Chemical regenerative turboshaft engine and working method

Abstract

The invention discloses a chemical regenerative turboshaft engine and a working method. The engine comprises a core engine system, an engine power system and a fuel supply system. The core machine system comprises an air inlet channel, an air compressor, a combustion chamber, a gas turbine and a power turbine. The engine electric power system comprises a power turbine generator, an energy management system, a hot ammonia turbine generator and a hot ammonia turbine. The fuel supply system comprises an aviation fuel storage tank, an aviation fuel pump, an aviation fuel preheater, a fuel premixing chamber, a liquid ammonia storage tank, a liquid ammonia pump, a primary chemical regenerator and a secondary chemical regenerator. Chemical heat sink of ammonia fuel is fully utilized to extract heat energy from tail gas waste heat of the turboshaft engine, the tail gas waste heat utilization rate is increased, and the heat efficiency of the engine is improved; and meanwhile, the thermal expansion performance of ammonia fuel decomposition mixed gas is fully utilized, a hot ammonia turbine is pushed to generate electricity, electric power extracted from an engine spindle by a circuit system is reduced, the output power of the power turbine is increased, and the overall energy utilization level of the engine is improved.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, specifically to a chemical regenerative turboshaft engine and its operating method. Background Technology

[0002] Currently, the carbon emissions from aircraft engines have reached 10% of the carbon emissions from the transportation industry. Furthermore, due to the characteristics of their high-altitude emissions and the influence of cirrus clouds, their environmental damage can reach more than 20%. Therefore, carbon emission reduction in aviation is gradually being put on the agenda.

[0003] Liquid ammonia fuel, as a zero-carbon fuel, has a higher energy density than hydrogen fuel, and its storage pressure and economic cost are far lower, making it a more economical and applicable fuel for aviation carbon reduction. However, compared to jet fuel, its energy density is lower, leading to an increase in the fuel carrying capacity and a decrease in the load capacity of turboshaft engines after adopting ammonia fuel. Therefore, it is necessary to further reduce the engine's fuel consumption rate and improve system efficiency. In addition, the use of fuel chemical regeneration reduces the mass flow rate of the regenerated cooling medium and the heat absorption, affecting the energy utilization rate of the turboshaft engine system.

[0004] Therefore, providing a chemical regenerative turboshaft engine and its operating method is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a chemical regenerative turboshaft engine and its operating method to solve the problem that the energy density of existing ammonia fuel is lower than that of aviation kerosene fuel, which leads to an increase in the fuel carrying capacity of turboshaft engines, a decrease in load capacity, and difficulty in further improving the overall efficiency of turboshaft engines after adopting ammonia fuel; at the same time, it solves the problems of large power demand of airborne electrical equipment, difficulty in extracting electrical power, and complex circuit transmission structure of existing turboshaft engines.

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

[0007] A chemical regenerative turboshaft engine includes a core engine system, an engine electrical system, and a fuel supply system. The core engine system includes an air intake, a compressor, a combustion chamber, a gas turbine, and a power turbine. The engine electrical system includes a power turbine generator, an energy management system, a hot ammonia turbine generator, and a hot ammonia turbine. The fuel supply system includes a jet fuel storage tank, a jet fuel pump, a jet fuel preheater, a fuel premixing chamber, a liquid ammonia storage tank, a liquid ammonia pump, a first-stage chemical regenerative engine, and a second-stage chemical regenerative engine. The outlet of the air intake is connected to the air inlet of the compressor, the outlet of the compressor is connected to the air inlet of the combustion chamber, the gas outlet of the combustion chamber is connected to the inlet of the gas turbine, and the gas turbine is connected to the compressor via a rotor shaft drive. 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 medium passage of the second-stage chemical regenerative engine, and the outlet of the working medium passage of the second-stage chemical regenerative engine is connected to the working medium passage of the first-stage chemical regenerative engine. The inlet of the first-stage chemical regenerator is connected to the outlet of the hot working fluid channel of the aviation kerosene preheater, and the outlet of the hot working fluid channel of the aviation kerosene preheater is connected to the engine exhaust nozzle, through which the combustion gas is discharged from the engine. The outlet of the aviation kerosene storage tank is connected to the inlet of the aviation kerosene fuel pump, the outlet of the aviation kerosene fuel pump is connected to the inlet of the cold working fluid channel of the aviation kerosene preheater, the outlet of the cold working fluid channel of the aviation kerosene preheater is connected to the aviation kerosene fuel inlet of the fuel premixing chamber, and the outlet of the fuel premixing chamber is connected to the fuel inlet of the combustion chamber. The outlet of the liquid ammonia storage tank is connected to the inlet of the liquid ammonia pump, the outlet of the liquid ammonia pump is connected to the inlet of the cold working fluid channel of the first-stage chemical regenerator, the outlet of the cold working fluid channel of the first-stage chemical regenerator is connected to the inlet of the hot ammonia turbine, the outlet of the hot ammonia turbine is connected to the inlet of the cold working fluid channel of the second-stage chemical regenerator, and the outlet of the cold working fluid channel of the second-stage chemical regenerator is connected to the ammonia fuel inlet of the fuel premixing chamber.

[0008] A method for operating a chemical regenerative turboshaft engine includes the following steps: Aviation kerosene in the aviation kerosene storage tank enters the cold working fluid channel of the aviation kerosene preheater through the suction action of the aviation kerosene fuel pump, and enters the fuel premixing chamber after being preheated by the fuel gas. Liquid ammonia fuel in the liquid ammonia storage tank is drawn into the cold working fluid channel of the first-stage chemical regenerator by the liquid ammonia pump. Under the heating action of the high-temperature gas, the ammonia fuel first undergoes a phase change, vaporizing from liquid ammonia into ammonia gas. After being catalyzed by the catalyst, it decomposes to generate some hydrogen and nitrogen. The high-temperature and high-pressure ammonia fuel mixture then enters the hot ammonia turbine to expand and do work, driving the hot ammonia turbine generator to generate electricity. The generated electricity is sent to the energy management system for distribution. After the mixture finishes doing work in the hot ammonia turbine, its temperature drops and it enters the second-stage chemical regenerator for a secondary reaction. The ammonia gas that has not reacted in the first-stage chemical regenerator continues to decompose to generate hydrogen and nitrogen. Then it is passed into the fuel premixing chamber, where it is fully mixed with the aviation kerosene before being passed into the combustion chamber to participate in the combustion reaction. Outside the turboshaft engine, air from the atmosphere is drawn into the intake duct, pressurized by the compressor, and then fed into the combustion chamber. After being fully mixed and burned with the fuel mixture in the combustion chamber, the air is fed into the gas turbine to do work. The rotation of the gas turbine drives the rotor shaft to rotate, which in turn drives the compressor to do work. After the gas has finished doing work in the gas turbine, it enters the power turbine, which drives the power turbine to rotate. The power turbine then drives the rotor shaft to rotate, which in turn drives the power turbine generator to rotate and generate electrical energy. The electrical energy is then sent to the energy management system for distribution. After the combustion gas finishes working in the power turbine, it enters the working medium passage in the secondary chemical regenerator to provide heat energy for the heating of the ammonia decomposition mixture and secondary decomposition. After the first heat exchange, the combustion gas enters the working medium passage in the primary chemical regenerator to provide heat energy for the liquid ammonia phase change and ammonia decomposition. Then it enters the combustion gas passage in the aviation kerosene preheater to provide heat for heating aviation kerosene. After heating, the combustion gas is diffused and expanded through the tail nozzle and then discharged into the atmosphere. At this time, the exhaust gas consists of water vapor, oxygen and nitrogen.

[0009] Therefore, the present invention provides a chemical regenerative turboshaft engine and its operating method. Compared with the prior art, the present invention has the following beneficial effects: 1) Using ammonia fuel, a zero-carbon fuel, as a supplementary fuel enables green aviation power fuel to replace some traditional fossil fuels, significantly reducing the concentration of carbon dioxide in the exhaust of the turboshaft engine system and reducing the engine's carbon emissions, which is in line with my country's aviation carbon emission reduction development plan. 2) The chemical heat sink of ammonia fuel is used to recover and reuse the waste heat of the turboshaft engine exhaust gas, converting the low-grade heat energy in the exhaust gas into electrical and chemical energy, thereby improving the energy quality of the turboshaft engine system and thus improving the efficiency of the turboshaft engine system. 3) By utilizing the high-temperature ammonia fuel decomposition mixture from the endothermic decomposition in the first-stage chemical regenerator to expand and generate electricity, the temperature and pressure of the mixture are reduced, the heat transfer temperature difference between the hot and cold working fluids in the second-stage chemical regenerator is increased, and the chemical endothermic capacity and decomposition rate of the ammonia working fluid decomposing the mixture are indirectly improved, further improving the utilization rate of waste heat from the turboshaft engine exhaust and improving the engine performance. 4) By generating electricity through a power turbine and ammonia fuel decomposition gas, the energy level of the engine system is improved. At the same time, the engine rotor is changed from mechanical transmission to electric transmission, which simplifies the transmission structure and reduces the weight of the transmission structure. This is conducive to further improving the power-to-weight ratio of the engine and has certain significance for promoting the development of future advanced turboshaft engine design. Attached Figure Description

[0010] 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.

[0011] Figure 1 The attached figure is a structural schematic diagram of a chemical regenerative turboshaft engine provided by the present invention. Detailed Implementation

[0012] 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.

[0013] like Figure 1As shown in the figure, an embodiment of the present invention discloses a chemical regenerative turboshaft engine, including a core engine system 1, an engine electrical system 2, and a fuel supply system 3; the core engine system 1 includes an air intake 11, a compressor 12, a combustion chamber 13, a gas turbine 14, and a power turbine 15; the engine electrical system 2 includes a power turbine generator 21, an energy management system 22, a hot ammonia turbine generator 23, and a hot ammonia turbine 24; the fuel supply system 3 includes a jet fuel storage tank 31, a jet fuel pump 32, a jet fuel preheater 33, a fuel premixing chamber 34, and liquid ammonia. The system includes a storage tank 35, a liquid ammonia pump 36, a primary chemical regenerator 37, and a secondary chemical regenerator 38. The outlet of the air inlet 11 is connected to the air inlet of the compressor 12, the outlet of the compressor 12 is connected to the air inlet of the combustion chamber 13, the gas outlet of the combustion chamber 13 is connected to the inlet of the gas turbine 14, and the gas turbine 14 is connected to the compressor 12 via a rotor shaft drive. The outlet of the gas turbine 14 is connected to the inlet of the power turbine 15, and the outlet of the power turbine 15 is connected to the inlet of the heat transfer fluid passage of the secondary chemical regenerator 38. The outlet of the hot working fluid channel of 8 is connected to the inlet of the hot working fluid channel of the first-stage chemical regenerator 37. The outlet of the hot working fluid channel of the first-stage chemical regenerator 37 is connected to the inlet of the hot working fluid channel of the aviation kerosene preheater 33. The outlet of the hot working fluid channel of the aviation kerosene preheater 33 is connected to the engine tailpipe, and exhausts the combustion gas from the engine through the tailpipe. The outlet of the aviation kerosene storage tank 31 is connected to the inlet of the aviation kerosene fuel pump 2. The outlet of the aviation kerosene fuel pump 32 is connected to the inlet of the cold working fluid channel of the aviation kerosene preheater 33. The outlet of the cold working fluid channel of the aviation kerosene preheater 33 is connected to the fuel premixing chamber 3. The jet fuel inlet of chamber 4 is connected, and the outlet of fuel premixing chamber 34 is connected to the fuel inlet of combustion chamber 13; the outlet of liquid ammonia storage tank 35 is connected to the inlet of liquid ammonia pump 36, the outlet of liquid ammonia pump 36 is connected to the inlet of cold working medium channel of primary chemical regenerator 37, the outlet of cold working medium channel of primary chemical regenerator 37 is connected to the inlet of hot ammonia turbine 24, the outlet of hot ammonia turbine 24 is connected to the inlet of cold working medium channel of secondary chemical regenerator 38, and the outlet of cold working medium channel of secondary chemical regenerator 38 is connected to the ammonia fuel inlet of fuel premixing chamber 34. This invention can fully utilize the chemical heat sink of ammonia fuel to extract thermal energy from the waste heat of turboshaft engine exhaust, improve the waste heat utilization rate of exhaust gas, and thus improve the thermal efficiency of the engine. At the same time, it can fully utilize the thermal expansion performance of the ammonia fuel decomposition mixture to drive the hot ammonia turbine 24 to generate electricity, solving the problems of large power demand, difficulty in power extraction, and complex circuit transmission structure of existing turboshaft engine airborne electrical equipment. It reduces the power extraction of the circuit system from the engine main shaft, increases the output power of the power turbine 15, and improves the overall energy utilization level of the engine.

[0014] It is understood that the connection mentioned in this implementation can be achieved through pipelines or by direct mechanical connection, as long as the gas or liquid is connected. In the diagram, solid lines represent air transmission pipelines, dashed lines represent fuel transmission pipelines, dashed lines at connection points represent gas transmission pipelines, and double solid lines represent power transmission.

[0015] This invention also discloses a method for operating a chemical regenerative turboshaft engine, comprising the following steps: Aviation kerosene in aviation kerosene storage tank 31 enters the cold working medium channel of aviation kerosene preheater 33 through the suction action of aviation kerosene fuel pump 32, and enters fuel premixing chamber 34 after being preheated by the gas; aviation kerosene fuel pump 32 extracts shaft power from gas turbine 14 to maintain normal operation of the pump. Liquid ammonia fuel in liquid ammonia storage tank 35 is drawn into the cold working fluid channel of primary chemical regenerator 37 by liquid ammonia pump 36. Liquid ammonia pump 36 extracts shaft work from gas turbine 14 to maintain normal pump operation. Under the heating action of high-temperature gas, ammonia fuel first undergoes a phase change, vaporizing from liquid ammonia to ammonia gas, and then decomposes into some hydrogen and nitrogen gas after being catalyzed by a catalyst. The high-temperature and high-pressure ammonia fuel mixture (a mixture of unreacted ammonia, nitrogen, and hydrogen gas) then enters the hot ammonia turbine 24 to expand and do work, driving the hot ammonia turbine generator 23 to generate electricity. The generated electrical energy is transmitted to the energy management system 22 for distribution. After the mixture finishes its work in step 4, its temperature drops and it enters the secondary chemical regenerator 38 for a secondary reaction. The unreacted ammonia in the primary chemical regenerator 37 continues to decompose into hydrogen and nitrogen. The ammonia fuel decomposition mixture at the outlet of the primary chemical regenerator 37 drives the hot ammonia turbine 24 to do work, which in turn drives the hot ammonia turbine generator 23 to generate electricity. This reduces the temperature of the mixture, increases the temperature difference between the hot and cold working fluids in the secondary chemical regenerator 38, increases the system's heat recovery, and improves the engine's energy utilization rate. Afterward, it is introduced into the fuel premixing chamber 34, where it is fully mixed with the aviation kerosene before being introduced into the combustion chamber 13 to participate in the combustion reaction. Outside the turboshaft engine, air from the atmosphere is drawn into the intake duct 11, pressurized by the compressor 12, and then fed into the combustion chamber 13. After being fully mixed and burned with the fuel mixture in the combustion chamber 13, the air is fed into the gas turbine 14 to do work. The rotation of the gas turbine 14 drives the rotor shaft to rotate, which in turn drives the compressor 12 to do work. After the gas has finished doing work in the gas turbine 14, it enters the power turbine 15, which drives the power turbine 15 to rotate. The power turbine 15 then drives the rotor shaft to rotate, which drives the power turbine generator 21 to rotate and generate electrical energy. The electrical energy is then sent to the energy management system 22 for distribution and supply to the airborne electrical devices, including the helicopter rotor. The use of electric rotors to replace traditional structures such as gearboxes and reducers reduces the weight of the engine's traditional structure and improves the engine's thrust-to-weight ratio. After the combustion gas finishes working in the power turbine 15, it enters the working medium channel in the secondary chemical regenerator 38 to provide heat energy for the heating of the ammonia decomposition mixture and secondary decomposition. After the first heat exchange, the combustion gas enters the working medium channel in the primary chemical regenerator 37 to provide heat energy for the liquid ammonia phase change and ammonia decomposition. Then it enters the combustion gas channel in the aviation kerosene preheater 33 to provide heat for heating aviation kerosene. After heating, the combustion gas is diffused and expanded through the tail nozzle and then discharged into the atmosphere. At this time, the exhaust gas contains water vapor, oxygen and nitrogen.

[0016] Specifically, the inner wall of the cold working fluid channel of the secondary chemical regenerator 38 is coated with a catalyst that promotes the decomposition reaction of ammonia fuel. The catalyst is a ruthenium-based catalyst, and catalyst supports CNFs and Al2O3 and co-catalyst KOH are added to improve the catalyst performance.

[0017] 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.

[0018] 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, characterized in that, The system includes a core engine system, an engine electrical system, and a fuel supply system. The core engine system includes an air intake, a compressor, a combustion chamber, a gas turbine, and a power turbine. The engine electrical system includes a power turbine generator, an energy management system, a hot ammonia turbine generator, and a hot ammonia turbine. The fuel supply system includes a jet fuel storage tank, a jet fuel pump, a jet fuel preheater, a fuel premixing chamber, a liquid ammonia storage tank, a liquid ammonia pump, a first-stage chemical regenerator, and a second-stage chemical regenerator. The outlet of the air intake is connected to the air inlet of the compressor, the outlet of the compressor is connected to the air inlet of the combustion chamber, the gas outlet of the combustion chamber is connected to the inlet of the gas turbine, and the gas turbine is connected to the compressor via a rotor shaft drive. 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 medium channel of the second-stage chemical regenerator, and the outlet of the working medium channel of the second-stage chemical regenerator is connected to the inlet of the working medium channel of the first-stage chemical regenerator. The outlet of the hot working fluid passage of the first-stage chemical regenerator is connected to the inlet of the hot working fluid passage of the aviation kerosene preheater. The outlet of the hot working fluid passage of the aviation kerosene preheater is connected to the engine exhaust nozzle, through which the combustion gas is discharged from the engine. The outlet of the aviation kerosene storage tank is connected to the inlet of the aviation kerosene fuel pump. The outlet of the aviation kerosene fuel pump is connected to the inlet of the cold working fluid passage of the aviation kerosene preheater. The outlet of the cold working fluid passage of the aviation kerosene preheater is connected to the aviation kerosene fuel inlet of the fuel premixing chamber. The outlet of the fuel premixing chamber is connected to the fuel inlet of the combustion chamber. The outlet of the liquid ammonia storage tank is connected to the inlet of the liquid ammonia pump. The outlet of the liquid ammonia pump is connected to the inlet of the cold working fluid passage of the first-stage chemical regenerator. The outlet of the cold working fluid passage of the first-stage chemical regenerator is connected to the inlet of the hot ammonia turbine. The outlet of the hot ammonia turbine is connected to the inlet of the cold working fluid passage of the second-stage chemical regenerator. The outlet of the cold working fluid passage of the second-stage chemical regenerator is connected to the ammonia fuel inlet of the fuel premixing chamber.

2. The operating method of a chemical regenerative turboshaft engine as described in claim 1, characterized in that, Includes the following steps: Aviation kerosene in the aviation kerosene storage tank enters the cold working fluid channel of the aviation kerosene preheater through the suction action of the aviation kerosene fuel pump, and enters the fuel premixing chamber after being preheated by the fuel gas. Liquid ammonia fuel in the liquid ammonia storage tank is drawn into the cold working fluid channel of the first-stage chemical regenerator by the liquid ammonia pump. Under the heating action of the high-temperature gas, the ammonia fuel first undergoes a phase change, vaporizing from liquid ammonia into ammonia gas. After being catalyzed by the catalyst, it decomposes to generate some hydrogen and nitrogen. The high-temperature and high-pressure ammonia fuel mixture then enters the hot ammonia turbine to expand and do work, driving the hot ammonia turbine generator to generate electricity. The generated electricity is sent to the energy management system for distribution. After the mixture finishes doing work in the hot ammonia turbine, its temperature drops and it enters the second-stage chemical regenerator for a secondary reaction. The ammonia gas that has not reacted in the first-stage chemical regenerator continues to decompose to generate hydrogen and nitrogen. Then it is passed into the fuel premixing chamber, where it is fully mixed with the aviation kerosene before being passed into the combustion chamber to participate in the combustion reaction. Outside the turboshaft engine, air from the atmosphere is drawn into the intake duct, pressurized by the compressor, and then fed into the combustion chamber. After being fully mixed and burned with the fuel mixture in the combustion chamber, the air is fed into the gas turbine to do work. The rotation of the gas turbine drives the rotor shaft to rotate, which in turn drives the compressor to do work. After the gas has finished doing work in the gas turbine, it enters the power turbine, which drives the power turbine to rotate. The power turbine then drives the rotor shaft to rotate, which in turn drives the power turbine generator to rotate and generate electrical energy. The electrical energy is then sent to the energy management system for distribution. After the combustion gas finishes working in the power turbine, it enters the working medium passage in the secondary chemical regenerator to provide heat energy for the heating of the ammonia decomposition mixture and secondary decomposition. After the first heat exchange, the combustion gas enters the working medium passage in the primary chemical regenerator to provide heat energy for the liquid ammonia phase change and ammonia decomposition. Then it enters the combustion gas passage in the aviation kerosene preheater to provide heat for heating aviation kerosene. After heating, the combustion gas is diffused and expanded through the tail nozzle and then discharged into the atmosphere. At this time, the exhaust gas consists of water vapor, oxygen and nitrogen.

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