A method for passive matching of turbine tip clearance based on engine demand

Abstract

The application discloses a turbine tip clearance passive matching method based on engine demand, belongs to the technical field of aero-engines, and comprises the following steps: determining a minimum allowable working clearance; determining a typical tip clearance analysis load spectrum; performing thermal analysis and deformation analysis on a rotor and a stator; performing tip clearance change rule analysis according to the deformation results of the rotor and the stator to obtain a tip clearance change rule; optimizing tip clearance matching according to different engine demands, the casing material, the structure and the cooling form; determining an initial cold-state clearance according to a narrow-point clearance and the minimum allowable working clearance; and performing iterative calculation to determine a final tip clearance matching scheme. The turbine rotor deformation and the turbine stator deformation are matched in the application, so that the turbine tip clearance can be as small as possible under the operating states that are paid attention to, that is, the turbine tip clearance is as small as possible under the premise of ensuring the safety of the engine, the turbine efficiency is improved, and the specific fuel consumption is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engines, in particular, to a passive turbine tip clearance matching method based on engine demand. BACKGROUND

[0002] The turbine tip clearance generally refers to the radial distance between the top end face of the engine turbine rotor blade and the outer ring of the turbine stator. Because of the pressure difference between the suction surface and the pressure surface of the rotor blade, the gas at the tip clearance position leaks, thereby significantly reducing the turbine and overall efficiency. Due to the change of engine working conditions, the turbine components will inevitably produce large temperature and stress changes, and the structure, material, thermal load and mechanical load of the turbine stator and the turbine rotor are different, so the turbine rotor and the casing radial deformation mismatch phenomenon will inevitably occur during engine operation, thereby causing the change of the tip clearance, and the change of the tip clearance has an important influence on the performance and reliability of the engine. Excessive tip clearance will lead to a decrease in engine performance, an increase in fuel consumption and a decrease in surge margin; and too small tip clearance may cause blade and casing scraping in severe working conditions with large load changes.

[0003] At present, a suitable cold-state tip clearance is usually adopted according to design experience and test running, which will cause two problems, one is that the turbine tip clearance is designed to be too large, which leads to a decrease in turbine efficiency and substandard engine performance; and the other is that the turbine tip clearance is designed to be too small, which will cause the rotor blade and the stator outer ring to scrape when the engine is in part of the working condition change, which may affect the safe and reliable operation of the engine.

[0004] At present, in small and medium-sized aero-engines, due to the reasons of weight and structure, a simple passive gap control is usually adopted. The passive gap control refers to ensuring the required gap in a certain main state (such as take-off state, maneuvering flight state, etc.) through design cooling and structure, and the gap in other states in the whole flight cycle is matched by the deformation of the rotor and the stator. The passive gap control is indirect, and the engine tip clearance cannot be kept at the best level in the whole flight cycle. Common passive gap control usually adopts the following methods: reducing the assembly gap and improving the sealing; designing a reasonable casing structure to reduce deformation; using wear-resistant coating on the blade top end to reduce tip wear, and using easy-to-wear coating on the outer ring of the casing to facilitate the slight cutting of the blade into the outer ring in the working condition of the engine; using appropriate materials and cooling to improve the thermal deformation matching of the casing and the rotor. The passive gap control technology has been widely applied in turboshaft, turboprop and small-bypass-ratio engines, and the description is attached Figure 1 A passive control of the gas turbine tip clearance is used for a certain turboshaft engine, an impact orifice plate is installed on the gas turbine casing, the temperature distribution of the casing is adjusted by designing the impact hole diameter, spacing and impact distance, so that the casing and the rotor are deformed to match.

[0005] The existing small and medium-sized aeroengines do not have a standard turbine tip clearance matching method, and the common practice is to reduce the assembly clearance, and an easy-to-abrade coating is used on the gas side of the stator outer ring, mainly based on the strength and service life of the parts to perform cooling design and material selection, and when the engine performance margin is large, no detailed tip clearance matching design is performed, thus causing a certain performance waste. SUMMARY

[0006] In view of at least one of the above technical problems, the present application provides a turbine tip clearance passive matching method based on engine requirements, which can match the turbine rotor deformation and turbine stator deformation to ensure that the turbine tip clearance is as small as possible under the key concerned operating state, that is, to reduce the turbine tip clearance as much as possible under the premise of ensuring engine safety, to improve turbine efficiency and to reduce fuel consumption.

[0007] According to one aspect of the present application, a turbine tip clearance passive matching method based on engine requirements is provided, comprising the following steps:

[0008] S100: determining the minimum allowable working clearance according to the engine design requirements;

[0009] S200: determining the typical tip clearance analysis load spectrum according to the use scenarios of the engine;

[0010] S300: performing thermal analysis and deformation analysis of the rotor and the stator through three-dimensional simulation to obtain the turbine rotor radial deformation response curve and the stator radial deformation response curve under the typical working load spectrum of the engine;

[0011] S400: analyzing the tip clearance variation law according to the deformation results of the rotor and the stator to obtain the tip clearance variation law;

[0012] S500: optimizing the tip clearance matching for the casing material, structure and cooling form according to different engine requirements;

[0013] S600: adding the minimum allowable working clearance to the turbine rotor radial deformation response curve to obtain the anti-scraping casing deformation curve, and obtaining the actual casing deformation curve through calculation, the intersection of the actual casing deformation curve and the anti-scraping casing deformation curve being the narrow point clearance, and the initial cold state clearance being determined according to the narrow point clearance and the minimum allowable working clearance;

[0014] S700: iteratively calculating steps S500 and S600 until the tip clearance meets the engine design requirements to determine the final tip clearance matching scheme.

[0015] In some embodiments of the present application, step S100 specifically comprises: determining the corresponding minimum allowable blade tip clearance based on each steady-state operating working condition of the engine, so that the turbine blade tip operating clearance is not less than the minimum allowable blade tip clearance.

[0016] In some embodiments of the present application, when determining the minimum allowable working clearance, the influence of at least one of the following factors on the deformation of the rotor and stator is considered: deflection caused by gravity and gyroscopic moment of maneuvering flight; ovality caused by mounting load; machining error and eccentricity; bearing radial clearance; rotor unbalance in normal state; deformation caused by engine surge; asymmetric thermal and pressure distortion; rotor whirl during hot engine restart; blade twist and rotor creep elongation.

[0017] In some embodiments of the present application, in step S200, the typical blade tip clearance analysis load spectrum includes the process of taxiing, taking off, climbing, cruising, descending and accelerating again.

[0018] In some embodiments of the present application, step S300 specifically comprises: performing rotor thermal analysis and deformation analysis by a three-dimensional finite element method to obtain the temperature field change of the rotor, and performing structural deformation analysis of the rotor under the condition of engine speed change to obtain the radial deformation result at the rotor blade tip; performing stator thermal analysis and deformation analysis by a three-dimensional finite element method to obtain the temperature field change of the stator, and performing structural deformation analysis of the stator under the condition of stator pressure load to obtain the radial deformation result at the outer ring of the stator.

[0019] In some embodiments of the present application, in step S400, the blade tip clearance is calculated according to the radial deformation result at the rotor blade tip and the radial deformation result at the outer ring of the stator by the following formula delta hot :

[0020] ;

[0021] In the formula, is the initial cold-state clearance, is the radial deformation at the outer ring of the stator, is the radial deformation at the rotor blade tip.

[0022] In some embodiments of the present application, in step S500, the part of the actual blade tip clearance that is greater than the minimum allowable working clearance is set as the excess clearance, and the blade tip clearance is matched and optimized according to the purpose and requirement of the engine. For an engine pursuing fuel consumption, the blade tip clearance in the cruising stage is preferentially matched, while the excess clearance in the whole flight cycle is also considered. For an engine pursuing maximum power, the blade tip clearance in the maximum power state is preferentially matched.

[0023] In some embodiments of the present application, in step S500, after the tip clearance matching optimization is completed, the integrated excess clearance is used to measure the clearance matching condition, the integrated excess clearance is the integral of the excess clearance over time, and the integrated excess clearance optimization effect is calculated by weighting and summing the integrated excess clearances of each stage of the engine, to obtain the integrated excess clearance optimization effect η:

[0024] ;

[0025] ;

[0026] In the formula, is the integrated excess clearance before optimization of each stage, is the integrated excess clearance after optimization of each stage, is the weighting coefficient of the integrated excess clearance of each stage, and the subscript i represents different working conditions of the engine.

[0027] In some embodiments of the present application, in step S500, after the weighting coefficients of the integrated excess clearances of each stage are determined, the clearance matching of the rotor-stator is performed by changing the casing material, structure and cooling form. The casing structure is determined at the initial design stage, and then the appropriate casing material and cooling temperature and cooling form are selected to change the response curve of the casing deformation, so as to achieve the corresponding tip clearance matching purpose. The integrated excess clearances of different schemes are compared to select the optimal optimization parameters, and finally the integrated excess clearance optimization effect is determined.

[0028] In some embodiments of the present application, in step S600, the narrow point clearance needs to be greater than the minimum allowable working clearance under any state of the engine.

[0029] The present application has the following beneficial effects:

[0030] The application is based on a passive matching method of turbine tip clearance according to engine requirements. Firstly, the minimum allowable working clearance is determined according to the design requirements. Then, the typical clearance analysis load spectrum is determined according to the use scenarios of the engine. The rotor and stator are analyzed by three-dimensional numerical simulation to obtain the variation law of the turbine tip clearance. Then, the deformation of the rotor and stator is matched and optimized according to the material, structure and cooling form of the casing. The initial cold-state clearance is determined according to the matching of the minimum allowable working clearance and the clearance at the narrow point. Whether the tip clearance meets the design requirements is judged. If yes, the tip clearance matching scheme is output. The method provides a train of thought for the control of turbine tip clearance of high-performance aero-engine. The rotor and stator material, casing structure and casing cooling are taken as the optimization direction of passive matching of tip clearance. An evaluation index for clearance matching optimization considering different uses and requirements of the engine is proposed. The tip clearance matching optimization is carried out according to different requirements. The application can analyze the turbine tip clearance and carry out clearance matching optimization according to different requirements of the engine. The turbine material and cooling are taken as the adjusting means. The optimized turbine tip clearance is evaluated in combination with the comprehensive excess clearance and other indexes. The control of the turbine tip clearance is realized. The purpose of improving the turbine efficiency, reducing the fuel consumption rate and improving the performance of the engine is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application. The application and its preferred embodiments are described and illustrated in conjunction with these drawings, wherein:

[0032] Figure 1 is a schematic diagram of a passive control structure of a turbine tip clearance of a certain turbo-shaft engine in the prior art;

[0033] Figure 2 is a flowchart of the preferred embodiment of the application;

[0034] Figure 3 is a schematic diagram of the variation law of the tip clearance of the preferred embodiment of the application;

[0035] Figure 4 is a schematic diagram of the radial expansion curve of the rotor and stator of the preferred embodiment of the application;

[0036] Figure 5 is a comparison diagram of the variation curves of the ideally matched and unmatched tip clearances of the preferred embodiment of the application. DETAILED DESCRIPTION

[0037] Please refer to the drawings in the specification Figure 2 A passive matching method of turbine tip clearance based on engine requirements, characterized in that it comprises the following steps:

[0038] S100: Determine the minimum allowable working clearance according to the engine design requirements;

[0039] S200: Determine the typical blade tip clearance analysis load spectrum according to the use scenario of the engine;

[0040] S300: Perform thermal analysis and deformation analysis of the rotor and stator through three-dimensional simulation to obtain the turbine rotor radial deformation response curve and the stator radial deformation response curve under the typical working load spectrum of the engine;

[0041] S400: According to the deformation results of the rotor and stator, analyze the blade tip clearance variation law to obtain the blade tip clearance variation law;

[0042] S500: According to different engine requirements, optimize the blade tip clearance matching for the casing material, structure and cooling form;

[0043] S600: Add the minimum allowable working clearance to the turbine rotor radial deformation response curve to obtain the anti-scraping casing deformation curve, and obtain the actual casing deformation curve through calculation. The intersection of the actual casing deformation curve and the anti-scraping casing deformation curve is the narrow point clearance. The initial cold state clearance is determined according to the narrow point clearance and the minimum allowable working clearance;

[0044] S700: Iteratively calculate steps S500 and S600 until the blade tip clearance meets the engine design requirements to determine the final blade tip clearance matching scheme.

[0045] In some embodiments, step S700 is followed by S800: outputting the blade tip clearance matching scheme. The blade tip clearance matching optimization scheme that meets the engine design requirements in step S700 is outputted, including the casing optimization scheme, the adjustment scheme of the initial cold state clearance, etc.

[0046] The application determines the minimum allowable working clearance according to the design requirements, determines the typical clearance analysis load spectrum according to the use scenarios of the engine, performs thermal analysis and deformation analysis on the rotor and stator through three-dimensional numerical simulation, thereby obtaining the variation law of the turbine tip clearance, and then optimizes the deformation of the rotor and stator by matching the material, structure and cooling form of the casing, determines the initial cold-state clearance according to the matching of the minimum allowable working clearance and the clearance at the narrow point, judges whether the tip clearance meets the design requirements, and outputs the tip clearance matching scheme if it meets the design requirements. The method provides a train of thought for the tip clearance control of high-performance aero-engine, takes the rotor and stator material, casing structure and casing cooling as the optimization direction of passive matching of the tip clearance, and proposes an evaluation index for the clearance matching optimization of engines considering different uses and requirements, and performs tip clearance matching optimization according to different requirements. The application can complete the analysis of the turbine tip clearance and the clearance matching optimization for different requirements of the engine, take the turbine material and cooling as the adjusting means, evaluate the optimized turbine tip clearance in combination with the comprehensive excess clearance and other indexes, realize the control of the turbine tip clearance at a more optimal level, and achieve the purposes of improving the turbine efficiency, reducing the fuel consumption rate of the engine and improving the performance.

[0047] Preferably, the step S100 specifically comprises: determining the corresponding minimum allowable tip clearance based on each steady-state running working state of the engine, so that the turbine tip running clearance is not less than the minimum allowable tip clearance.

[0048] Here, the meaning of the minimum allowable working clearance is that for each steady-state running working state of the engine, the corresponding minimum allowable tip clearance is proposed, that is, the turbine tip running clearance cannot be less than the minimum allowable working clearance, otherwise it may have a harmful effect on the engine. Considering many factors in the running process of the engine, the minimum allowable working clearance is determined, which can avoid the collision and grinding between the turbine rotor tip and the turbine stator outer ring.

[0049] Preferably, when determining the minimum allowable working clearance, the influence of at least one of the following factors on the deformation of the rotor and stator is considered: deflection caused by gravity and gyroscopic moment of maneuvering flight; ovality caused by installation load; machining error and eccentricity; bearing radial clearance; rotor unbalance in normal state; deformation caused by engine surge; asymmetric heat and pressure distortion; rotor whirl when the hot engine restarts; blade twist and rotor creep elongation.

[0050] It should be noted that the deflection caused by gravity and gyroscopic moment of maneuvering flight should be considered, the rotor is subjected to a couple at the support site due to the gravity load and the gyroscopic moment during maneuvering flight, thereby generating bending deflection; the ovality caused by mounting load should be considered, the load transmitted by the engine mounting joint is distributed on the casing, and the ovality of the casing is caused due to the uneven load in the circumferential direction; the machining error and eccentricity, i.e. the eccentricity of the casing and the rotor generated during manufacturing, should be considered; the bearing radial clearance should be considered, the existence of the bearing radial clearance affects the position of the rotor, thereby causing the clearance between the rotor and the casing to change; the normal rotor unbalance should be considered, the rotor unbalance inevitably exists in the engine rotor under normal conditions, thereby causing the tip clearance to exist unevenly in the circumferential direction; the deformation caused by engine surge should be considered; the asymmetric thermal and pressure distortion should be considered, the asymmetric thermal and pressure distortion causes the asymmetric thermal and pressure deformation of the shaft, thereby causing the clearance to be uneven in the circumferential direction; the rotor whirl caused by the hot engine restarting should be considered, the rotor whirl is caused by the rotor thermal bending due to the phenomenon of "hot up and cold down" during the hot starting of the rotor; the blade twist and the rotor creep elongation should be considered.

[0051] Preferably, in step S200, the typical tip clearance analysis load spectrum includes the processes of taxiing, taking off, climbing, cruising, descending and accelerating again.

[0052] It should be noted that when determining the typical tip clearance analysis load spectrum, the typical working conditions should be selected according to the working characteristics of the engine, such as the processes of taxiing, taking off, climbing, cruising, descending and accelerating again should be included in the load spectrum. The duration of taxiing and taking off is specified according to the actual working scene of the engine, the working state duration of the long stage such as climbing and cruising can meet the requirement of stable rotor temperature, and the process of descending and accelerating again can be appropriately shortened to simulate the phenomenon that the tip clearance rapidly decreases during the process of accelerating again after decelerating of the engine.

[0053] Preferably, step S300 specifically comprises: performing rotor thermal analysis and deformation analysis by a three-dimensional finite element method to obtain the temperature field change of the rotor, and performing structural deformation analysis of the rotor in combination with the condition of the engine speed change to obtain the radial deformation result of the rotor tip; performing stator thermal analysis and deformation analysis by a three-dimensional finite element method to obtain the temperature field change of the stator, and performing structural deformation analysis of the stator in combination with the condition of the stator pressure load to obtain the radial deformation result of the outer ring of the stator.

[0054] It can be understood that, by means of the rotor thermal analysis and deformation analysis by the three-dimensional finite element method, the temperature field change of the rotor is obtained through three-dimensional numerical simulation calculation, and then the temperature field result is taken as the input of the deformation analysis, combined with the engine speed change and other conditions, the structural deformation analysis of the rotor is carried out, and the radial deformation result of the rotor blade tip is obtained; the stator thermal analysis and deformation analysis are carried out by the three-dimensional finite element method, the temperature field change of the stator is obtained through three-dimensional numerical simulation calculation, and then the temperature field result is taken as the input of the deformation analysis, combined with the stator pressure load and other conditions, the structural deformation analysis of the stator is carried out, and the radial deformation result of the outer ring (gas face) of the stator is obtained.

[0055] Preferably, in step S400, the blade tip clearance is calculated according to the radial deformation result of the rotor blade tip and the radial deformation result of the outer ring of the stator by the following formula delta hot :

[0056] ;

[0057] In the formula, is the initial cold-state clearance, is the radial deformation of the outer ring of the stator, is the radial deformation of the rotor blade tip, and the blade tip clearance change rule can be obtained by assuming that the initial cold-state clearance is 0, please refer to the attached drawings of the specification Figure 3 . After the radial deformation results of the rotor and the stator are obtained by analyzing the blade tip clearance change rule, the turbine blade tip clearance can be calculated by the above-mentioned blade tip clearance delta hot calculation formula.

[0058] Preferably, in step S500, the part of the actual blade tip clearance that is greater than the minimum allowable working clearance is set as the excess clearance, the excess clearance is the difference between the actual blade tip clearance and the minimum allowable working clearance corresponding to the state, and the blade tip clearance is matched and optimized according to the purpose and demand of the engine; for the engine pursuing fuel consumption, the blade tip clearance of the cruising stage is matched preferentially, and the excess clearance of the entire flight cycle is also considered; for the engine pursuing maximum power, the blade tip clearance of the maximum power state is matched preferentially.

[0059] It can be understood that, by means of step S300, the turbine rotor-stator radial deformation (expansion) response curve under the typical working load spectrum of the engine can be obtained, as shown in the attached Figure 4As shown, to ensure that the tip clearance is greater than the minimum allowable clearance throughout the entire flight mission, the minimum allowable working clearance needs to be added to the rotor deformation curve to obtain the anti-scrape casing deformation curve (i.e., the casing deformation curve required to prevent scraping), which is the optimal matching casing deformation (expansion) response curve of the rotor-stator in the ideal state. It should be noted that the outer ring is hung on the casing, and the casing deformation curve is actually the deformation curve of the outer ring.

[0060] Further, the rotor deformation curve and the actual casing deformation curve are superimposed, and the tip clearance is the difference between the radial deformations (expansions) of the two curves. By adjusting the cold-state clearance to change the position of the actual casing deformation curve, the actual casing deformation curve is made higher than the anti-scrape casing deformation curve, and the difference between the radial deformations (expansions) of the two curves is kept to a minimum. At this time, the intersection of the two curves is called the minimum clearance point, i.e., the narrow point clearance.

[0061] Please refer to Figure 5 The part greater than the minimum allowable working clearance is called excess clearance, which is defined as the difference between the tip clearance and the minimum allowable clearance corresponding to the state. The goal of tip clearance matching is to eliminate all excess clearances in all states, and the excess clearance is caused by the mismatch between the casing expansion and the rotor expansion response. To eliminate all excess clearances in all states, the ideal situation is to make the tip clearance equal to the minimum allowable clearance, and the expansion responses of the casing and the rotor are consistent, so that the tip clearance variation (the difference between the maximum clearance and the minimum clearance) is 0.

[0062] It should be noted that the actual minimum allowable clearance is not the same in all states. Generally, the minimum allowable clearance required in the take-off state is relatively large, so Figure 5 the minimum allowable clearance in the above formula can be considered as the larger value of the required clearance in all states. In the actual clearance matching process, it is also impossible to make the rotor-stator synchronous deformation, i.e., the tip clearance variation is not 0. Therefore, in the actual clearance matching optimization, the excess clearance needs to be eliminated according to the purpose and demand of the engine. For engines pursuing fuel consumption, the tip clearance in the cruising stage is matched first, and the excess clearance in the entire flight cycle is also considered. For engines pursuing maximum power, the tip clearance in the maximum power state is matched first.

[0063] Preferably, after the tip clearance matching optimization is completed in step S500, the comprehensive excess clearance is used to measure the clearance matching condition, the comprehensive excess clearance is the integral of the excess clearance over time, and the comprehensive excess clearance is calculated by weighting and summing the comprehensive excess clearances of each stage of the engine to obtain the comprehensive excess clearance optimization effect η:

[0064] ;

[0065] ;

[0066] wherein, is the total excess clearance before optimization of each stage, is the total excess clearance after optimization of each stage, is the weighting coefficient of the total excess clearance of each stage, and subscript i represents different working conditions of the engine.

[0067] It can be understood that for a civil engine pursuing low fuel consumption and good economy, several states with large proportion in the engine working load spectrum can be selected, and the weighting coefficient K is distributed according to the proportion of different states in time, and the total excess clearance of several states is optimized, so as to reduce the turbine tip clearance level of the main working state in the whole working load spectrum, thereby realizing the lowest possible fuel consumption of the engine. For an engine pursuing maximum take-off power, states with high power demand such as maximum take-off state can be selected, and the weighting coefficient is focused on this state, and the weighting coefficients of other states are distributed or not distributed according to the situation, so as to optimize the tip clearance of the maximum take-off state, thereby improving the power of the engine and meeting the power demand of the engine in the specified state.

[0068] Preferably, in step S500, after determining the weighting coefficient of the total excess clearance of each stage, the gap matching of the rotor and the stator is performed by changing the casing material, structure and cooling form. The casing structure is determined at the initial design stage, and then the appropriate casing material and cooling temperature and cooling form are selected to change the response curve of the casing deformation, so as to achieve the purpose of matching the corresponding tip clearance. The optimization parameters are selected by comparing the total excess clearances of different schemes, and the optimization effect of the total excess clearance is finally determined.

[0069] Preferably, in step S600, the initial cold state clearance is determined by the minimum allowable working clearance and the optimized narrow point clearance, that is, the narrow point clearance should be greater than the minimum allowable working clearance in any state.

[0070] It can be understood that the initial cold state clearance is determined by the minimum allowable working clearance and the optimized narrow point clearance, that is, the narrow point clearance should be greater than the minimum allowable working clearance, and the above condition should be met in any state. Because the minimum allowable working clearance in different states of the engine can be different, in general, the minimum allowable working clearance during take-off is relatively large compared with that during cruising.

[0071] It should be noted that one optimization may not necessarily meet all requirements, and steps S500 and S600 are iteratively calculated until the engine design requirements are met.

[0072] In summary, the method of the application relates to a turbine tip clearance passive matching method process based on engine requirements; relates to a method of tip clearance matching analysis and a method of tip clearance matching optimization; relates to the evaluation of tip clearance matching optimization according to the comprehensive excess clearance optimization effect according to the requirements of the engine. The turbine tip clearance passive matching method process based on engine requirements proposed in the application can complete the analysis of the turbine tip clearance and the clearance matching optimization according to the different requirements of the engine. The turbine material and cooling are used as the adjusting means, the optimized turbine tip clearance is evaluated by combining the comprehensive excess clearance and other indicators, the control of the turbine tip clearance level is realized, the turbine efficiency is improved, the fuel consumption rate of the engine is reduced, and the performance of the engine is improved.

[0073] It should be noted that in this document, the terms "comprising", "including", or any other variant thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements recited, but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0074] It should be understood that in the foregoing description of embodiments of the present specification, for the purpose of facilitating understanding of one feature, the present specification combines various features in a single embodiment, figure or description thereof for the purpose of simplifying the present specification. However, this does not mean that the combination of these features is necessary, and a person skilled in the art can certainly mark out part of the device as a separate embodiment to understand it after reading the present specification. That is, the embodiments in the present specification can also be understood as the integration of multiple secondary embodiments. And the content of each secondary embodiment is also valid when there are less than all the features of a single previously disclosed embodiment.

Claims

1. A method for passive matching of turbine tip clearance based on engine demand, characterized in that, The method comprises the following steps: S100: determining a minimum allowable working clearance according to engine design requirements; S200: determining a typical blade tip clearance analysis load spectrum according to the use scenario of the engine; S300: performing thermal analysis and deformation analysis of the rotor and the stator through three-dimensional simulation to obtain a turbine rotor radial deformation response curve and a stator radial deformation response curve under a typical working load spectrum of the engine; S400: performing blade tip clearance variation law analysis according to the deformation results of the rotor and the stator to obtain the blade tip clearance variation law; S500: optimizing the blade tip clearance matching for the casing material, structure and cooling form according to different engine requirements; setting the part of the actual blade tip clearance that is greater than the minimum allowable working clearance as an excess clearance, and optimizing the blade tip clearance matching according to the use and requirements of the engine; for an engine that pursues fuel consumption, the blade tip clearance in the cruising stage is preferentially matched, and the excess clearance in the entire flight cycle is also considered; for an engine that pursues maximum power, the blade tip clearance in the maximum power state is preferentially matched; after the blade tip clearance matching optimization is completed, a comprehensive excess clearance is used to measure the clearance matching, the comprehensive excess clearance is the integral of the excess clearance over time, the comprehensive excess clearance optimization effect is calculated by weighted summation of the comprehensive excess clearances in each stage of the engine, and the comprehensive excess clearance optimization effect η is obtained; ； ； wherein is the total excess gap before optimization for each stage, is the total excess gap after optimization for each stage, is the weighting factor of the total excess gap for each stage, subscript i represents different working conditions of the engine; S600: adding the minimum allowable working clearance to the turbine rotor radial deformation response curve to obtain an anti-scraping casing deformation curve, obtaining an actual casing deformation curve through calculation, and determining an initial cold-state clearance according to the intersection point of the actual casing deformation curve and the anti-scraping casing deformation curve as the narrow-point clearance; S700: iteratively calculating steps S500 and S600 until the blade tip clearance meets the engine design requirements to determine a final blade tip clearance matching scheme.

2. A method of passive matching of turbine tip clearance based on engine demand according to claim 1, characterized in that, Step S100 specifically comprises: determining a corresponding minimum allowable blade tip clearance based on each steady-state running working state of the engine, so that the turbine blade tip running clearance is not less than the minimum allowable blade tip clearance.

3. A method of passive matching of turbine tip clearance based on engine demand according to claim 2, wherein, When determining the minimum allowable working clearance, the influence of at least one of the following factors on the deformation of the rotor and the stator is considered: deflection caused by gravity and gyroscopic moment in maneuvering flight; ovality caused by installation load; machining error and eccentricity; bearing radial clearance; rotor unbalance in normal state; deformation caused by engine surge; asymmetric heat and pressure distortion; rotor whirl during restart of the hot engine; blade twist and rotor creep elongation.

4. The method of claim 1, wherein, In step S200, the typical blade tip clearance analysis load spectrum includes the processes of ground slow, take-off, climbing, cruising, descending and accelerating.

5. The method of claim 1, wherein, Step S300 specifically comprises: performing rotor thermal analysis and deformation analysis through a three-dimensional finite element method to obtain the temperature field change of the rotor, and performing structural deformation analysis of the rotor in combination with the engine speed change condition to obtain the radial deformation result at the rotor blade tip; performing stator thermal analysis and deformation analysis through a three-dimensional finite element method to obtain the temperature field change of the stator, and performing structural deformation analysis of the stator in combination with the stator pressure load condition to obtain the radial deformation result at the outer ring of the stator.

6. A method of passive matching of turbine tip clearance based on engine demand according to claim 5, wherein, In step S400, the tip clearance is calculated according to the radial deformation result at the rotor tip and the radial deformation result at the stator outer ring by the following formula δ hot : ； wherein is the initial cold gap, is the radial deformation at the stator outer ring, Δ is the radial deformation at the rotor tip.

7. A method of passive matching of turbine tip clearance based on engine demand as recited in claim 1, wherein, In step S500, after determining the weighting coefficients of the comprehensive excess gap of each stage, the gap matching of the rotor and stator is performed by changing the casing material, structure and cooling form. The casing structure is determined at the initial design stage, and then the appropriate casing material and cooling temperature and cooling form are selected to change the response curve of the casing deformation, so as to achieve the corresponding tip gap matching purpose. The comprehensive excess gap of different schemes is compared to select the optimal parameters, and finally the optimization effect of the comprehensive excess gap is determined.

8. The method of claim 1, wherein, In step S600, the narrow point gap needs to be greater than the minimum allowable working gap in any state of the engine.

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