Method for determining cold-state blade tip gap between aero-engine rotor blade and casing

Abstract

The invention belongs to the technical field of design of a cold-state blade tip gap between an aero-engine rotor blade and a cartridge receiver, and particularly relates to a method for determining the cold-state blade tip gap between the aero-engine rotor blade and the cartridge receiver. According to the method, the steady-state point is calculated, including the overall flexural deflection of the rotor, the local variation caused by rotor and stator machining runout, the rotor bearing clearance and the like, and transition state calculation is added while steady-state point calculation is performed, so that the actual use scene of the aero-engine can be better considered, and the long-term use requirement is met.

Description

Technical Field

[0001] The present application belongs to the technical field of cold tip clearance design between an aircraft engine rotor blade and a casing, and specifically relates to a method for determining the cold tip clearance between an aircraft engine rotor blade and a casing. Background Art

[0002] During an aircraft's takeoff and landing cycle, the temperature and stress of an aircraft engine's rotating mechanical components fluctuate dramatically depending on the operating state. Due to differences in the structure, materials, stress conditions, and heat exchange between the rotor components and the casing, this process inevitably causes the radial displacement of the blade tips to deviate from that of the casing, resulting in changes in tip clearance. Aircraft engine tip clearance, the radial distance between the rotor blades and the casing, has a significant impact on aircraft engine performance, especially for advanced aircraft engines.

[0003] To ensure that aircraft engines can deliver power normally, especially during transient conditions, it's crucial to prevent friction or scratching between the rotor blades and the casing. Without special measures, a large tip clearance between the rotor blades and the casing is essential. However, this large tip clearance increases blowby losses, severely impacting aircraft engine performance, increasing fuel consumption, and raising engine operating temperatures, negatively impacting engine reliability and lifespan.

[0004] As the thrust-to-weight ratio requirements for aircraft engines become increasingly higher, the thermal cycle parameters of the entire engine are gradually improved, and the requirements for component efficiency are becoming more and more stringent. It is becoming increasingly important to determine the reasonable cold tip clearance between the rotor blades and the corresponding casing. This is because the cold tip clearance is not only an important factor affecting component efficiency, but also determines whether the rotor blades and the casing will rub against each other. It is an important parameter affecting the safe operation of aircraft engines.

[0005] Currently, most aircraft engine cold tip clearances are determined by referring to existing models with similar load levels or using test pieces. This is somewhat blind, lacks scientific basis and data support, and does not fully consider the factors affecting tip clearance.

[0006] As the load on aircraft engine components increases, available reference data becomes increasingly scarce. Usually, a certain percentage of the rotor blade extension is used as the value of the cold tip clearance, or only the deformation of the rotor disc rim, rotor blade tip, and corresponding casing inner wall at a certain state point is considered to calculate the cold tip clearance value, which is then corrected and improved based on existing experience. This technical solution has the following defects:

[0007] 1) Only three factors affecting the tip clearance are simply considered, namely the deformation of the rotor disc rim, the deformation of the rotor blade tip and the deformation of the corresponding casing inner wall. There is a lack of comprehensive consideration of the factors affecting the rotor tip clearance, such as the overall flexural deformation of the aircraft engine rotor, the local changes caused by the machining runout of the rotor and stator, the rotor bearing clearance, and extreme working conditions, such as the emergency shutdown of the aircraft engine.

[0008] 2) The deformation amount is determined only based on the deformation calculation of a certain steady-state point of the aircraft engine. The tip clearance determined by this single operating point lacks a comprehensive assessment of the impact of other steady-state points, which will lead to a decrease in the assessment accuracy of aircraft engine component performance and overall performance at non-design operating points. And the one-way coupling calculation method is obviously used, as follows Figure 1 As shown in the figure, the secondary effects of the thermal state of the tip clearance on the performance of aircraft engine components, overall performance and air system are not considered, which further reduces the simulation accuracy of the tip clearance.

[0009] 3) The changing characteristics of the blade tip clearance in the transient state of the aircraft engine are not considered. The aircraft engine has an extreme value of the blade tip clearance during the deceleration process, such as Figure 2 Due to insufficient understanding of the full-speed variation characteristics of tip clearance, rotor blade tip wear occurs during actual aircraft engine operation, which in turn affects the safety of aircraft engine operation and causes premature degradation of overall engine performance.

[0010] This application is proposed in view of the above-mentioned technical defects. Summary of the Invention

[0011] The purpose of this application is to provide a method for determining the cold tip clearance between the rotor blades and the casing of an aircraft engine, so as to meet the needs of high-load components to operate with high efficiency and high reliability under major operating points and meet the requirements for long-term use of aircraft engines.

[0012] The technical solution of this application is:

[0013] A method for determining the cold tip clearance between an aero-engine rotor blade and a casing comprises:

[0014] Step 1: Determine the steady-state point and typical transition state process of the blade tip clearance design benchmark, and clarify the boundary conditions of the blade tip clearance design;

[0015] Step 2: According to the boundary conditions of the steady-state point, establish the calculation and analysis model of the rotor and casing, carry out the deformation calculation and analysis of the steady-state rotor and casing, and calculate the deformation of the rotor wheel rim δ at the steady-state point. d , deformation of the rotor blade tip δ b , the deformation of the inner wall of the casing δ c ;

[0016] Step 3: According to the typical transition state process, based on the calculation and analysis model of the rotor and casing, carry out the deformation calculation and analysis of the transition state rotor and casing, and calculate the maximum value of the wheel rim deformation δ under the typical transition state. d ', the extreme value of the deformation of the rotor blade tip δ b ', the maximum deformation value δ of the inner wall of the casing c ';

[0017] Step 4: Based on the boundary conditions of the blade tip clearance design, the calculation and analysis of the deflection deformation of the entire rotor of the aircraft engine in the steady state and transition state are carried out to obtain the influence of the deflection deformation of the entire rotor on the deformation of the rotor blade tip δ zt ;

[0018] Step 5: Determine the extreme value of the rotor pivot bearing clearance δ z ;

[0019] Step 6: Determine the rotor and stator runout influence δ t ;

[0020] Step 7: Based on δ d , δ b , δ c , δ d '、δ b '、δ c '、δ zt , δ z , δ t , using the cold tip clearance calculation formula, the theoretical minimum cold tip clearance S is calculated. m ;

[0021] The calculation formula for cold blade tip clearance is:

[0022] S m =S p -max(δ c ,δ c ')+K×{max(δ b ,δ b ')-max(δ d ,δ d ')}+δ zt +δ z +K×δ t

[0023] in,

[0024] S p The working clearance of the rotor blade tip is the reserved clearance value in the hot state. Different aircraft engine components have different values.

[0025] K is the influence coefficient of cold tip clearance calculation.

[0026] According to at least one embodiment of the present application, step 1 of the above-mentioned method for determining the cold tip clearance between an aircraft engine rotor blade and a casing is specifically as follows:

[0027] According to the use requirements and flight mission envelope of the aircraft engine installation object, the steady-state point and typical transition state process of the tip clearance design benchmark are determined, and the boundary conditions of the tip clearance design are clarified. Among them, the steady-state point is the steady-state limit operating point.

[0028] According to at least one embodiment of the present application, step six of the above-mentioned method for determining the cold tip clearance between an aircraft engine rotor blade and a casing is specifically as follows:

[0029] According to the calculation results of the dimension chain and geometric tolerance of the rotor system and stator casing, the deformation caused by the requirements of the rotor and stator processing drawings is obtained, and the rotor and stator runout influence δ is obtained. t .

[0030] According to at least one embodiment of the present application, the above-mentioned method for determining the cold tip clearance between an aircraft engine rotor blade and a casing further includes:

[0031] Step 8: Based on the theoretical minimum cold tip clearance S m , carry out engineering analysis and calculation of cold blade tip clearance, carry out two-way coupling calculation and analysis, and obtain the actual cold blade tip clearance.

[0032] According to at least one embodiment of the present application, the engineering analysis and calculation of the cold tip clearance in step eight of the above-mentioned method for determining the cold tip clearance between the aircraft engine rotor blade and the casing includes:

[0033] The theoretical minimum cold tip clearance S m Substitute back and perform strength deformation analysis at steady state point and transition state to obtain hot tip clearance at each steady state point and transition state;

[0034] Substitute the hot tip clearance at each steady-state point and transition state to perform component performance analysis and obtain the theoretical minimum cold tip clearance S m Impact on component performance;

[0035] The theoretical minimum cold tip clearance S m Substitute the impact of component performance, conduct overall performance analysis, and obtain the theoretical minimum cold tip clearance S m Secondary effects on overall performance;

[0036] In the theoretical minimum cold tip clearance S m Based on the secondary effects on components and overall performance, the theoretical minimum cold tip clearance S is obtained. m Impact on air system and temperature field.

[0037] According to at least one embodiment of the present application, the bidirectional coupling calculation and analysis work in step eight of the above-mentioned method for determining the cold tip clearance between the rotor blades and the casing of an aircraft engine refers to obtaining more accurate boundary conditions for calculating the rotor deformation and casing deformation through iterative calculation of component performance and overall performance under the condition of superimposing the actual cold tip clearance, thereby obtaining a more realistic deformation amount, fully considering the actual situation of gas-thermal-solid coupling, and performing iterations to obtain the actual cold tip clearance with higher accuracy.

[0038] According to at least one embodiment of the present application, while performing engineering analysis and calculation of the cold tip clearance in step eight of the above-mentioned method for determining the cold tip clearance between the rotor blades and the casing of an aircraft engine, an asynchronous vibration calculation and analysis of the rotor blades is performed, and a bidirectional coupling calculation and analysis process is introduced to obtain the actual cold tip clearance.

[0039] According to at least one embodiment of the present application, in step eight of the above-mentioned method for determining the cold tip clearance between an aircraft engine rotor blade and a casing, performing calculation and analysis of the asynchronous vibration of the rotor blade includes:

[0040] Conduct unsteady flow and aerodynamic damping analysis on the rotor blade tip;

[0041] Conduct vibration response analysis of blades and disks under asynchronous vibration conditions. The blades and disks can be integral blisks.

[0042] Perform vibration stress analysis and calculation on typical parts of rotor blades;

[0043] Determine whether the vibration stress at the local position of the rotor blade meets the fatigue design requirements;

[0044] If the vibration stress at a local position of the rotor blade does not meet the fatigue design requirements, determine whether the cold tip clearance exceeds the cold tip clearance engineering analysis range. If it does not exceed the cold tip clearance engineering analysis range, redefine the cold tip clearance and iterate the engineering analysis calculation of the cold tip clearance. If it exceeds the cold tip clearance engineering analysis range, re-optimize the design of the rotor blade profile and the flow path of related components to reduce the local vibration stress of the rotor blade to meet the fatigue design requirements, and then redefine the cold tip clearance.

[0045] If the vibration stress at the local position of the rotor blade meets the fatigue design requirements, the rotor blade vibration amplitude calculation and analysis is performed. The result of the rotor blade asynchronous vibration calculation and analysis is substituted into the two-way coupling calculation and analysis process to finally obtain the actual cold tip clearance value considering the asynchronous vibration problem.

[0046] According to at least one embodiment of the present application, in step eight of the above-mentioned method for determining the cold tip clearance between the rotor blades and the casing of an aircraft engine, the asynchronous vibration calculation and analysis of the rotor blades is performed only on the compression components, wherein the compression components include fans and compressors.

[0047] According to at least one embodiment of the present application, the above-mentioned method for determining the cold tip clearance between an aircraft engine rotor blade and a casing further includes step nine:

[0048] The actual cold tip clearance is safety checked. If the safety requirements are met, the actual cold tip clearance is confirmed. If the safety requirements are not met, return to step 1 to obtain the actual cold tip clearance again.

[0049] This application has at least the following beneficial technical effects:

[0050] The method for determining the cold tip clearance between an aircraft engine rotor blade and a casing disclosed in the above embodiment improves the original design calculation method, comprehensively considers the factors affecting the tip clearance, establishes a cold tip clearance calculation formula, achieves accurate calculation of the cold tip clearance, and incorporates the tip clearance requirements of the non-integral order vibration problem of the rotor blade into the design calculation. In the cold tip clearance design process, a branch for the asynchronous vibration influence of the compression component is added and carried out in parallel with the bidirectional coupling calculation. Through the asynchronous vibration response calculation, a reasonable cold tip clearance value is iteratively determined according to the local vibration stress constraint conditions of the blade. Compared with the aforementioned cold tip clearance calculation results, a comprehensive selection is made to ensure the long-term safe operation of the aircraft engine. Compared with the existing methods, the method has the following advantages:

[0051] 1. In addition to considering the influence of the deformation of the rotor disc rim, the deformation of the rotor blade tip and the deformation of the corresponding casing inner wall on the tip clearance, the influence of the overall flexural deformation of the aircraft engine rotor, the local changes caused by the machining runout of the rotor and stator, the rotor bearing clearance and the extreme operating conditions on the rotor tip clearance are also considered. A calculation formula for the cold tip clearance is established to make the calculated cold tip clearance value more scientific and comprehensive.

[0052] 2. On the basis of steady-state point evaluation, the relevant calculation of blade tip clearance for typical transition state is added. The two-way coupling calculation method is used to calculate the main influencing factors of blade tip clearance under transition state, and the relevant deformation amounts in the blade tip clearance calculation formula are obtained. Compared with the steady-state point calculation results, the maximum value is substituted into the blade tip clearance calculation formula to obtain the cold-state blade tip clearance considering the transition state changes, and fully consider its secondary effects on component performance, overall performance and air system. Through two-way coupling iterative calculation, a more accurate cold-state blade tip clearance value is obtained, which is equivalent to incorporating the influence of blade tip clearance within the full envelope range into the calculation process.

[0053] 3. In the calculation of the tip clearance of the compression system, an additional branch of the asynchronous vibration factor is added to consider the impact of the tip clearance value on the asynchronous vibration of the compression system blade tip. By calculating its vibration response, a reasonable tip clearance value is guaranteed to keep the blade vibration stress within an acceptable range, and a reasonable cold tip clearance is comprehensively selected.

[0054] 4. The influence coefficient K is introduced into the cold tip clearance calculation formula, making the formula applicable to various typical components such as fans, compressors, and high- and low-pressure turbines. This expands the applicability of the cold tip clearance calculation formula and improves the reliability of the cold tip clearance calculation results. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a schematic diagram of a typical one-way coupling calculation method for cold tip clearance of current aero-engines;

[0056] Figure 2 It is a schematic diagram of the tip clearance variation characteristics under a typical flight mission;

[0057] Figure 3 Schematic diagram of a method for determining cold tip clearance between an aircraft engine rotor blade and a casing provided in an embodiment of the present application;

[0058] Figure 4 Schematic diagram of a bidirectional coupling calculation method for cold-state tip clearance of an aircraft engine provided by an embodiment of the present application;

[0059] Figure 5 It is a schematic diagram of the parameters related to the cold tip clearance calculation formula provided in the embodiment of the present application.

[0060] In order to better illustrate this embodiment, some contents of the drawings may be omitted, enlarged or reduced, which is only used for illustrative purposes and should not be construed as limiting the present application. DETAILED DESCRIPTION

[0061] To make the technical solution and its advantages of this application more clear, the technical solution of this application will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described here are only some of the embodiments of this application and are only used to explain this application, not to limit this application. It should be noted that for ease of description, only the parts relevant to this application are shown in the accompanying drawings, and other relevant parts can refer to the general design.

[0062] In addition, unless otherwise defined, the technical or scientific terms used in the description of this application shall have the ordinary meanings understood by those skilled in the art to which this application belongs. The term "include" as used in the description of this application means that the concepts preceding the term include the concepts listed after the term and their equivalents, without excluding other related concepts.

[0063] A method for determining the cold tip clearance between an aircraft engine rotor blade and a casing, such as Figure 3 As shown in the figure, based on the existing calculation method of the tip clearance of aircraft engines, the main factors affecting the tip clearance are integrated, such as the flexural deformation of the rotor as a whole, the local variation caused by the runout of the rotor and stator processing, the rotor bearing clearance, etc., and at the same time as the steady-state point calculation, the transition state calculation is added, which can better consider the actual use scenario of the aircraft engine and meet the long-term use requirements. In addition, the concept of bidirectional coupling calculation is adopted to fully consider the secondary effects of the hot tip clearance on the performance of the components, the overall performance and the air system, and iterative fluid-solid thermal coupling calculation is performed to obtain a more accurate hot tip clearance calculation result, as shown in the figure. Figure 4 shown.

[0064] Step 1: Determine the steady-state point and typical transition state process of the blade tip clearance design benchmark, and clarify the boundary conditions of the blade tip clearance design.

[0065] According to the use requirements and flight mission envelope of the aircraft engine installation object, the steady-state point and typical transition state process of the tip clearance design benchmark are determined, and the boundary conditions of the tip clearance design are clarified. Among them, the steady-state point is the steady-state limit operating point.

[0066] Step 2: According to the boundary conditions of the steady-state point, establish the calculation and analysis model of the rotor and casing, carry out the deformation calculation and analysis of the steady-state rotor and casing, and calculate the deformation of the rotor wheel rim δ at the steady-state point. d , deformation of the rotor blade tip δ b , the deformation of the inner wall of the casing δ c .

[0067] Step 3: According to the typical transition state process, based on the calculation and analysis model of the rotor and casing, carry out the deformation calculation and analysis of the transition state rotor and casing, and calculate the maximum value of the wheel rim deformation δ under the typical transition state. d ', the extreme value of the deformation of the rotor blade tip δ b ', the maximum deformation value δ of the inner wall of the casing c '.

[0068] Step 4: Based on the boundary conditions of the blade tip clearance design, the calculation and analysis of the deflection deformation of the entire rotor of the aircraft engine in the steady state and transition state are carried out to obtain the influence of the deflection deformation of the entire rotor on the deformation of the rotor blade tip δ zt .

[0069] Step 5: Determine the extreme value of the rotor pivot bearing clearance δ z .

[0070] Since the radial deformation of the rotor pivot is already included in the flexural deformation of the entire rotor, the subsequent calculation of the cold tip clearance only needs to consider the bearing clearance, and there is no need to repeatedly substitute the hot radial deformation of the bearing. The extreme value δ of the rotor pivot bearing clearance can be obtained by consulting relevant materials. z .

[0071] Step 6: Determine the rotor and stator runout influence δ t .

[0072] According to the calculation results of the dimension chain and geometric tolerance of the rotor system and stator casing, the deformation caused by the requirements of the rotor and stator processing drawings is obtained, that is, the rotor and stator runout influence δ t , including the change in tip clearance caused by the back-and-forth movement of the rotor blades due to the axial exclusion of bearing movement, which is substituted into the subsequent calculation of the cold tip clearance.

[0073] Step 7: Based on δ d , δ b , δ c , δ d '、δ b '、δ c '、δ zt , δ z , δ t , using the cold tip clearance calculation formula, the theoretical minimum cold tip clearance S is calculated. m .

[0074] The calculation formula for cold blade tip clearance is:

[0075] S m =S p -max(δ c ,δ c ')+K×{max(δ b ,δ b ')-max(δ d ,δ d ')}+δ zt +δ z +K×δ t

[0076] in,

[0077] S p The working clearance of the rotor blade tip is the reserved clearance value in the hot state. Different aircraft engine components have different values.

[0078] K is the influence coefficient for cold tip clearance calculation, which can be an empirical value, such as 1.1 to 1.2.

[0079] Theoretical minimum cold tip clearance S mGenerally, the initial value can be taken as 0.2mm according to experience, which implies the maximum acceptable cutting amount of the abradable coating of the receiver.

[0080] The above cold tip clearance calculation formula includes the main factors affecting the tip clearance, and through transition state calculation, the transition state value of each parameter is obtained. Compared with the steady-state point calculation result, the maximum value is substituted into the formula for calculation, which can effectively avoid the rotor blade tip wear during actual use due to insufficient understanding of the full-speed change characteristics of the tip clearance in the cold tip clearance selection process.

[0081] Taking into account the differences in configuration, aerodynamic performance, structural design, etc. between compression components and turbine components in aircraft engines, and considering that the first term in the cold tip clearance calculation formula is either obtained by strength simulation calculation or the actual bearing clearance extreme value, both are definite values, the influence coefficient K is introduced into the rotor and stator runout influence quantity. Different values ​​can be selected based on actual experience according to different components or different levels of multi-stage components, so as to meet the calculation requirements of cold tip clearance for different components, so that the cold tip clearance calculation formula has universality.

[0082] Step 8: Based on the theoretical minimum cold tip clearance S m , carry out engineering analysis and calculation of cold blade tip clearance, carry out two-way coupling calculation and analysis, and obtain the actual cold blade tip clearance.

[0083] The engineering analysis and calculation of cold tip clearance includes:

[0084] The theoretical minimum cold tip clearance S m Substitute back and perform strength deformation analysis at steady state point and transition state to obtain hot tip clearance at each steady state point and transition state;

[0085] Substitute the hot tip clearance at each steady-state point and transition state to perform component performance analysis and obtain the theoretical minimum cold tip clearance S m Impact on component performance;

[0086] The theoretical minimum cold tip clearance S m Substitute the impact of component performance, conduct overall performance analysis, and obtain the theoretical minimum cold tip clearance S m Secondary effects on overall performance;

[0087] In the theoretical minimum cold tip clearance S m Based on the secondary effects on components and overall performance, the theoretical minimum cold tip clearance S is obtained. m Impact on air system and temperature field.

[0088] Bidirectional coupling calculation and analysis refers to the iterative calculation of component performance and overall performance under the condition of superimposing the actual cold tip clearance, so as to obtain more accurate boundary conditions for the calculation of rotor deformation and casing deformation, thereby obtaining a more realistic deformation amount, fully considering the actual situation of gas-thermal-solid coupling, and iterating with the above steps to obtain a higher accuracy of the actual cold tip clearance.

[0089] Taking into account the increasingly frequent problem of asynchronous vibration failure of compression component blade tips in recent years, while conducting engineering analysis and calculation of cold tip clearance, asynchronous vibration calculation and analysis of rotor blades are also carried out, and the two-way coupling calculation and analysis process is brought into play to obtain the actual cold tip clearance.

[0090] For compression components, such as fans and compressors, asynchronous vibration calculation and analysis of rotor blades is performed. This work is not required for high- and low-pressure turbines, including:

[0091] Conduct unsteady flow and aerodynamic damping analysis on the rotor blade tip;

[0092] Conduct vibration response analysis of blades and disks under asynchronous vibration conditions. The blades and disks can be integral blisks.

[0093] Perform vibration stress analysis and calculation on typical parts of rotor blades;

[0094] Determine whether the vibration stress at the local position of the rotor blade meets the fatigue design requirements;

[0095] If the vibration stress at the local position of the rotor blade does not meet the fatigue design requirements, it is determined whether the cold tip clearance exceeds the cold tip clearance engineering analysis range. If it does not exceed the cold tip clearance engineering analysis range, the cold tip clearance is re-determined and the engineering analysis calculation of the cold tip clearance is iteratively performed; if it exceeds the cold tip clearance engineering analysis range, it indicates that the cold tip clearance has no room for further adjustment, and it is necessary to re-optimize the design of the rotor blade profile and the flow path and other aerodynamic related parameters of its related components to reduce the local vibration stress of the rotor blade and meet the fatigue design requirements, and then re-determine the cold tip clearance;

[0096] If the vibration stress at the local position of the rotor blade meets the fatigue design requirements, the rotor blade vibration amplitude calculation and analysis is performed. The result of the rotor blade asynchronous vibration calculation and analysis is substituted into the two-way coupling calculation and analysis process to finally obtain the actual cold tip clearance value considering the asynchronous vibration problem.

[0097] Step 9: Perform safety check on the actual cold tip clearance. If the safety requirements are met, confirm the actual cold tip clearance. If the safety requirements are not met, return to step 1 to obtain the actual cold tip clearance again.

[0098] The method for determining the cold tip clearance between an aircraft engine rotor blade and a casing disclosed in the above embodiment has the following advantages:

[0099] 1. On the basis of the existing tip clearance design technology, the factors affecting the rotor tip clearance, such as the overall flexural deformation of the whole rotor, the local change caused by the machining runout of the rotor and stator, and the extreme value of the rotor bearing clearance, are taken into consideration to form a cold tip clearance calculation formula with higher calculation accuracy, which can make the calculated cold tip clearance value more scientific and comprehensive.

[0100] 2. Based on the existing tip clearance design technology, the transitional tip clearance assessment steps and result data are added to better meet the actual use scenarios of aircraft engines and the long-term use requirements of aircraft engines. At the same time, the bidirectional coupling calculation concept is adopted to fully consider the secondary effects of hot tip clearance on component performance, overall performance and air system, and iterative fluid-solid thermal coupling calculation can obtain hot tip clearance calculation results with higher accuracy.

[0101] 3. In response to the frequent asynchronous vibration failures of blade tips in compression components, the asynchronous vibration response and blade vibration stress analysis calculations are added to ensure that no items are missed in the blade tip clearance design, eliminate the asynchronous vibration problem from the design source, and ensure the stable and reliable operation of the aircraft engine.

[0102] 4. The influence coefficient K is introduced into the cold tip clearance calculation formula, making the formula applicable to various typical components such as fans, compressors, and high- and low-pressure turbines. This expands the applicability of the cold tip clearance calculation formula and improves the reliability of the cold tip clearance calculation results.

[0103] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or replacements to the relevant technical features, and the technical solutions after these changes or replacements will fall within the scope of protection of the present application.

Claims

1. A method for determining the cold tip clearance between an aircraft engine rotor blade and a casing, characterized in that: include: Step 1: Determine the steady-state point and typical transition state process of the blade tip clearance design benchmark, and clarify the boundary conditions of the blade tip clearance design; Step 2: According to the boundary conditions of the steady-state point, establish the calculation and analysis model of the rotor and casing, carry out the deformation calculation and analysis of the steady-state rotor and casing, and calculate the deformation of the rotor wheel rim δ at the steady-state point. d , deformation of the rotor blade tip δ b , the deformation of the inner wall of the casing δ c ; Step 3: According to the typical transition state process, based on the calculation and analysis model of the rotor and casing, carry out the deformation calculation and analysis of the transition state rotor and casing, and calculate the maximum value of the wheel rim deformation δ under the typical transition state. d ', the extreme value of the deformation of the rotor blade tip δ b ', the maximum deformation value δ of the inner wall of the casing c '; Step 4: Based on the boundary conditions of the blade tip clearance design, the calculation and analysis of the deflection deformation of the entire rotor of the aircraft engine in the steady state and transition state are carried out to obtain the influence of the deflection deformation of the entire rotor on the deformation of the rotor blade tip δ zt ; Step 5: Determine the extreme value of the rotor pivot bearing clearance δ z ; Step 6: Determine the rotor and stator runout influence δ t ; Step 7: Based on δ d , δ b , δ c , δ d '、δ b '、δ c '、δ zt , δ z , δ t , using the cold tip clearance calculation formula, the theoretical minimum cold tip clearance S is calculated. m ; The calculation formula for cold blade tip clearance is: S m =S p -max(δ c ,d c ')+K×{max(δ b ,d b ')-max(δ d ,d d ')}+d zt +d z +K×δ t in, S p The working clearance of the rotor blade tip is the reserved clearance value in the hot state. Different aircraft engine components have different values. K is the influence coefficient of cold tip clearance calculation.

2. The method for determining the cold tip clearance between an aircraft engine rotor blade and a casing according to claim 1, characterized in that: Step 1 is as follows: According to the use requirements and flight mission envelope of the aircraft engine installation object, the steady-state point and typical transition state history of the tip clearance design benchmark are determined, and the boundary conditions of the tip clearance design are clarified, wherein the steady-state point is the steady-state limit operating point.

3. The method for determining the cold tip clearance between an aircraft engine rotor blade and a casing according to claim 2, characterized in that: Step six is ​​as follows: According to the calculation results of the dimension chain and geometric tolerance of the rotor system and stator casing, the deformation caused by the requirements of the rotor and stator processing drawings is obtained, and the rotor and stator runout influence δ is obtained. t .

4. The method for determining the cold tip clearance between an aircraft engine rotor blade and a casing according to claim 3, characterized in that: Also includes: Step 8: Based on the theoretical minimum cold tip clearance S m , carry out engineering analysis and calculation of cold blade tip clearance, carry out two-way coupling calculation and analysis, and obtain the actual cold blade tip clearance.

5. The method for determining the cold tip clearance between an aircraft engine rotor blade and a casing according to claim 4, characterized in that: The engineering analysis and calculation of cold tip clearance in step eight includes: The theoretical minimum cold tip clearance S m Substitute back and perform strength deformation analysis at steady state point and transition state to obtain hot tip clearance at each steady state point and transition state; Substitute the hot tip clearance at each steady-state point and transition state to perform component performance analysis and obtain the theoretical minimum cold tip clearance S m Impact on component performance; The theoretical minimum cold tip clearance S m Substitute the impact of component performance, conduct overall performance analysis, and obtain the theoretical minimum cold tip clearance S m Secondary effects on overall performance; In the theoretical minimum cold tip clearance S m Based on the secondary effects on components and overall performance, the theoretical minimum cold tip clearance S is obtained. m Impact on air system and temperature field.

6. The method for determining the cold tip clearance between an aircraft engine rotor blade and a casing according to claim 5, characterized in that: The bidirectional coupling calculation and analysis work in step eight refers to obtaining more accurate boundary conditions for rotor deformation and casing deformation calculation through iterative calculation of component performance and overall performance under the condition of superimposing actual cold tip clearance, thereby obtaining more realistic deformation. By fully considering the actual situation of gas-thermal-solid coupling and performing iterations, a higher accuracy of actual cold tip clearance can be obtained.

7. The method for determining the cold tip clearance between an aircraft engine rotor blade and a casing according to claim 6, characterized in that: In step eight, while performing engineering analysis and calculation of the cold tip clearance, the asynchronous vibration calculation and analysis of the rotor blades are performed, and the two-way coupling calculation and analysis process is brought in to obtain the actual cold tip clearance.

8. The method for determining the cold tip clearance between an aircraft engine rotor blade and a casing according to claim 7, characterized in that: In step eight, the asynchronous vibration calculation and analysis of the rotor blades is performed, including: Conduct unsteady flow and aerodynamic damping analysis on the rotor blade tip; Conduct vibration response analysis of blades and disks under asynchronous vibration conditions. The blades and disks can be integral blisks. Perform vibration stress analysis and calculation on typical parts of rotor blades; Determine whether the vibration stress at the local position of the rotor blade meets the fatigue design requirements; If the vibration stress at a local position of the rotor blade does not meet the fatigue design requirements, determine whether the cold tip clearance exceeds the cold tip clearance engineering analysis range. If it does not exceed the cold tip clearance engineering analysis range, redefine the cold tip clearance and iterate the engineering analysis calculation of the cold tip clearance. If it exceeds the cold tip clearance engineering analysis range, re-optimize the design of the rotor blade profile and the flow path of related components to reduce the local vibration stress of the rotor blade to meet the fatigue design requirements, and then redefine the cold tip clearance. If the vibration stress at the local position of the rotor blade meets the fatigue design requirements, the rotor blade vibration amplitude calculation and analysis is performed. The result of the rotor blade asynchronous vibration calculation and analysis is substituted into the two-way coupling calculation and analysis process to finally obtain the actual cold tip clearance value considering the asynchronous vibration problem.

9. The method for determining the cold tip clearance between an aircraft engine rotor blade and a casing according to claim 8, characterized in that: In step eight, the asynchronous vibration calculation and analysis of the rotor blades is performed only for the compression components, wherein the compression components include the fan and the compressor.

10. The method for determining the cold tip clearance between an aircraft engine rotor blade and a casing according to claim 9, characterized in that: Also includes step nine: The actual cold tip clearance is safety checked. If the safety requirements are met, the actual cold tip clearance is confirmed. If the safety requirements are not met, return to step 1 to obtain the actual cold tip clearance again.

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