Power device of low-temperature fuel direct injection gas compressor, control method and aero-engine

Abstract

The invention discloses a power device of a low-temperature fuel direct injection gas compressor, a control method and an aero-engine, and belongs to the technical field of aero-engines. The power device comprises an engine body and a low-temperature fuel storage and transportation system; the low-temperature fuel storage and transportation system comprises a hydrogen storage tank and a flow distributor, the hydrogen storage tank is connected with a first channel and a second channel, and the flow distributor is used for controlling the flow of fuel entering the first channel and the second channel from the hydrogen storage tank. The first channel penetrates through the exhaust nozzle heat exchanger to exchange heat with high-temperature fuel gas in the exhaust nozzle, the tail end of the first channel is connected with a combustion nozzle, and the combustion nozzle is used for spraying fuel subjected to heat exchange to the combustion chamber; the tail end of the second channel is connected with a fuel atomization nozzle, and the fuel atomization nozzle is used for spraying low-temperature fuel to at least one of the interstage or the front end of the compressor unit. The technical problems that an indirect cooling heat exchanger arranged in the air compressor is complex in structure, space is limited, and pneumatic loss is large are solved.

Description

Technical Field

[0001] This application relates to the field of aero-engine technology, specifically to the power plant, control method, and aero-engine of a cryogenic fuel direct injection compressor. Background Technology

[0002] As the design pressure ratio of aero engines continues to increase, compressors require more compression work, leading to a reduction in the effective power available for thrust output from the gas turbine. Simultaneously, the temperature and pressure of air continue to rise during compression, making subsequent compression by the compressor more difficult and further increasing the overall compression work, which limits further improvements in engine thermal efficiency. To reduce compressor compression power consumption, traditional aero engines can incorporate an intercooling system in the compressor's intermediate stage. By cooling the air during compression, the compression curve returns to a lower temperature range, thereby reducing the power required for subsequent compression and improving the overall thermal efficiency of the engine. However, traditional intercooling technology requires a dedicated intercooler heat exchanger inside the compressor, using an external or intermediate cooling medium for heat exchange. This makes the size, weight, structural complexity, and maintainability of the heat exchanger limiting factors, resulting in limited application of this technology in conventional turbine engines.

[0003] In hydrogen fuel cell engines, due to the extremely low temperature and abundant available cold energy of liquid hydrogen, existing technologies have proposed an indirect cooling scheme that utilizes hydrogen fuel as a cold source. This involves placing an indirect heat exchanger between the low-pressure and high-pressure compressor stages, allowing direct or indirect heat exchange between the liquid hydrogen and the high-temperature compressed air within the compressor, thereby reducing the gas temperature and compression power consumption. This structure utilizes the inherent cooling capacity of hydrogen fuel, combining indirect cooling with fuel supply, theoretically improving overall efficiency.

[0004] However, such interstage cooling solutions still require heat exchangers to be placed in the compact interstage space of the compressor. The internal space of the compressor is very limited, and its blades, disks, and flow channels are already optimized to the limit for aerodynamic performance and strength. Adding heat exchangers between stages presents the following main problems: First, the structural layout is extremely difficult, requiring changes to the casing, flow channels, and even blade layout, resulting in poor engineering feasibility; Second, the heat exchanger itself introduces additional flow resistance, reducing the compressor's flow capacity and aerodynamic efficiency, and even adversely affecting stability. Summary of the Invention

[0005] This application provides a power unit, control method, and aero-engine for a cryogenic fuel direct injection compressor, in order to solve the technical problem that the design of heat exchangers in compressors is difficult and will have an adverse effect on the stability of compressors.

[0006] According to one aspect of this application, a power unit, control method and aero engine for a cryogenic fuel direct injection compressor are provided, including an engine body and a cryogenic fuel storage and transportation system; The engine body includes an air intake, a compressor unit, a combustion chamber, and a tail nozzle heat exchanger arranged sequentially along the axial direction. The cryogenic fuel storage and transportation system includes a hydrogen storage tank and a flow distributor. The hydrogen storage tank is connected to a first channel and a second channel, respectively. The flow distributor is used to control the fuel flow rate from the hydrogen storage tank into the first channel and the second channel, respectively. The first channel passes through the tailpipe heat exchanger to exchange heat with the high-temperature gas in the tailpipe, and the tail end of the first channel is connected to a combustion nozzle, which is used to inject the heat-exchanged fuel into the combustion chamber. The tail end of the second channel is connected to a fuel atomizing nozzle, which is used to inject cryogenic fuel into at least one of the stages or front end of the compressor unit, so that the injected cryogenic fuel is mixed with the compressed air in the compressor unit and enters the combustion chamber together with the compressed air.

[0007] Optionally, the compressor unit includes multiple stator blades and multiple rotor blades arranged along the axial direction, with the stator blades and rotor blades alternately distributed along the axial direction; when the fuel atomizing nozzle is used to inject fuel into the interstage of the compressor unit, the fuel atomizing nozzle is located on the inner wall of the casing between adjacent stator blades and rotor blades, so that the injected cryogenic fuel can directly enter the flow channel of the corresponding interstage.

[0008] Optionally, multiple fuel atomizing nozzles are arranged along the axial direction of the compressor unit and are respectively distributed at the interstage positions between different stator blades and rotor blades; at least two adjacent fuel atomizing nozzles constitute a group of atomizing nozzles, forming multiple groups of atomizing nozzles distributed along the axial direction; the injection pressure and / or injection quantity of each atomizing nozzle group are set to different parameters according to the pressure and temperature conditions corresponding to the compressor stage.

[0009] Optionally, the injection angle of the atomizing nozzle group relative to the mainstream direction of the compressor increases progressively with each compressor stage, so that the injection angle of the atomizing nozzle group closer to the intake is smaller than the injection angle of the atomizing nozzle group farther from the intake.

[0010] Optionally, each atomizing nozzle assembly is equipped with a corresponding switching valve for controlling fuel flow and on / off status.

[0011] Optionally, the first channel is provided with a pressure regulating valve and a flow regulating valve. The pressure regulating valve is used to stabilize the fuel pressure after heat exchange by the tail nozzle heat exchanger, and the flow regulating valve is used to regulate the fuel flow supplied to the combustion nozzle.

[0012] Optionally, when the fuel atomizing nozzle is used to inject fuel into the front end of the compressor unit, the fuel atomizing nozzle is installed in the guide section of the air intake and / or the compressor unit inlet, for injecting cryogenic fuel into the intake air entering the front end of the compressor unit at a preset injection angle.

[0013] Optionally, the fuel atomizing nozzle and the outer side of the second channel are provided with a heat insulation structure, the heat insulation structure including a carbon fiber winding layer and / or a double-layer tube heat insulation layer.

[0014] According to another aspect of this application, a power unit control method for a cryogenic fuel direct injection compressor is also provided, for the power unit of the aforementioned cryogenic fuel direct injection compressor, characterized in that: S1. Start-up phase: During engine start-up and low-power operation, the flow distributor controls the flow distributor to deliver all liquid fuel from the hydrogen storage tank to the tail nozzle heat exchanger through the first channel, and injects it into the combustion chamber through the combustion nozzle, so as to maintain normal engine operation when there is no cooling requirement. S2. After the engine power is increased, intercooling is performed. When the engine reaches its maximum state and needs to further increase the output power, the flow distributor is controlled to deliver part of the liquid fuel to the fuel atomizing nozzle through the second channel, and the fuel atomizing nozzle is activated to inject into the compressor stage, so that the low temperature fuel is directly mixed into the compressed air between the corresponding stages of the compressor, thereby reducing the air temperature between the compressor stages and reducing the compression work. S3. After the engine power continues to increase, pre-cooling is performed. The fuel atomizing nozzle is controlled to inject low-temperature fuel into the compressor unit inlet at the front end of the intake duct, so that the injected fuel is pre-mixed with the intake air entering the compressor unit to reduce the temperature of the compressor unit inlet air. S4. Forming combined cooling: With both the intercooling injection between compressor stages and the precooling injection at the front end of the compressor stage activated, the intercooling injection acts on the middle and rear sections of the compressor stage, and the precooling injection acts on the compressor inlet, forming a superimposed cooling effect along the axial direction of the compressor stage, thereby achieving a reduction in compression work and an improvement in the overall thermal efficiency of the engine brought about by combined cooling.

[0015] Furthermore, an aircraft engine is also provided, comprising the aforementioned power unit of a cryogenic fuel direct injection compressor.

[0016] In summary, this application includes at least one of the following beneficial technical effects: This application solves the technical problems of complex structure, limited space, large aerodynamic losses, and potential weakening of compressor stability caused by arranging an intercooled heat exchanger inside the compressor through a combined design of the first and second channels. The first channel passes through the tail nozzle heat exchanger, allowing liquid hydrogen to exchange heat with the high-temperature combustion gas in the tail nozzle region and be converted into gaseous or supercritical fuel. The heat exchanger is located in the tail nozzle rather than inside the compressor, thus completely avoiding the structural modifications, casing enlargement, or blade arrangement changes required to add heat exchangers between compressor stages. It also avoids blockage of the compressor flow channels and additional pressure losses, and has no adverse effect on compressor stability. At the same time, the first channel preheats the hydrogen fuel, ensuring good injection and mixing conditions when the fuel enters the combustion chamber.

[0017] Building upon this, the second channel of this application directly injects cryogenic hydrogen fuel between compressor stages and / or at the front end, allowing the cold energy of liquid hydrogen to act directly on the high-temperature compressed air within the compressor through a mixing process. This method eliminates the need for a physical heat exchanger, avoiding the flow obstruction, local flow distortion, or boundary layer thickening associated with heat exchangers, and also does not affect the compressor's flow capacity. The injection-mixing cooling method achieves intercooling and precooling functions without altering the compressor's inherent structure. It avoids the difficulties of arranging traditional heat exchangers and creates effective temperature control at different locations within the compressor, helping to reduce compression work, improve aerodynamic matching, and enhance overall thermal efficiency.

[0018] In addition to the purposes, features, and advantages described above, this application has other purposes, features, and advantages. A further detailed description of this application will be provided below with reference to the figures. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the intercooled power unit of the cryogenic fuel direct injection compressor of this application; Figure 2 This is a schematic diagram of fuel injection into the interstage of the compressor unit according to this application; Figure 3 This is a schematic diagram of the injection of cryogenic fuel into the front end of the compressor unit according to this application; Figure 4 This is a schematic diagram illustrating the simultaneous injection of cryogenic fuel into the interstage and front-end of the compressor unit according to this application.

[0020] Legend: 1. Intake duct; 2. Stator blades; 3. Rotor blades; 4. Combustion chamber; 5. Gas turbine; 6. Power turbine; 7. Tail nozzle heat exchanger; 8. Hydrogen storage tank; 9. Bottle valve; 10. Flow distributor; 11. Switch valve; 12. Fuel atomizing nozzle; 13. Pressure regulating valve; 14. Flow regulating valve; 15. Combustion nozzle. Detailed Implementation

[0021] The embodiments of this application are described in detail below with reference to the accompanying drawings; however, this application may be implemented in a variety of different ways as defined and covered below.

[0022] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0023] This application discloses an intercooled power unit for a cryogenic fuel direct injection compressor, including an engine body and a cryogenic fuel storage and transportation system. The engine body includes an intake duct 1, a compressor unit, a combustion chamber 4, and a tail nozzle heat exchanger 7 arranged sequentially along the axial direction. The cryogenic fuel storage and transportation system includes a hydrogen storage tank 8 and a flow distributor 10. The hydrogen storage tank 8 is connected to a first channel and a second channel. The flow distributor 10 is used to control the fuel flow rate entering the first channel and the second channel from the hydrogen storage tank 8. The first channel passes through the tail nozzle heat exchanger 7 to exchange heat with the high-temperature gas in the tail nozzle. The tail end of the first channel is connected to a combustion nozzle 15, which is used to inject the heat-exchanged fuel into the combustion chamber 4. The tail end of the second channel is connected to a fuel atomizing nozzle 12, which is used to inject cryogenic fuel into at least one of the stages or the front end of the compressor unit, so that the injected cryogenic fuel mixes with the compressed air in the compressor unit and enters the combustion chamber 4 together with the compressed air.

[0024] Reference Figure 1 The indirect-cooled power unit of this embodiment comprises two main parts: the engine body and the cryogenic fuel storage and transportation system. The engine body, along its axial direction, includes an intake duct 1, a compressor unit, a combustion chamber 4, and a tailpipe heat exchanger 7. A gas turbine 5 and a power turbine 6 are disposed between the combustion chamber 4 and the tailpipe heat exchanger 7. The intake duct 1 guides outside air into the compressor unit, which compresses the air in stages before sending it into the combustion chamber 4. Inside the combustion chamber 4, hydrogen fuel mixes with the compressed air and burns to form high-temperature gas. This high-temperature gas then expands through the turbine to perform work and is discharged into the tailpipe heat exchanger 7 for further energy exchange.

[0025] The cryogenic fuel storage and transportation system includes a hydrogen storage tank 8 and a flow distributor 10 connected to it. The hydrogen storage tank 8 stores cryogenic liquid hydrogen fuel. During engine operation, the flow distributor 10 distributes the fuel as needed into a first channel and a second channel. The first channel delivers the liquid fuel to the exhaust nozzle heat exchanger 7, where the liquid hydrogen exchanges heat with the high-temperature exhaust gas, causing the fuel to change from a cryogenic liquid state to a gaseous or supercritical state. The heat-exchanged fuel enters the combustion nozzle 15 from the end of the first channel. The combustion nozzle 15 injects the heat-exchanged fuel into the combustion chamber 4 to mix with compressed air for stable combustion.

[0026] The second channel differs from the first channel in that its primary function is not to provide fuel to combustion chamber 4, but rather to directly utilize the low-temperature characteristics of liquid hydrogen to perform interstage cooling or pre-cooling of the compressor unit. Interstage cooling refers to the injection of low-temperature hydrogen fuel into a specific interstage location within the compressor unit, allowing the fuel to directly mix with the high-temperature compressed air in that stage. Because the compressor temperature rises progressively during multi-stage compression, the interstage air temperature is typically high. Injecting liquid hydrogen into this location allows for rapid absorption of heat from the air, significantly reducing its temperature before it enters the next compression stage. This temperature reduction reduces the compression work required for subsequent compressions, thereby improving the overall compressor efficiency. The core characteristic of interstage cooling is that the injection location is inside the compressor, in the interstage region between the stator and rotor, with the fuel primarily acting in the mid-to-late stages of compression. In contrast, pre-cooling refers to the mixing of low-temperature hydrogen fuel with the incoming air before it enters the compressor unit, i.e., at the front of intake duct 1 or at the compressor inlet. By injecting liquid hydrogen at the compressor inlet, the temperature of the air entering the compressor is reduced before compression begins, lowering the starting temperature of the entire compression process and thus improving the overall thermodynamic state of the compressor. The core characteristic of pre-cooling is that the injection point is before the compressor inlet, acting on the initial state of the entire compression process. In this technical solution, the second channel can choose to implement intermittent cooling or pre-cooling according to the engine operating conditions, or implement both cooling methods sequentially at different stages, allowing the compressor to achieve a wider range of cooling effects. Intermittent cooling mainly reduces the inlet temperature of the high-pressure section, while pre-cooling mainly reduces the inlet temperature of the low-pressure section. These two methods create different temperature regulation effects in the axial direction of the compressor, providing a significant reduction in compression work and an improvement in overall thermal efficiency for the engine.

[0027] The second channel is connected to a fuel atomizing nozzle 12 at its tail end. This nozzle injects cryogenic liquid hydrogen in a mist or micro-spray form into the interstage or front-end position of the compressor unit, allowing the liquid hydrogen to rapidly mix with the high-temperature compressed air inside the compressor over a short distance. After mixing, the cryogenic hydrogen fuel significantly reduces the temperature of the compressed air, thereby reducing the compression work in subsequent compression stages. Simultaneously, it achieves fuel-air premixing, providing a more uniform fuel-air mixture for subsequent combustion. After the cryogenic hydrogen fuel is injected into the compressor interstage or front-end, the resulting gaseous or supercritical hydrogen fuel is transported to the combustion chamber 4 along with the compressed air. Because the mixing process has already reduced the temperature of the compressed air, the overall compression power consumption of the compressor is reduced, thereby improving the engine's cycle efficiency. At the same time, the hydrogen fuel injected into the compression system can also enter the combustion chamber 4 as part of the premixed fuel, making combustion more stable and efficient.

[0028] The intercooled power unit in this embodiment effectively improves the airflow state of the compressor by directly injecting cryogenic liquid hydrogen into the compressor unit. This eliminates the need for additional physical heat exchangers between compressor stages, avoiding the structural complexity, increased weight, and aerodynamic losses associated with traditional intercoolers. This structure not only simplifies the cooling path of the hydrogen fuel cell engine but also offers greater engineering feasibility and improved thermal efficiency.

[0029] Reference Figure 2 In one embodiment, the compressor unit includes multi-stage stator blades 2 and multi-stage rotor blades 3 arranged along the axial direction, with the stator blades 2 and rotor blades 3 alternately distributed along the axial direction; when the fuel atomizing nozzle 12 is used to inject fuel into the interstage of the compressor unit, the fuel atomizing nozzle 12 is located at the corresponding inner wall position of the casing between adjacent stator blades 2 and rotor blades 3, so that the injected cryogenic fuel can directly enter the flow channel of the corresponding interstage.

[0030] A typical aero-engine compressor unit consists of multiple axially arranged compressor stages. Each stage includes a row of fixed stator blades 2 and a row of rotating rotor blades 3. The stator blades 2 are mounted on the compressor casing and are used to change the direction of the incoming airflow and provide a suitable inlet angle for the subsequent rotor blades 3. The rotor blades 3 are mounted on the compressor rotor disk and rotate at high speed with the rotor, thereby inputting energy and compressing the airflow. The stators and rotors of each stage are arranged alternately along the axial direction to form a multi-stage compression structure, achieving a step-by-step increase in air pressure. In this embodiment, when cryogenic fuel is used for interstage cooling of the compressor, the fuel atomizing nozzle 12 is located on the inner wall of the casing between adjacent stator blades 2 and rotor blades 3. The inner wall of the casing is located at the outer edge of the compressor flow channel and is the structural part connecting the stator blades 2 and covering the entire compressor flow channel. Installing the fuel atomizing nozzle 12 at this position allows the injected cryogenic fuel to directly enter the flow channel area between the stator and rotor without changing the internal aerodynamic structure of the compressor.

[0031] Since the area between the stator and rotor is the primary heating section within each stage of the compressor, the temperature of the high-temperature compressed air continues to rise as it passes through the stator and rotor blades 3. Therefore, injecting cryogenic hydrogen fuel at this location allows the fuel to quickly mix with the compressed air in that stage and rapidly absorb heat, effectively reducing the temperature of the air in that stage. This injection method reduces the compression work required for the subsequent rotor blades 3 to further compress the air, thereby reducing overall compression power consumption. Furthermore, placing the atomizing nozzle on the inner wall of the casing avoids impacting the blade structure and eliminates the need for additional heat exchangers inside the compressor, maintaining the overall aerodynamic shape and flow characteristics of the compressor. The nozzle's placement on a fixed part of the casing also facilitates pipeline connection and maintenance and can withstand the temperature changes caused by liquid hydrogen injection.

[0032] In one embodiment, multiple fuel atomizing nozzles 12 are arranged along the axial direction of the compressor unit and are respectively distributed at the interstage positions between different stator blades 2 and rotor blades 3; at least two adjacent fuel atomizing nozzles 12 constitute a group of atomizing nozzles, forming multiple groups of atomizing nozzles distributed along the axial direction; the injection pressure and / or injection quantity of each atomizing nozzle group are set to different parameters according to the pressure and temperature conditions corresponding to the compressor stage.

[0033] To ensure optimal cooling of the cryogenic fuel between different compressor stages, this embodiment arranges multiple fuel atomizing nozzles 12 at various locations along the axial direction of the compressor unit. These nozzles are fixedly installed in different interstage regions of the casing, so that each nozzle corresponds to a specific compressor stage. As the air temperature and pressure increase progressively along the axial direction at each stage of the compressor, nozzles at different locations can perform jet cooling based on the thermal state of the corresponding stage.

[0034] To facilitate the control and management of multiple nozzles, this embodiment groups at least two adjacent fuel atomizing nozzles 12 together, forming multiple nozzle groups along the axial direction of the entire compressor. The number of nozzles in each nozzle group can be set according to the compressor stage spacing, flow channel geometry, and cooling requirements. By using the grouping method of the intercooled power unit of the cryogenic fuel direct injection compressor, staged and segmented cooling control can be achieved, making the injection behavior better matched with the compressor operating state, and also facilitating modular management of the injection behavior by the control system.

[0035] The injection parameters of each atomizing nozzle group are set differently according to the air conditions of its respective compressor stage. The compressor compresses air stage by stage along the axial direction, and the pressure ratio, temperature rise, and air density vary significantly between different stages. Therefore, the injection parameters need to be determined separately based on the aerodynamic and thermodynamic conditions of each stage. Typically, the air temperature and pressure corresponding to nozzle groups located at the compressor inlet or early stages are lower. To avoid excessive cooling affecting the operational stability of the low-pressure compressor, their injection pressure can be set to a lower range, and the injection volume can also be configured at a smaller proportion. As the air gradually heats up in the middle and high-pressure sections of the compressor, its temperature and pressure increase significantly, making cooling more urgent. Therefore, nozzle groups located in the middle and later stages can be set with higher injection pressures and larger injection volumes to ensure a sufficient temperature reduction after mixing. The injection pressure is usually set with reference to the static and total pressure levels of the stage, allowing the injection flow to smoothly enter the interstage channel and fully mix with the mainstream air. The injection volume is set based on the air temperature rise, airflow mass flow rate, and the desired temperature reduction for that stage. By analyzing the air temperature, pressure, and flow data of different stages, a set of injection parameter distributions that are adjusted step by step according to the compressor axial direction can be formed, so that the injection intensity matches the thermal load of the air in that stage.

[0036] This multi-stage, axially aligned, and grouped structure allows for more precise adaptation of cryogenic hydrogen fuel injection to the temperature distribution of each stage of the compressor, improving overall cooling efficiency and reducing unnecessary fuel consumption. Furthermore, the presence of multiple nozzle groups allows the system to selectively activate different nozzle groups based on engine operating conditions, achieving greater operational flexibility.

[0037] In one embodiment, the spray angle of the atomizing nozzle group relative to the main direction of the compressor increases progressively with each compressor stage, so that the spray angle of the atomizing nozzle group closer to the intake duct 1 is smaller than the spray angle of the atomizing nozzle group farther away from the intake duct 1.

[0038] In this embodiment, to accommodate the varying characteristics of the compressor's axial airflow angle, velocity, and density with each stage, the injection angle of each atomizing nozzle assembly relative to the compressor's mainstream direction is designed to increase progressively. The airflow velocity in the front section of the compressor is high, and the airflow direction is relatively close to the axial direction. Therefore, the nozzle assembly located near the inlet duct 1 has a smaller injection angle, allowing the injected liquid hydrogen to quickly enter the compressor flow channel along the mainstream direction and form initial mixing with the airflow. A smaller injection angle facilitates spray penetration and maintains a stable mixing interface with the high-speed airflow, avoiding disruption of the flow structure of the front section of the compressor.

[0039] As air flows towards the rear section of the compressor, its velocity gradually decreases while its temperature and density gradually increase. The high-temperature air requires a more intense jet mixing effect to achieve effective cooling. Therefore, the injection angle of the nozzle assemblies located in the middle and high-pressure sections of the compressor is correspondingly increased. This allows the spray to achieve a wider mixing range upon entering the flow channel, thereby expanding the contact area between the cryogenic hydrogen fuel and the compressed air, improving mixing uniformity and cooling efficiency. The progressively increasing injection angle also allows the diffusion pattern of the spray jet to match the characteristics of the downstream airflow, avoiding problems such as insufficient spray range or limited mixing.

[0040] In one embodiment, each atomizing nozzle group is equipped with a corresponding on / off valve 11 for controlling fuel flow and on / off status. In this embodiment, to achieve independent control of multiple nozzle groups and avoid unnecessary waste of cooling capacity or local overcooling of the compressor caused by simultaneous injection of all nozzles, this application provides an independent on / off valve 11 on the fuel supply branch of each atomizing nozzle group. The on / off valve 11 is installed in the second channel branch pipeline connected to the nozzle group and is used to adjust the fuel flow of the nozzle group or completely shut off the injection of the nozzle group.

[0041] Since different nozzle groups are located in different stages of the compressor, they need to be started or stopped under different engine operating conditions. Therefore, the structure of one switching valve 11 for each group allows the injection control unit to activate or deactivate the nozzle groups step by step according to the engine status. For example, when the engine is under high power, only the nozzle groups located in the middle and later stages can be activated first to meet the cooling requirements of the high-temperature air section; when the engine enters a higher power state, the nozzle groups located in the front stages can be gradually activated, so that the injection behavior can be increased step by step according to the cooling requirements. The switching valve 11, as the control switch of a single module, enables the nozzle groups to have the ability to control each other without interference, ensuring flexible scheduling of the cooling strategy.

[0042] The switching valve 11 not only controls the opening and closing of the injection, but also adjusts the injection flow rate of the nozzle group by regulating the valve core position, achieving continuous or graded adjustment of the injection intensity. This allows the nozzle group to more precisely adapt to the cooling requirements of different temperature ranges. Since each switching valve 11 only controls the injection behavior of its corresponding nozzle group without affecting other nozzle groups, the entire injection cooling system has modular and hierarchical control characteristics. This allows the intermittent cooling strategy to not only be finely divided spatially, but also flexibly allocate cooling capacity according to engine status in time. By setting the switching valve 11 at the nozzle group level rather than the single nozzle level, this embodiment maintains structural simplicity while considering control flexibility and engineering feasibility. This enables the injection cooling system to adapt to different operating conditions without increasing control difficulty, thereby better improving the compressor's online cooling effect.

[0043] In one embodiment, a pressure regulating valve 13 and a flow regulating valve 14 are provided on the first channel between the tail nozzle heat exchanger 7 and the combustion nozzle 15. The pressure regulating valve 13 is used to stabilize the fuel pressure after heat exchange by the tail nozzle heat exchanger 7, and the flow regulating valve 14 is used to regulate the fuel flow supplied to the combustion nozzle 15.

[0044] In this embodiment, to ensure a stable pressure and flow rate of hydrogen fuel supplied to the combustion chamber 4 via the first channel, two key control components, a pressure regulating valve 13 and a flow regulating valve 14, are installed along the fuel delivery path of the first channel. After liquid hydrogen passes through the tailpipe heat exchanger 7 in the first channel, its temperature, pressure, and density fluctuate due to changes in the heat exchange process and tailpipe exhaust conditions. Without further pressure stabilization, the pressure of the fuel after heat exchange may change adversely, affecting the injection quality of the combustion nozzle 15. Therefore, in this embodiment, the pressure regulating valve 13 is arranged within the first channel section between the tailpipe heat exchanger 7 and the combustion nozzle 15 to regulate the pressure of the fuel after heat exchange, ensuring that the fuel entering the combustion nozzle 15 remains within a relatively stable operating pressure range and guaranteeing the stability of the fuel injection and atomization process.

[0045] The pressure regulating valve 13 and the flow regulating valve 14 are arranged in series along the first channel between the tailpipe heat exchanger 7 and the combustion nozzle 15, forming a fuel delivery link for heat exchange, pressure stabilization, flow regulation, and injection in the first channel. The combination of the two not only solves the problem of easy fluctuation in fuel pressure after heat exchange, but also gives the first channel precise flow control capability, thereby ensuring that the combustion chamber 4 can obtain stable and reliable fuel injection conditions under different operating conditions, improving the overall operating stability and combustion efficiency of the engine.

[0046] Reference Figure 3In one embodiment, to achieve the pre-cooling function of the compressor inlet air, the fuel atomizing nozzle 12 can also be arranged in the guide section of the intake duct 1 or at the compressor unit inlet, for injecting cryogenic hydrogen fuel into the airflow entering the compressor front end. The guide section of the intake duct 1 is usually located between the engine intake port and the first rotor blade 3 of the compressor. The airflow at this location has not yet entered the compressor compression section, and its flow direction, velocity, and turbulence characteristics are relatively stable, making it a preferred area for fuel injection and mixing. Therefore, arranging the fuel atomizing nozzle 12 in the guide section allows the cryogenic fuel to be initially mixed with the air over a longer path, thereby achieving temperature reduction before the air enters the compressor.

[0047] In one embodiment, when the fuel atomizing nozzle 12 is used to inject fuel to the front end of the compressor unit, the fuel atomizing nozzle 12 is installed in the intake duct 1 and is used to inject cryogenic fuel into the intake air entering the front end of the compressor unit at a preset injection angle.

[0048] Specifically, in front-end precooling applications, the fuel atomizing nozzle 12 can be positioned in the inlet duct 1 guide section, the compressor inlet, or both, depending on the engine structure and cooling requirements. When the nozzle is positioned in the inlet duct 1 guide section, the cryogenic hydrogen fuel is fully mixed with the incoming air along a longer path before entering the compressor, which can uniformly reduce the inlet temperature over a large area, thus improving overall temperature uniformity. When the nozzle is positioned at the compressor inlet, the injected cryogenic fuel can directly act on the air entering the compressor at the position closest to the compression stage, achieving a rapid and direct temperature drop, allowing the compression process to start from a lower initial temperature, suitable for high-power operating conditions that require rapid adjustment of the inlet temperature. When the nozzle is simultaneously positioned in the guide section and the compressor inlet, a segmented precooling effect can be achieved axially through superposition, allowing the inlet air to receive both uniform basic cooling and further cooling before entering the first compressor stage, thus balancing cooling range, mixing uniformity, and cooling response speed, providing more flexible and stronger precooling capabilities for different flight conditions.

[0049] To ensure injection stability and mixing efficiency, the fuel atomizing nozzle 12 employs a preset injection angle at its front end, ensuring the injection direction forms an optimal angle with the mainstream airflow. This preset injection angle is typically determined based on the geometry of the intake duct 1, the airflow direction, and the aerodynamic structure of the compressor inlet. This ensures the spray fully enters the mainstream intake air region while preventing excessive deviation in the injection direction, which could cause the spray to adhere to the guide surface or casing. By appropriately setting the injection angle, the injected fuel can achieve a good diffusion pattern, resulting in stable and uniform mixing with the incoming airflow, thus enhancing the pre-cooling effect.

[0050] In one embodiment, a heat insulation structure is provided on the outside of the fuel atomizing nozzle 12 and the second channel, the heat insulation structure including a carbon fiber winding layer and / or a double-layer tube heat insulation layer.

[0051] In this embodiment, to ensure that the second channel for conveying cryogenic hydrogen fuel and the fuel atomizing nozzle 12 at its end maintain a stable cryogenic environment during operation and to prevent heat transfer from the external high-temperature airflow or casing structure to the cryogenic pipeline, heat insulation structures are provided on the outside of the second channel pipeline and the nozzle. Since the temperature of liquid hydrogen is much lower than the ambient temperature, without effective heat insulation measures, external heat will inevitably cause the cryogenic fuel to boil, generate pressure fluctuations, or even gas lock, and may cause instability in the injection flow field. Therefore, it is necessary to establish efficient heat insulation protection on the outside of the entire injection channel.

[0052] The insulation structure can utilize carbon fiber winding, which is lightweight, has low thermal conductivity, and high strength, providing excellent insulation while maintaining a compact structure. The carbon fiber material is wound in multiple layers to form a composite insulation layer, effectively reducing the transfer of external heat to the cryogenic fuel and preventing deformation or fatigue of the pipeline and nozzle structure due to thermal shock. In another embodiment, the insulation structure can employ a double-layer tube insulation layer, with a low thermal conductivity isolation cavity formed between the two layers. This cavity can be an empty structure or filled with inert gas to further reduce heat transfer efficiency. The double-layer tube structure maintains high thermal stability under high-speed liquid hydrogen flow and drastic temperature changes, providing more uniform and reliable insulation performance for the injection system. In some embodiments, the carbon fiber winding layer and the double-layer tube insulation layer can also be used in combination. The outer carbon fiber layer provides mechanical strength and impact resistance, while the inner double-tube structure provides efficient insulation, allowing the second channel to maintain a suitable cryogenic state under long-term operation or high-load injection conditions. With the aforementioned insulation structure, the second channel and nozzle can operate stably for extended periods in the near-extremely low-temperature hydrogen fuel environment, preventing fuel property instability due to external heat intrusion, thus ensuring the controllability and repeatability of the injection cooling process. This insulation arrangement not only improves the reliability of injection cooling but also provides greater engineering feasibility for the entire intercooled power system.

[0053] Reference Figure 4 This embodiment also discloses a control method for a cryogenic fuel direct injection compressor, including: S1. During the start-up phase, when the engine is starting and operating at low power, the flow distributor 10 controls the flow distributor to ensure that all the liquid fuel from the hydrogen storage tank 8 is delivered to the tail nozzle heat exchanger 7 through the first channel and injected into the combustion chamber 4 through the combustion nozzle 15. S2. After the engine power is increased, intercooling is performed. When the engine reaches its maximum state and needs to further increase the output power, the flow distributor 10 is controlled to deliver part of the liquid fuel to the fuel atomizing nozzle 12 through the second channel, and the fuel atomizing nozzle 12 is opened to inject fuel into the compressor unit between stages. S3. After the engine power continues to increase, pre-cooling is performed, and the fuel atomizing nozzle 12 is controlled to inject low-temperature fuel into the compressor unit inlet position at the front end of the intake duct 1. S4. Combined cooling is formed, so that the intercooling injection acts on the middle and rear section of the compressor unit, and the precooling injection acts on the compressor unit inlet, and a superimposed cooling effect is formed along the axial direction of the compressor unit.

[0054] During startup, the engine operates at low speed and low pressure ratio. At this stage, the compressor's compression work demand is low, and the air temperature at the compressor inlet and between stages is low, so cooling requirements are not significant. Therefore, the flow distributor 10 controls all the liquid hydrogen fuel output from the hydrogen storage tank 8 to enter the first channel. It then passes through the tailpipe heat exchanger 7 to exchange heat with the high-temperature exhaust gas. After being regulated by the pressure regulating valve 13 and the flow control valve 14, it is injected into the combustion chamber 4 through the combustion nozzle 15. During this stage, the second channel injection cooling is not activated, thus avoiding unnecessary waste of cooling capacity and reducing disturbance to the compressor flow field.

[0055] When the engine reaches its maximum thrust and requires further increases, the air temperature in the middle and later stages of the compressor rises significantly, increasing the compression work demand. At this point, additional cooling capacity is needed to reduce compression power consumption. The control system adjusts the flow distributor 10 to a split-flow mode, allowing some liquid hydrogen to be delivered to the fuel atomizing nozzle 12 via the second channel, and opening the nozzles located between compressor stages to inject liquid hydrogen into the corresponding interstage channels. This interstage cooling injection directly reduces the air temperature in the middle and later stages, thereby reducing the downstream compression load and improving the compressor's operational stability.

[0056] As the engine continues to increase power, the compressor inlet air temperature rises, the overall pressure ratio increases, and a significant temperature rise begins to occur in the compressor front section. To prevent excessively high compressor inlet temperature from affecting the corrective speed margin and increasing compression work, the control system further instructs the fuel atomizing nozzle 12 to perform pre-cooling injection at the compressor front end, so that liquid hydrogen is mixed and cooled before the air enters the compressor. Pre-cooling injection and intercooling injection, acting at different points, work together to improve the compressor's thermal state.

[0057] Ultimately, under high thrust or sustained high load conditions, the control logic keeps both intercooled injection and precooled injection running simultaneously. This allows the mid-to-late stage interstage injections to provide localized enhanced cooling, while the front-end injections provide overall inlet cooling, thus creating a continuous, superimposed temperature regulation distribution along the compressor axis. Through this combined cooling method, the compressor's inlet temperature, mid-stage temperature, and high-pressure stage temperature are individually matched and regulated, significantly reducing total compression work and improving the engine's overall thermal efficiency and operational stability.

[0058] This embodiment also discloses an aero-engine that integrates the aforementioned cryogenic fuel direct injection compressor's intercooled power unit, enabling the power unit to operate normally as a component of the engine throughout its flight envelope. The aero-engine includes an intake system, compressor, combustion chamber 4, turbine, exhaust nozzle, and hydrogen fuel-related storage, transportation, control, and injection mechanisms. The intercooled power unit of the cryogenic fuel direct injection compressor is installed in a position corresponding to the engine's main air passage, allowing liquid hydrogen injection cooling to directly act on the compressor's internal air or compressor inlet airflow.

[0059] In its integrated configuration, the hydrogen storage tank 8 and flow distributor 10, as part of the airborne hydrogen fuel supply system, are fixedly installed in the engine mount or engine block structure and connected to the tail nozzle heat exchanger 7 and compressor unit via a first channel and a second channel, respectively. The heat exchange structure in the first channel, together with the engine tail nozzle, forms a fuel pretreatment path, allowing the heat-exchanged hydrogen fuel to be stably injected into the combustion chamber 4 in gaseous form, thus forming the engine's main fuel supply path. The second channel, together with the nozzle system, forms the compressor cooling path, achieving variable cooling capacity of the compressor by injecting cryogenic fuel into the front end of the compressor unit or between different stages.

[0060] During flight, the engine control system dynamically coordinates the nozzle assemblies, valves, and channels in the intercooled propulsion unit according to thrust requirements and compressor operating status commands, selectively executing intercooling, precooling, or combined cooling modes under different operating conditions. The intercooled propulsion unit and the engine body achieve effective matching in structure, control, and thermodynamics, allowing liquid hydrogen fuel to not only participate in combustion as an energy source but also serve as a cooling medium to improve the compressor's compression process. Through deep integration with the overall engine, this aero-engine achieves higher cycle efficiency, superior compressor stability, and a wider adjustable thrust range, making it suitable for high-performance, high-efficiency aero-propulsion systems.

[0061] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A power unit for a cryogenic fuel direct injection compressor, characterized in that: Including the engine block and the cryogenic fuel storage and transportation system; The engine body includes an intake duct (1), a compressor unit, a combustion chamber (4) and a tail nozzle arranged sequentially along the axial direction, as well as a tail nozzle heat exchanger (7) disposed in the tail nozzle; The cryogenic fuel storage and transportation system includes a hydrogen storage tank (8) and a flow distributor (10). The hydrogen storage tank (8) is connected to a first channel and a second channel respectively. The flow distributor (10) is used to control the fuel flow rate from the hydrogen storage tank (8) into the first channel and the second channel respectively. The first channel passes through the tail nozzle heat exchanger (7) to exchange heat with the high-temperature gas in the tail nozzle, and the tail end of the first channel is connected to a combustion nozzle (15), which is used to inject the heat-exchanged fuel into the combustion chamber (4). The tail end of the second channel is connected to a fuel atomizing nozzle (12), which is used to inject cryogenic fuel into at least one of the interstage and front end of the compressor unit, so that the injected cryogenic fuel is mixed with the compressed air in the compressor unit and enters the combustion chamber (4) together with the compressed air.

2. The power unit of the cryogenic fuel direct injection compressor according to claim 1, characterized in that: The compressor unit includes multi-stage stator blades (2) and multi-stage rotor blades (3) arranged along the axial direction, wherein the stator blades (2) and the rotor blades (3) are alternately distributed along the axial direction; The fuel atomizing nozzle (12) is positioned on the inner wall of the casing between adjacent stator blades (2) and rotor blades (3), so that the injected cryogenic fuel can directly enter the flow channel between the corresponding stages.

3. The power unit of the cryogenic fuel direct injection compressor according to claim 2, characterized in that: Multiple fuel atomizing nozzles (12) are arranged along the axial direction of the compressor unit, and the multiple fuel atomizing nozzles (12) are distributed one-to-one at the interstage positions between different stator blades (2) and rotor blades (3); At least two adjacent fuel atomizing nozzles (12) constitute a group of atomizing nozzles, forming multiple groups of atomizing nozzles distributed along the axial direction. The injection pressure and / or injection quantity of each atomizing nozzle group are set to different parameters according to the pressure and temperature conditions corresponding to the compressor stage.

4. The power unit of the cryogenic fuel direct injection compressor according to claim 3, characterized in that: The spray angle of the atomizing nozzle group relative to the main direction of the compressor increases step by step according to the compressor stage, so that the spray angle of the atomizing nozzle group closer to the intake (1) is smaller than the spray angle of the atomizing nozzle group farther away from the intake (1).

5. The power unit of the cryogenic fuel direct injection compressor according to claim 3, characterized in that: Each group of atomizing nozzles is equipped with a corresponding switching valve (11) for controlling fuel flow and on / off status.

6. The power unit of the cryogenic fuel direct injection compressor according to claim 1, characterized in that: The first channel is provided with a pressure regulating valve (13) and a flow regulating valve (14) located between the tail nozzle heat exchanger (7) and the combustion nozzle (15). The pressure regulating valve (13) is used to stabilize the fuel pressure after heat exchange by the tail nozzle heat exchanger (7), and the flow regulating valve (14) is used to regulate the fuel flow supplied to the combustion nozzle (15).

7. The power unit of the cryogenic fuel direct injection compressor according to claim 1, characterized in that: The fuel atomizing nozzle (12) is installed in the guide section of the air intake (1) and / or the compressor unit inlet, for injecting cryogenic fuel into the intake air entering the front end of the compressor unit at a preset injection angle.

8. The power unit of the cryogenic fuel direct injection compressor according to claim 1, characterized in that: The fuel atomizing nozzle (12) and the outer side of the second channel are provided with a heat insulation structure, which includes a carbon fiber winding layer and / or a double-layer tube heat insulation layer.

9. A power unit control method for a cryogenic fuel direct injection compressor, used in the power unit of the cryogenic fuel direct injection compressor according to any one of claims 1-8, characterized in that, Includes the following steps: S1. During the start-up phase, during the start-up and low-power operation phase of the aircraft engine, the flow distributor (10) controls the flow distributor to deliver all the liquid fuel from the hydrogen storage tank (8) to the tail nozzle heat exchanger (7) through the first channel, and injects it into the combustion chamber (4) through the combustion nozzle (15) to maintain normal engine operation when there is no cooling requirement. S2. After the power of the aircraft engine is increased, it is intercooled. When the aircraft engine reaches its maximum state and needs to further increase its output power, the flow distributor (10) controls the flow distributor to deliver part of the liquid fuel to the fuel atomizing nozzle (12) through the second channel, and starts the injection of the fuel atomizing nozzle (12) into the compressor stage, so that the low temperature fuel is directly mixed into the compressed air between the corresponding stages of the compressor, thereby reducing the air temperature between the compressor stages to reduce the compression work. S3. After the power of the aircraft engine continues to increase, pre-cooling is performed. The fuel atomizing nozzle (12) is controlled to inject low-temperature fuel into the compressor unit inlet position at the front end of the intake duct (1), so that the injected fuel is pre-mixed with the intake air entering the compressor unit to reduce the temperature of the compressor unit inlet air. S4. Forming combined cooling: With both the intercooling injection between compressor stages and the precooling injection at the front end of the compressor stage activated, the intercooling injection acts on the middle and rear sections of the compressor stage, and the precooling injection acts on the compressor inlet, forming a superimposed cooling effect along the axial direction of the compressor stage, thereby achieving a reduction in compression work and an improvement in the overall thermal efficiency of the engine brought about by combined cooling.

10. An aircraft engine, comprising the power unit of a cryogenic fuel direct injection compressor as described in any one of claims 1-8.

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