Low-pressure turbine inclined drum disc structure for high-speed dynamic balance oil accumulation prevention and checking method

Abstract

The invention discloses a low-pressure turbine inclined drum disc structure for high-speed dynamic balance oil accumulation prevention and a checking method, and belongs to the technical field of low-pressure turbine structural design. The low-pressure turbine inclined drum disc structure for high-speed dynamic balance oil accumulation prevention comprises low-pressure rotors and a drum arranged between the low-pressure rotors; an inner cavity of the drum is communicated with a lubricating oil overflow channel of a low-pressure turbine bearing assembly, the side wall of the drum is obliquely arranged relative to the axis of a low-pressure turbine to enable the drum to be a conical surface, an oil hole is formed in the end, away from the axis of the low-pressure turbine, of the side wall of the drum, and lubricating oil in the inner cavity of the drum is discharged from the oil hole under the centrifugal force and the guiding effect of the side wall of the drum. The technical problem that high-speed dynamic balance vibration is too large due to the fact that a straight drum low-pressure turbine rotor does not discharge oil in time can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of low-pressure turbine structure design, and in particular to a low-pressure turbine inclined drum disc structure and a calibration method for high-speed dynamic balancing and oil accumulation prevention. Background Art

[0002] The low-pressure turbine shaft is a flexible shaft, and its operating speed is higher than the critical bending speed. The imbalance of the low-pressure turbine rotor is reduced by high-speed dynamic balancing of the low-pressure turbine rotor, thereby controlling the deflection of the low-pressure turbine shaft at the critical speed and operating speed, ensuring good vibration, safety and reliability of the engine.

[0003] During the high-speed dynamic balancing process, the lubricating oil will enter the drum through the gap between the bearing cavity and the sealing ring due to the lack of high-pressure gas sealing. If it is not removed in time, the lubricating oil will accumulate at the bottom of the drum. As the lubricating oil accumulates, the imbalance of the low-pressure turbine rotor increases, and the high-speed dynamic balancing vibration exceeds the limit, resulting in the inability to reach the required critical speed. At present, in order to solve the problem of lubricating oil accumulation in the low-pressure turbine drum structure, a straight drum design is generally adopted, and air holes are provided on the straight drum. During the high-speed dynamic balancing process of the low-pressure rotor, the lubricating oil is thrown out from the air holes by centrifugal force.

[0004] The existing straight-drum low-pressure turbine rotor can prevent the lubricating oil from accumulating at the bottom of the drum and meet the normal operation requirements of the low-pressure rotor at high-speed dynamic balancing. However, the straight-drum low-pressure turbine rotor throws out the lubricating oil through the air holes. If the hole diameter is too small or the drilling position is inappropriate, the lubricating oil may not be discharged in time, which will still cause excessive vibration in the high-speed dynamic balancing. Summary of the invention

[0005] The present invention provides a low-pressure turbine inclined drum disc structure and a calibration method for high-speed dynamic balancing and oil accumulation prevention, so as to solve the technical problem that the straight drum low-pressure turbine rotor oil is not discharged in time, resulting in excessive high-speed dynamic balancing vibration.

[0006] According to one aspect of the present invention, a calibration method for a low-pressure turbine swash drum disc structure for high-speed dynamic balancing and oil accumulation prevention is provided, characterized in that: A low-pressure turbine inclined drum disc structure for high-speed dynamic balancing and oil accumulation prevention comprises a low-pressure rotor and a drum arranged between the low-pressure rotors, wherein the inner cavity of the drum is connected to the lubricating oil overflow channel of the low-pressure turbine bearing assembly, the side wall of the drum is arranged obliquely relative to the axis of the low-pressure turbine so that the drum has a conical surface, and an oil hole is opened at one end of the side wall of the drum that is farther away from the axis of the low-pressure turbine, so that the lubricating oil in the inner cavity of the drum is discharged from the oil hole under the guidance of the centrifugal force and the side wall of the drum; The verification method includes the following steps: The radial velocity Vy2, tangential velocity Vz2 and axial velocity Vx2 of the lubricating oil at the outlet of the rotating part are calculated according to the rotating speed ω of the rotating part, the radius R1 at the oil hole inlet, the radius R2 at the oil hole outlet and the angle α between the oil hole and the shaft; the injection velocity V2 of the lubricating oil at the outlet of the rotating part is calculated according to the radial velocity Vy2, the tangential velocity Vz2 and the axial velocity Vx2; the equivalent pressure difference P of the lubricating oil at the outlet of the rotating part is calculated according to the injection velocity V2 of the lubricating oil at the outlet of the rotating part, the lubricating oil density ρ and the speed coefficient η; the equivalent pressure difference P of the lubricating oil at the outlet of the rotating part, the lubricating oil density ρ, the number of oil holes Z, The oil hole diameter d is used to calculate the oil mass flow rate m at the rotating part outlet; if the oil mass flow rate m at the rotating part outlet is greater than n times the oil mass flow rate of the nozzle during high-speed dynamic balancing, and n is 2 to 5, it means that the configuration of the oil hole can discharge the oil entering the inclined drum in time to ensure the normal high-speed dynamic balancing of the low-pressure rotor; the unit of oil density ρ is kg / m3, the speed coefficient η is 0.9 to 0.95, the unit of rotating part speed ω is rad / s, the unit of radius R1 at the oil hole inlet is mm, the unit of radius R2 at the oil hole outlet is mm, and the unit of oil hole diameter d is mm.

[0007] Optionally, the radial velocity Vy2, tangential velocity Vz2, and axial velocity Vx2 of the lubricating oil at the outlet of the rotating part are calculated according to the rotating speed ω of the rotating part, the radius R1 at the oil hole inlet, the radius R2 at the oil hole outlet, and the angle α between the oil hole and the shaft:

[0008] The formula for calculating the injection velocity V2 of the lubricating oil at the outlet of the rotating part according to the radial velocity Vy2, the tangential velocity Vz2, and the axial velocity Vx2 is: .

[0009] Optionally, the formula for calculating the equivalent pressure difference P of the lubricating oil at the outlet of the rotating part according to the injection speed V2 of the lubricating oil at the outlet of the rotating part, the density ρ of the lubricating oil and the speed coefficient η is: .

[0010] Optionally, the formula for calculating the lubricating oil mass flow rate m at the outlet of the rotating part according to the equivalent pressure difference P of the lubricating oil at the outlet of the rotating part, the lubricating oil density ρ, the number of oil holes Z, and the oil hole diameter d is: .

[0011] Optionally, the oil hole is perpendicular to the inner wall of the drum.

[0012] Optionally, there are multiple oil ports evenly distributed along the axial direction of the drum.

[0013] Optionally, the low-pressure turbine bearing assembly includes a bearing seat, a low-pressure turbine stub shaft, and two bearings arranged between the bearing seat and the low-pressure turbine stub shaft. A lubricating oil nozzle connected to the oil inlet pipe is installed on the bearing seat, and the gap between the bearing cavity and the bearing seat forms an oil overflow channel.

[0014] Optionally, a sealing ring is provided between the bearing seat and the low-pressure turbine stub shaft, and the sealing ring seals the lubricating oil overflow channel to reduce the amount of lubricating oil overflow.

[0015] Optionally, the preset configuration of the position, diameter and number of the oil holes makes the mass flow rate of the lubricating oil in the oil holes greater than the mass flow rate of the lubricating oil in the nozzle during high-speed dynamic balancing.

[0016] In summary, the present application includes at least one of the following beneficial technical effects: By setting the drum rotor cone surface tilted relative to the low-pressure pivot, the drum turns the cone surface structure, thereby utilizing the centrifugal force generated by high-speed rotation and the guiding effect of the drum rotor surface to make the lubricating oil entering the drum cavity flow rapidly downstream away from the axis along the trend surface, which not only prevents the accumulation of oil inside the low-pressure rotor, but also effectively reduces the problem of excessive high-speed dynamic balance vibration caused by oil accumulation; The position, diameter and number of the oil holes are preset to ensure that the mass flow of the oil holes is greater than the mass flow of the nozzle oil supply under high-speed dynamic balancing conditions (usually 2 to 5 times the nozzle flow). The design ensures that during high-speed operation, the lubricating oil entering the inclined drum can be discharged in time and will not accumulate inside the rotor, thereby avoiding abnormal dynamic balancing vibration caused by oil accumulation.

[0017] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 It is a schematic diagram of the structure of the low-pressure turbine inclined drum disc used for high-speed dynamic balancing and oil accumulation prevention of the present invention; Figure 2 This is a schematic diagram of the oil hole position of the present invention; Figure 3 Schematic diagram of oil hole calculation parameters.

[0019] Legend: 1. Low-pressure shaft; 2. Oil inlet pipe; 3. Oil supply seat; 4. Lubricating oil nozzle; 5. Bearing; 6. Low-pressure turbine short shaft; 7. Sealing ring; 8. Support seat; 9. Bearing seat; 10. Low-pressure turbine rotor; 11. Oil hole. DETAILED DESCRIPTION

[0020] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0021] The following is combined with Figure 1-3 This application is described in further detail.

[0022] The embodiment of the present application discloses a low-pressure turbine inclined drum disc structure for high-speed dynamic balancing and oil accumulation prevention.

[0023] Reference Figure 1 A low-pressure turbine inclined drum disc structure for high-speed dynamic balancing and oil accumulation prevention includes a low-pressure rotor and a drum arranged between the low-pressure rotors. The inner cavity of the drum is connected to the lubricating oil overflow channel of the low-pressure turbine bearing assembly. The side wall of the drum is inclined relative to the axis of the low-pressure turbine so that the drum has a conical surface. An oil hole is opened on the end of the side wall of the drum that is farther away from the axis of the low-pressure turbine, so that the lubricating oil in the inner cavity of the drum is discharged from the oil hole under the guidance of the centrifugal force and the side wall of the drum.

[0024] The low-pressure rotor constitutes the core rotating component of the turbine, and the drum, as the oil chamber inside the rotor, is mainly responsible for collecting and discharging the lubricating oil entering the rotor to avoid oil accumulation leading to abnormal dynamic balance and excessive vibration. In order to solve the problem of lubricating oil being retained inside the rotor due to untimely oil discharge in the traditional straight drum structure, an inclined drum structure is adopted. This structure enables the lubricating oil to flow to the oil hole quickly with the help of centrifugal force and guiding effect to ensure the stability of the dynamic balance state of the rotor when it is running at high speed. The inclined drum is installed inside the low-pressure rotor, and its inner cavity is connected to the lubricating oil overflow channel of the low-pressure turbine bearing assembly. The side wall of the drum is not perpendicular to the rotor axis, but is set at a specific inclination angle to form a cone-like structure. The specific value of the inclination angle α needs to be determined according to the actual rotor speed, lubricating oil properties and oil discharge requirements. Generally, it is necessary to ensure that the inclination angle can provide sufficient guiding effect and will not have a negative impact on the rigidity and balance of the overall rotor structure during design. By setting the tilt, the lubricating oil in the drum can flow to the oil hole along the inclined surface under the action of centrifugal force, thereby improving the oil discharge efficiency and preventing the lubricating oil from being retained inside the rotor for a long time. The conical surface structure can form a clear lubricating oil flow channel when rotating at high speed, effectively improving the discharge path of the lubricating oil.

[0025] Reference Figure 1 and Figure 2, the oil hole is perpendicular to the inner wall of the drum. The oil hole is perpendicular to the inner wall of the drum, ensuring that the oil outlet direction of the oil discharge port is consistent with the normal direction of the inner wall of the drum. It can ensure that under the high-speed rotation of the rotor and the action of centrifugal force, the oil is sprayed out from the oil hole in a direct and stable manner, avoiding the deviation of the oil flow direction caused by the inclination of the orifice, and ensuring that the oil can quickly leave the inside of the drum. When the oil hole is perpendicular to the inner wall of the drum, the oil does not need to experience additional flow direction bending or deflection at the orifice during the discharge process, thereby reducing the flow resistance and energy loss caused by the angle change. The oil leaves in a relatively pure jet flow, which helps to improve the oil discharge efficiency, ensure that the oil can be discharged in the shortest time, and prevent the oil from being retained and accumulated. At the same time, the discharged oil can avoid flowing along the inner wall of the drum as much as possible, preventing the oil from flowing back or being retained on the inner wall due to friction with the inner wall or disturbance. In this way, the oil can quickly leave the oil hole area, thereby reducing the retention time of the oil inside the drum and reducing the risk of oil accumulation.

[0026] There are multiple oil ports evenly distributed along the axial direction of the drum. By evenly distributing the oil ports along the inner cavity of the drum, it is ensured that the oil in the inner cavity of the drum can be fully discharged, avoiding the accumulation of oil in local areas. This design uses the centrifugal force and the effect of the concentrated hole to achieve a continuous and precise oil discharge channel. This evenly distributed design effectively prevents the unbalanced moment and vibration risks caused by local oil retention, optimizes the flow field, accurately calculates the oil flow pressure and dispersion, and further improves the stability and dynamic performance balance of the low-pressure vortex at high-speed operation.

[0027] The low-pressure turbine bearing assembly includes a bearing seat, a low-pressure turbine stub shaft, and two bearings arranged between the bearing seat and the low-pressure turbine stub shaft. A lubricating oil nozzle connected to the oil inlet pipe is installed on the bearing seat, and the gap between the bearing cavity and the bearing seat forms an oil overflow channel.

[0028] During the actual assembly, the bearing seat is first fixed on the predetermined position of the low-pressure pivot, and then the first bearing, the low-pressure pivot and the second bearing are installed on the central axis inside the bearing seat in sequence, ensuring that the short shaft and the bearing seat remain coaxial and are immediately embedded in the bearing. The oil inlet pipe is set on the oil supply seat and connected to the lubricating oil nozzle. The lubricating oil nozzle connected to the oil inlet pipe installed on the bearing seat accurately injects the lubricating oil into the bearing cavity, and the gap between the bearing seat and the bearing cavity constitutes the lubricating oil overflow channel, which guides the excess or leaking lubricating oil into the inner cavity of the inclined drum, and cooperates with the preset oil discharge hole configuration structure in the drum to jointly optimize the overall oil discharge effect and ensure the stable operation of the low-pressure bearing under high-speed dynamic balancing.

[0029] A sealing ring is arranged between the bearing seat and the short shaft of the low-pressure turbine, and the sealing ring is sealed on the oil overflow channel to reduce the amount of oil overflow. The sealing ring arranged between the bearing seat and the short shaft of the low-pressure round shaft mainly plays the role of sealing the oil overflow channel, thereby effectively reducing the excessive oil overflow caused by centrifugal force or other related factors. Specifically, during the manufacturing process, a special sealing groove is machined at one end of the bearing seat or the short shaft of the low-pressure round shaft, and the position of the groove is closely connected with the oil overflow channel. The sealing ring is made of wear-resistant and high-temperature resistant materials, usually rubber or metal composite materials, and is designed as a snap-on or press-in structure. During installation, the sealing ring is accurately embedded in the sealing groove, forming a close contact between the bearing seat and the short shaft. This sealing configuration can remain stable under high-speed rotation and vibration conditions, effectively preventing the lubricating oil from jumping through the overflow channel in large quantities, while ensuring that sufficient oil can still carry the bearing for lubrication. This not only ensures the lubrication performance of the bearing, but also prevents excessive oil from entering the rotor, thereby affecting the high-speed dynamic balance.

[0030] The preset configuration of the position, diameter and number of oil holes makes the mass flow of lubricating oil in the oil holes greater than the mass flow of lubricating oil in the nozzle during high-speed dynamic balancing. By optimizing the position, diameter and number, the mass flow of the discharged oil can be accurately controlled, so that even at high-speed rotation, the flow of oil formed by centrifugal force and guiding action is fast enough to input the oil introduced by the oral nozzle oil supply, thereby maintaining the dynamic balance of the oil inside the piston and reducing the imbalance caused by uneven oil. The specific position, diameter and number of the oil holes need to be determined through theoretical calculation, numerical simulation and experimental verification during design.

[0031] In the traditional straight drum design, the bottom usually requires additional support structures (such as reinforcing ribs or thickened radial plates) to ensure sufficient rigidity and strength to prevent vibration and deformation caused by oil accumulation. However, the inclined drum structure uses its own inclined design and the guiding effect of centrifugal force to enable the lubricating oil entering the drum to flow outward along the inclined surface faster, reducing the possibility of oil being retained at the bottom. Therefore, no additional reinforcement measures are required to support the bottom of the drum, which not only reduces the weight of the structure but also simplifies the manufacturing process. In addition, the inclined drum structure optimizes the force distribution, maintains the overall rigidity, and reduces the amount of material used, thereby achieving the goal of lightweighting.

[0032] Weight reduction has a number of positive effects on the performance of aircraft engines. First, it improves fuel efficiency and reduces the engine thrust-to-weight ratio, allowing aircraft to carry less fuel and fly farther. Second, after the engine mass is reduced, the maneuverability of the aircraft is significantly improved, especially in application scenarios such as fighter jets that require extremely high flexibility. Weight reduction can enhance the climb rate, turning speed and overall tactical capabilities. In addition, reducing the weight of the structure can also reduce the inertia of the turbine rotor, reduce vibration and imbalance, and improve the stability and reliability of the engine, thereby extending its service life and reducing maintenance costs. These advantages make weight reduction a key optimization direction in the design of modern aircraft engines.

[0033] Reference Figure 3 The present invention also provides a method for verifying a low-pressure turbine inclined drum disc structure for high-speed dynamic balancing and oil accumulation prevention, which comprises the following steps: S100, calculating the radial velocity Vy2, tangential velocity Vz2, and axial velocity Vx2 of the lubricating oil at the outlet of the rotating part according to the rotating speed ω of the rotating part, the radius R1 at the oil hole inlet, the radius R2 at the oil hole outlet, and the angle α between the oil hole and the shaft; S200, calculating the injection velocity V2 of the lubricating oil at the outlet of the rotating part according to the radial velocity Vy2, the tangential velocity Vz2, and the axial velocity Vx2; S300, calculating the equivalent pressure difference P of the lubricating oil at the outlet of the rotating part according to the injection speed V2 of the lubricating oil at the outlet of the rotating part, the density ρ of the lubricating oil and the speed coefficient η; S400, calculating the lubricating oil mass flow rate m at the outlet of the rotating part according to the equivalent pressure difference P of the lubricating oil at the outlet of the rotating part, the density ρ of the lubricating oil, the number of oil holes Z, and the diameter d of the oil holes; S500, if the mass flow rate m of the lubricating oil at the outlet of the rotating part is greater than n times the mass flow rate of the lubricating oil of the nozzle during high-speed dynamic balancing, and n is 2 to 5, it means that the configuration of the oil holes can discharge the lubricating oil entering the inclined drum in time, ensuring the normal high-speed dynamic balancing of the low-pressure rotor; Lubricating oil density ρ unit: kg / m3, speed coefficient η=0.9~0.95, rotating part speed ω unit: rad / s, oil hole inlet radius R1 unit: mm, oil hole outlet radius R2 unit: mm, oil hole diameter d unit: mm.

[0034] Based on the basic principles of fluid mechanics and rotational motion, S100 divides the overall flow of oil at the oil hole outlet into three gradients: gap, tangential and connection, so as to fully describe the dynamic characteristics of oil during discharge. Specifically, through the angle ω of the rotating part and the radius R1 at the hole inlet and the radius R2 at the outlet, the radial velocity generated by the centrifugal force can be calculated, which reflects the acceleration effect of oil when rotating from a smaller area radius to an incremental radius. At the same time, due to the overall rotational motion of the rotor, the oil at the outlet will inevitably obtain a tangential Vz2 proportional to the outlet radius Vy2. The partial speed reflects the kinetic energy obtained by the oil as the rotor rotates; in addition, due to the angle α of the oil hole relative to the adjacent series angle, the oil not only moves upward at the gap and tangential speeds during injection, but also generates a quantity Vx2 along the integrity. The quantity obtained by taking the tangent of the gap velocity further supplements the complete description of the overall movement of the oil; by calculating these three quantities separately, the overall injection velocity of the oil at the oil hole outlet can be determined, which provides the necessary data support for the subsequent calculation of the equivalent pressure difference P and mass flow rate based on the injection velocity, oil density ρ and velocity factor η.

[0035] Specifically, the radial velocity Vy2, tangential velocity Vz2, and axial velocity Vx2 of the lubricating oil at the outlet of the rotating part are calculated according to the rotating speed ω of the rotating part, the radius R1 at the oil hole inlet, the radius R2 at the oil hole outlet, and the angle α between the oil hole and the shaft:

[0036] S200 assumes the speed of the oil at the oil hole outlet as a three-dimensional vector, and uses the Pythagorean theorem to combine the gradients of motion, that is, the bearing speed Vy2, the tangential speed Vz2 and the filling speed Vx2 are regarded as the three gradients of the vector in the orthogonal coordinate system, and the overall injection speed V2 is obtained by squaring, taking the union and then taking the square root, thereby fully describing the total kinetic energy of the oil when it leaves the rotating part; the core of this method is to recognize that in rotating machinery, the oil not only moves in a single direction, but is also affected by centrifugal force, rotational inertia and geometric guidance to form a complex three-dimensional flow field. By decomposing the complex motion into simple orthogonal speeds, the classic vector synthesis principle can be used to accurately calculate the total injection amount of the oil.

[0037] Specifically, the formula for calculating the injection speed V2 of the lubricating oil at the outlet of the rotating part according to the radial speed Vy2, the tangential speed Vz2, and the axial speed Vx2 is: .

[0038] S300 is based on the energy conservation speed principle and the kinetic energy and pressure energy conversion relationship in fluid dynamics. It reflects the energy of the oil by converting the oil injection V2 at the outlet of the rotating part into the corresponding kinetic energy density (i.e. 0.5ρV2²). Due to the energy loss such as friction and turbulence in the actual flow, in order to more accurately reflect the actual movement state of the oil, the velocity coefficient η is introduced to correct the injection velocity, so that the corrected velocity (V2 / η) can more truly represent the effective flow rate of the oil. The corrected kinetic energy density 0.5ρ(V2 / η)² is used to calculate the equivalent pressure difference P formed by the oil at the outlet. This equivalent pressure difference represents the effective driving force generated by the conversion of kinetic energy into static pressure during the high-speed injection process of the oil.

[0039] Specifically, the formula for calculating the equivalent pressure difference P of the lubricating oil at the outlet of the rotating part according to the injection speed V2 of the lubricating oil at the outlet of the rotating part, the density ρ of the lubricating oil and the speed coefficient η is: .

[0040] The S300 principle is based on the hole flow theory and the law of conservation of energy in fluid mechanics, that is, the equivalent pressure difference P formed by the lubricating oil at the outlet of the rotating part is used as the driving force, and the mass flow rate m of the oil through the oil hole is derived through the combined relationship with the oil density ρ and the geometric parameters of the oil hole (oil hole diameter d and number Z). The basic idea is to regard each oil hole as a small nozzle. The oil flows through the oil hole at a certain speed under the action of the equivalent pressure difference. The cross-sectional area of ​​the oil hole is proportional to the square of the diameter d, and the total flow of multiple oil holes is the accumulation of the flow of a single oil hole. Therefore, by calculating the oil in a single oil hole The theoretical flow velocity at the location, combined with the density of the oil and the effective area of ​​the oil hole, can be used to calculate the mass flow rate of the oil at that location; the introduction of the equivalent pressure difference P is to consider the difference between the actual flow velocity and the ideal flow velocity caused by factors such as friction, turbulence and energy loss in the actual flow, so that the calculation is closer to the actual working state, and then provide designers with a basis for quantitatively evaluating whether the oil hole configuration can achieve sufficient oil discharge under high-speed rotation and high-speed dynamic balancing conditions, ensuring that excess lubricating oil can be discharged in time to prevent oil from accumulating inside the rotor and affecting the dynamic balance and stable operation of the overall system.

[0041] Specifically, the formula for calculating the mass flow rate m of the lubricating oil at the outlet of the rotating part according to the equivalent pressure difference P of the lubricating oil at the outlet of the rotating part, the density of the lubricating oil ρ, the number of oil holes Z, and the diameter of the oil hole d is: .

[0042] S500 ensures that the oil discharge capacity far exceeds the oil supply by setting the mass flow rate m of the lubricating oil at the outlet of the rotating part to be 2 to 5 times greater than the mass flow rate of the nozzle oil supply, so that the lubricating oil entering the inclined drum can be quickly discharged under the strong centrifugal force and guiding effect generated by high-speed rotation, without forming oil accumulation inside the rotor and the inclined drum, avoiding local imbalance and excessive vibration caused by uneven oil distribution; at the same time, this design ensures that the bearing can still obtain a stable and sufficient supply of lubricating oil, preventing excessive oil from interfering with the dynamic balance. By quantitatively comparing the ratio of oil discharge and oil supply flow, the designer can optimize the number, position and diameter of the oil holes in the design stage, ensuring that the oil discharge system can discharge excess lubricating oil in a timely and effective manner under actual working conditions, maintaining the overall oil balance of the rotor, thereby achieving stable, reliable and low-vibration operation of the low-pressure rotor under high-speed operation.

[0043] The principle of the present invention is to design a low-pressure turbine rotor system with an inclined drum structure and optimized oil hole configuration, so as to achieve efficient discharge of oil while ensuring bearing lubrication, thereby preventing unbalanced vibration caused by oil accumulation inside the rotor and the inclined drum. The core is to use the centrifugal force generated by the high-speed rotation of the rotor and the guiding effect of the drum to make the lubricating oil entering the inclined drum flow along the inner wall of the drum to be discharged from the oil holes preset on the outer side. Through the precise design and configuration of the geometric parameters of the oil holes (such as the radius at the inlet and outlet of the oil holes, the angle between the oil holes and the rotor shaft, the diameter and number of the oil holes), it is ensured that the mass flow rate of oil discharge at the oil holes is significantly higher than the flow rate of oil supply from the bearing nozzle (usually required to be 2 to 5 times), so that the excess oil can be quickly and effectively discharged under high-speed dynamic balancing conditions. At the same time, a series of calculation methods based on fluid dynamics and the principle of energy conservation are used to decompose the radial, tangential and axial velocity components of the oil at the outlet, and then synthesize them to obtain the total injection velocity, and thus calculate the equivalent pressure difference and oil mass flow rate. This complete design scheme that combines theory and practice ensures that the supply and discharge of lubricating oil achieve dynamic balance, effectively avoiding rotor imbalance and vibration problems caused by oil accumulation, thereby ensuring the stability and reliability of the low-pressure turbine rotor at high-speed operation.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for verifying a low-pressure turbine inclined drum structure for high-speed dynamic balancing and oil accumulation prevention, characterized in that: A low-pressure turbine inclined drum disc structure for high-speed dynamic balancing and oil accumulation prevention comprises a low-pressure rotor and a drum arranged between the low-pressure rotors, wherein the inner cavity of the drum is connected to the lubricating oil overflow channel of the low-pressure turbine bearing assembly, the side wall of the drum is arranged obliquely relative to the axis of the low-pressure turbine so that the drum has a conical surface, and an oil hole is opened at one end of the side wall of the drum that is farther away from the axis of the low-pressure turbine, so that the lubricating oil in the inner cavity of the drum is discharged from the oil hole under the guidance of the centrifugal force and the side wall of the drum; The verification method includes the following steps: The radial velocity Vy2, tangential velocity Vz2 and axial velocity Vx2 of the lubricating oil at the outlet of the rotating part are calculated according to the rotating speed ω of the rotating part, the radius R1 at the oil hole inlet, the radius R2 at the oil hole outlet and the angle α between the oil hole and the shaft; The injection speed V2 of the lubricating oil at the outlet of the rotating part is calculated according to the radial speed Vy2, the tangential speed Vz2 and the axial speed Vx2; The equivalent pressure difference P of the lubricating oil at the outlet of the rotating part is calculated according to the injection speed V2 of the lubricating oil at the outlet of the rotating part, the density ρ of the lubricating oil and the speed coefficient η; The lubricating oil mass flow rate m at the outlet of the rotating part is calculated according to the equivalent pressure difference P of the lubricating oil at the outlet of the rotating part, the density ρ of the lubricating oil, the number of oil holes Z, and the diameter d of the oil holes; If the mass flow rate m of the lubricating oil at the outlet of the rotating part is greater than n times the mass flow rate of the lubricating oil at the nozzle during high-speed dynamic balancing, and n is 2 to 5, it means that the configuration of the oil holes can discharge the lubricating oil entering the inclined drum in time, ensuring the normal high-speed dynamic balancing of the low-pressure rotor; Lubricating oil density ρ unit: kg / m3, speed coefficient η=0.9~0.95, rotating part speed ω unit: rad / s, oil hole inlet radius R1 unit: mm, oil hole outlet radius R2 unit: mm, oil hole diameter d unit: mm.

2. The calibration method for a low-pressure turbine inclined drum disc structure for high-speed dynamic balancing and oil accumulation prevention according to claim 1 is characterized in that: According to the rotating speed ω of the rotating part, the radius R1 at the oil hole inlet, the radius R2 at the oil hole outlet, and the angle α between the oil hole and the shaft, the formula for calculating the radial velocity Vy2, tangential velocity Vz2, and axial velocity Vx2 of the lubricating oil at the rotating part outlet is: ； ； ； The formula for calculating the injection velocity V2 of the lubricating oil at the outlet of the rotating part according to the radial velocity Vy2, the tangential velocity Vz2, and the axial velocity Vx2 is: .

3. The calibration method for the low-pressure turbine inclined drum disc structure for high-speed dynamic balancing and oil accumulation prevention according to claim 2 is characterized in that: The formula for calculating the equivalent pressure difference P of the lubricating oil at the outlet of the rotating part according to the injection velocity V2 of the lubricating oil at the outlet of the rotating part, the density ρ of the lubricating oil and the speed coefficient η is: .

4. The calibration method for a low-pressure turbine inclined drum disc structure for high-speed dynamic balancing and oil accumulation prevention according to claim 3 is characterized in that: The formula for calculating the mass flow rate m of the lubricating oil at the outlet of the rotating part is as follows: .

5. The calibration method for a low-pressure turbine inclined drum disc structure for high-speed dynamic balancing and oil accumulation prevention according to claim 1 is characterized in that: The oil hole is perpendicular to the inner wall of the drum.

6. The calibration method for the low-pressure turbine inclined drum disc structure for high-speed dynamic balancing and oil accumulation prevention according to claim 5 is characterized in that: A plurality of oil holes are evenly distributed along the axial direction of the drum.

7. The calibration method for a low-pressure turbine inclined drum disc structure for high-speed dynamic balancing and oil accumulation prevention according to claim 5 is characterized in that: The low-pressure turbine bearing assembly includes a bearing seat, a low-pressure turbine stub shaft, and two bearings arranged between the bearing seat and the low-pressure turbine stub shaft. A lubricating oil nozzle connected to the oil inlet pipe is installed on the bearing seat, and the gap between the bearing cavity and the bearing seat forms an oil overflow channel.

8. The calibration method for a low-pressure turbine inclined drum disc structure for high-speed dynamic balancing and oil accumulation prevention according to claim 7 is characterized in that: A sealing ring is arranged between the bearing seat and the low-pressure turbine short shaft, and the sealing ring seals the lubricating oil overflow channel to reduce the amount of lubricating oil overflow.

9. The calibration method for a low-pressure turbine inclined drum disc structure for high-speed dynamic balancing and oil accumulation prevention according to claim 7 is characterized in that: The preset configuration of the position, diameter and number of the oil holes makes the mass flow rate of the lubricating oil in the oil holes greater than the mass flow rate of the lubricating oil in the nozzle during high-speed dynamic balancing.

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