A supercritical carbon dioxide power cycle system for cold gas pre-cooling

Abstract

This invention discloses a supercritical carbon dioxide power generation cycle system for precooling cold air. This supercritical carbon dioxide power generation cycle system is connected to the air-cooling system of an aero-engine. The aero-engine air-cooling system includes a compressor, a turbine shaft, and a high-temperature turbine assembly. The compressor and the high-temperature turbine assembly are connected via the turbine shaft. The high-temperature turbine assembly drives the compressor to generate high-pressure gas A via the turbine shaft. The supercritical carbon dioxide power generation cycle system includes a compressor, a generator, a turbine assembly, a regenerator, and a cooler connected in sequence. A spherical concave spiral heat exchanger is connected between the turbine assembly and the regenerator. The concave spiral heat exchanger is placed in the turbine shaft, and supercritical carbon dioxide is disposed within the spherical concave spiral heat exchanger. This invention is small in size and light in weight, not only solving the problem of thermal protection for aero-engines but also effectively improving the overall thermal efficiency of aero-engines.

Description

Technical Field

[0001] This invention relates to the field of power generation technology, and more specifically, to a supercritical carbon dioxide power generation cycle system for precooling cold air. Background Technology

[0002] According to the thermodynamic mechanism of gas turbine engines, increasing the inlet gas temperature can effectively improve the engine's thermal efficiency and output power. Typically, a 56°C increase in inlet gas temperature can increase engine thermal efficiency by 2%-4% and thrust by 8%-13%. This has led to a year-on-year increase in the inlet gas temperature of aero-engine turbines, with some turbine inlet temperatures currently far exceeding the temperature resistance range of the materials used. If the downstream hot-end components of the combustion chamber are not adequately cooled, they will inevitably be corroded and damaged by the combustion gases, severely affecting the normal operation of the aero-engine. Therefore, the application of efficient cooling technology to hot-end components is essential, enabling them to operate below the material's temperature resistance limit, thereby ensuring the safe, reliable, and long-duration operation of the aero-engine. The common practice is to introduce high-pressure gas compressed by the compressor into the hot-end components after combustion chamber via the turbine shaft for cooling; therefore, the temperature of the cooled gas directly determines the cooling effect of the hot-end components.

[0003] The supercritical CO2 power generation cycle system consists of components such as a compressor, heat exchanger, and turbine. It utilizes the excellent heat exchange capacity and low compression power consumption of the high-pressure, high-density CO2 working fluid under supercritical conditions. It absorbs heat from external heat sources through the heat exchanger to obtain efficient power output. It has the advantages of high energy density, high cycle thermal efficiency, and small size.

[0004] Currently, there is an urgent need to develop a supercritical carbon dioxide power generation cycle system for precooling cold air. Summary of the Invention

[0005] The purpose of this invention is to provide a supercritical carbon dioxide power generation cycle system for precooling cold air, so as to overcome the defects of the prior art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A supercritical carbon dioxide power generation cycle system for precooling cold air is disclosed. This supercritical carbon dioxide power generation cycle system is connected to an aero-engine air-cooling system. The aero-engine air-cooling system includes a compressor, a turbine shaft, and a high-temperature turbine assembly. The compressor and the high-temperature turbine assembly are connected via the turbine shaft. The high-temperature turbine assembly drives the compressor to form high-pressure gas A via the turbine shaft. The supercritical carbon dioxide power generation cycle system includes a compressor, a generator, a turbine assembly, a regenerator, and a cooler connected in sequence. A spherical concave spiral heat exchanger is connected between the turbine assembly and the regenerator. The concave spiral heat exchanger is placed in the turbine shaft, and supercritical carbon dioxide is disposed within the spherical concave spiral heat exchanger.

[0008] Furthermore, the spiral heat exchanger with spherical recesses is provided with multiple spherical recesses at equal intervals.

[0009] Furthermore, the spiral heat exchanger with spherical recesses has three spherical recesses on the same cross-section, but no spherical recesses are provided on the windward side of the spiral heat exchanger with spherical recesses. The diameter of the spherical recesses is less than 0.4D, where D is the diameter of the spiral tube in the spiral heat exchanger with spherical recesses.

[0010] Furthermore, the compressor, generator, and turbine are coaxially connected.

[0011] Furthermore, the inlet side of the spherical concave spiral heat exchanger is upstream of the high-pressure gas A in the turbine shaft, and the heat of the high-pressure gas A in the turbine shaft is conducted to the supercritical carbon dioxide in the spherical concave spiral heat exchanger.

[0012] Furthermore, the compressor inlet is connected to the cooler outlet, the turbine outlet is connected to the hot-side inlet of the regenerator, the compressor outlet is connected to the cold-side inlet of the regenerator, the regenerator hot-side outlet is connected to the cooler inlet, the regenerator cold-side outlet is connected to the inlet of the spiral heat exchanger with spherical concave shape, and the spiral heat exchanger with spherical concave shape is connected to the turbine inlet.

[0013] Compared with existing technologies, the advantages of this invention are as follows: This invention provides a supercritical carbon dioxide power generation cycle system for pre-cooling cold air, effectively combining the air-cooling system of an aero-engine and the supercritical carbon dioxide power generation cycle system. This not only solves the problem of thermal protection for aero-engines but also allows for further increases in the turbine inlet temperature, effectively improving the overall thermal efficiency and thrust of the aero-engine. This invention can effectively reduce the temperature of the cold air in the turbine shaft, thereby effectively protecting hot-end components such as the turbine from corrosion by combustion gases, ensuring the normal operation of the entire aero-engine, extending the service life of hot-end components, and the electricity generated by the cycle can also power the electronic equipment of the aircraft. The spherical recessed area of ​​the spiral heat exchanger effectively increases the disturbance of supercritical carbon dioxide inside the tube, avoiding the occurrence of heat transfer deterioration inside the tube and enhancing the heat transfer intensity inside the tube. Due to the presence of the spherical recess, the heat transfer area outside the tube increases, effectively transferring the heat of the cold air in the aero-engine turbine shaft to the supercritical carbon dioxide inside the spiral heat exchanger. There is no recessed area on the windward side, reducing aerodynamic losses caused by installing the spiral heat exchanger in the turbine shaft. This invention is small in size and light in weight and will not affect the overall performance of the engine. Attached Figure Description

[0014] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the supercritical carbon dioxide power generation cycle system for precooling cold air according to the present invention.

[0016] Figure 2 This is a schematic diagram of the spiral heat exchanger with spherical concave shape according to the present invention.

[0017] Figure 3 This is a schematic cross-sectional view of the spherical recessed region in the spiral heat exchanger with spherical recesses of the present invention.

[0018] In the diagram: 1. Compressor; 2. Turbine shaft; 3. High-temperature turbine assembly; 4. Compressor; 5. Generator; 6. Turbine assembly; 7. Regenerator; 8. Cooler; 9. Spiral heat exchanger with spherical recess; 10. Spherical recess. Detailed Implementation

[0019] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0020] See Figures 1-3 As shown, this embodiment discloses a supercritical carbon dioxide power generation cycle system for precooling cold air, which is applied to the thermal protection and cycle power generation of aero engines. The supercritical carbon dioxide power generation cycle system is connected to the air cooling system of the aero engine.

[0021] The air-cooling system of the aero-engine includes a compressor 1, a turbine shaft 2, and a high-temperature turbine device 3. The compressor 1 and the high-temperature turbine device 3 are connected through the turbine shaft 2. The high-temperature turbine device 3 drives the compressor 1 through the turbine shaft 2 to form high-pressure gas A. A portion of the high-pressure gas A enters the turbine shaft 2 to provide cooling air for the hot-end components such as the high-temperature turbine device 3, ensuring the normal operation of the hot-end components.

[0022] The supercritical carbon dioxide power generation cycle system includes a compressor 4, a generator 5, a turbine unit 6, a regenerator 7, and a cooler 8 connected in sequence. A spherical concave spiral heat exchanger 9 is connected between the turbine unit 6 and the regenerator 7. The concave spiral heat exchanger 9 is placed in the turbine shaft 2. Supercritical carbon dioxide is installed inside the spherical concave spiral heat exchanger 9. The turbine unit 6 outputs mechanical energy to drive the compressor 4 and the generator 5. The electrical energy generated by the generator 5 is used to power the electronic equipment of the aircraft.

[0023] In this embodiment, the spiral heat exchanger 9 with spherical recesses has multiple spherical recesses 10 arranged at equal intervals. Three spherical recesses 10 are arranged on the same cross-section of the spiral heat exchanger 9. No spherical recesses 10 are provided on the windward side of the spiral heat exchanger 9. The diameter of each spherical recess 10 is less than 0.4D, where D is the diameter of the spiral tube in the spiral heat exchanger 9. The spherical recess area 10 of the spiral heat exchanger 9 can effectively improve the disturbance of supercritical carbon dioxide inside the tube, avoiding the occurrence of heat transfer deterioration inside the tube and enhancing the heat transfer intensity inside the tube. Due to the presence of the spherical recesses, the heat transfer area outside the tube is increased, effectively transferring the heat of the cold air in the turbine shaft of the aero-engine to the supercritical carbon dioxide inside the heat exchanger. The absence of a recess structure on the windward side reduces the aerodynamic losses caused by installing the spiral heat exchanger with spherical recesses in the turbine shaft.

[0024] In this embodiment, the compressor 4, generator 5, and turbine 6 are coaxially connected.

[0025] In this embodiment, the inlet side of the spherical concave spiral heat exchanger 9 is upstream of the high-pressure gas A in the turbine shaft 2, which can effectively transfer the heat of the high-pressure gas A in the turbine shaft 2 to the supercritical carbon dioxide in the spherical concave spiral heat exchanger 9.

[0026] In this embodiment, the inlet of the compressor 4 is connected to the outlet of the cooler 8, the outlet of the turbine device 6 is connected to the hot-side inlet of the regenerator 7, the outlet of the compressor 4 is connected to the cold-side inlet of the regenerator 7, the hot-side outlet of the regenerator 7 is connected to the inlet of the cooler 8, the cold-side outlet of the regenerator 7 is connected to the inlet of the spiral heat exchanger 9 with spherical concave shape, and the outlet of the spiral heat exchanger 9 with spherical concave shape is connected to the inlet of the turbine device 6.

[0027] In this embodiment, the inlet section of compressor 4 is used as the starting point of the cycle. After being pressurized by compressor 4, the supercritical carbon dioxide state changes from low temperature and low pressure I to low temperature and high pressure II. After being preheated by the hot side of regenerator 7, the supercritical carbon dioxide state changes from low temperature and high pressure II to medium temperature and high pressure III. After absorbing the heat of high pressure gas A in turbine shaft 2 in the spherical concave spiral heat exchanger 9, the supercritical carbon dioxide in the medium temperature and high pressure III state changes from medium temperature and high pressure III to high temperature and high pressure IV. After the supercritical carbon dioxide in the high temperature and high pressure IV state expands and does work through turbine device 6, the supercritical carbon dioxide state changes from high temperature and high pressure IV to medium temperature and low pressure V. At this time, the turbine... Device 6 coaxially drives compressor 4 and generator 5. Compressor 4 pressurizes the supercritical carbon dioxide in low-temperature, low-pressure state I, while generator 5 supplies power to the aircraft's electronic equipment. The supercritical carbon dioxide in medium-temperature, low-pressure state V is pre-cooled by the cold side of regenerator 7, and some of its heat is transferred to the supercritical carbon dioxide in low-temperature, high-pressure state II, changing its state from medium-temperature, low-pressure V to low-temperature, low-pressure VI. The supercritical carbon dioxide in low-temperature, low-pressure VI is then cooled by external air from the aircraft engine via cooler 8, changing its state from low-temperature, low-pressure V to low-temperature, low-pressure I, and re-enters compressor 4, completing one closed-loop cycle. After one cycle, the temperature of the high-pressure gas A in turbine shaft 2 drops significantly and is transported through turbine shaft 2 to the hot-end components requiring cooling.

[0028] The spacing of the spherical recesses 10 and the length of the spiral heat exchanger 9 need to be determined based on the amount of high-pressure gas A in the turbine shaft 2. Generally, the greater the amount of high-pressure gas A, the smaller the spacing of the spherical recesses 10 needs to be to ensure that heat transfer does not deteriorate inside the tube. If the length of the spiral heat exchanger 9 is too long, the diameter T of the spherical recesses 10 needs to be reduced to avoid forming large flow resistance inside the spiral tube.

[0029] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, the patent owner may make various modifications or alterations within the scope of the appended claims, and such modifications or alterations shall be within the scope of protection of the present invention as long as they do not exceed the scope of protection described in the claims.

Claims

1. A supercritical carbon dioxide power generation cycle system for precooling cold air, characterized in that, The supercritical carbon dioxide power generation cycle system is connected to the air-cooling system of an aero-engine. The air-cooling system of the aero-engine includes a compressor, a turbine shaft, and a high-temperature turbine assembly. The compressor and the high-temperature turbine assembly are connected through the turbine shaft. The high-temperature turbine assembly drives the compressor through the turbine shaft to form high-pressure gas A. The supercritical carbon dioxide power generation cycle system includes a compressor, a generator, a turbine assembly, a regenerator, and a cooler connected in sequence. A spherical concave spiral heat exchanger is connected between the turbine assembly and the regenerator. The spherical concave spiral heat exchanger is placed in the turbine shaft. Supercritical carbon dioxide is disposed inside the spherical concave spiral heat exchanger. The spiral heat exchanger with spherical recesses has multiple spherical recesses arranged at equal intervals. The spiral heat exchanger with spherical recesses has three spherical recesses on the same cross section, and no spherical recesses are provided on the windward side of the spiral heat exchanger with spherical recesses. The diameter of the spherical recesses is less than 0.4D, where D is the diameter of the spiral tube in the spiral heat exchanger with spherical recesses. The compressor, generator, and turbine are coaxially connected. The inlet side of the spherical concave spiral heat exchanger is upstream of the high-pressure gas A in the turbine shaft, and the heat of the high-pressure gas A in the turbine shaft is transferred to the supercritical carbon dioxide in the spherical concave spiral heat exchanger. The compressor inlet is connected to the cooler outlet, the turbine outlet is connected to the hot-side inlet of the regenerator, the compressor outlet is connected to the cold-side inlet of the regenerator, the regenerator hot-side outlet is connected to the cooler inlet, the regenerator cold-side outlet is connected to the inlet of the spiral heat exchanger with spherical concave shape, and the spiral heat exchanger with spherical concave shape is connected to the turbine inlet.

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