been widely applied to gas turbines on the ground and ships. This technology can effectively reduce the compressor power consumption and fuel consumption rate, enabling the design pressure ratio of the compressor to be further increased and improving the thermal efficiency of the engine. Therefore, if the third - working - fluid indirect heat - exchange technology, the cooling air technology, and the intercooling and recuperation technology are simultaneously applied to a hydrogen - fuel aero - engine and a reasonable scheme framework is proposed, numerous thermal management objectives such as hydrogen - fuel preheating, inter - stage compressor air cooling, turbine cooling air cooling, and gas waste heat utilization will be achieved. This will provide a basis for the design of future hydrogen - fuel aero - engines. Therefore, it is very necessary to design a hydrogen - fuel turbofan engine scheme based on the third - working - fluid indirect heat - exchange technology. Summary of the Invention

[0005] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a hydrogen - fuel turbofan engine based on the third - working - fluid indirect heat - exchange technology.

[0006] To achieve the above - mentioned purpose, the present invention provides the following solutions:

[0007] The present invention provides a hydrogen - fuel turbofan engine based on the third - working - fluid indirect heat - exchange technology, including: a fan, a low - pressure compressor, a high - pressure compressor, a combustion chamber, a high - pressure turbine, a low - pressure turbine, a nozzle, a liquid - hydrogen tank, and a heat - exchange system. The heat - exchange system includes a first air heat - exchange system, a second air heat - exchange system, a hydrogen - fuel heat - exchange system, and a gas heat - exchange system;

[0008] The fan is connected to the low - pressure compressor and the bypass duct based on an air flow path. Among them, the air passing through the bypass duct is discharged after expansion to generate thrust. The low - pressure compressor is connected to the first air heat - exchange system based on an air flow path. The first air heat - exchange system is connected to the high - pressure compressor. The high - pressure compressor is connected to the second heat - exchange system through an air flow path. The second heat - exchange system is connected to the high - pressure turbine and the gas heat - exchange system through an air flow path. The gas heat - exchange system is connected to the combustion chamber through an air flow path. The combustion chamber is connected to the high - pressure turbine through a gas flow path. The high - pressure turbine is connected to the low - pressure turbine through a gas flow path. The low - pressure turbine is connected to the gas heat - exchange system through a gas flow path. The gas heat - exchange system is connected to the nozzle through a gas flow path;

[0009] The liquid hydrogen tank is connected to the hydrogen fuel heat exchange system through a hydrogen fuel flow channel. The hydrogen fuel heat exchange system is connected to the combustion chamber through a hydrogen fuel flow channel. The hydrogen fuel heat exchange system is connected to the first heat exchange system and the second heat exchange system through a third working fluid flow channel. The first heat exchange system and the second heat exchange system are connected to the hydrogen fuel heat exchange system through the third working fluid flow channel in a cycle.

[0010] The first air heat exchange system is used to realize the heat exchange between the high-temperature air discharged from the low-pressure compressor and the third working fluid.

[0011] The second air heat exchange system is used to realize the heat exchange between a part of the high-temperature air discharged from the high-pressure compressor and the third working fluid.

[0012] The hydrogen fuel heat exchange system is used to realize the heat exchange between the third working fluid after heat exchange and the liquid hydrogen, and preheat the liquid hydrogen.

[0013] The gas heat exchange system is used to realize the heat exchange between the high-temperature gas discharged from the low-pressure turbine and the remaining air discharged from the high-pressure compressor, and recover the waste heat of the high-temperature gas.

[0014] Preferably, the first air heat exchange system is an air-third working fluid intercooler. The outlet of the low-pressure compressor is connected to the air flow channel inlet of the air-third working fluid intercooler through an air flow channel. The air flow channel outlet of the air-third working fluid intercooler is connected to the air flow channel inlet of the high-pressure compressor through an air flow channel. The hydrogen fuel heat exchange system is connected to the third working fluid flow channel inlet of the air-third working fluid intercooler through a third working fluid flow channel. The third working fluid flow channel outlet of the air-third working fluid intercooler is connected to a third working fluid circulation pump through a third working fluid flow channel. The third working fluid circulation pump is connected to the hydrogen fuel heat exchange system through a third working fluid flow channel.

[0015] Preferably, the second air heat exchange system is a compressor bleed-air-third working fluid heat exchanger. The air flow channel outlet of the high-pressure compressor is connected to the air flow channel inlet of the compressor bleed-air-third working fluid heat exchanger. The air flow channel outlet of the compressor bleed-air-third working fluid heat exchanger is connected to the cooling air flow channel inlet of the high-pressure turbine. The hydrogen fuel heat exchange system is connected to the third working fluid flow channel inlet of the compressor bleed-air-third working fluid heat exchanger through a third working fluid flow channel. The third working fluid flow channel outlet of the compressor bleed-air-third working fluid heat exchanger is connected to the third working fluid circulation pump through a third working fluid flow channel.

[0016] Preferably, the hydrogen fuel heat exchange system is a hydrogen fuel - tertiary working fluid heat exchanger. The tertiary working fluid circulation pump is connected to the inlet of the tertiary working fluid flow path of the hydrogen fuel - tertiary working fluid heat exchanger through a tertiary working fluid flow path. The outlet of the tertiary working fluid flow path of the hydrogen fuel - tertiary working fluid heat exchanger is connected to the inlet of the tertiary working fluid flow path of the regulating valve and the compressor bleed air - tertiary working fluid heat exchanger through a tertiary working fluid flow path. The regulating valve is connected to the inlet of the tertiary working fluid flow path of the air - tertiary working fluid intercooler through a tertiary working fluid flow path. The liquid hydrogen tank is connected to the inlet of the hydrogen fuel flow path of the hydrogen fuel - tertiary working fluid heat exchanger through a hydrogen fuel flow path. The outlet of the hydrogen fuel flow path of the hydrogen fuel - tertiary working fluid heat exchanger is connected to the inlet of the hydrogen fuel flow path of the combustion chamber through a hydrogen fuel flow path.

[0017] Preferably, the gas heat exchange system is a gas - air recuperator. The outlet of the gas flow path of the low - pressure turbine is connected to the inlet of the gas flow path of the gas - air recuperator through a gas flow path. The outlet of the gas flow path of the gas - air recuperator is connected to the inlet of the gas flow path of the tail nozzle through a gas flow path. The outlet of the air flow path of the high - pressure compressor is connected to the inlet of the air flow path of the gas - air recuperator through an air flow path. The outlet of the air flow path of the gas - air recuperator is connected to the inlet of the air flow path of the combustion chamber through an air flow path.

[0018] According to the specific embodiments provided by the present invention, the following technical effects are disclosed by the present invention:

[0019] The present invention provides a hydrogen - fuel turbofan engine based on indirect heat exchange of a tertiary working fluid, including a fan, a low - pressure compressor, a high - pressure compressor, a combustion chamber, a high - pressure turbine, a low - pressure turbine, a tail nozzle, a liquid hydrogen tank, and a heat exchange system. The heat exchange system includes a first air heat exchange system, a second air heat exchange system, a hydrogen fuel heat exchange system, and a gas heat exchange system. The present invention realizes the following multi - functional coupling of multiple thermal management through a tertiary working fluid:

[0020] 1) A multi - stage heat load collaborative distribution mechanism. Different from the traditional intercooled recuperated engine that uses air - air heat exchange, this system introduces supercritical helium as an intermediate working fluid to establish a triple - heat coupling network for preheating liquid hydrogen fuel (low - temperature section), intercooling of compressors (medium - temperature section), and cooling of turbine cooling air (high - temperature section). The three - level temperature zones form a heat flow gradient matching through a closed - cycle of helium working fluid, integrating the traditional scattered thermal management modules into a unified thermodynamic system, and improving the overall thermal efficiency of the engine;

[0021] 2) The intercooler-recuperator synergistically amplifies the waste heat recovery efficiency. In a traditional intercooled recuperated engine, reducing the inlet temperature of the high-pressure compressor by the intercooler will simultaneously decrease the temperature difference across the recuperator, resulting in a decline in the recuperation efficiency. In the present invention, by transferring the heat load of the intercooler to the third working fluid system (instead of the traditional air-air heat exchange), the inlet temperature of the gas side of the recuperator is increased, and the inlet temperature of the air side is decreased. The temperature difference between the two sides is further enlarged compared with the traditional structure, enabling an increase in the heat transfer amount of the recuperator and a higher waste heat recovery rate.

[0022] 3) Dynamic thermal control adjustment. By means of a regulating valve provided in the branch of the air-third working fluid intercooler, the dynamic flow distribution of the helium working fluid between the air intercooling heat exchange branch and the compressor bleed heat exchange branch is realized. When the engine is in the high-thrust operating condition, the opening of the regulating valve is reduced to preferentially ensure the temperature reduction requirement of the turbine cooling air by increasing the cooling effect of the compressor bleed; when in the cruise operating condition, the opening of the regulating valve is increased to increase the helium flow rate in the intercooler branch, so as to improve the thermal efficiency of the engine and reduce the fuel consumption rate. This dynamic thermal control adjustment keeps the system always in the optimal thermodynamic state, and the overall thermal efficiency is improved compared with the fixed flow distribution scheme. Brief Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 It is a schematic structural diagram of a hydrogen fuel turbofan engine based on indirect heat exchange of a third working fluid according to the present invention.

[0025] Reference numerals: 1, inlet of the fan; 1.1, bypass air flow; 1.2, bypass duct outlet; 2, air flow path inlet of the low-pressure compressor; 3, air flow path outlet of the low-pressure compressor; 4, air flow path inlet of the high-pressure compressor; 5, air flow path outlet of the high-pressure compressor; 5.1, air flow path inlet of the gas-air recuperator; 5.2, air flow path inlet of the compressor bleed-third working fluid heat exchanger; 5.3, air flow path inlet of the combustion chamber; 5.4, air flow path inlet of the high-pressure turbine; 6, hydrogen fuel flow path inlet of the hydrogen fuel-third working fluid heat exchanger; 6.1, hydrogen fuel flow path inlet of the combustion chamber; 7, gas flow path inlet of the high-pressure turbine; 8, gas flow path inlet of the low-pressure turbine; 9, gas flow path inlet of the gas-air recuperator; 10, gas flow path inlet of the nozzle; 11, gas flow path outlet of the nozzle; 12, inlet of the third working fluid flow path of the hydrogen fuel-third working fluid heat exchanger; 13, outlet of the third working fluid flow path of the hydrogen fuel-third working fluid heat exchanger; 13.1, inlet of the third working fluid flow path of the air-third working fluid intercooler; 13.2, inlet of the third working fluid flow path of the compressor bleed-third working fluid heat exchanger; 14.1, outlet of the third working fluid flow path of the air-third working fluid intercooler; 14.2, outlet of the third working fluid flow path of the compressor bleed-third working fluid heat exchanger; 15, third working fluid circulation pump. Detailed implementation manners

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] The object of the present invention is to provide a hydrogen fuel turbofan engine based on indirect heat exchange of a third working fluid, and use the indirect heat exchange technology of the third working fluid, the cooling air technology and the intercooling and recuperation technology to achieve many thermal management objectives such as fuel preheating, air cooling and waste heat utilization of the hydrogen fuel turbofan engine.

[0028] To make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0029] As Figure 1 shown, the present invention provides a hydrogen fuel turbofan engine based on indirect heat exchange of a third working fluid, including: a fan, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine, a nozzle, a liquid hydrogen tank and a heat exchange system, and the heat exchange system includes a first air heat exchange system, a second air heat exchange system, a hydrogen fuel heat exchange system and a gas heat exchange system;

[0030] The fan is connected to the low-pressure compressor and the bypass duct based on an air flow path. Among them, the air passing through the bypass duct is expanded and then discharged to generate thrust. After the air is inhaled by the inlet 1 of the fan and preliminarily pressurized, the air is divided into two streams. One is the bypass air stream 1.1, which flows to the bypass duct, is expanded in the bypass duct, and is discharged from the bypass duct outlet 1.2 to generate thrust; the other is the core air stream, which enters the low-pressure compressor through the air flow path inlet 2 of the low-pressure compressor, is pressurized, and then flows out from the air flow path outlet 3 of the low-pressure compressor. The low-pressure compressor is connected to the first air heat exchange system based on an air flow path. The first air heat exchange system is connected to the high-pressure compressor. The high-pressure compressor is connected to the second heat exchange system through an air flow path. The second heat exchange system is connected to the high-pressure turbine and the gas heat exchange system through an air flow path. The gas heat exchange system is connected to the combustion chamber through an air flow path. The gas flow path outlet of the combustion chamber is connected to the gas flow path inlet 7 of the high-pressure turbine through a gas flow path. The gas flow path outlet of the high-pressure turbine is connected to the gas flow path inlet 8 of the low-pressure turbine through a gas flow path. The gas flow path outlet of the low-pressure turbine is connected to the gas heat exchange system through a gas flow path. The gas heat exchange system is connected to the gas flow path inlet 10 of the tail pipe through a gas flow path, and after accelerating and expanding in the tail pipe, it flows out from the gas flow path outlet 11 of the tail pipe to generate another part of the thrust of the engine;

[0031] The liquid hydrogen tank is connected to the hydrogen fuel heat exchange system through a hydrogen fuel flow path. The hydrogen fuel heat exchange system is connected to the combustion chamber through a hydrogen fuel flow path. The hydrogen fuel heat exchange system is connected to the first heat exchange system and the second heat exchange system through a third working fluid flow path. The first heat exchange system and the second heat exchange system are connected to the hydrogen fuel heat exchange system through a third working fluid flow path in a cycle;

[0032] The first air heat exchange system is used to realize the heat exchange between the high-temperature air discharged from the low-pressure compressor and the third working fluid;

[0033] The second air heat exchange system is used to realize the heat exchange between the high-temperature air discharged from the high-pressure compressor and the third working fluid;

[0034] The hydrogen fuel heat exchange system is used to realize the heat exchange between the third working fluid after heat exchange and the liquid hydrogen to preheat the liquid hydrogen;

[0035] The gas heat exchange system is used to realize the heat exchange between the high-temperature gas discharged from the low-pressure turbine and the air discharged from the high-pressure compressor to recover the waste heat of the high-temperature gas.

[0036] The first air heat exchange system is an air-third working fluid intercooler. The outlet of the low-pressure compressor is connected to the air flow path inlet 3 of the air-third working fluid intercooler through an air flow path. The air flow path outlet of the air-third working fluid intercooler is connected to the air flow path inlet 4 of the high-pressure compressor through an air flow path. The hydrogen fuel heat exchange system is connected to the third working fluid flow path inlet 13.1 of the air-third working fluid intercooler through a third working fluid flow path. The third working fluid flow path outlet 14.1 of the air-third working fluid intercooler is connected to the third working fluid circulation pump 15 through a third working fluid flow path. The third working fluid circulation pump 15 is connected to the hydrogen fuel heat exchange system through a third working fluid flow path.

[0037] The second air heat exchange system is a compressor bleed air-third working fluid heat exchanger. The air flow path outlet 5 of the high-pressure compressor is connected to the air flow path inlet 5.2 of the compressor bleed air-third working fluid heat exchanger. The air flow path outlet of the compressor bleed air-third working fluid heat exchanger is connected to the air flow path inlet 5.4 of the high-pressure turbine. The hydrogen fuel heat exchange system is connected to the third working fluid flow path inlet 13.2 of the compressor bleed air-third working fluid heat exchanger through a third working fluid flow path. The third working fluid flow path outlet 14.2 of the compressor bleed air-third working fluid heat exchanger is connected to the third working fluid circulation pump 15 through a third working fluid flow path.

[0038] The hydrogen fuel heat exchange system is a hydrogen fuel-third working fluid heat exchanger. The third working fluid circulation pump 15 is connected to the inlet 12 of the third working fluid flow path of the hydrogen fuel-third working fluid heat exchanger through a third working fluid flow path. The outlet 13 of the third working fluid flow path of the hydrogen fuel-third working fluid heat exchanger is connected to a regulating valve through a third working fluid flow path. The regulating valve is connected to the third working fluid flow path inlet 13.1 of the air-third working fluid intercooler through a third working fluid flow path. The liquid hydrogen tank is connected to the hydrogen fuel flow path inlet 6 of the hydrogen fuel-third working fluid heat exchanger through a hydrogen fuel flow path. The hydrogen fuel flow path outlet of the hydrogen fuel-third working fluid heat exchanger is connected to the hydrogen fuel flow path inlet 6.1 of the combustion chamber through a hydrogen fuel flow path.

[0039] The gas heat exchange system is a gas-air recuperator. The gas flow path outlet of the low-pressure turbine is connected to the gas flow path inlet 9 of the gas-air recuperator through a gas flow path. The gas flow path outlet of the gas-air recuperator is connected to the gas flow path inlet 10 of the tail pipe through a gas flow path. The air flow path outlet 5 of the high-pressure compressor is connected to the air flow path inlet 5.1 of the gas-air recuperator through an air flow path. The air flow path outlet of the gas-air recuperator is connected to the air flow path inlet 5.3 of the combustion chamber through an air flow path.

[0040] An introduction to the entire operation process of the present invention: After the fan inhales air and initially pressurizes it, the air is divided into two streams. One is the bypass airflow, flowing into the bypass duct, expanding in the bypass duct and then discharging to generate thrust. The other is the core airflow, flowing into the core duct. First, it flows out after being pressurized by the low-pressure compressor, and then further flows out after being pressurized again by the high-pressure compressor. It enters the gas-air recuperator. After the high-pressure and high-temperature air is heated by the gas, it flows into the combustion chamber, mixes with the hydrogen fuel and burns to generate high-pressure and high-temperature gas. The gas enters the high-pressure turbine, expands and does work in the high-pressure turbine to drive the high-pressure turbine. The high-pressure turbine and the high-pressure compressor are coaxial, and thus drive the high-pressure compressor to operate. The high-pressure turbine guides the gas into the low-pressure turbine. The gas further expands and does work in the low-pressure turbine to drive the low-pressure turbine. The low-pressure turbine and the fan as well as the low-pressure compressor are coaxial, and thus drive the fan and the low-pressure compressor to operate. The low-pressure turbine guides the gas into the gas-air recuperator. After the gas is cooled by the air flowing out of the high-pressure compressor, it flows into the tail nozzle, accelerates and expands in the tail nozzle and then discharges to generate another part of the thrust of the engine;

[0041] The hydrogen fuel turbofan engine is provided with a heat exchange system. Among them, the air-third working medium intercooler and the compressor bleed-air-third working medium heat exchanger are connected in parallel on two branch flow paths of the third working medium. The hydrogen fuel-third working medium heat exchanger is located on the main flow path of the third working medium and is connected in series with the third working medium circulation pump. The regulating valve is arranged in the branch of the air-third working medium intercooler to regulate the flow distribution of the third working medium and achieve the best thermodynamic working state of the whole machine under different flight conditions. The air exchanges heat with the third working medium in the air-third working medium intercooler after passing through the low-pressure compressor, and then enters the high-pressure compressor after heat exchange. The high-pressure compressor outputs two parts of air. One part exchanges heat with the third working medium in the compressor bleed-air-third working medium heat exchanger and then flows into the high-pressure turbine to cool the high-pressure turbine blades. The other part enters the gas-air recuperator to exchange heat with the high-temperature gas introduced by the low-pressure turbine to recover the waste heat at the outlet of the low-pressure turbine, increase the temperature of the air entering the combustion chamber for combustion, reduce the fuel consumption, and then enters the combustion chamber to be mixed and burned with the hydrogen fuel;

[0042] After the liquid hydrogen flows out of the liquid hydrogen tank, it flows into the hydrogen fuel-third working medium heat exchanger. After being completely vaporized by the heating of the third working medium, it flows into the combustion chamber to be mixed and burned with the air. The third working medium is driven by the third working medium circulation pump to flow out. After being cooled by the hydrogen fuel-third working medium heat exchanger on the main path, it flows out and is divided into two streams, flowing to the air-third working medium intercooler and the compressor bleed-air-third working medium heat exchanger respectively. After mixing, it flows into the third working medium circulation pump again to form a closed-loop flow. The flow rates of the third working medium in the two branches are regulated by the regulating valve located on the branch of the air-third working medium intercooler.

[0043] When the turbofan engine is operating, the present invention uses a third working fluid for indirect heat exchange. The third working fluid transfers the heat of the high-temperature air between the high- and low-pressure compressors and the bleed air from the high-pressure compressor to the liquid hydrogen fuel to preheat the liquid hydrogen, so that it is completely vaporized to facilitate subsequent combustion. At the same time, the closed-loop flow of the third working fluid is adopted to indirectly utilize the cryogenic liquid hydrogen heat sink. In addition, a recuperator is used to recover and utilize the waste heat at the outlet of the low-pressure turbine, improve the engine thermal efficiency, reduce the engine fuel consumption rate, and enhance the economy.

[0044] The creative core of the present invention lies in the first collaborative architecture design of the third working fluid circulation system and the gas recuperation system in a hydrogen-fueled turbofan engine. The present invention realizes the following functional couplings of multiple thermal management through the third working fluid:

[0045] 1) Multi-stage thermal load collaborative distribution mechanism. Different from the traditional intercooled recuperated engine that uses air-air heat exchange, this system introduces supercritical helium as an intermediate working fluid to establish a triple thermal coupling network of liquid hydrogen fuel preheating (low-temperature section), compressor intercooling (medium-temperature section), and turbine cooling air cooling (high-temperature section). The three temperature zones form a heat flow gradient matching through the closed-loop circulation of the helium working fluid, integrating the traditional dispersed thermal management modules into a unified thermodynamic system and improving the overall thermal efficiency of the engine;

[0046] 2) Intercooler-recuperator collaborative amplification of waste heat recovery benefits. In a traditional intercooled recuperated engine, reducing the inlet temperature of the high-pressure compressor by the intercooler will simultaneously reduce the temperature difference on both sides of the recuperator, resulting in a decrease in the recuperation efficiency. In the present invention, by transferring the intercooler thermal load to the third working fluid system (instead of the traditional air-air heat exchange), the inlet temperature of the gas side of the recuperator is increased, and the inlet temperature of the air side is decreased. The temperature difference between the two sides is further enlarged compared with the traditional structure, increasing the heat transfer amount of the recuperator and improving the waste heat recovery rate;

[0047] 3) Thermal control dynamic regulation. By setting a regulating valve in the branch of the air-third working fluid intercooler, the dynamic distribution of the flow rate of the helium working fluid in the air intercooling heat exchange branch and the bleed air heat exchange branch is realized. When the engine is in a high-thrust operating condition, the opening of the regulating valve is reduced to preferentially ensure the cooling requirement of the turbine cooling air by increasing the cooling effect of the bleed air. When in a cruise operating condition, the opening of the regulating valve is increased to increase the helium flow rate in the intercooler branch to improve the engine thermal efficiency and reduce the fuel consumption rate. This thermal control dynamic regulation keeps the system always in the optimal thermodynamic state, and the overall thermal efficiency is improved compared with the fixed flow rate distribution scheme.

[0048] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other.

[0049] In this article, specific examples are used to elaborate on the principles and implementation modes of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation modes and application scopes. To sum up, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A hydrogen fuel turbofan engine based on indirect heat exchange with a third working medium, characterized in that: include: A fan, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine, a tail nozzle, a liquid hydrogen tank and a heat exchange system, wherein the heat exchange system includes a first air heat exchange system, a second air heat exchange system, a hydrogen fuel heat exchange system and a gas heat exchange system; The fan is connected to the low-pressure compressor and the outer duct based on an air flow channel, wherein the air passing through the outer duct is discharged after expansion to generate thrust, the low-pressure compressor is connected to the first air heat exchange system based on the air flow channel, the first air heat exchange system is connected to the high-pressure compressor, the high-pressure compressor is connected to the second heat exchange system through the air flow channel, the second heat exchange system is connected to the high-pressure turbine and the gas heat exchange system through the air flow channel, the gas heat exchange system is connected to the combustion chamber through the air flow channel, the combustion chamber is connected to the high-pressure turbine through the gas flow channel, the high-pressure turbine is connected to the low-pressure turbine through the gas flow channel, the low-pressure turbine is connected to the gas heat exchange system through the gas flow channel, and the gas heat exchange system is connected to the tail nozzle through the gas flow channel; The liquid hydrogen tank is connected to the hydrogen fuel heat exchange system through a hydrogen fuel flow channel, the hydrogen fuel heat exchange system is connected to the combustion chamber through a hydrogen fuel flow channel, the hydrogen fuel heat exchange system is connected to the first heat exchange system and the second heat exchange system through a third working fluid flow channel, and the first heat exchange system and the second heat exchange system are cyclically connected to the hydrogen fuel heat exchange system through the third working fluid flow channel; The first air heat exchange system is used to realize heat exchange between the high-temperature air discharged from the low-pressure compressor and the third working medium; The second air heat exchange system is used to achieve heat exchange between part of the high-temperature air discharged from the high-pressure compressor and the third working medium; The hydrogen fuel heat exchange system is used to realize heat exchange between the third working fluid and liquid hydrogen after heat exchange, and preheat the liquid hydrogen; The gas heat exchange system is used to achieve heat exchange between the high-temperature gas discharged from the low-pressure turbine and the remaining air discharged from the high-pressure compressor, and is used to recover the waste heat of the high-temperature gas.

2. The hydrogen fuel turbofan engine according to claim 1, characterized in that: The first air heat exchange system is an air-third working fluid intercooler, the outlet of the low-pressure compressor is connected to the air flow channel inlet of the air-third working fluid intercooler through an air flow channel, the air flow channel outlet of the air-third working fluid intercooler is connected to the air flow channel inlet of the high-pressure compressor through an air flow channel, the hydrogen fuel heat exchange system is connected to the third working fluid flow channel inlet of the air-third working fluid intercooler through the third working fluid flow channel, the third working fluid flow channel outlet of the air-third working fluid intercooler is connected to the third working fluid circulation pump through the third working fluid flow channel, and the third working fluid circulation pump is connected to the hydrogen fuel heat exchange system through the third working fluid flow channel.

3. The hydrogen fuel turbofan engine according to claim 2, characterized in that: The second air heat exchange system is a compressor bleed air-third working fluid heat exchanger, the air flow channel outlet of the high-pressure compressor is connected to the air flow channel inlet of the compressor bleed air-third working fluid heat exchanger, the air flow channel outlet of the compressor bleed air-third working fluid heat exchanger is connected to the cooling air flow channel inlet of the high-pressure turbine, the hydrogen fuel heat exchange system is connected to the third working fluid flow channel inlet of the compressor bleed air-third working fluid heat exchanger through the third working fluid flow channel, and the third working fluid flow channel outlet of the compressor bleed air-third working fluid heat exchanger is connected to the third working fluid circulation pump through the third working fluid flow channel.

4. The hydrogen fuel turbofan engine according to claim 3, characterized in that: The hydrogen fuel heat exchange system is a hydrogen fuel-third working fluid heat exchanger, the third working fluid circulation pump is connected to the inlet of the third working fluid flow channel of the hydrogen fuel-third working fluid heat exchanger through the third working fluid flow channel, the outlet of the third working fluid flow channel of the hydrogen fuel-third working fluid heat exchanger is connected to the regulating valve and the third working fluid flow channel inlet of the compressor bleed air-third working fluid heat exchanger through the third working fluid flow channel, the regulating valve is connected to the third working fluid flow channel inlet of the air-third working fluid intercooler through the third working fluid flow channel, the liquid hydrogen tank is connected to the hydrogen fuel flow channel inlet of the hydrogen fuel-third working fluid heat exchanger through the hydrogen fuel flow channel, and the hydrogen fuel flow channel outlet of the hydrogen fuel-third working fluid heat exchanger is connected to the hydrogen fuel flow channel inlet of the combustion chamber through the hydrogen fuel flow channel.

5. The hydrogen fuel turbofan engine according to claim 4, characterized in that: The gas heat exchange system is a gas-air reheater, the gas flow channel outlet of the low-pressure turbine is connected to the gas flow channel inlet of the gas-air reheater through the gas flow channel, the gas flow channel outlet of the gas-air reheater is connected to the gas flow channel inlet of the tail nozzle through the gas flow channel, the air flow channel outlet of the high-pressure compressor is connected to the air flow channel inlet of the gas-air reheater through the air flow channel, and the air flow channel outlet of the gas-air reheater is connected to the air flow channel inlet of the combustion chamber through the air flow channel.

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