Method for determining key parameters of an aeroengine bird ingestion based on local damage of a blade

Abstract

The application provides an aero-engine bird ingestion key parameter determination method based on local damage of a blade, comprising: determining a bird ingestion key parameter, determining a bird ingestion key parameter range according to an engine bird ingestion requirement specification, an engine working state, a blade structure and an aircraft flight speed; obtaining a structural damage condition of a fan rotor blade under different bird ingestion key parameter combinations; determining a blade leading edge damage parameter; determining a damage evaluation parameter calculation method for indicating that maximum damage of the blade is respectively a drop, a tear and a dent; obtaining a maximum damage degree of the blade and a corresponding damage evaluation parameter under different bird ingestion key parameter combinations according to the blade leading edge damage parameter; comparing the maximum damage degree and the corresponding damage evaluation parameter, and determining a bird ingestion key parameter combination under a most serious damage state according to the fact that the drop is more serious than the tear damage and the tear is more serious than the dent damage; and the bird ingestion key parameter combination corresponding to the maximum damage evaluation parameter is an aero-engine blade bird ingestion key parameter.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aero-engines, and particularly relates to a method for determining key parameters of bird ingestion of an aero-engine based on local damage of a blade. BACKGROUND

[0002] Bird ingestion of an aero-engine has always been a major accident that seriously endangers the flight safety of an airplane. After bird ingestion of an aero-engine, a bird will first hit the fan rotor blades at the inlet of the engine, causing the blades to produce dents, deformation, tearing cracks, chunks and even breakage, and causing a series of secondary damage, thereby causing the aerodynamic performance of the blades to decrease, the thrust of the engine to decrease, and the engine to be possibly damaged, causing the engine to stall, or even the broken blades to penetrate the casing and fly out, directly endangering the safety of passengers and causing accidents of the airplane being destroyed and people being killed.

[0003] To ensure the safety and economy of an aero-engine, the bird ingestion resistance of a blade becomes an important content in the design process of the engine, and the bird ingestion resistance design and evaluation of the fan rotor blades need to be carried out in the design process of the engine to ensure that the blades of the engine meet the bird ingestion resistance requirements.

[0004] In the bird ingestion resistance design and evaluation of the blades of an aero-engine, key parameters of the bird ingestion resistance design and evaluation of the blades need to be determined, including the mass of a bird, the speed of the bird, the rotational speed of the blade and the radius of the blade impact position.

[0005] In the prior art, methods that can be used to determine the key parameters of the bird ingestion resistance of a blade include an aero-engine fan bird ingestion airworthiness compliance analysis method (CN 106649937 A) and an aero-engine fan rotor blade bird impact evaluation state and parameter determination method (201910735493.6).

[0006] For the aero-engine fan bird ingestion airworthiness compliance analysis method (CN 106649937 A), key bird ingestion parameters CIP combinations (including the speed of a bird, the rotational speed of a blade and the radius of a blade impact position) are defined, key impact parameters S L , S R , D I and D T are defined, a comprehensive key impact parameter SCIP combination is defined, the SCIP combination is the sum of the key impact parameters of all affected blades under each CIP parameter, and is calculated according to formula 1:

[0007]

[0008] Then, a simulation method is used to calculate the SCIP under each CIP parameter, and the CIP state corresponding to the maximum SCIP value is the key parameter of bird ingestion resistance.

[0009] However, in this method, the bird mass is not considered in the bird impact key parameters, and the bird impact key parameters are not comprehensive; at the same time, the key impact parameters defined in the determination process (blade leading edge stress S L , root stress S R , impact point displacement D I and tip relative displacement D T ) are mainly overall damage parameters of the blade, and do not consider local damage of the leading edge in the actual impact process. The bird impact key parameters determined according to these key impact parameters are not comprehensive and cannot reflect the local damage in the actual bird impact damage.

[0010] For the method for evaluating the state and determining the parameters of bird impact on the fan rotor blade of an aero-engine (201910735493.6), the impact mode and impact energy under different bird speeds, blade rotation speeds and blade impact positions are calculated by using theoretical formulas, and the state and corresponding parameters with the largest impact capacity are selected as the anti-bird impact key parameters.

[0011] For this method, the impact energy is mainly calculated based on theoretical formulas, and the anti-deformation ability of the structure of the impacted part itself cannot be considered, and the bird impact key parameters cannot be directly determined from the damage situation. SUMMARY

[0012] The purpose of the present application is to provide a method for determining key parameters of bird ingestion of an aero-engine based on local damage of a blade, to solve or alleviate at least one problem in the background art.

[0013] The technical solution of the present application is: a method for determining key parameters of bird ingestion of an aero-engine based on local damage of a blade, the method comprising:

[0014] S1, determining bird impact key parameters, the bird impact key parameters including bird mass m, bird speed V, fan blade rotation speed W and bird impact blade position radius R, determining the range of bird impact key parameters according to engine bird ingestion requirement specifications, engine operating state, blade structure and aircraft flight speed;

[0015] S2, obtaining structural damage of the fan rotor blade under different combinations of bird impact key parameters;

[0016] S3, determining blade leading edge damage parameters, the blade leading edge damage parameters including maximum damage degree of the blade, local concave circumferential depth h, tear crack length l, spalling length s, spalling height f and spalling radius r;

[0017] S4, determining damage evaluation parameter calculation methods for representing maximum damage of the blade as spalling, tearing and concave, obtaining maximum damage degree of the blade and corresponding damage evaluation parameters under different combinations of bird impact key parameters according to the blade leading edge damage parameters;

[0018] S5, comparing the maximum damage degree and the corresponding damage evaluation parameter obtained in step S4, determining the bird impact key parameter combination in the most serious damage state according to the fact that the block is more serious than the tear damage and the tear is more serious than the dent damage, and the bird impact key parameter combination corresponding to the maximum damage evaluation parameter is the key parameter of the aero-engine blade anti-bird impact.

[0019] Further, the structural damage of the fan rotor blade under different bird impact key parameter combinations is obtained through dynamic simulation or test.

[0020] Further, the maximum damage degree of the blade is the maximum damage type of the blade caused by the direct impact of the bird on the blade, including dent, tear and block;

[0021] The local dent circumferential depth h is the length of the dent along the blade profile direction after the dent occurs at the leading edge;

[0022] The tear crack length l is the length of the crack along the blade profile direction after the tear crack occurs at the leading edge;

[0023] The block length s is the length of the block along the blade profile direction after the block occurs at the leading edge;

[0024] The block height f is the length of the block along the radial direction of the leading edge after the block occurs at the leading edge, wherein the block radius r=(r 上 +r 下 ) / 2, r 上 is the maximum radius of the block leading edge, and r 下 is the minimum radius of the block leading edge.

[0025] Further, the damage evaluation parameter Φ calculation method for the block condition is:

[0026]

[0027] In the formula, m is the number of blade blocks, s i is the block length of each blade block, f i is the block height, r i is the block radius, i is an integer in the range of 1 to m, and m is an integer greater than 1.

[0028] Further, the damage evaluation parameter Φ calculation method for the tear condition is:

[0029] Φ=max(hl j )

[0030] In the formula, g is the number of blade tear cracks, hl j is the relative tear crack length of each blade, j is an integer in the range of 1 to g, and g is an integer greater than 1.

[0031] Further, the relative tear crack length hl = l / S 弦 , S 弦 is the chord length of the blade at the maximum position of the concave. 凹陷

[0032] Further, the damage evaluation parameter Φ for the concave case is calculated as follows:

[0033]

[0034] In the formula, n is the number of tear cracks of the blade, hh x is the relative local concave circumferential depth of each blade, x is an integer in the range of 1-n, and n is an integer greater than 1.

[0035] Further, the local concave circumferential depth hh = h / S 间隙 , S 间隙 is the chord length of the blade at the maximum position of the concave. 凹陷 间隙 = 2 * π * R 凹陷 / k, k is the number of blades in an integral circle.

[0036] The method for determining the bird ingestion critical parameter of the aero-engine provided by the application includes the bird mass, the parameter is more comprehensive, and the method mainly determines the actual local damage of the blade after bird impact, and can simultaneously consider the strength problem and the aerodynamic performance problem caused by bird impact, and the determination basis is more comprehensive and reasonable. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions provided by the application, the drawings will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the application.

[0038] Figure 1 is a flow chart of the method for determining the bird impact resistance critical parameter of the aero-engine blade of the application.

[0039] Figure 2 is a schematic diagram of the local concave circumferential depth h in an embodiment of the application.

[0040] Figure 3 is a schematic diagram of the tear crack length l in an embodiment of the application.

[0041] Figure 4 is a schematic diagram of the edge drop block damage parameter in an embodiment of the application. DETAILED DESCRIPTION

[0042] ​​For the purpose, technical solutions and advantages of the present application, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application.

[0043] As shown in the method for determining key parameters of fan blade bird strike resistance based on local damage of fan blade provided by the present application includes the following processes: Figure 1

[0044] S1, determining bird strike key parameters and parameter range.

[0045] The bird strike key parameters defined in the present application include bird mass m, bird speed V, fan blade speed W and bird strike position radius R. According to the engine bird swallowing requirement specification, engine working state, blade structure and aircraft flight speed, the bird strike key parameter range is determined.

[0046] S2, bird strike key parameter range blade bird strike damage analysis.

[0047] Using dynamics simulation or test, the structural damage of fan rotor blade under different bird strike key parameter combinations is obtained.

[0048] S3, determining blade leading edge damage parameters and extracting the parameters.

[0049] The blade leading edge damage parameters defined in the present application include maximum damage degree of blade, local dent circumferential depth h, tear crack length l, drop length s, drop height f and drop radius r.

[0050] The maximum damage degree of blade is the maximum damage type of blade caused by bird direct impact on blade, including dent, tear and drop;

[0051] The local dent circumferential depth h is the length or depth of dent along the blade profile direction after dent appears on the leading edge, and the definition is shown in Figure 2 ;

[0052] The tear crack length l is the length or depth of crack along the blade profile direction after tear crack appears on the leading edge, and the definition is shown in Figure 3 ;

[0053] The drop length s is the length or depth of drop along the blade profile direction after drop appears on the leading edge of blade;

[0054] The drop height f is the length of drop along the radial direction of leading edge after drop appears on the leading edge of blade, and the drop length s, drop height f and drop radius r are shown in Figure 4 , wherein the drop radius r=(r 上 +r 下 ) / 2, r 上 is the maximum radius of drop leading edge, and r 下 is the minimum radius of drop leading edge.​

[0055] S4. Determine and calculate the parameters for evaluating leaf damage.

[0056] The blade leading edge damage parameters were dimensionless, and the relative leading edge damage parameters were determined, including the relative local indentation circumferential depth hh and the relative tear crack length hl.

[0057] The circumferential depth of the local depression is hh = h / S 间隙 S 间隙 R is the radius of the maximum location of the depression. 凹陷 The circumferential gap at the leading edge of adjacent blades, S 间隙 =2*π*R 凹陷 / k, where k is the number of blades in a complete circle;

[0058] Relative tear crack length hl = l / S 弦 S 弦 R is the radius of the maximum location of the depression. 凹陷 The chord length of the leaf blade.

[0059] The damage evaluation parameter Φ is characterized as follows: the maximum damage to the blade is judged and divided into three categories: chipping, tearing and denting.

[0060] For the first type of blade breakage, assuming there are m blade breakages, and each breakage has a breakage length si, breakage height fi, and breakage radius ri, where i is an integer in the range of 1 to m, and m is an integer greater than 1, the damage evaluation parameter Φ is:

[0061] For the second tearing scenario, assuming there are g blades with tearing cracks, and the relative tearing crack length hl for each blade... j j is an integer in the range of 1 to g, and g is an integer greater than 1. The damage evaluation parameter Φ is: Φ = max(hl j Equation (3)

[0062] For the third type of indentation, assuming there are n blades with tearing cracks, the relative circumferential depth of the local indentation for each blade is hh x x is an integer in the range of 1 to n, and n is an integer greater than 1. The damage evaluation parameter Φ is:

[0063] Using the blade leading edge damage parameters extracted in step S3, the maximum degree of blade damage and the corresponding damage evaluation parameters under different combinations of key bird strike parameters are obtained.

[0064] S5. Determination of key parameters for bird strike on blades.

[0065] The maximum damage degree obtained in step S4 and the corresponding damage evaluation parameter are compared to determine the bird impact key parameter, and the process includes:

[0066] First, the maximum damage degree of the blade leading edge is compared. The drop block is more serious than the tear damage, and the tear is more serious than the dent damage. The bird impact key parameter combination in the most serious damage state is determined;

[0067] Then, according to the most serious damage degree, the damage evaluation parameter Φ is calculated according to the damage evaluation parameter calculation method in step 4. The larger the damage evaluation parameter Φ, the more serious the damage. The bird impact key parameter combination corresponding to the maximum damage evaluation parameter Φ is the key parameter of the aero-engine blade anti-bird impact.

[0068] The method for determining the bird impact key parameter of the aero-engine provided in the application includes the bird mass, the parameters are more comprehensive, and the method mainly depends on the actual local damage of the blade leading edge after bird impact, and can consider the strength problem and the aerodynamic performance problem caused by bird impact at the same time, and the determination basis is more comprehensive and reasonable.

[0069] The above is only a specific embodiment of the application, but the protection scope of the application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the application, which should be covered within the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A method for determining key parameters of bird-eating aircraft engines based on localized blade damage, characterized in that, The method includes: S1. Determine the key parameters of bird strike, including bird mass m, bird velocity V, fan blade speed W, and radius R of the bird impacting the blade. Determine the range of key parameters of bird strike based on the engine bird ingestion requirements, engine operating status, blade structure, and aircraft flight speed. S2. Obtain the structural damage of the fan rotor blades under different combinations of key bird strike parameters; S3. Determine the blade leading edge damage parameters, which include the maximum degree of blade damage, the circumferential depth of the local indentation h, the tear crack length l, the spall length s, the spall height f, and the spall radius r. S4. Determine the calculation method for damage evaluation parameters characterizing the maximum damage to the blade as flakes, tears, and dents. Based on the blade leading edge damage parameters, obtain the maximum damage degree of the blade and the corresponding damage evaluation parameters under different combinations of key bird strike parameters. Specifically, the calculation method for the damage evaluation parameter Φ in the case of flakes is as follows: In the formula, m is the number of blade fragments that have fallen off, and s i The length of the debris drop for each blade, f i For the height of the falling block, r i Let i be the radius of the falling block, i be an integer in the range of 1 to m, and m be an integer greater than 1; The damage evaluation parameter Φ for tearing is calculated as follows: Φ = max(hl j ), where hl j Let hl be the relative tear crack length of the j-th blade, where j is an integer in the range of 1 to g, and the relative tear crack length hl = l / S 弦 S 弦 R is the radius of the maximum location of the depression. 凹陷 The chord length of the leaf blade; The calculation method for the damage evaluation parameter Φ for indentation is as follows: In the formula, n represents the number of tearing cracks appearing on the blade, and hh x Let h be the circumferential depth of the relative local indentation of the x-th blade, where x is an integer in the range of 1 to n, and n is an integer greater than 1. The circumferential depth of the relative local indentation is hh = h / S. 间隙 S 间隙 R is the radius of the maximum location of the depression. 凹陷 The circumferential gap at the leading edge of adjacent blades, S 间隙 =2*π*R 凹陷 / k, where k is the number of blades in a complete circle; S5. Compare the maximum damage level obtained in step S4 with the corresponding damage evaluation parameters, and determine the combination of key bird strike parameters under the most severe damage state according to the severity of the chipping damage compared to the tearing damage and the severity of the tearing damage compared to the denting damage. The combination of key bird strike parameters corresponding to the maximum damage evaluation parameters is the key bird strike resistance parameter of the aero-engine blade.

2. The method for determining key parameters of aero-engine bird-eating based on local blade damage as described in claim 1, characterized in that, The structural damage of fan rotor blades under different combinations of key bird strike parameters was obtained through dynamic simulation or experiments.

3. The method for determining key parameters of aero-engine bird-eating based on local blade damage as described in claim 1, characterized in that, The maximum degree of damage to the blade refers to the maximum type of damage to the blade caused by a direct impact from a bird, including dents, tears, and chipping. The circumferential depth h of the local depression is the length of the depression along the airfoil direction after the depression appears at the leading edge; The tear crack length l is the length of the crack along the blade direction after the tear crack appears at the leading edge; The length s of the detached piece is the length of the detached piece along the blade shape direction after the detached piece appears at the leading edge of the blade; The debris height f is the length of the debris along the radial direction of the leading edge after it appears on the blade's leading edge, where the debris radius r = (r 上 +r 下 ) / 2, r 上 r is the maximum radius of the leading edge of the falling block. 下 This is the minimum radius of the leading edge of the falling block.

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