Supercritical CO2 axial flow turbine units and their axial force measurement and adjustment methods

Abstract

This invention discloses a supercritical CO2 axial flow turbine unit and its axial force measurement and adjustment method. The axial flow turbine unit includes: an axial flow turbine body, comprising a main shaft, an impeller, and an exhaust casing, wherein the exhaust casing includes: a casing body; an enclosure member disposed within an axial cavity, the enclosure member being a cavity with one open end abutting against the outlet end of the impeller, sealing the cavity through the outlet end of the impeller, the impeller and the enclosure member forming a sealed pressure regulating cavity; and multiple connecting ribs for connecting and fixing the enclosure member to the casing body; a high-pressure working fluid storage tank and a low-pressure working fluid storage tank; wherein the pressure regulating cavity is in fluid communication with both the high-pressure and low-pressure working fluid storage tanks, the high-pressure working fluid storage tank supplying high-pressure working fluid to the pressure regulating cavity, and the low-pressure working fluid storage tank receiving low-pressure working fluid from the pressure regulating cavity. This invention obtains axial force and allows for adjustment of axial force over a wide range without affecting the function of the main components of the turbine unit.

Description

Technical Field

[0001] This invention relates to the field of axial force measurement and adjustment of supercritical carbon dioxide axial flow turbine units, and more specifically to a supercritical carbon dioxide axial flow turbine unit with controllable axial force and a method for measuring and adjusting the axial force thereon. Background Technology

[0002] Supercritical carbon dioxide turbines are characterized by high pressure, high speed, and complex operating conditions, resulting in significant axial forces that vary considerably with changing operating conditions. Axial forces play a crucial role in the stable operation of supercritical carbon dioxide turbines. On the one hand, excessive axial forces place higher demands on the bearing capacity, greatly increasing the design complexity. On the other hand, if the axial force exceeds the bearing's capacity during operation, it can cause bearing failure and damage to internal moving and stationary components of the turbine unit. Therefore, effectively controlling the axial force over a wide range without increasing its design requirements, and accurately measuring and controlling the turbine's axial force, is a key challenge in supercritical carbon dioxide turbine design.

[0003] In existing technologies, due to the limitations of turbine shaft system dimensions, axial force is generally difficult to measure, or can only be measured directly by designing a force sensor inside the bearing. Such a sensor affects the bearing design and increases the difficulty of shaft system design. Furthermore, traditional adjustment methods have a limited adjustment range, making it difficult to achieve adjustment across the entire operating range during actual turbine operation.

[0004] Therefore, there is an urgent need in this field for a device that can be designed without increasing axial force, without affecting the turbine shaft system design, and can adapt to various supercritical carbon dioxide turbine operating conditions, can control axial force over a wide range, and preferably can accurately measure and adjust axial force. Summary of the Invention

[0005] The purpose of this invention is to provide a supercritical carbon dioxide axial flow turbine unit and its axial force measurement and adjustment method, to solve the problems of small axial force adjustment range and difficulty in axial force measurement in the prior art. This invention allows for axial force adjustment over a wide range without damaging the main components of the turbine unit, affecting the turbine shaft design and the maximum load it can withstand, and enables accurate axial force adjustment through axial force measurement and calculation.

[0006] In a first aspect of the invention, an axial force-controllable supercritical carbon dioxide axial flow turbine unit is provided, the axial flow turbine unit comprising:

[0007] An axial flow turbine body, the axial flow turbine body including a main shaft, an impeller fixed to the end of the main shaft for driving the main shaft to rotate, and an exhaust casing for providing peripheral fixed support for the impeller, wherein the exhaust casing includes:

[0008] The casing body is arranged around the outer periphery of the impeller and has an axial cavity for the flow of supercritical carbon dioxide after work is done.

[0009] An enclosure, arranged within the axial cavity, the enclosure being an open-end cavity abutting against the outlet end of the impeller, sealing the cavity through the outlet end of the impeller; the impeller and the enclosure forming a closed pressure regulating cavity, the pressure regulating cavity being coaxially arranged with the main shaft; and

[0010] Multiple connecting ribs, the multiple connecting ribs being used to connect and fix the enclosure to the housing body;

[0011] A high-pressure working fluid storage tank, wherein the pressure of the high-pressure working fluid storage tank is greater than 20 MPa, and

[0012] A low-pressure working fluid storage tank, wherein the pressure of the low-pressure working fluid storage tank is less than 2 MPa;

[0013] The pressure regulating chamber is in fluid communication with both the high-pressure working medium storage tank and the low-pressure working medium storage tank. The high-pressure working medium storage tank supplies high-pressure working medium to the pressure regulating chamber, and the low-pressure working medium storage tank receives low-pressure working medium from the pressure regulating chamber.

[0014] In another preferred embodiment, the temperature of the supercritical carbon dioxide entering the working fluid of the axial turbine body is 400–600°C, and the pressure is 13.5–19.5 MPa.

[0015] In another preferred embodiment, the supercritical carbon dioxide enters the axial turbine body through the working fluid inlet. When it passes the stationary blades mounted on the baffle, the working fluid (carbon dioxide) further expands and accelerates, and changes the airflow direction, so that the airflow impacts the blades on the axial impeller at a suitable angle, converting the kinetic energy of the working fluid into mechanical energy. The axial impeller rotates and drives the main shaft to rotate, so as to output energy.

[0016] In another preferred embodiment, the axial flow turbine unit achieves bidirectional adjustment of axial force by controlling the pressure within the pressure regulating chamber.

[0017] In another preferred embodiment, the axial flow turbine unit adjusts the axial force provided by the pressure regulating chamber from -25000N to +25000N.

[0018] In another preferred embodiment, the opening end of the surround is sealed to the outlet end of the impeller by a comb-tooth seal.

[0019] In another preferred embodiment, one end of the connecting rib is fixedly connected to the closed end of the enclosure, and the other end is fixedly connected to the casing body.

[0020] In another preferred embodiment, the plurality of connecting ribs are arranged to be circumferentially spaced apart about the axis of the main shaft.

[0021] In another preferred embodiment, the pressure regulating chamber is in fluid communication with the high-pressure working fluid storage tank through a pressure regulating vent hole, and in fluid communication with the low-pressure working fluid storage tank through a pressure regulating vent hole.

[0022] In another preferred embodiment, both the pressure regulating vent and the pressure regulating exhaust vent are through holes extending from the pressure regulating chamber through the enclosure, the connecting rib, and the casing body to the outside.

[0023] In another preferred embodiment, the number of pressure regulating air intake holes is at least one; the number of pressure regulating exhaust holes is at least one.

[0024] In another preferred embodiment, when there are multiple pressure regulating air inlets and pressure regulating exhaust outlets, the pressure regulating air inlets and pressure regulating exhaust outlets are arranged to be circumferentially spaced apart about the axis of the main shaft.

[0025] In another preferred embodiment, a first pressure regulating valve is provided on the pipeline from the pressure regulating chamber to the high-pressure working medium storage tank. The first pressure regulating valve is used to control the amount of high-pressure working medium injected from the high-pressure working medium storage tank into the pressure regulating chamber, thereby increasing the pressure in the pressure regulating chamber.

[0026] In another preferred embodiment, a discharge valve is provided on the pipeline from the pressure regulating chamber to the low-pressure working medium storage tank. The discharge valve is used to control the amount of working medium discharged from the pressure regulating chamber into the low-pressure working medium storage tank, thereby reducing the pressure in the pressure regulating chamber.

[0027] In another preferred embodiment, the axial turbine body is further provided with a sealing cavity, which is formed by the main shaft, a partition plate that abuts against the inlet end of the impeller and is sleeved on the main shaft, a cover plate, and a dry gas sealing device sleeved on the main shaft.

[0028] In another preferred embodiment, the sealed cavity is in fluid communication with the high-pressure working medium storage tank, which is used to supply high-pressure working medium to the sealed cavity.

[0029] In another preferred embodiment, the sealed cavity is in fluid communication with the high-pressure working fluid storage tank through a sealed pressure tap.

[0030] In another preferred embodiment, the sealing pressure hole is provided on the cover plate and is a through hole extending from the sealing cavity through the cover plate to the outside.

[0031] In another preferred embodiment, a second pressure regulating valve is provided on the pipeline from the high-pressure working medium storage tank to the pressure regulating chamber. The second pressure regulating valve is used to control the amount of high-pressure working medium injected from the high-pressure working medium storage tank into the sealing chamber, thereby increasing the pressure inside the sealing chamber.

[0032] In another preferred embodiment, the axial flow turbine unit achieves unidirectional adjustment of the axial force by controlling the pressure within the sealed cavity.

[0033] In another preferred embodiment, the axial force of the axial turbine unit is unidirectionally adjusted by controlling the amount of high-pressure working fluid injected from the high-pressure working fluid storage tank into the sealed cavity.

[0034] In another preferred embodiment, the unidirectional adjustment is performed by applying a force along the main shaft axis from the impeller inlet end to the impeller outlet end.

[0035] In another preferred embodiment, the axial flow turbine unit adjusts the axial force provided by the sealed cavity from 0 to 3000 N.

[0036] In another preferred embodiment, the axial flow turbine unit further includes a measurement module comprising multiple pressure sensors for measuring the pressure at the turbine impeller inlet, outlet, sealing cavity, and pressure regulating cavity.

[0037] In another preferred embodiment, pressure taps are designed at the turbine impeller inlet, turbine impeller outlet, sealing cavity, and regulating cavity to connect the working fluid at each location to the axial force measuring pressure sensor, which measures the pressure at each location to calculate the turbine axial force.

[0038] In another preferred embodiment, pressure taps are provided at both the impeller inlet and the impeller outlet, and pressure sensors are installed at each pressure tap to measure the impeller inlet pressure P. in and the impeller outlet pressure P out .

[0039] In another preferred embodiment, pressure inlet holes are provided at the inlet and outlet of the pressure regulating chamber, and pressure sensors are provided at the inlet pressure inlet hole and / or outlet pressure inlet hole to measure the pressure P of the pressure regulating chamber. control .

[0040] In another preferred embodiment, a pressure inlet is provided at the inlet of the sealing cavity, and a pressure sensor is provided at the pressure inlet to measure the pressure P of the sealing cavity. seal .

[0041] In another preferred embodiment, the axial turbine unit further includes a controller for using pressure data from the pressure sensor (the impeller inlet pressure P) as a basis for... in The impeller outlet pressure P out The pressure P in the pressure regulating chamber control and the pressure P of the sealed cavity seal The design parameters of the axial flow turbine unit include: the radius R1 of the main shaft, the radial distance R2 from the center of the main shaft to the outer edge of the impeller inlet side, the radial distance R3 from the center of the main shaft to the outer edge of the impeller outlet side, the radial distance R4 from the center of the main shaft to the inner edge of the impeller outlet side, the radial distance R5 from the center of the main shaft to the outer edge of the impeller outlet side, the radial distance R6 from the center of the main shaft to the outer edge of the impeller inlet side, and the radial distance R7 from the center of the main shaft to the outer edge of the dry gas sealing device. seal1 and the radial distance R from the axis of the main shaft to the inner edge of the dry gas sealing device. seal2 The axial force resultant of the axial flow turbine unit is calculated by adjusting the pressure P in the pressure regulating chamber. control and the pressure P of the sealed cavity seal To adjust the axial force.

[0042] In another preferred embodiment, a comb-tooth seal is designed between the impeller and the turbine exhaust casing to maintain the pressure within the turbine exhaust pressure regulating chamber.

[0043] In another preferred embodiment, the inlet pressure of the supercritical carbon dioxide axial flow turbine body is in the range of 13.5 to 19.5 MPa, and the turbine outlet pressure is in the range of 8 to 9 MPa.

[0044] In another preferred embodiment, the axial turbine unit includes a high-speed motor, which is coaxially connected to the axial turbine body.

[0045] In another preferred embodiment, the high-speed motor is a starter-generator integrated motor.

[0046] In another preferred embodiment, during startup, the integrated starter-generator motor drives the turbine to operate; during power generation, the integrated starter-generator motor converts the turbine's shaft power into electrical energy.

[0047] In a second aspect of the invention, a method for measuring and adjusting the axial force of a supercritical carbon dioxide axial-flow turbine unit with controllable axial force is provided, the method comprising:

[0048] (1) Provide an axial turbine unit as described in any of the preceding items;

[0049] (2) The resultant axial force F of the axial flow turbine unit is the axial force F1 at the impeller disk inlet side, the axial force F2 at the impeller blade inlet side, the axial force F3 at the blade outlet side, the axial force F4 at the impeller disk outlet side, the axial force F5 exerted by the adjustable cavity on the impeller, and optionally the dry gas sealing axial force F from the sealing cavity. seal sum;

[0050] (3) The axial force resultant force F of the axial flow turbine unit is adjusted by adjusting the pressure regulating chamber and optionally adjusting the pressure in the sealing chamber.

[0051] In another preferred embodiment, in step (2), the impeller inlet pressure P in Units: MPa, impeller outlet pressure P out Units: MPa, pressure in regulating chamber P control Unit: MPa. The following parameters are obtained: axial force F1 at the impeller inlet, axial force F2 at the blade inlet, axial force F3 at the blade outlet, axial force F4 at the impeller outlet, axial force F5 exerted by the adjustable cavity on the impeller; and optionally, pressure P through the sealing cavity. seal Obtain the axial force F of the dry gas seal seal ;

[0052] in,

[0053] Where m represents dividing the force-bearing surface of the impeller disk into m equal annular regions, each annular region having the same radial width, where m is 20-100; f n This represents the axial force on the inlet side experienced by the nth annular region, in N.

[0054]

[0055] Where, P n P represents the inlet-side pressure experienced by the nth annular region, in MPa. n-1 The inlet-side pressure (r) represents the pressure exerted on the (n-1)th annular region, in MPa. n Represents the radial distance from the axis of the main shaft to the outer edge of the nth annular region, in meters (m).

[0056]

[0057] Where R1 represents the radius of the main shaft, in meters; R2 represents the radial distance from the center of the main shaft to the outer edge of the inlet side of the wheel, in meters; P0 = P in ;u n The tangential velocity of the nth annular region is expressed in m / min.n-1 This represents the tangential velocity of the (n-1)th annular region, in m / min.

[0058]

[0059] Wherein, N is the rotational speed of the impeller, in r / min;

[0060] Wherein, the (n-1)th annular region is adjacent to the nth annular region, and the (n-1)th annular region is inside the nth annular region (i.e., the (n-1)th annular region is closer to the center of the impeller than the nth annular region);

[0061]

[0062] Wherein, R6 represents the radial distance from the axis of the main shaft to the outer edge of the inlet side of the impeller, in meters (m).

[0063]

[0064] Wherein, R5 represents the radial distance from the axis of the main shaft to the outer edge of the outlet side of the impeller, in meters; R3 represents the radial distance from the axis of the main shaft to the outer edge of the outlet side of the impeller, in meters.

[0065]

[0066] Wherein, R4 represents the radial distance from the axis of the main shaft to the inner edge of the outlet side of the wheel, in meters;

[0067]

[0068]

[0069] Among them, R seal1 R represents the radial distance from the center of the main shaft to the outer edge of the dry gas seal device, in meters (m). seal2 This indicates the radial distance from the center of the main shaft to the inner edge of the dry gas sealing device, in meters (m).

[0070] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Attached Figure Description

[0071] 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.

[0072] Figure 1 This is an overall schematic diagram of a supercritical carbon dioxide axial flow turbine unit with controllable axial force, as described in one embodiment of the present invention.

[0073] Figure 2 yes Figure 1 A longitudinal section view of the supercritical carbon dioxide axial flow turbine body in the image;

[0074] Figure 3 for Figure 2 A schematic diagram of the axial force composition of a supercritical carbon dioxide axial flow turbine unit.

[0075] The labels in each of the attached figures are as follows:

[0076] 1. Integrated starter motor;

[0077] 2. Axial flow turbine body;

[0078] 2.3 Sealed cavity;

[0079] 3. First pressure regulating valve;

[0080] 4. Drain valve;

[0081] 5. Low-pressure working fluid storage tank;

[0082] 6. High-pressure working fluid storage tank;

[0083] 7. Second pressure regulating valve;

[0084] 8. Measurement module;

[0085] 2.1 Dry gas seal;

[0086] 2.2 Cover plate;

[0087] 2.3 Sealed cavity;

[0088] 2.4. Seal the pressure tapping hole;

[0089] 2.5. Intake casing;

[0090] 2.6 Impeller;

[0091] 2.7 Pressure regulating air vent;

[0092] 2.8. Exhaust casing;

[0093] 2.9 Pressure regulating exhaust port;

[0094] 2.10, Pressure regulating chamber;

[0095] 2.11. Comb-tooth seal;

[0096] 2.12. Partition;

[0097] 2.13. Enclosure components;

[0098] 2.14. Spindle;

[0099] 2.15 Connecting ribs. Detailed Implementation

[0100] Through extensive and in-depth research and screening, the inventors have developed for the first time a supercritical carbon dioxide axial-flow turbine unit with controllable axial force, along with its axial force measurement and adjustment method. This invention allows for axial force adjustment over a wide range without damaging the main components of the turbine unit, affecting the turbine shaft design, or limiting the maximum load it can withstand. Furthermore, axial force adjustment can be accurately performed through measurement and calculation. This invention was completed based on these findings.

[0101] the term

[0102] As used in this article, the term "supercritical carbon dioxide (sCO2)" refers to a state of carbon dioxide that differs from gas and liquid under high pressure and high temperature (exceeding its critical point temperature and pressure: critical point temperature 31.1℃, critical point pressure 7.38MPa), exhibiting advantages such as high density, high thermal conductivity, and low viscosity. These properties make it a highly efficient working fluid in thermodynamic cycles.

[0103] As used herein, the term "supercritical carbon dioxide axial-flow turbine body" refers to an axial-flow turbine device that uses supercritical carbon dioxide (sCO2) as the working medium. The body is the core structure of the turbine, primarily used to efficiently convert thermal energy into mechanical energy, and has broad application prospects in energy, power generation, and industrial power systems.

[0104] As used herein, the term "starter-generator integrated motor" is an electromechanical device that integrates starting and power generation functions into a single unit. The starter-generator integrated motor can act as a starter, providing the necessary power to start the equipment. For example, in a car engine, the starter-generator integrated motor can replace a traditional starter to start the engine. When the equipment is running, the motor can act as a generator, converting mechanical energy into electrical energy to charge the battery or power the system.

[0105] The main advantages of this invention include:

[0106] (a) Obtain axial force data without damaging the main components of the turbine unit, without affecting the turbine unit shaft system design and the maximum force load it can withstand;

[0107] (b) Axial force can be adjusted over a wide range;

[0108] (c) The axial force data is accurate;

[0109] (d) Axial force can be adjusted quickly.

[0110] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, the accompanying drawings are schematic diagrams, and therefore the apparatus and device of the present invention are not limited to the size or scale of the schematic diagrams.

[0111] It should be noted that in the claims and specification of this patent, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0112] Example

[0113] The axial force controllable supercritical carbon dioxide axial flow turbine unit of this embodiment can adjust the axial force over a wide range without damaging the main components of the turbine unit, without affecting the turbine unit shaft system design and the maximum force load it can withstand. The axial force can be accurately adjusted through axial force measurement and calculation.

[0114] This embodiment of the axial flow turbine unit includes a supercritical carbon dioxide axial flow turbine body 2, which functions to convert the thermal energy of a high-temperature, high-pressure working fluid into shaft power. Supercritical carbon dioxide enters the axial flow turbine body 2 through the working fluid inlet. As it passes the stationary blades mounted on the baffle 2.12, the working fluid (carbon dioxide) further expands and accelerates, changing the airflow direction. This causes the airflow to impact the blades on the axial flow impeller 2.6 at a suitable angle, converting the kinetic energy of the working fluid into mechanical energy. The axial flow impeller 2.6 rotates, driving the main shaft 2.14 to rotate, thus outputting energy. The temperature of the supercritical carbon dioxide working fluid entering the axial flow turbine body is 400–600°C, and the pressure is 13.5–19.5 MPa. The turbine inlet pressure is in the range of 13.5–19.5 MPa, and the turbine outlet pressure is in the range of 8–9 MPa.

[0115] The axial turbine body 2 includes a main shaft 2.14, an impeller 2.6 fixed to the end of the main shaft 2.14 for driving the main shaft 2.14 to rotate, and an exhaust casing 2.8 for providing peripheral fixed support for the impeller 2.6. The exhaust casing 2.8 includes a casing body, an enclosure 2.13, and multiple connecting ribs 2.15. The casing body is arranged around the outer periphery of the impeller 2.6 and has an axial cavity for the flow of supercritical carbon dioxide after work. The enclosure 2.13 is arranged in the axial cavity and is an open cavity at one end. The open end of the cavity abuts against the outlet end of the impeller 2.6, and the outlet end of the impeller 2.6 seals the cavity. The impeller 2.6 and the enclosure 2.13 form a closed pressure regulating cavity 2.10, which is coaxially arranged with the main shaft 2.14. Multiple connecting ribs 2.15 connect and fix the enclosure 2.13 to the casing body. The open end of the enclosure 2.13 is sealed to the outlet end of the impeller 2.6 by a comb-tooth seal 2.11, thereby maintaining the pressure within the turbine exhaust pressure regulating chamber 2.10. One end of the connecting rib 2.15 is fixedly connected to the closed end of the enclosure 2.13, and the other end is fixedly connected to the casing body. Multiple connecting ribs 2.15 are evenly spaced circumferentially about the axis of the main shaft 2.14. The high-pressure working fluid enters from the intake inlet of the intake casing 2.5, performs work at the impeller 2.6, and is discharged through the axial cavity of the exhaust casing 2.8.

[0116] The axial flow turbine unit of this embodiment also includes a high-pressure working fluid storage tank 6 and a low-pressure working fluid storage tank 5. The pressure regulating chamber 2.10 is fluidly connected to the high-pressure working fluid storage tank 6 through a pressure regulating bleed port 2.7, and to the low-pressure working fluid storage tank 5 through a pressure regulating exhaust port 2.9. The high-pressure working fluid storage tank 6 supplies high-pressure working fluid (high-pressure carbon dioxide, pressure > 20 MPa) to the pressure regulating chamber 2.10, and the low-pressure working fluid storage tank 5 receives low-pressure working fluid (low-pressure carbon dioxide) from the pressure regulating chamber 2.10. The pressure of the high-pressure working fluid storage tank 6 is greater than 20 MPa; the pressure of the low-pressure working fluid storage tank 5 is less than 2 MPa. Both the pressure regulating bleed port 2.7 and the pressure regulating exhaust port 2.9 are through holes extending from the pressure regulating chamber 2.10 through the surrounding member 2.13, the connecting rib 2.15, and the casing body to the outside. There is at least one pressure regulating bleed port 2.7; there is at least one pressure regulating exhaust port 2.9. When there are multiple pressure regulating air inlet holes 2.7 and pressure regulating exhaust holes 2.9, the pressure regulating air inlet holes 2.7 and pressure regulating exhaust holes 2.9 are arranged to be evenly spaced circumferentially about the axis of the main shaft 2.14.

[0117] A first pressure regulating valve 3 is installed on the pipeline from the pressure regulating chamber 2.10 to the high-pressure working medium storage tank 6. The first pressure regulating valve 3 is used to control the amount of high-pressure working medium injected from the high-pressure working medium storage tank 6 into the pressure regulating chamber 2.10. A discharge valve 4 is installed on the pipeline from the pressure regulating chamber 2.10 to the low-pressure working medium storage tank 5. The discharge valve 4 is used to control the amount of working medium discharged from the pressure regulating chamber 2.10 into the low-pressure working medium storage tank 5. The pressure in the pressure regulating chamber 2.10 is controlled by controlling the first pressure regulating valve 3 and the discharge valve 4.

[0118] The axial flow turbine unit achieves bidirectional adjustment of axial force by controlling the pressure within the pressure regulating chamber 2.10. The axial force adjustment range provided by the pressure regulating chamber 2.10 is -25000N to +25000N.

[0119] In this embodiment, the axial turbine body 2 is further provided with a sealing cavity 2.3. The sealing cavity 2.3 is formed by a main shaft 2.14, a partition plate 2.12 that abuts against the inlet end of the impeller 2.6 and is sleeved on the main shaft 2.14, a cover plate, and a dry gas sealing device sleeved on the main shaft 2.14. This sealing cavity 2.3 is the turbine dry gas seal 2.1. The sealing cavity 2.3 is in fluid communication with the high-pressure working fluid storage tank 6, which is used to supply high-pressure working fluid to the sealing cavity 2.3. The sealing cavity 2.3 is in fluid communication with the high-pressure working fluid storage tank 6 through a sealing pressure tap 2.4. The sealing pressure tap 2.4 is provided on the cover plate and is a through hole from the sealing cavity 2.3 through the cover plate to the outside. A second pressure regulating valve 7 is provided on the pipeline from the high-pressure working fluid storage tank 6 to the sealing cavity 2.3. The second pressure regulating valve 7 is used to control the amount of high-pressure working fluid injected from the high-pressure working fluid storage tank 6 into the sealing cavity 2.3, thereby increasing the pressure inside the sealing cavity 2.3.

[0120] Dry gas seal 2.1 is a sealing technology primarily used in rotating equipment (such as compressors and pumps) that uses dry gas to form a seal and prevent leakage. Dry gas seal 2.1 utilizes a pair of relatively rotating sealing rings, one fixed and the other rotating. The surfaces of these two rings are precision-machined to create a tiny gap (typically only a few micrometers) during operation. Sealing gas is injected into the gap, generating a gas film that isolates the fluid medium within the sealed space, thus achieving a seal.

[0121] The axial flow turbine unit achieves unidirectional adjustment of axial force by controlling the pressure within the sealed cavity 2.3. For example, the axial force of the axial flow turbine unit can be unidirectionally adjusted by controlling the amount of high-pressure working fluid (high-pressure carbon dioxide) injected from the high-pressure working fluid storage tank 6 into the sealed cavity 2.3. The axial force adjustment range provided by the axial flow turbine unit through the sealed cavity 2.3 is 0 to 3000 N.

[0122] The high-pressure working medium storage tank 6, which is in fluid communication with the sealed cavity 2.3, and the high-pressure working medium storage tank 6, which is in fluid communication with the pressure regulating cavity 2.10, can be the same high-pressure working medium storage tank or different high-pressure working medium storage tanks. (See attached figure for this embodiment.) Figure 1 The image shows the same high-pressure working fluid storage tank 6.

[0123] When the axial turbine body 2 is working, due to the high pressure of the working fluid inside, both the turbine impeller 2.6 and the turbine dry gas seal 2.1 will generate a large axial force.

[0124] Significant adjustment of axial force cannot be achieved solely through the sealing cavity 2.3. First, if a large amount of working fluid is filled in, the working fluid will enter the turbine mainstream, affecting turbine efficiency. Second, the turbine sealing cavity pressure cannot be significantly adjusted due to the limitations imposed by the impeller outlet pressure and the dry gas seal 2.1.

[0125] The high-pressure working fluid storage tank 6 and the low-pressure working fluid storage tank 5 are connected to the pressure regulating chamber 2.10 through connecting pipelines, the first pressure regulating valve 3 and the discharge valve 4 respectively. By filling the pressure regulating chamber 2.10 with a large amount of air from the high-pressure working fluid storage tank 6 or releasing a large amount of air from the pressure regulating chamber 2.10 to the low-pressure working fluid storage tank 5, the pressure inside the pressure regulating chamber 2.10 can be significantly adjusted, thereby achieving significant bidirectional adjustment of the axial force.

[0126] The axial flow turbine unit also includes a measurement module 8. The measurement module 8 consists of multiple pressure sensors to measure the pressure at the turbine impeller inlet, outlet, sealing cavity 2.3, and pressure regulating cavity 2.10. Pressure taps are designed at the turbine impeller inlet, turbine outlet, sealing cavity 2.3, and regulating cavity 2.10 to connect the working fluid at each location to the axial force measurement pressure sensor, used to measure the pressure at each location to calculate the turbine axial force.

[0127] Specifically, pressure taps are installed at both the impeller inlet and outlet, and pressure sensors are installed at each pressure tap to measure the impeller inlet pressure P. in and impeller outlet pressure P out Pressure taps are also provided at both the inlet and outlet of the pressure regulating chamber 2.10. Pressure sensors are installed at the inlet and / or outlet pressure taps to measure the pressure P in the pressure regulating chamber. control A pressure tap is installed at the inlet of the sealed cavity, and a pressure sensor is installed at the pressure tap to measure the pressure P in the sealed cavity. seal .

[0128] Axial flow turbine units also include high-speed motors. The high-speed motor consists of a rotor, bearings, a stator, and a high-speed motor casing, with the turbine mounted at one end of the rotor. The high-speed motor is a starter-generator integrated motor (a motor that combines the functions of a starter motor and a generator). In start-up mode, the high-speed motor drives the turbine; in generator mode, the high-speed motor converts the turbine's shaft power into electrical energy.

[0129] like Figure 1 As shown: The supercritical carbon dioxide axial flow turbine unit includes a high-speed motor, a supercritical carbon dioxide axial flow turbine body 2 arranged coaxially with the high-speed motor, a pressure regulating module, and a measurement module 8. Here, the high-pressure working fluid storage tank 6, the low-pressure working fluid storage tank 5, the first pressure regulating valve 3, the second pressure regulating valve 7, the discharge valve 4, and the connecting pipes connecting them to the pressure regulating chamber 2.10 and the sealing chamber 2.3 are collectively referred to as the pressure regulating module.

[0130] The high-speed motor is a starter-generator integrated motor 1. In the starting condition, the starter-generator integrated motor 1 drives the turbine to rotate. In the power generation condition, the starter-generator integrated motor 1 converts the turbine's shaft power into electrical energy. The high-pressure working fluid storage tank 6 (pressure greater than 20 MPa) is filled with air into the sealed chamber 2.3 through the second pressure regulating valve 7, which can realize a small-amplitude unidirectional adjustment of the turbine unit's axial force. The high-pressure working fluid storage tank 6 is filled with air into the pressure regulating chamber 2.10 through the first pressure regulating valve 3, which can realize an increase in the pressure of the pressure regulating chamber 2.10. The pressure regulating chamber exhausts air into the low-pressure working fluid storage tank 5 (pressure less than 2 MPa) through the discharge valve 4, which realizes a decrease in the pressure of the pressure regulating chamber 2.10, thereby realizing a large-amplitude bidirectional adjustment of the axial force.

[0131] The parameters measured by measurement module 8 include: sealing cavity pressure P seal Impeller inlet pressure P in Impeller outlet pressure P out Pressure P in the regulating chamber control Turbine mass flow rate, and other parameters, can be used to calculate the axial force of the axial flow turbine unit.

[0132] like Figure 2 As shown, the working principle of the supercritical carbon dioxide axial flow turbine body is as follows: High-temperature (400–600℃), high-pressure (13.5–19.5 MPa) supercritical carbon dioxide working fluid enters the axial flow turbine body through the working fluid inlet. After passing through the stationary blades mounted on baffle 2.12, the working fluid further expands and accelerates, changing the airflow direction. This causes the airflow to impact the blades on the axial flow impeller at a suitable angle, converting the kinetic energy of the working fluid into mechanical energy. The axial flow impeller then rotates and outputs energy. To achieve a seal between the rotating and stationary parts, leaking working fluid is introduced into the sealing cavity 2.3, and the high-pressure working fluid is sealed through a dry gas seal 2.1, with a leakage rate of <0.1%.

[0133] During turbine startup, speed increase, and variable load operation, the turbine axial force will vary greatly with the operating conditions, so axial force control is required. Figure 1 The high-pressure working fluid storage tank 6 is connected to the sealing chamber 2.3 through the pressure regulating valve 7. Air is introduced into the chamber through the sealing pressure tap, which can realize the one-way small range adjustment of the axial force of the turbine unit. Due to the limitation of the dry gas seal 2.1 and the impeller, the pressure variation range of the sealing chamber 2.3 is small. The axial force adjustment capacity of the sealing chamber is about 3000N.

[0134] The high-pressure working fluid storage tank 6 is connected to the pressure regulating air inlet 2.7 via the pressure regulating valve 3, and can be filled with air into the pressure regulating chamber 2.10 to increase the pressure in the pressure regulating chamber. The pressure regulating chamber 2.10 is connected to the pressure regulating exhaust port 2.9. Figure 1 The discharge valve 4 in the middle discharges gas to the low-pressure working fluid storage tank 5 (pressure less than 2 MPa), thereby reducing the pressure in the pressure regulating chamber. Therefore, the pressure regulating chamber can achieve bidirectional adjustment of axial force. Since the pressure regulating chamber is located in the exhaust section of the axial flow turbine, filling and releasing gas into the pressure regulating chamber will not affect the performance of the axial flow turbine body. The pressure regulating capacity is large, and the axial force adjustment capacity of the chamber is approximately ±25000 N.

[0135] like Figure 3 The diagram shows the axial force composition of a supercritical carbon dioxide axial flow turbine unit, where the turbine combined force F is shown in Equation 1.

[0136] F = F t +F seal (1)

[0137] In the formula F t The resultant axial force acting on the impeller is calculated using the formula (2).

[0138] F t ==F1+F2+F3+F4+F5 (2)

[0139] Among them, F1 is the axial force on the inlet side of the wheel; F2 is the axial force on the inlet side of the blade; F3 is the axial force on the outlet side of the blade; F4 is the axial force on the outlet side of the wheel; and F5 is the axial force of the adjustable cavity.

[0140] F seal The axial force on the dry gas seal 2.1 is calculated using the formula (3).

[0141]

[0142] Among them, R seal1 R represents the radial distance from the center of the main shaft to the outer edge of the dry gas seal device, in meters (m). seal2 This indicates the radial distance from the center of the main shaft to the inner edge of the dry gas sealing device, in meters (m).

[0143] The F1 calculation method is as follows:

[0144] The force-bearing surface of F1 is divided into 40 equal annular regions, and then the annular regions are added together to obtain F1. Each of the annular regions has the same radial width.

[0145] The formula for calculating F1 is shown in equation (4).

[0146]

[0147] f n This represents the axial force on the inlet side experienced by the nth annular region, in N. (Partial axial force f) n It is equal to the product of pressure and area, and the calculation formula is shown in (5), where n ranges from 1 to 40.

[0148]

[0149] Where r0 = R2. P n P represents the inlet-side pressure experienced by the nth annular region, in MPa. n-1 The inlet-side pressure (r) represents the pressure exerted on the (n-1)th annular region, in MPa. n This represents the radial distance from the axis of the main shaft to the outer edge of the nth annular region, in meters (m).

[0150] radius R n The calculation formula is shown in (6), where n ranges from 1 to 40.

[0151]

[0152] Pressure p n The calculation formula is shown in (7). The value of n in the formula ranges from 1 to 40.

[0153]

[0154] Where P0 = P in R1 represents the radius of the main shaft, in meters; R2 represents the radial distance from the center of the main shaft to the outer edge of the inlet side of the wheel, in meters; P0 = P in ;u n The tangential velocity of the nth annular region is expressed in m / min. n-1 This represents the tangential velocity of the (n-1)th annular region, in m / min.

[0155] Tangential velocity u n The calculation formula is shown in equation (8), with the unit being m / s. N is the rotational speed, with the unit being r / min, and the value of n ranges from 0 to 40.

[0156]

[0157] Wherein, N is the rotational speed of the impeller, in r / min.

[0158] The (n-1)th annular region is adjacent to the nth annular region, and the (n-1)th annular region is inside the nth annular region.

[0159] The calculation method for F2 is shown in equation (9):

[0160]

[0161] Wherein, R6 represents the radial distance from the axis of the main shaft to the outer edge of the inlet side of the impeller, in meters.

[0162] The calculation method for F3 is as shown in equation (10):

[0163]

[0164] Wherein, R5 represents the radial distance from the axis of the main shaft to the outer edge of the outlet side of the impeller, in meters; R3 represents the radial distance from the axis of the main shaft to the outer edge of the outlet side of the impeller, in meters.

[0165] The calculation method for F4 is as shown in equation (11):

[0166]

[0167] Wherein, R4 represents the radial distance from the axis of the main shaft to the inner edge of the outlet side of the wheel, in meters.

[0168] The calculation method for F5 is as shown in equation (12):

[0169]

[0170] The turbine combined force F can be obtained from the above formula, and the pressure P in the pressure regulating chamber can be adjusted accordingly. control and sealing cavity pressure P seal This is used to control the combined turbine force F, thereby achieving a wide range of axial force adjustment. The above calculations are performed by a controller (not shown).

[0171] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A supercritical carbon dioxide axial flow turbine unit, characterized in that, The axial flow turbine unit includes: An axial flow turbine body, the axial flow turbine body including a main shaft, an impeller fixed to the end of the main shaft for driving the main shaft to rotate, and an exhaust casing for providing peripheral fixed support for the impeller, wherein the exhaust casing includes: The casing body is arranged around the outer periphery of the impeller and has an axial cavity for the flow of supercritical carbon dioxide after work is done. An enclosure, arranged within the axial cavity, the enclosure being an open-end cavity abutting against the outlet end of the impeller, sealing the cavity through the outlet end of the impeller; the impeller and the enclosure forming a closed pressure regulating cavity, the pressure regulating cavity being coaxially arranged with the main shaft; and Multiple connecting ribs, the multiple connecting ribs being used to connect and fix the enclosure to the housing body; A high-pressure working fluid storage tank, wherein the pressure of the high-pressure working fluid storage tank is greater than 20 MPa, and A low-pressure working fluid storage tank, wherein the pressure of the low-pressure working fluid storage tank is less than 2 MPa; The pressure regulating chamber is in fluid communication with both the high-pressure working medium storage tank and the low-pressure working medium storage tank. The high-pressure working medium storage tank supplies high-pressure working medium to the pressure regulating chamber, and the low-pressure working medium storage tank receives low-pressure working medium from the pressure regulating chamber.

2. The axial flow turbine unit as described in claim 1, characterized in that, The axial flow turbine unit achieves bidirectional adjustment of axial force by controlling the pressure in the pressure regulating chamber.

3. The axial flow turbine unit as described in claim 2, characterized in that, The axial flow turbine unit adjusts the axial force provided by the pressure regulating chamber from -25000N to +25000N.

4. The axial flow turbine unit as described in claim 1, characterized in that, One end of the connecting rib is connected and fixed to the closed end of the enclosure, and the other end is connected and fixed to the casing body.

5. The axial flow turbine unit as described in claim 1, characterized in that, The axial turbine body is also provided with a sealing cavity, which is formed by the main shaft, a partition plate that abuts against the inlet end of the impeller and is sleeved on the main shaft, a cover plate, and a dry gas sealing device sleeved on the main shaft.

6. The axial flow turbine unit as described in claim 5, characterized in that, The sealed cavity is in fluid communication with the high-pressure working medium storage tank, and the high-pressure working medium storage tank is used to supply high-pressure working medium to the sealed cavity.

7. The axial flow turbine unit as described in claim 5, characterized in that, The axial flow turbine unit achieves unidirectional adjustment of axial force by controlling the pressure within the sealed cavity.

8. The axial flow turbine unit as described in claim 7, characterized in that, The axial flow turbine unit adjusts the axial force provided by the sealed cavity from 0 to 3000 N.

9. A method for measuring and adjusting the axial force of a supercritical carbon dioxide axial flow turbine unit, characterized in that, The method includes: (1) An axial flow turbine unit as described in any one of claims 1-8 is provided, wherein the axial flow turbine body is further provided with a sealing cavity, the sealing cavity being formed by the main shaft, a partition plate abutting against the inlet end of the impeller and sleeved on the main shaft, a cover plate and a dry gas sealing device sleeved on the main shaft; (2) The resultant axial force F of the axial flow turbine unit is the axial force F1 at the impeller disk inlet side, the axial force F2 at the impeller blade inlet side, the axial force F3 at the blade outlet side, the axial force F4 at the impeller disk outlet side, the axial force F5 exerted by the pressure regulating chamber on the impeller, and optionally the dry gas sealing axial force F from the sealing chamber. seal sum; (3) The axial force resultant force F of the axial flow turbine unit is adjusted by adjusting the pressure regulating chamber and optionally adjusting the pressure in the sealing chamber.

10. The method as described in claim 9, characterized in that, Through the impeller inlet pressure P in Units: MPa, impeller outlet pressure P out Units: MPa, pressure in regulating chamber P control Unit: MPa, obtaining the axial force F1 at the impeller inlet, the axial force F2 at the blade inlet, the axial force F3 at the blade outlet, the axial force F4 at the impeller outlet, the axial force F5 exerted by the pressure regulating chamber on the impeller; and optionally, the pressure P through the sealing chamber. seal Obtain the axial force F of the dry gas seal seal ; in, Where m represents dividing the force-bearing surface of the impeller disk into m equal annular regions, each annular region having the same radial width, where m is 20-100; f n This represents the axial force on the inlet side experienced by the nth annular region, in N. Where, P n P represents the inlet-side pressure experienced by the nth annular region, in MPa. n-1 The inlet-side pressure (r) represents the pressure exerted on the (n-1)th annular region, in MPa. n Represents the radial distance from the axis of the main shaft to the outer edge of the nth annular region, in meters (m). Where R1 represents the radius of the main shaft, in meters; R2 represents the radial distance from the center of the main shaft to the outer edge of the inlet side of the wheel, in meters; P0 = P in ;u n The tangential velocity of the nth annular region is expressed in m / min. n-1 This represents the tangential velocity of the (n-1)th annular region, in m / min. Wherein, N is the rotational speed of the impeller, in r / min; Wherein, the (n-1)th annular region is adjacent to the nth annular region, and the (n-1)th annular region is inside the nth annular region; Wherein, R6 represents the radial distance from the axis of the main shaft to the outer edge of the inlet side of the impeller, in meters (m). Wherein, R5 represents the radial distance from the axis of the main shaft to the outer edge of the outlet side of the impeller, in meters; R3 represents the radial distance from the axis of the main shaft to the outer edge of the outlet side of the impeller, in meters. Wherein, R4 represents the radial distance from the axis of the main shaft to the inner edge of the outlet side of the wheel, in meters; Among them, R seal1 R represents the radial distance from the center of the main shaft to the outer edge of the dry gas seal device, in meters (m). seal2 This indicates the radial distance from the center of the main shaft to the inner edge of the dry gas sealing device, in meters (m).

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