Engine rotor and stator coaxiality eccentricity optimization method

Abstract

The invention belongs to the field of engine rotor and stator design, and particularly relates to an engine rotor and stator coaxiality eccentricity optimization method, which comprises the following steps: establishing a measurement reference coordinate system and a least square circle for an elastic support bearing in a structure simplified model in a matching manner, and obtaining discrete sampling point position data on the least square circle; calculating the downward eccentricity c of the elastic support by adopting a least square method; a high-pressure turbine process shaft is designed and is in centering fit with a high-pressure compressor rotor rear shaft, and a labyrinth simulation surface is designed; the final eccentric adjustment amount of the coaxiality of the sealing labyrinth and the air oil retainer is calculated; the influence of engine rotor shaft fit clearance, bearing radial clearance and static elastic support deformation on the coaxiality of the rotor and the stator can be measured and determined in advance, a high-pressure turbine simulation process shaft is designed, and eccentric compensation adjustment is performed on the engine rotor and the stator during assembly, so that the engine rotor and the stator are finally coaxial after being assembled, and collision and abrasion of the rotor and the stator are avoided; the service life of the engine is prolonged and the maintenance cost of the engine is reduced.

Description

Technical Field

[0001] This application belongs to the field of engine rotor-stator design, and specifically relates to a method for optimizing the coaxiality eccentricity of engine rotor-stator. Background Technology

[0002] Aircraft have extremely stringent requirements for engine failure rates. Engine rotor-stator rubbing has become one of the common engine failures. This paper proposes an optimization method for the coaxiality eccentricity of engine rotor-stator to ensure the coaxiality of the sealing clearance of the high-pressure turbine rotor-stator, achieve oil sealing of the bearing cavity, and prevent the air baffle ring from rubbing against the teeth. This solves the problems that may cause engine failures such as oil leakage and excessive vibration, which will extend the engine's service life and ensure the safety of aircraft operation.

[0003] Engines typically employ a rotor-stator centering fit. After the rotor and stator are assembled, their coaxiality cannot be directly measured and adjusted. Due to the influence of rotor fit clearance, bearing radial clearance, and stator elastic support deformation, the coaxiality of the engine rotor and stator often becomes eccentric and cannot be guaranteed. In severe cases, rotor-stator rubbing failure may occur, which will shorten the engine's service life, increase engine maintenance costs, and affect engine operating safety.

[0004] Therefore, how to achieve effective coaxiality design of rotor and stator is a problem that needs to be solved. Summary of the Invention

[0005] The purpose of this application is to provide a method for optimizing the coaxiality eccentricity of engine rotor and stator, so as to solve the problem that the coaxiality of engine rotor and stator often cannot be guaranteed due to eccentricity.

[0006] The technical solution of this application is: a method for optimizing the coaxiality eccentricity of engine rotor and stator, comprising:

[0007] The relevant installation structure of the high-pressure turbine shaft is simplified, and a simplified structural model is established; the structural offset data in the simplified structural model is obtained.

[0008] Calculate the eccentricity d of the comb teeth based on the structural offset data;

[0009] A measurement reference coordinate system and a least squares circle are established for the elastic support bearing fit in the simplified structural model. The position data of discrete sampling points on the least squares circle are obtained, and the downward eccentricity c of the elastic support is calculated by the least squares method.

[0010] Design the high-pressure turbine process shaft and center it with the rear shaft of the high-pressure compressor rotor, designing it as a grate simulated surface; collect the offset data of the high-pressure turbine process shaft and calculate the final eccentric adjustment amount of the coaxiality of the sealing grate and the air baffle ring;

[0011] The engine rotor and stator are coaxially adjusted based on the final eccentricity adjustment of the coaxiality between the sealing teeth and the air baffle ring.

[0012] Preferably, the structural offset data in the simplified structural model includes: an upward displacement 'a' of the high-pressure turbine shaft front end sleeve tooth fit clearance at the 6-point bearing, and a radial clearance 'b' of the bearing; a downward eccentricity 'c' of the high-pressure turbine shaft due to the weight G of the high-pressure turbine rotor acting on the elastic support; assuming the relative distance between the high-pressure turbine shaft sleeve tooth and the 6-point bearing is 'm', and the relative distance between the 6-point bearing and the grating tooth is 'n', the downward eccentricity 'd' of the grating tooth will occur.

[0013] Preferably, the eccentricity d of the comb teeth is:

[0014] ;

[0015] In the formula, the high-pressure turbine shaft sleeve tooth fit clearance a and the bearing radial clearance b can be directly confirmed by dimensional measurement, and the downward eccentricity c can be directly measured by installing a high-pressure turbine simulated rotor.

[0016] Preferably, in the measurement reference coordinate system, O is set as the center of the circle determined by the least squares method, O1 is the center of the measurement reference coordinate system, the radius of the least squares circle is R, and θ i For discrete sampling points P i The angle between the x-axis and the x-axis, r i The actual circle radius (O1P) measured from O1 i Discrete sampling point P i The radial deviation to the least squares circle is ε i The eccentric distance between the center O and the center O1 is e, the angle between OO1 and the X-axis is α, i is the number of measured points, and x and y are the coordinate components of the center O.

[0017] Preferably, the specific method for calculating the downward eccentricity c of the elastic support using the least squares method is as follows:

[0018] Find the partial derivatives of Q with respect to R, x, and y, and set them equal to zero. The solution is:

[0019] ;

[0020] The deformation Δr was obtained by finite element calculation. i After transformation, the coordinate components of the center of the least squares circle are:

[0021] ;

[0022] Since the elastic support is subjected to gravity, which is directed vertically downwards, x=0. The downward eccentricity c of the elastic support can be obtained by directly calculating y.

[0023] Preferably, the offset data of the high-pressure turbine process shaft includes:

[0024] The front end of the high-pressure turbine process shaft has a downward displacement a' due to the fit clearance of the bushing teeth behind the high-pressure compressor rotor. At the 6-point bearing, there is a radial clearance b'. Let the relative distance between the high-pressure turbine process shaft and the 6-point bearing be m, and the relative distance between the 6-point bearing and the grate teeth be n. This will cause the simulated grate teeth of the process shaft to produce a downward eccentricity of d'.

[0025] Preferably, the method for calculating the final eccentricity adjustment of the coaxiality between the sealing grate teeth and the air baffle ring is as follows:

[0026] The calculated downward eccentricity d' of the simulated process shaft teeth is:

[0027] ;

[0028] Subtracting the downward eccentricity d' of the simulated grate teeth from the eccentricity d of the grate teeth yields:

[0029] ;

[0030] Δ refers to the final eccentricity adjustment amount for the coaxiality of the sealing teeth and the air baffle ring.

[0031] This application discloses a method for optimizing the coaxiality eccentricity of the engine rotor and stator. It can measure and determine in advance the influence of the engine rotor shaft fitting clearance, bearing radial clearance, and stator elastic support deformation on the coaxiality of the rotor and stator. It can design a high-pressure turbine simulation process shaft and compensate for the eccentricity of the engine rotor and stator during assembly, so as to achieve the final coaxiality of the engine rotor and stator after assembly, avoid rotor-stator rubbing, extend the engine service life, reduce engine maintenance costs, and ensure engine working safety. Attached Figure Description

[0032] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0033] Figure 1 This is a schematic diagram of the installation structure of the high-pressure turbine unit in this application;

[0034] Figure 2 This is a simplified diagram of the high-pressure turbine shaft installation for this application;

[0035] Figure 3 This is a schematic diagram of the least squares data processing method in this application;

[0036] Figure 4 This is a schematic diagram of the high-pressure turbine process shaft assembly structure of this application;

[0037] Figure 5 This is a simplified diagram of the high-pressure turbine process shaft installation for this application;

[0038] Figure 6This is a flowchart of the eccentric process design for this application. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] like Figure 1 As shown, the engine's high-pressure turbine unit consists of a rotor and a stator. The rotor comprises a high-pressure turbine shaft, bearing inner rings, adjusting shims, grating teeth, a first-stage high-pressure turbine disk assembly, a second-stage high-pressure turbine disk assembly, and locating pins. The stator consists of a flexible support, an air baffle ring, etc. During installation, the front end of the high-pressure turbine shaft is first aligned with the rear shaft of the high-pressure compressor rotor using a toothed centering connection. Then, the rear end of the high-pressure turbine shaft is aligned using the inner and outer bearing rings. The bearings are roller bearings; the outer ring is mounted on the combustion chamber flexible support, and the inner ring is mounted on the high-pressure turbine shaft. The first-stage and second-stage high-pressure turbine disk assemblies are fixed to the end of the high-pressure turbine shaft using locating pins.

[0041] A method for optimizing the coaxiality eccentricity of engine rotor and stator includes the following steps:

[0042] Step S100: Simplify the relevant installation structure of the high-pressure turbine shaft and establish a simplified structural model; obtain the structural offset data in the simplified structural model.

[0043] like Figure 2 As shown, under ideal conditions, when the high-pressure turbine unit is installed, the high-pressure turbine grates and the air baffle ring are installed concentrically, simplifying the relevant installation structure of the high-pressure turbine shaft. Due to the downward force of the high-pressure turbine rotor at the rear end, the high-pressure turbine shaft will shift upward with the bearing as the fulcrum. At the bearing, due to the downward radial clearance and deformation of the elastic support, the high-pressure turbine shaft will shift downward at this point.

[0044] The structural offset data in the simplified structural model include: an upward displacement 'a' of the clearance between the front end sleeve teeth of the high-pressure turbine shaft at the 6-point bearing, and a radial clearance 'b' of the bearing; a downward eccentricity 'c' of the high-pressure turbine shaft caused by the weight G of the high-pressure turbine rotor acting on the elastic support; and a downward eccentricity 'd' caused by the relative distance 'm' between the high-pressure turbine shaft sleeve teeth and the 6-point bearing, and a relative distance 'n' between the 6-point bearing and the grating teeth.

[0045] Step S200: Calculate the eccentricity d of the tooth according to the structural offset data.

[0046] Preferably, the eccentricity d of the comb teeth is:

[0047] ;

[0048] In the formula, the high-pressure turbine shaft sleeve tooth fit clearance a and the bearing radial clearance b can be directly confirmed by dimensional measurement. The downward eccentricity c is obtained by directly measuring by installing a high-pressure turbine simulated rotor (designed according to the weight and center of gravity of the high-pressure turbine rotor), or by first calculating the deformation through finite element static analysis, and then calculating the eccentricity of the elastic support bearing mating surface using the least squares method.

[0049] Step S300: Establish a measurement reference coordinate system and a least squares circle for the elastic support bearing fit in the simplified structural model, obtain the position data of discrete sampling points on the least squares circle, and calculate the downward eccentricity c of the elastic support using the least squares method.

[0050] like Figure 3 In the measurement reference coordinate system, O is set as the center of the circle determined by the least squares method, O1 is the center of the measurement reference coordinate system, and the radius of the least squares circle is R, θ i For discrete sampling points P i The angle between the x-axis and the x-axis, r i The actual circle radius (O1P) measured from O1 i Discrete sampling point P i The radial deviation to the least squares circle is ε i The eccentric distance between the center O and the center O1 is e, the angle between OO1 and the X-axis is α, i is the number of measured points (total n), and x and y are the coordinate components of the center O.

[0051] Preferably, the specific method for calculating the downward eccentricity c of the elastic support using the least squares method is as follows:

[0052] Based on geometric relationships, the following can be calculated:

[0053] ;

[0054] After simplification, we get:

[0055] :

[0056] According to the principle of least squares:

[0057] ;

[0058] Find the partial derivatives of Q with respect to R, x, and y, and set them equal to zero. The solution is:

[0059] ;

[0060] The deformation Δr was obtained by finite element calculation.i After transformation, the coordinate components of the center of the least squares circle are:

[0061] ;

[0062] Since elastic supports are generally subjected to gravity, which acts vertically downwards, x=0, the downward eccentricity c of the elastic support can be obtained by directly calculating y.

[0063] Step S400: Design the high-pressure turbine process shaft and center it with the rear shaft of the high-pressure compressor rotor to form a simulated grate surface; collect the offset data of the high-pressure turbine process shaft and calculate the final eccentric adjustment amount of the coaxiality of the sealing grate and the air baffle ring.

[0064] like Figure 4 The front end of the high-pressure turbine process shaft is designed as a smooth shaft structure to simulate the front end teeth of the real high-pressure turbine shaft, and is aligned with the rear shaft of the high-pressure compressor rotor. The rear end is designed as the outer diameter positioning surface of the bearing inner ring, and is aligned with the rolling elements of the 6-point bearing. Finally, the outer diameter of the comb tooth is simulated and designed as a comb tooth simulation surface, which is aligned with the air baffle ring to simulate horizontal centering guidance during actual engine assembly.

[0065] Due to manufacturing precision deviations between the process shaft and the actual shaft, and because the process shaft is not affected by the gravity of the high-pressure turbine rotor, the installation position of the process shaft differs from that of the actual high-pressure turbine shaft during assembly, simulating the high-pressure turbine shaft. Influenced by the weight of the process shaft, the front gear teeth face downwards, and the bearings also face downwards due to radial clearance. Since the process shaft is relatively lightweight, the deformation of the elastic support is negligible. Figure 5 As shown.

[0066] The offset data for the high-pressure turbine process shaft includes:

[0067] The front end of the high-pressure turbine process shaft has a downward displacement a' due to the fit clearance of the bushing teeth behind the high-pressure compressor rotor. At the 6-point bearing, there is a radial clearance b'. Let the relative distance between the high-pressure turbine process shaft and the 6-point bearing be m, and the relative distance between the 6-point bearing and the grate teeth be n. This will cause the simulated grate teeth of the process shaft to produce a downward eccentricity of d'.

[0068] The calculated downward eccentricity d' of the simulated process shaft teeth is:

[0069] ;

[0070] Subtracting the downward eccentricity d' of the simulated grate teeth from the eccentricity d of the grate teeth yields:

[0071] ;

[0072] Δ refers to the final eccentricity adjustment amount for the coaxiality of the sealing teeth and the air baffle ring.

[0073] Step S500: Adjust the engine rotor and stator coaxially according to the final eccentricity adjustment of the coaxiality of the sealing grate and the air baffle ring.

[0074] During assembly, first, a simulated process shaft is used. At the simulated engagement point between the ferrule and the air baffle ring, the air baffle ring is offset downwards by a Δ. When the high-pressure turbine shaft is actually installed, this ensures the concentricity of the actual engine's high-pressure turbine shaft and stator, theoretically allowing the concentricity to be adjusted to 0mm. The process flow for the concentricity offset design is summarized as follows: Figure 6 As shown.

[0075] The outer diameter of the high-pressure turbine shaft grates and the inner diameter of the air baffle ring form the coaxiality of the rotor and stator. The outer diameter of the grates generates an eccentricity d' when the high-pressure turbine shaft is installed, and an eccentricity d when the high-pressure turbine shaft is actually installed. The combined eccentricity adjustment compensation amount Δ of the grates is generated. At this time, by adjusting the position of the air baffle ring in advance, the same eccentricity Δ is generated, which can ensure the coaxiality of the engine rotor and stator.

[0076] In summary, this application has the following advantages:

[0077] The impact of engine rotor shaft fit clearance, bearing radial clearance, and stator elastic support deformation on rotor-stator coaxiality can be measured and determined in advance. A high-pressure turbine simulation process shaft can be designed, and the eccentricity compensation adjustment of engine rotor-stator can be performed during assembly to achieve final coaxiality of engine rotor-stator after assembly, avoid rotor-stator rubbing, extend engine service life, reduce engine maintenance costs, and ensure engine working safety.

[0078] Finally, it should be noted that the accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0079] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for optimizing the coaxiality eccentricity of engine rotor and stator, characterized in that, include: The relevant installation structure of the high-pressure turbine shaft is simplified, and a simplified structural model is established; Obtain structural offset data from the simplified structural model; Calculate the eccentricity d of the comb teeth based on the structural offset data; A measurement reference coordinate system and a least squares circle are established for the elastic support bearing fit in the simplified structural model. The position data of discrete sampling points on the least squares circle are obtained, and the downward eccentricity c of the elastic support is calculated by the least squares method. Design the high-pressure turbine process shaft and center it with the rear shaft of the high-pressure compressor rotor, designing it as a grate simulated surface; collect the offset data of the high-pressure turbine process shaft and calculate the final eccentric adjustment amount of the coaxiality of the sealing grate and the air baffle ring; The engine rotor and stator are coaxially adjusted based on the final eccentricity adjustment of the coaxiality between the sealing teeth and the air baffle ring.

2. The engine rotor-stator coaxiality eccentricity optimization method as described in claim 1, characterized in that, The structural offset data in the simplified structural model includes: an upward displacement 'a' of the clearance between the front end sleeve teeth of the high-pressure turbine shaft at the 6-point bearing, and a radial clearance 'b' of the bearing; a downward eccentricity 'c' of the high-pressure turbine shaft caused by the weight G of the high-pressure turbine rotor acting on the elastic support; assuming the relative distance between the high-pressure turbine shaft sleeve teeth and the 6-point bearing is 'm', and the relative distance between the 6-point bearing and the grating teeth is 'n', the downward eccentricity 'd' of the grating teeth will occur.

3. The engine rotor-stator coaxiality eccentricity optimization method as described in claim 2, characterized in that, The eccentricity d of the comb teeth is: ； In the formula, the high-pressure turbine shaft sleeve tooth fit clearance a and the bearing radial clearance b can be directly confirmed by dimensional measurement, and the downward eccentricity c can be directly measured by installing a high-pressure turbine simulated rotor.

4. The method for optimizing the coaxiality eccentricity of the engine rotor and stator as described in claim 1, characterized in that: In the measurement reference coordinate system, O is set as the center of the circle determined by the least squares method, O1 is the center of the measurement reference coordinate system, and the radius of the least squares circle is R, θ i For discrete sampling points P i The angle between the x-axis and the x-axis, r i The actual circle radius (O1P) measured from O1 i Discrete sampling point P i The radial deviation to the least squares circle is ε i The eccentric distance between the center O and the center O1 is e, the angle between OO1 and the X-axis is α, i is the number of measured points, and x and y are the coordinate components of the center O.

5. The engine rotor-stator coaxiality eccentricity optimization method as described in claim 4, characterized in that: The specific method for calculating the downward eccentricity c of an elastic support using the least squares method is as follows: Find the partial derivatives of Q with respect to R, x, and y, and set them equal to zero. The solution is: ； The deformation Δr was obtained by finite element calculation. i After transformation, the coordinate components of the center of the least squares circle are: ； Since the elastic support is subjected to gravity, which is directed vertically downwards, x=0. The downward eccentricity c of the elastic support can be obtained by directly calculating y.

6. The method for optimizing the coaxiality eccentricity of the engine rotor and stator as described in claim 1, characterized in that: The offset data of the high-pressure turbine process shaft includes: The front end of the high-pressure turbine process shaft has a downward displacement a' due to the fit clearance of the bushing teeth behind the high-pressure compressor rotor. At the 6-point bearing, there is a radial clearance b'. Let the relative distance between the high-pressure turbine process shaft and the 6-point bearing be m, and the relative distance between the 6-point bearing and the grate teeth be n. This will cause the simulated grate teeth of the process shaft to produce a downward eccentricity of d'.

7. The engine rotor-stator coaxiality eccentricity optimization method as described in claim 6, characterized in that, The calculation method for the final eccentricity adjustment of the coaxiality between the sealing teeth and the air baffle ring is as follows: The calculated downward eccentricity d' of the simulated process shaft teeth is: ； Subtracting the downward eccentricity d' of the simulated grate teeth from the eccentricity d of the grate teeth yields: ； Δ refers to the final eccentricity adjustment amount for the coaxiality of the sealing teeth and the air baffle ring.

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