Chemical regenerative turboshaft engine based on ammonia fuel intercooling

Abstract

The invention discloses a chemical regenerative turboshaft engine based on ammonia fuel intercooling, and belongs to the technical field of aero-engines. The system comprises a gas inlet channel, a low-pressure gas compressor, a fuel evaporator, a high-pressure gas compressor, a combustion chamber, a gas turbine, a power turbine, a chemical regenerator and an exhaust nozzle which are sequentially communicated, and a liquid ammonia storage tank, the fuel evaporator and the chemical regenerator which are sequentially communicated through a fuel pump. The method is characterized in that liquid ammonia firstly absorbs heat of air at an outlet of a low-pressure compressor in a fuel evaporator and is vaporized, inlet indirect cooling of a high-pressure compressor is achieved, and power consumption of the high-pressure compressor is reduced; and the generated ammonia gas absorbs the waste heat of the tail gas in the chemical heat regenerator and is subjected to catalytic decomposition to generate a mixture of hydrogen and nitrogen, so that the waste heat is converted into high-grade chemical energy, and the combustion characteristic is improved. The pressure ratio, the output power and the total heat efficiency of the engine are effectively improved, and meanwhile zero carbon emission is achieved.

Description

Technical Field

[0001] This invention relates to the field of aero-engines, and more particularly to turboshaft engines incorporating regenerative chemical regeneration, primarily addressing issues such as high carbon emissions, low compressor pressure ratios, and limited engine performance in existing aviation kerosene turboshaft engines. Simultaneously, it fully utilizes the small hydrogen molecules generated from ammonia fuel cracking to improve the combustion performance of the turboshaft engine. Background Technology

[0002] As the core power unit of aircraft, the technological development of aero engines directly affects the performance, efficiency, and environmental impact of the aviation industry. Traditional aero engines typically use aviation kerosene as fuel. While possessing high energy density and mature combustion technology, they emit large amounts of carbon dioxide (CO2) and nitrogen oxides (NOx) during operation. x Carbon emissions exert significant pressure on global climate change and the atmospheric environment. With increasingly stringent global requirements for carbon reduction and environmental protection, developing clean and efficient aero-engine technologies has become an important direction for the industry.

[0003] Liquid ammonia (NH3), as a hydrogen-rich carrier and zero-carbon fuel, has been considered a promising alternative fuel in the aviation industry in recent years due to its CO2-free combustion, relatively safe storage and transportation, and low cost. Ammonia can be produced from renewable energy sources, achieving carbon neutrality throughout its entire life cycle, which helps the aviation industry fundamentally reduce carbon emissions. However, ammonia fuel still faces several key technical challenges in practical aero-engine applications: First, ammonia's mass energy density and volumetric energy density are lower than jet fuel, requiring more fuel to be carried for the same range, affecting the aircraft's payload and range capabilities; second, ammonia has a slow combustion rate, low flame temperature, and narrow combustible range, resulting in low direct combustion efficiency and a tendency for combustion instability and decreased combustion chamber efficiency; furthermore, ammonia fuel may still generate a certain amount of NO during high-temperature combustion. x The combustion process needs to be optimized to control emissions.

[0004] To improve the performance of ammonia-fueled engines, existing technologies typically focus on two aspects: increasing thermal efficiency and optimizing the combustion process. In turboshaft engines, increasing the compressor pressure ratio is an effective way to improve thermal efficiency, but simply increasing the pressure ratio leads to a significant increase in compressor power consumption, resulting in limited improvement in overall system efficiency. Meanwhile, traditional turboshaft engines contain a large amount of waste heat in their exhaust gases, which is usually emitted directly without being utilized, resulting in energy waste. If this waste heat could be recovered and used to improve fuel energy grade or combustion, it is expected to improve the overall energy utilization rate of the engine.

[0005] Therefore, there is an urgent need to develop a novel ammonia-fueled turboshaft engine system that can effectively reduce compressor energy consumption, increase pressure ratio and output power, and fully utilize exhaust waste heat to improve the combustion characteristics of ammonia. This would achieve zero carbon emissions while simultaneously improving or even enhancing the engine's overall performance. This invention addresses these issues by proposing an ammonia-fueled turboshaft engine solution that combines interstage cooling and chemical regeneration. Interstage cooling is achieved through the heat absorption of liquid ammonia phase change, and exhaust waste heat is recovered through catalytic decomposition. This aims to synergistically improve system efficiency and environmental performance in both thermodynamic cycle and combustion chemistry aspects. Summary of the Invention

[0006] In view of this, the present invention provides a chemical regenerative turboshaft engine based on ammonia fuel intercooling to solve the problems of high carbon emissions, low compressor pressure ratio, and limited engine performance of existing turboshaft engines. At the same time, it fully utilizes the small hydrogen molecules generated by the decomposition of ammonia fuel to improve the combustion performance of the turboshaft engine.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A chemical regenerative turboshaft engine based on ammonia fuel intercooling includes: an intake duct, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a gas turbine, a power turbine, a transmission structure, a liquid ammonia storage tank, a fuel pump, a fuel evaporator, a chemical regenerator, and a tail nozzle. The outlet of the air intake duct is connected to the air inlet of the low-pressure compressor, the outlet of the low-pressure compressor is connected to the inlet of the working fluid passage of the fuel evaporator, the outlet of the working fluid passage of the fuel evaporator is connected to the inlet of the high-pressure compressor, the outlet of the high-pressure compressor is connected to the inlet of the combustion chamber, the outlet of the combustion chamber is connected to the inlet of the gas turbine, the outlet of the gas turbine is connected to the inlet of the power turbine, the outlet of the power turbine is connected to the inlet of the working fluid passage of the chemical regenerator, and the outlet of the working fluid passage of the chemical regenerator is connected to the tail nozzle. The outlet of the liquid ammonia storage tank is connected to the inlet of the fuel pump, the outlet of the fuel pump is connected to the inlet of the cold working fluid channel of the fuel evaporator, the outlet of the cold working fluid channel of the fuel evaporator is connected to the inlet of the cold working fluid channel of the chemical regenerator, and the outlet of the cold working fluid channel of the chemical regenerator is connected to the fuel inlet of the combustion chamber.

[0009] Through the above technical solution, this invention innovatively couples the two core processes of phase change intercooling and catalytic decomposition reheating by uniquely arranging liquid ammonia fuel to flow sequentially through the fuel evaporator and chemical reheater. This achieves multiple technical effects in a single system, such as reducing the high-pressure compressor inlet temperature to increase the pressure ratio and output power, recovering exhaust heat to improve the overall energy utilization rate, and decomposing ammonia into hydrogen to improve combustion performance. Ultimately, under the premise of using zero-carbon ammonia fuel, it significantly improves the overall thermal efficiency and environmental performance of the turboshaft engine.

[0010] Preferably, in the aforementioned chemical regenerative turboshaft engine based on ammonia fuel intercooling, the fuel evaporator is a partitioned heat exchanger. Its cold working fluid passage is used for the flow of liquid ammonia or ammonia gas, and its hot working fluid passage is used for the flow of compressed air from the low-pressure compressor. A phase change of liquid ammonia occurs within the fuel passage of the fuel evaporator. The latent heat of this phase change effectively reduces the air temperature at the inlet of the high-pressure compressor, thereby reducing compressor power consumption and contributing to further increasing the compressor's pressure ratio and improving the engine's output power.

[0011] Preferably, in the aforementioned chemical regenerative turboshaft engine based on ammonia fuel intercooling, the chemical regenerative unit is a partition wall heat exchanger. Its cold working fluid passage is equipped with a catalytic decomposition device to promote the endothermic decomposition of ammonia into hydrogen and nitrogen. Its hot working fluid passage is used to circulate exhaust gas from the power turbine. In the chemical regenerative unit, ammonia undergoes a decomposition reaction upon heating to generate hydrogen and nitrogen, converting thermal energy into chemical energy stored in the fuel, thus improving the energy grade. Simultaneously, it absorbs the waste heat from the exhaust gas after power generation, improving the engine's energy utilization rate and enhancing the system's thermal efficiency.

[0012] Preferably, in the aforementioned chemical regenerative turboshaft engine based on ammonia fuel intercooling, the medium flowing through the fuel pipeline connecting the outlet of the cold working fluid passage of the chemical regenerator and the combustion chamber is a mixture of ammonia, hydrogen, and nitrogen. The inlet of the fuel passage of the chemical regenerator is ammonia fuel, and the outlet gas is a mixture of a small amount of unreacted ammonia and small-molecule hydrogen and nitrogen generated from ammonia decomposition, thus improving the combustion characteristics of ammonia fuel.

[0013] Preferably, in the above-mentioned chemical regenerative turboshaft engine based on ammonia fuel intercooling, the low-pressure compressor and the high-pressure compressor are coaxially connected and driven by the same rotor shaft.

[0014] Preferably, in the above-mentioned chemical regenerative turboshaft engine based on ammonia fuel intercooling, the gas turbine is coaxially connected to the rotor shaft that drives the low-pressure compressor and the high-pressure compressor, for driving their rotation.

[0015] Preferably, in the above-mentioned chemical regenerative turboshaft engine based on ammonia fuel intercooling, the power turbine is coaxially connected to the transmission structure.

[0016] Preferably, in the above-mentioned chemical regenerative turboshaft engine based on ammonia fuel intercooling, the output end of the transmission structure is connected to and drives the rotor.

[0017] Preferably, in the aforementioned chemical regenerative turboshaft engine based on ammonia fuel intercooling, the fuel pump is a mechanically driven pump, whose power input shaft is connected to the engine's high-pressure rotor shaft or an accessory gearbox driven by the high-pressure rotor shaft. The fuel pump extracts shaft power from the high-pressure turbine to maintain normal pump operation.

[0018] Preferably, in the above-mentioned chemical regenerative turboshaft engine based on ammonia fuel intercooling, the liquid ammonia storage tank is a pressure-resistant container for storing and supplying liquid ammonia.

[0019] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a chemical regenerative turboshaft engine based on ammonia fuel intercooling, which has the following beneficial effects: 1. This invention utilizes the phase change endothermic reaction of ammonia fuel to extract heat from between compressor stages, improving energy utilization efficiency. Simultaneously, it reduces the inlet air temperature of the high-pressure compressor, decreasing its power consumption and enhancing engine performance. Furthermore, it also helps to further increase the compressor's pressure ratio, improving the engine's output power.

[0020] 2. This invention utilizes the chemical decomposition reaction of ammonia fuel to absorb heat from engine exhaust gas, extracting waste heat and improving the engine's energy utilization rate. Simultaneously, the decomposition of ammonia fuel into smaller hydrogen molecules improves its combustion performance.

[0021] 3. This invention uses ammonia fuel, a zero-carbon fuel, as the fuel, to replace traditional aviation kerosene with green aviation power fuel, fundamentally solving the carbon emission problem of the engine and achieving zero carbon emissions for the aircraft engine. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 The attached figure is a schematic diagram of the structure of the chemical regenerative turboshaft engine based on ammonia fuel intercooling provided by the present invention.

[0024] in: 1 is the air intake; 2 is the low-pressure compressor; 3 is the high-pressure compressor; 4 is the combustion chamber; 5 is the gas turbine; 6 is the power turbine; 7 is the transmission structure; 8 is the liquid ammonia storage tank; 9 is the fuel pump; 10 is the fuel evaporator; 11 is the chemical regenerator; 12 is the tail nozzle; 13 is the rotor. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] See appendix Figure 1 The present invention discloses a chemical regenerative turboshaft engine based on ammonia fuel intercooling, comprising: an intake duct 1, a low-pressure compressor 2, a high-pressure compressor 3, a combustion chamber 4, a gas turbine 5, a power turbine 6, a transmission structure 7, a liquid ammonia storage tank 8, a fuel pump 9, a fuel evaporator 10, a chemical regenerator 11, and a tail nozzle 12. The inlet of intake duct 1 is connected to the outside atmosphere. The outlet of intake duct 1 is connected to the inlet of low-pressure compressor 2. The outlet of low-pressure compressor 2 is connected to the inlet of the hot working medium channel of fuel evaporator 10. The outlet of the hot working medium channel of fuel evaporator 10 is connected to the inlet of high-pressure compressor 3. The outlet of high-pressure compressor 3 is connected to the inlet of combustion chamber 4. The outlet of combustion chamber 4 is connected to the inlet of gas turbine 5. The outlet of gas turbine 5 is connected to the inlet of power turbine 6. The outlet of power turbine 6 is connected to the inlet of the hot working medium channel of chemical regenerator 11. The outlet of the hot working medium channel of chemical regenerator 11 is connected to the tail nozzle 12. The outlet of the liquid ammonia storage tank 8 is connected to the inlet of the fuel pump 9, the outlet of the fuel pump 9 is connected to the inlet of the cold working medium channel of the fuel evaporator 10, the outlet of the cold working medium channel of the fuel evaporator 10 is connected to the inlet of the cold working medium channel of the chemical regenerator 11, and the outlet of the cold working medium channel of the chemical regenerator 11 is connected to the fuel inlet of the combustion chamber 4.

[0027] To further optimize the above technical solution, the fuel evaporator 10 is a partitioned heat exchanger, with its cold working medium channel used for the flow of liquid ammonia or ammonia gas, and its hot working medium channel used for the flow of compressed air from the low-pressure compressor 2.

[0028] To further optimize the above technical solution, the chemical regenerator 11 is a partition wall heat exchanger, and its cold working fluid channel is equipped with a catalytic decomposition device to promote the endothermic decomposition of ammonia into hydrogen and nitrogen; its hot working fluid channel is used to circulate the exhaust gas from the power turbine 6.

[0029] To further optimize the above technical solution, the medium flowing in the fuel pipeline connecting the cold working medium channel outlet of the chemical regenerator 11 and the combustion chamber 4 is a mixture of ammonia, hydrogen and nitrogen.

[0030] To further optimize the above technical solution, the low-pressure compressor 2 and the high-pressure compressor 3 are coaxially connected and driven by the same rotor shaft.

[0031] To further optimize the above technical solution, the gas turbine 5 is coaxially connected to the rotor shaft that drives the low-pressure compressor 2 and the high-pressure compressor 3, and is used to drive their rotation.

[0032] To further optimize the above technical solution, the power turbine 6 is coaxially connected with the transmission structure 7.

[0033] To further optimize the above technical solution, the output end of the transmission structure 7 is connected to and drives the rotor 13.

[0034] To further optimize the above technical solution, the fuel pump 9 is a mechanically driven pump, and its power input shaft is connected to the high-pressure rotor shaft of the engine or an accessory gearbox driven by the high-pressure rotor shaft.

[0035] To further optimize the above technical solution, the liquid ammonia storage tank 8 is a pressure-resistant container used for storing and supplying liquid ammonia.

[0036] The working process of the chemical regenerative turboshaft engine based on ammonia fuel intercooling provided in this embodiment is as follows: Liquid ammonia fuel in liquid ammonia storage tank 8 is drawn into the cold working fluid channel of fuel evaporator 10 by fuel pump 9. Under the heating effect of inlet air, the ammonia fuel first undergoes a phase change, vaporizing from liquid ammonia into ammonia gas, and then enters the cold working fluid channel of chemical regenerator 11. Heated by tail gas and then cracked by catalysis to generate some hydrogen and nitrogen gas. The high-temperature, high-pressure ammonia fuel mixture then enters combustion chamber 4 for combustion.

[0037] Outside the turboshaft engine, atmospheric air is drawn into intake 1, pressurized by low-pressure compressor 2, and then fed into fuel evaporator 10 to heat liquid ammonia. It is then further pressurized by high-pressure compressor 3 and fed into combustion chamber 4 to mix thoroughly with fuel for combustion. Finally, it is fed into gas turbine 5 to perform work. The rotation of gas turbine 5 drives the rotor shaft, which in turn drives high-pressure compressor 3 and low-pressure compressor 2 to perform work. After the gas completes its work in gas turbine 5, it enters power turbine 6, driving its rotation. Power turbine 6 then drives transmission structure 7, which in turn drives rotor 13 to rotate.

[0038] After the combustion gas finishes working in the power turbine 6, it enters the heat medium passage in the chemical regenerator 11 to provide heat energy for ammonia cracking. After heating, the combustion gas is diffused and expanded through the tail nozzle 12 before being discharged into the atmosphere. At this time, the main components of this exhaust gas are water vapor, oxygen and nitrogen.

[0039] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0040] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A chemical regenerative turboshaft engine based on ammonia fuel intercooling, characterized in that, include: Air intake (1), low-pressure compressor (2), high-pressure compressor (3), combustion chamber (4), gas turbine (5), power turbine (6), transmission structure (7), liquid ammonia storage tank (8), fuel pump (9), fuel evaporator (10), chemical regenerator (11) and tail nozzle (12). The outlet of the intake duct (1) is connected to the intake port of the low-pressure compressor (2), the outlet of the low-pressure compressor (2) is connected to the inlet of the working medium channel of the fuel evaporator (10), the outlet of the working medium channel of the fuel evaporator (10) is connected to the inlet of the high-pressure compressor (3), the outlet of the high-pressure compressor (3) is connected to the inlet of the combustion chamber (4), the outlet of the combustion chamber (4) is connected to the inlet of the gas turbine (5), the outlet of the gas turbine (5) is connected to the inlet of the power turbine (6), the outlet of the power turbine (6) is connected to the inlet of the working medium channel of the chemical regenerator (11), and the outlet of the working medium channel of the chemical regenerator (11) is connected to the tail nozzle (12). The outlet of the liquid ammonia storage tank (8) is connected to the inlet of the fuel pump (9), the outlet of the fuel pump (9) is connected to the inlet of the cold working medium channel of the fuel evaporator (10), the outlet of the cold working medium channel of the fuel evaporator (10) is connected to the inlet of the cold working medium channel of the chemical regenerator (11), and the outlet of the cold working medium channel of the chemical regenerator (11) is connected to the fuel inlet of the combustion chamber (4).

2. The chemical regenerative turboshaft engine based on ammonia fuel intercooling according to claim 1, characterized in that, The fuel evaporator (10) is a partitioned heat exchanger, with its cold working medium channel for flowing liquid ammonia or ammonia gas, and its hot working medium channel for flowing compressed air from the low-pressure compressor (2).

3. A chemical regenerative turboshaft engine based on ammonia fuel intercooling according to claim 1 or 2, characterized in that, The chemical regenerator (11) is a partition wall heat exchanger. Its cold working medium channel is equipped with a catalytic decomposition device to promote the heat absorption and decomposition of ammonia into hydrogen and nitrogen. Its hot working medium channel is used to circulate the exhaust gas from the power turbine (6).

4. A chemical regenerative turboshaft engine based on ammonia fuel intercooling according to claim 3, characterized in that, The medium flowing through the fuel pipeline connecting the outlet of the cold working medium channel of the chemical regenerator (11) and the combustion chamber (4) is a mixture of ammonia, hydrogen and nitrogen.

5. A chemical regenerative turboshaft engine based on ammonia fuel intercooling according to claim 1, characterized in that, The low-pressure compressor (2) is coaxially connected to the high-pressure compressor (3) and is driven by the same rotor shaft.

6. A chemical regenerative turboshaft engine based on ammonia fuel intercooling according to claim 5, characterized in that, The gas turbine (5) is coaxially connected to the rotor shaft that drives the low-pressure compressor (2) and the high-pressure compressor (3) for driving their rotation.

7. A chemical regenerative turboshaft engine based on ammonia fuel intercooling according to claim 1, characterized in that, The power turbine (6) is coaxially connected to the transmission structure (7).

8. A chemical regenerative turboshaft engine based on ammonia fuel intercooling according to claim 7, characterized in that, The output end of the transmission structure (7) is connected to and drives the rotor (13).

9. A chemical regenerative turboshaft engine based on ammonia fuel intercooling according to claim 1, characterized in that, The fuel pump (9) is a mechanically driven pump, and its power input shaft is connected to the high-pressure rotor shaft of the engine or an accessory gearbox driven by the high-pressure rotor shaft.

10. A chemical regenerative turboshaft engine based on ammonia fuel intercooling according to claim 1, characterized in that, The liquid ammonia storage tank (8) is a pressure-resistant container used for storing and supplying liquid ammonia.

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