A turbine mechanical shaft structure with low blast loss and balanced axial thrust

Abstract

The present invention discloses a turbine mechanical shaft structure with low blast loss and balanced axial thrust, including a shaft, a positive and negative pressure integrated multifunctional pump, etc., wherein an annular groove is provided in the middle of the blast section of the shaft; the bearing and the thrust load sensor are backed against the end walls on both sides of the blast section; the end wall side and the groove side of the blast section of the shaft are both arranged with sealing teeth; the unit housing is a split housing; the shaft and the unit housing form a bearing chamber, a blast chamber and an axial balance chamber; the thrust balance arm end wall is arranged with sealing teeth and the balance chamber is divided into left and right chambers; the sealing ring is arranged in the unit housing and the groove of the blast section of the shaft, and is fixed by a pin block; the pressure sensor is arranged in the blast chamber for real-time pressure monitoring, the air suction port of the positive and negative pressure integrated multifunctional pump is arranged in the blast chamber, and the air jet is arranged in the left and right axial balance chambers. The present invention can be applied to extreme conditions, has a simple structure, is economical and reliable, and has broad application prospects.

Description

Technical Field

[0001] The invention relates to a turbine machinery shaft structure, in particular to a turbine machinery shaft structure with low blast loss and balanced axial thrust. Background Art

[0002] As one of the core components of the turbine machinery energy conversion process, the shaft not only needs to transmit torque during operation, but also needs to withstand interference such as axial thrust caused by the pressure difference between the working area and the non-working area. Its dynamic characteristics are of great significance to the safe, stable and efficient operation of the system. In recent years, with the continuous improvement of the industrial field's requirements for power systems, turbine machinery equipment has developed in the direction of large-scale, intelligent, high-speed and high-energy density. For the shaft, its workload continues to increase. The high speed not only brings challenges to its critical speed, unbalanced response and stability, but also leads to an increase in the blast loss of the system, which is not conducive to the improvement of system performance. In addition, large-scale and high-energy-density turbine machinery also increases the axial thrust on the shaft. Traditional shaft materials and structural designs for balancing shaft forces are difficult to meet the growing requirements of axial thrust, which brings new challenges to the selection of shaft materials and the safety of operation.

[0003] Although great achievements have been made in reducing shaft losses and balancing axial thrust in the past, the new energy situation has put forward higher requirements for turbine machinery, and the operating conditions of the shaft have become more severe. Improving shaft efficiency and operating safety is crucial for the efficient and stable operation of turbine machinery equipment. Summary of the invention

[0004] The purpose of the present invention is to address the deficiencies in the prior art and provide a turbine machinery shaft structure with low blast loss and balanced axial thrust, which can be used in high-load extreme operating conditions, has a simple structure, high safety and economy, and has broad application prospects.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A turbine mechanical shaft structure with low blast loss and balancing axial thrust, comprising a shaft, a bearing, a unit housing, a sealing tooth, a thrust balancing arm, a sealing ring, a pin block, a pressure sensor, a positive and negative pressure integrated multifunctional pump, and a thrust load sensor; wherein the shaft is a stepped shaft, comprising three parts: a bearing section on both sides and a middle blast section, and an annular groove is provided in the middle of the blast section; the bearing sections on both sides of the shaft are respectively provided with bearings and thrust load sensors, the bearings and thrust load sensors are used as a set and are backed against the end walls on both sides of the blast section; sealing teeth are arranged on the end wall side and the groove side of the blast section of the shaft; the unit housing is a split housing, comprising a detachable upper cover plate and a lower seat, and is assembled by external bolts; a bearing chamber, a blast chamber and an axial balancing chamber are formed between the shaft and the unit housing (3);

[0007] The thrust balance arm is fixed on the unit housing and extends into the axial balance chamber, which is used to divide the axial balance chamber into two chambers, left and right. The end wall of the thrust balance arm is provided with sealing teeth; the sealing ring is arranged in the groove of the unit housing and the blower section of the rotating shaft, and is fixed by a pin block;

[0008] The pressure sensor is arranged in the blast chamber through the through hole on the unit casing, and is used for real-time monitoring of the pressure in the blast chamber. The suction port of the positive and negative pressure integrated multifunctional pump is arranged in the blast chamber through the through hole on the unit casing, and the air jet is arranged in the left and right axial balance chambers through the through hole on the thrust balance arm. The positive and negative pressure integrated multifunctional pump can realize directional suction and blowing.

[0009] A further improvement of the present invention is that the sealing teeth are circular teeth, triangular teeth, parabolic teeth, high-low teeth, longitudinal teeth or oblique teeth.

[0010] A further improvement of the present invention is that the number of sealing teeth arranged is 3 to 8, and the ratio of the tooth thickness to the tooth height of the sealing teeth is between 0.2 and 1.

[0011] A further improvement of the present invention is that the number of teeth of the sealing ring corresponds to the number of teeth of the sealing teeth, and the ratio of tooth thickness to tooth height is between 0.2 and 1.

[0012] A further improvement of the present invention is that the sealing rings and the sealing teeth are arranged in staggered shapes to form a staggered-tooth labyrinth sealing unit, and a plurality of annular air chambers arranged in sequence are formed between the sealing rings and the sealing teeth to increase the flow resistance of the working medium through the area.

[0013] A further improvement of the present invention is that the thrust balance arm is a circular component.

[0014] A further improvement of the present invention is that, during the operation of the rotating shaft, a pressure sensor is used to monitor the pressure value of the blast chamber in real time. When the pressure value of the blast chamber is greater than the set value, the positive and negative pressure integrated multifunctional pump draws air through the exhaust port to ensure that the pressure value of the blast chamber is always maintained at a low state and the rotating shaft always maintains a low blast loss.

[0015] A further improvement of the present invention is that, during the operation of the rotating shaft, the magnitude and direction of the axial thrust on the rotating shaft are obtained through the thrust load sensor, and then the positive and negative pressure integrated multifunctional pump adjusts the pressure of the left and right chambers of the axial balance chamber through the jet port, and the axial thrust on the rotating shaft is balanced by the pressure difference between the left and right sides of the axial balance chamber, so that it is less than the allowable axial thrust, and the relationship is satisfied as follows:

[0016]

[0017]

[0018] Among them, F 0 is the permissible axial thrust of the shaft, It is the axial thrust of the rotating shaft when the axial balance chamber is not working. is the axial balance chamber balance force, π is the circumference, r 2 is the radius of the blast section, r 1 is the inner radius of the blast section groove, P l is the pressure in the left chamber of the axial balance chamber, P r It is the pressure in the right side of the axial balance chamber.

[0019] The present invention has at least the following beneficial technical effects:

[0020] 1. The present invention has reasonable design, simple structure, convenient installation, good reliability, adaptability to various working environments, and improves the operating efficiency and safety of the shaft;

[0021] 2. Labyrinth sealing units are arranged on both sides of the blast section. The sealing units increase the flow resistance of the working fluid through this area, prevent the high-pressure leakage flow from entering the blast chamber, effectively reduce the blast loss of the blast chamber, and thus improve the shaft efficiency;

[0022] 3. A pressure sensor and an air extraction port are arranged in the blast chamber. The pressure sensor monitors the pressure in the blast chamber in real time. When the turbine unit is in an extreme operating condition or a faulty operating condition causing the pressure in the blast chamber to increase, the positive and negative pressure integrated multifunctional pump extracts air through the air extraction port, so that the pressure value in the blast chamber is always maintained at a low state, and the shaft maintains a low blast loss state, thereby improving the stability and robustness of the shaft;

[0023] 4. Thrust load sensors are arranged on both sides of the blast section, and an axial balance chamber is opened in the middle, which is divided into two left and right chambers by the thrust balance arm. During the operation of the shaft, the thrust load sensor monitors the size and direction of the axial thrust on the shaft in real time, and then the positive and negative pressure integrated multifunctional pump adjusts the pressure of the left and right chambers of the axial balance chamber through the air jet. The pressure difference between the left and right sides of the axial balance chamber can effectively balance the axial thrust on the shaft, improve the safety and reliability of the shaft operation, and reduce the difficulty of bearing selection;

[0024] 5. The sealing ring adopts a split toothed sealing ring, which is easy to load, unload and replace. When the seal fails, the performance of the sealing structure can be restored by simply replacing the sealing ring, which is highly economical. The sealing ring is made of graphite or a metal material with a lower hardness, which is lower than the shaft material. When the shaft vibration causes the sealing component to rub, the sealing ring with a relatively low hardness will wear first, and the shaft will not be affected, which improves the safety of the shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is an axial cross-sectional view of a turbine mechanical shaft structure with low blast loss and balanced axial thrust according to the present invention;

[0026] Description of reference numerals:

[0027] 1. Rotating shaft, 2. Bearing, 3. Unit housing, 4. Bearing chamber, 5. Blowing chamber, 6. Sealing teeth, 7. Thrust balance arm, 8. Axial balance chamber, 9. Sealing ring, 10. Pin block, 11. Pressure sensor, 12. Positive and negative pressure integrated multifunctional pump, 13. Air extraction port, 14. Thrust load sensor, 15. Air jet port. A1, A2, B1, B2, and C1 are different cross sections. DETAILED DESCRIPTION

[0028] The following is a detailed description of an embodiment of the present invention in conjunction with the accompanying drawings. This embodiment is based on the technical solution of the present invention and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiment.

[0029] like Figure 1 As shown, the present invention provides a turbine machinery shaft structure with low blast loss and balanced axial thrust, including a shaft 1, a bearing 2, a unit housing 3, a bearing chamber 4, a blast chamber 5, a sealing tooth 6, a thrust balance arm 7, an axial balance chamber 8, a sealing ring 9, a pin block 10, a pressure sensor 11, a positive and negative pressure integrated multifunctional pump 12, an exhaust port 13, a thrust load sensor 14, and an air jet 15.

[0030] The rotating shaft 1 is a stepped shaft, including two bearing sections and a blast section, and an annular groove is provided in the middle of the blast section; the bearing sections on both sides of the rotating shaft 1 are respectively installed with bearings 2 and thrust load sensors 14, which are used as a set and back against the end walls on both sides of the blast section; the end wall side and the groove side of the blast section of the rotating shaft 1 are both arranged with sealing teeth 6. The unit housing 3 is a split housing, including a detachable upper cover plate and a lower seat, which are assembled by external bolts. A bearing chamber 4, a blast chamber 5 and an axial balance chamber 8 are formed between the rotating shaft 1 and the unit housing 3.

[0031] The thrust balance arm 7 is fixed on the unit housing 3 and extends into the axial balance chamber 8, and is used to divide the axial balance chamber 8 into two chambers, left and right. The thrust balance arm 7 can be a circular component made of steel (or other metal materials), and its size and thickness should meet the requirements of bearing the pressure difference between the axial balance chambers on both sides; the end wall of the thrust balance arm 7 is also arranged with sealing teeth 6. The sealing teeth 6 can be various structural forms such as circular teeth, triangular teeth, parabolic teeth, high and low teeth, longitudinal tree teeth, oblique teeth, etc. The number of sealing teeth 6 arranged is 3 to 8, and the ratio of the tooth thickness to the tooth height of the sealing teeth 6 is between 0.2 and 1.

[0032] The sealing ring 9 is arranged in the groove of the unit housing 3 and the blast section of the rotating shaft 1, and is fixed by the pin block 10. The sealing ring 9 is a split toothed sealing ring, which is divided into an upper ring body and a lower ring body. The upper and lower ring bodies are connected by staggered tooth connecting buckles. The number of teeth of the sealing ring 9 corresponds to the number of teeth of the sealing teeth 6. The ratio of tooth thickness to tooth height is between 0.2 and 1. Graphite or metal materials with lower hardness are used to ensure the strength and wear resistance of the sealing ring 9 during operation. The teeth of the sealing ring 9 and the sealing teeth 6 are staggered, and together they constitute a staggered tooth labyrinth seal unit. A plurality of annular air chambers arranged in sequence are formed between the sealing ring 9 and the sealing teeth 6 to increase the flow resistance of the working medium through this area.

[0033] The pressure sensor 11 is arranged in the blast chamber 5 through the through hole on the unit housing 3, and is used for real-time monitoring of the pressure in the blast chamber 5. The suction port 13 of the positive and negative pressure integrated multifunctional pump 12 is arranged in the blast chamber 5 through the through hole on the unit housing 3, and the air jet 15 is arranged in the left and right axial balance chambers 8 through the through hole on the thrust balance arm 7. The positive and negative pressure integrated multifunctional pump 12 can realize directional suction and blowing.

[0034] The principles and processes of the present invention are mainly as follows:

[0035] During the operation of the rotating shaft 1, there may be high-temperature and high-pressure leakage fluid on the A or B side. The leakage fluid leaks from the high-pressure side to the low-pressure side along the chamber formed by the rotating shaft 1 and the unit casing 3, so that a relatively high pressure is maintained in the blast chamber 5. The high-pressure state of the blast chamber 5 will cause the rotating shaft 1 to produce a large blast loss, reducing the efficiency and operating reliability of the turbine machinery. In theory, in order to reduce the blast loss, it is necessary to reduce the pressure in the blast chamber 5 as much as possible. The sealing teeth 6 and the sealing ring 9 at the A1 and B1 sections together constitute a staggered-tooth labyrinth seal unit, and many annular air chambers arranged in sequence are formed between the sealing ring 9 and the sealing teeth 6. When the fluid passes through the gap between each sealing tooth 6 and the sealing ring 9, the flow area decreases sharply, the flow rate increases, and the pressure energy of the fluid is converted into kinetic energy to form a jet. The jet then enters the annular air chamber to form a vortex, which converts part of the kinetic energy of the fluid into heat energy, reducing the flow rate of the fluid. The sealing unit at the A1 and B1 sections increases the flow resistance of the working fluid through the area, prevents the high-pressure leakage flow from entering the blast chamber 5, reduces the blast loss in the blast chamber 5, and thus improves the unit efficiency. During the start-up and shutdown process of the turbine unit, variable operating conditions, and fault conditions, the rotating shaft 1 will experience increased vibration amplitude or radial displacement, resulting in a decrease or failure of the sealing effect at the A1 and B1 sections. The present invention uses a pressure sensor 11 to monitor the pressure value of the blast chamber 5 in real time. When the pressure value of the blast chamber 5 is greater than the set value, the positive and negative pressure integrated multifunctional pump 12 evacuates air through the exhaust port 13 to ensure that the pressure value of the blast chamber 5 is always maintained at a low state, and the rotating shaft 1 always maintains a low blast loss.

[0036] During the operation of the turbine machinery, the rotating shaft 1 not only needs to transmit torque, but also needs to withstand the axial thrust caused by the pressure difference between the working area and the non-working area. If the axial thrust is not well balanced, it will cause the rotating shaft 1 to undergo axial displacement, resulting in friction between the moving and static parts. The friction will cause a large amount of heat to be generated at the contact point, causing local overheating of the rotor, which may cause serious accidents such as bending of the rotating shaft, endangering the safe and stable operation of the rotating shaft 1. The rotating shaft 1 of the present invention is arranged with thrust load sensors 14 on the end faces of both sides of the blast section 5, which can monitor the axial thrust of the rotating shaft at any time. An axial balance chamber 8 is opened in the middle of the blast section 5, and is divided into two left and right chambers by the thrust balance arm 7. During the operation of the rotating shaft 1, the magnitude and direction of the axial thrust of the rotating shaft are obtained through the thrust load sensor 14, and then the positive and negative pressure integrated multifunctional pump 12 adjusts the pressure of the left and right chambers of the axial balance chamber 8 through the jet port 15, and uses the pressure difference between the left and right sides of the axial balance chamber 8 to balance the axial thrust of the rotating shaft 1, so that it is less than the allowable axial thrust, and the relationship it satisfies is as follows:

[0037]

[0038]

[0039] Among them, F0 is the permissible axial thrust of the shaft, It is the axial thrust of the rotating shaft when the axial balance chamber is not working. is the axial balance chamber balance force, π is the circumference, r 2 is the radius of the blast section, r 1 is the inner radius of the blast section groove, P l is the pressure in the left chamber of the axial balance chamber, P r It is the pressure in the right side of the axial balance chamber.

[0040] At the same time, labyrinth seal units are arranged at sections A1 and B1 to prevent the high-pressure gas in the axial balance chamber 8 from leaking to the blast chambers on both sides, ensuring that the pressure in the blast chamber 5 is not affected by the pressure change in the axial balance chamber 8. The labyrinth seal unit at section C1 prevents the high-pressure side gas in the axial balance chamber 8 from leaking to the low-pressure side, ensuring that the axial balance chamber 8 functions normally and stably.

[0041] In addition, the sealing ring 9 is made of graphite or a metal material with a lower hardness, which is lower in hardness than the shaft material. When the shaft vibration causes the sealing assembly to rub, the sealing ring 9 with a relatively lower hardness will wear first, and the shaft 1 will not be affected, thereby improving the safety of the shaft 1. The sealing ring 9 adopts a split design, which is convenient for loading and unloading and replacement. When the seal fails, the performance of the sealing structure can be restored by simply replacing the sealing ring 9. The turbine mechanical shaft structure with low blast loss and balancing axial thrust of the present invention can automatically balance the axial thrust according to the operating conditions, while reducing the blast loss of the shaft, and can ensure that the shaft can still operate efficiently and stably under extreme conditions. Compared with the traditional shaft structure, the shaft is of great significance for further improving the efficiency, reliability and economy of the shaft.

Claims

1. A turbine mechanical shaft structure with low blast loss and balanced axial thrust, characterized in that: It comprises a rotating shaft (1), a bearing (2), a unit housing (3), a sealing tooth (6), a thrust balance arm (7), a sealing ring (9), a pin block (10), a pressure sensor (11), a positive and negative pressure integrated multifunctional pump (12), and a thrust load sensor (14); wherein, The rotating shaft (1) is a stepped shaft, comprising three parts: bearing sections on both sides and a middle blast section, and an annular groove is provided in the middle of the blast section; the bearing sections on both sides of the rotating shaft (1) are respectively provided with bearings (2) and thrust load sensors (14), the bearings (2) and thrust load sensors (14) are used as a set, and are backed against the end walls on both sides of the blast section; sealing teeth (6) are arranged on the end wall side and the groove side of the blast section of the rotating shaft (1); the unit housing (3) is a split housing, comprising a detachable upper cover plate and a lower seat, and is assembled by external bolts; a bearing chamber (4), a blast chamber (5) and an axial balance chamber (8) are formed between the rotating shaft (1) and the unit housing (3); The thrust balance arm (7) is fixed on the unit housing (3) and extends into the axial balance chamber (8), and is used to divide the axial balance chamber (8) into two chambers, a left chamber and a right chamber. A sealing tooth (6) is arranged on the end wall of the thrust balance arm (7); a sealing ring (9) is arranged in the groove of the unit housing (3) and the blowing section of the rotating shaft (1), and is fixed by a pin block (10); The pressure sensor (11) is arranged in the blast chamber (5) through a through hole on the unit housing (3) and is used to monitor the pressure in the blast chamber (5) in real time. The suction port (13) of the positive and negative pressure integrated multifunctional pump (12) is arranged in the blast chamber (5) through a through hole on the unit housing (3). The air jet (15) is arranged in the left and right axial balance chambers (8) through a through hole on the thrust balance arm (7). The positive and negative pressure integrated multifunctional pump (12) can realize directional suction and blowing. During the operation of the rotating shaft (1), a pressure sensor (11) is used to monitor the pressure value of the blast chamber (5) in real time. When the pressure value of the blast chamber (5) is greater than a set value, the positive and negative pressure integrated multifunctional pump (12) evacuates air through the air suction port (13), thereby ensuring that the pressure value of the blast chamber (5) is always maintained at a low state, and the rotating shaft (1) always maintains a low blast loss.

2. A turbine machinery shaft structure with low blast loss and balanced axial thrust according to claim 1, characterized in that: The sealing teeth (6) are circular teeth, triangular teeth, parabolic teeth, high-low teeth, longitudinal teeth or oblique teeth.

3. The turbine machinery shaft structure with low blast loss and balanced axial thrust according to claim 1, characterized in that: The number of sealing teeth (6) arranged is 3 to 8, and the ratio of the tooth thickness to the tooth height of the sealing teeth (6) is between 0.2 and 1.

4. The turbine machinery shaft structure with low blast loss and balanced axial thrust according to claim 1, characterized in that: The number of teeth of the sealing ring (9) corresponds to the number of teeth of the sealing teeth (6), and the ratio of tooth thickness to tooth height is between 0.2 and 1.

5. A turbine machinery shaft structure with low blast loss and balanced axial thrust according to claim 4, characterized in that: The sealing ring (9) and the sealing teeth (6) are arranged in staggered tooth shapes, together forming a staggered tooth labyrinth seal unit, and a plurality of annular air chambers arranged in sequence are formed between the sealing ring (9) and the sealing teeth (6), thereby increasing the flow resistance of the working medium passing through the area.

6. The turbine machinery shaft structure with low blast loss and balanced axial thrust according to claim 1, characterized in that: The thrust balance arm (7) is a circular component.

7. The turbine machinery shaft structure with low blast loss and balanced axial thrust according to claim 1, characterized in that: During the operation of the rotating shaft (1), the magnitude and direction of the axial thrust on the rotating shaft are obtained through the thrust load sensor (14), and then the positive and negative pressure integrated multifunctional pump (12) adjusts the pressure of the left and right chambers of the axial balance chamber (8) through the air jet (15), and uses the pressure difference on the left and right sides of the axial balance chamber (8) to balance the axial thrust on the rotating shaft (1) so that it is less than the allowable axial thrust, which satisfies the following relationship: Among them, F0 is the allowable axial thrust of the shaft, It is the axial thrust of the rotating shaft when the axial balance chamber is not working. is the axial balance chamber balance force, π is the circumference, r2 is the radius of the blast section, r1 is the inner radius of the blast section groove, P l is the pressure in the left chamber of the axial balance chamber, P r It is the pressure in the right side of the axial balance chamber.

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