A method and system for analyzing bird impact load on a leading edge of an aeroengine blade
By using bird model simulation and formula calculation, the bird strike impact load on the leading edge of aero-engine blades can be quickly analyzed, solving the problems of high cost and low efficiency in existing technologies. This enables rapid analysis of multiple operating conditions and multiple parts, supporting blade design optimization and safety assessment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- AECC SICHUAN GAS TURBINE RES INST
- Filing Date
- 2026-04-14
- Publication Date
- 2026-07-14
Smart Images
Figure CN122020863B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of bird strike resistance design technology for aero-engine blades, and discloses a method and system for analyzing bird strike impact loads on the leading edge of aero-engine blades. Background Technology
[0002] With the rapid development of aviation technology, the number of bird strike incidents involving various aircraft is increasing year by year, seriously impacting aviation safety. Among these incidents, the engine section accounts for the highest proportion of bird strikes. After a bird strike, the fan blades and other air intake components of an aero-engine are highly susceptible to impact damage, leading to deterioration in aerodynamic performance and dynamic response of the entire aircraft structure, posing a significant threat to the safety of the engine and even the aircraft itself. To achieve a higher thrust-to-weight ratio, one of the key technologies employed in modern high-performance aero-engines is to increase the flow rate per unit frontal area and stage pressure ratio of fan / compressor components while reducing the number of stages and blades, without compromising stage efficiency. Therefore, structurally, this tends towards thin-walled leading edges and integral bladed disks. While these technologies significantly improve blade aerodynamic performance, they also reduce the blade's resistance to bird strikes, leading to flight safety issues. The bird-absorbing capability of an aero-engine is one of the key criteria for airworthiness certification; therefore, the bird-strike resistant design of modern high-performance engine blades is crucial.
[0003] Current engine blade bird strike protection design is mainly carried out through three-dimensional finite element simulation analysis. Although the accuracy is high, the computational cost is very high because the solver requires a very small time step. At the same time, since there are many engine operating conditions verified by national military standards or airworthiness requirements, some qualitative parameters are specified in a large range (such as takeoff speed, which may be between 50m / s and 150m / s). In addition, the impact site is only qualitatively specified as a "critical part". These factors cause the cost of using finite element calculation in actual analysis to increase exponentially. Summary of the Invention
[0004] The purpose of this invention is to provide a method and system for analyzing bird strike impact loads on the leading edge of aero-engine blades, which can improve the analysis efficiency of bird strike impact loads on the leading edge of blades, reduce the analysis cycle and cost, and facilitate multi-condition and multi-part calculation and analysis.
[0005] To achieve the above-mentioned technical effects, the technical solution adopted by the present invention is as follows:
[0006] A method for analyzing bird strike impact loads on the leading edge of an aero-engine blade, comprising:
[0007] Bird strike simulations of the leading edge of an aero-engine blade were conducted using a bird model. Based on the attribute parameters of the bird model, the structural parameters of the engine, and the state parameters of the engine under test conditions, the time it takes for the bird model to be cut off by the blade during the blade strike, the maximum contact area of the bird fragment acting on the blade surface, and the stabilizing pressure of the bird fragment at the impact point between the blade leading edge and the bird model were analyzed. The bird fragment refers to the piece cut off by the blade from the bird model.
[0008] Based on the stabilizing pressure of the bird block and the maximum contact area of the bird block, the peak impact force borne by the blade during the cutting of the bird model was obtained.
[0009] The product of the peak impact force experienced by the blade during the cutting of the bird model and the time it takes for the bird model to be cut off by the blade is taken as the impact load of the bird strike at the leading edge of the blade.
[0010] Furthermore, the steps for analyzing and obtaining the time when the bird model was severed by the leaf during the leaf-bird collision include:
[0011] The tangential linear velocity at the point of impact between the blade leading edge and the bird model is determined based on the blade rotation speed and the radius of the point where the blade leading edge impacts the bird model.
[0012] Based on the tangential linear velocity at the point of impact between the leading edge of the blade and the bird model, and the diameter of the bird model, the time it takes for the bird model to be cut off by the blade is analyzed.
[0013] Furthermore, the time at which the bird model is cut off by the leaf is determined by the following formula:
[0014] ;
[0015] in: The time it takes for the bird model to be cut by the leaf; The diameter of the bird model; The tangential linear velocity is the point of impact between the leading edge of the blade and the bird model.
[0016] Furthermore, the steps for analyzing and obtaining the maximum contact area of the bird fragments acting on the blade surface include:
[0017] Based on the tangential linear velocity at the point of impact between the leading edge of the blade and the bird model and the axial velocity of the bird model, the angle between the incident direction of the bird model and the engine axis is analyzed and obtained.
[0018] Based on the diameter of the bird model and the angle between the incident direction of the bird model and the engine axis, the maximum contact area of the bird block acting on the blade surface is obtained through analysis.
[0019] Furthermore, the maximum contact area of the bird block acting on the blade surface is determined by the following formula:
[0020] ;
[0021] in: The maximum contact area of the bird block acting on the blade surface; The angle between the incident direction of the bird model and the direction of the engine axis.
[0022] Furthermore, the steps for analyzing and obtaining the bird block stabilization pressure borne by the leading edge of the blade and the impact point of the bird model include:
[0023] Based on the axial velocity of the bird model and the tangential linear velocity of the impact point between the blade leading edge and the bird model, the relative velocity of the bird block with respect to the impact point between the blade leading edge and the bird model is obtained. Then, combined with the geometric intake angle of the blade leading edge and the angle between the incident direction of the bird model and the engine axis, the normal velocity of the bird block relative to the chord direction of the blade leading edge is obtained.
[0024] Based on the normal velocity of the bird block relative to the chordal direction of the blade leading edge and the density of the bird model, the stagnant pressure of the bird block at the impact point between the blade leading edge and the bird model is obtained.
[0025] Furthermore, the bird block stabilizing pressure borne by the leading edge of the blade at the impact point of the bird model is determined by the following formula:
[0026] ;
[0027] in: The stabilizing pressure of the bird block at the point of impact between the leading edge of the blade and the bird model; The density of the bird model; The axial velocity of the bird model; The rotational speed of the blades; The radius of the point of impact between the leading edge of the blade and the bird model; The geometric intake angle is the leading edge of the blade.
[0028] Furthermore, the peak impact force experienced by the blade during the cutting of the bird model is determined by the following formula:
[0029] ;
[0030] in: This represents the peak impact force experienced by the bird model during the process of cutting the blade.
[0031] Furthermore, the expression for the impact load of the bird strike on the leading edge of the blade is:
[0032] ;
[0033] in: Impact load of bird strike on the leading edge of the blade
[0034] A bird strike impact load analysis system for the leading edge of an aero-engine blade, based on the aforementioned bird strike impact load analysis method for the leading edge of an aero-engine blade, includes:
[0035] The bird strike simulation analysis module is used to conduct bird strike simulations of the leading edge of an aero-engine blade using a bird model. Based on the attribute parameters of the bird model, the structural parameters of the engine, and the state parameters of the engine under test conditions, the module analyzes and obtains the time when the bird model is cut off by the blade during a bird strike, the maximum contact area of the bird fragment acting on the blade surface, and the bird fragment stagnant pressure borne by the blade leading edge at the impact point with the bird model; the bird fragment is the piece cut off by the blade from the bird model.
[0036] The peak impact force analysis module is used to analyze and obtain the peak impact force borne by the blade during the cutting of the bird model based on the bird block stagnant pressure and the maximum contact area of the bird block.
[0037] The impact load analysis module is used to calculate the impact load of the bird strike on the leading edge of the blade as the product of the peak impact force experienced by the blade during the cutting of the bird model and the time it takes for the bird model to be cut by the blade.
[0038] Compared with the prior art, the beneficial effects of this invention are:
[0039] This invention rapidly analyzes and obtains the impact load on the leading edge of a blade from a bird strike by comprehensively considering the property parameters of the bird model, the structural parameters of the engine, and the state parameters under test conditions. This replaces the traditional finite element analysis method and improves the analysis efficiency of the impact load on the leading edge of a blade from a bird strike. Compared with the traditional finite element analysis method, this invention can not only significantly shorten the analysis cycle and reduce costs, but also achieve rapid analysis of impact loads in multiple conditions and multiple parts by adjusting the property parameters of the bird model, the structural parameters of the engine, and the state parameters under test conditions. This provides strong support for the design optimization and safety assessment of aero-engine blades. Attached Figure Description
[0040] Figure 1 This is a flowchart illustrating the bird strike impact load analysis method for the leading edge of an aero-engine blade in this embodiment.
[0041] Figure 2 This is a schematic diagram of a bird model with a blade cut in the embodiment;
[0042] Figure 3 This is a structural block diagram of the bird strike impact load analysis system for the leading edge of an aero-engine blade in this embodiment. Detailed Implementation
[0043] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the above-described subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.
[0044] See Figure 1 This invention provides a method for analyzing bird strike impact loads on the leading edge of an aero-engine blade, comprising:
[0045] Bird strike simulations of the leading edge of an aero-engine blade were conducted using a bird model. Based on the attribute parameters of the bird model, the structural parameters of the engine, and the state parameters of the engine under test conditions, the time it takes for the bird model to be cut off by the blade during the blade strike, the maximum contact area of the bird fragment acting on the blade surface, and the stabilizing pressure of the bird fragment at the impact point between the blade leading edge and the bird model were analyzed. The bird fragment refers to the piece cut off by the blade from the bird model.
[0046] Based on the stabilizing pressure of the bird block and the maximum contact area of the bird block, the peak impact force borne by the blade during the cutting of the bird model was obtained.
[0047] The product of the peak impact force experienced by the blade during the cutting of the bird model and the time it takes for the bird model to be cut off by the blade is taken as the impact load of the bird strike at the leading edge of the blade.
[0048] This invention rapidly analyzes and obtains the impact load on the leading edge of a blade from a bird strike by comprehensively considering the property parameters of the bird model, the structural parameters of the engine, and the state parameters under test conditions. This replaces the traditional finite element analysis method and improves the analysis efficiency of the impact load on the leading edge of a blade from a bird strike. Compared with the traditional finite element analysis method, this invention can not only significantly shorten the analysis cycle and reduce costs, but also achieve rapid analysis of impact loads in multiple conditions and multiple parts by adjusting the property parameters of the bird model, the structural parameters of the engine, and the state parameters under test conditions. This provides strong support for the design optimization and safety assessment of aero-engine blades.
[0049] Example
[0050] When the bird model is launched at a certain speed along a direction parallel to the engine axis, the rotation of the blades causes the blade leading edge to cut the bird model at the point of impact, breaking it into pieces. These pieces act on the blade, generating enormous local contact forces that cause plastic deformation at the blade leading edge, leading to bulging, curling, tearing, and even chipping. Simultaneously, the bird pieces endure immense impact pressure, causing them to transition from a solid to a fluid state.
[0051] During the cutting process, the impact force of the bird model on the blade can be decomposed into a tangential force parallel to the leading edge of the blade and a normal force perpendicular to the tangential direction. The tangential force causes the bird block to slide towards the trailing edge of the blade without damaging the blade, while the normal force causes the blade to bend or twist, thus causing damage to the blade.
[0052] This embodiment further elaborates on the method for analyzing bird strike impact loads on the leading edge of aero-engine blades. This method assumes the bird model is a cylindrical model with a length-to-diameter ratio of 2:1, and uses an axial velocity... The incident light was cut into several bird pieces by the leaves, such as... Figure 2 As shown. The method for analyzing bird strike impact loads on the leading edge of aero-engine blades specifically includes the following steps:
[0053] Step 1: Determine the engine's structural parameters, including the geometric intake angle of the blade leading edge. The radius of the impact point between the leading edge of the blade and the bird model The radius of the point of impact between the leading edge of the blade and the bird model This refers to the radial distance from the center of the point of impact between the blade leading edge and the bird model to the engine axis. Based on the engine's test operating conditions during the bird strike, the engine's state parameters under those conditions are determined, including blade rotational speed. The assessment conditions include aircraft takeoff and landing conditions, etc.
[0054] Based on the test conditions of engine bird strike, and according to the engine's bird strike resistance design requirements under these conditions, or the national military standards regarding engine bird strike resistance requirements under these conditions, the attribute parameters of the bird model are set. These attribute parameters include the mass of the bird model. and density And the axial velocity of the bird model along the engine axis during the bird strike. Among them, the density of the bird model The value range is 900~950 kg / m 3 .
[0055] Step 2: Analyze the time it took for the bird model to be severed by the leaf during the bird strike. Specific steps include:
[0056] First, the bird model in this embodiment is a cylindrical bird model with a length-to-diameter ratio of 2:1. The diameter of the bird model is determined based on its mass and density using the following formula:
[0057] ;
[0058] in: The diameter of the bird model; The mass of the bird model; This represents the density of the bird model.
[0059] Then, based on the blade rotation speed The radius of the impact point between the leading edge of the blade and the bird model ,pass Determine the tangential linear velocity of the blade leading edge at the point of impact with the bird model. .
[0060] Finally, based on the tangential linear velocity of the blade leading edge at the point of impact with the bird model... and the diameter of the bird model The time it took for the bird model to be cut off by the leaf was analyzed. .
[0061] Step 3: Analyze and obtain the maximum contact area of the bird piece acting on the blade surface; the bird piece is a block of the blade cut from a bird model. Specific steps include:
[0062] First, based on the tangential linear velocity of the blade leading edge at the point of impact with the bird model... Axial velocity of the bird model ,pass The angle between the incident direction of the bird model and the engine axis was obtained through analysis. .
[0063] Then, due to the relative velocity between the bird model and the blade, the cutting section of the bird block has an inclination angle of . The ellipse. Therefore, when the bird model is completely cut from one side to the other along the direction of the relative velocity vector, the maximum contact area of the bird block acting on the blade surface is obtained through the maximum contact area formula. Confirmed, among which: The maximum contact area of the bird block acting on the blade surface; The diameter of the bird model; The angle between the incident direction of the bird model and the direction of the engine axis.
[0064] Step 4: Analyze and obtain the bird impact stabilization pressure experienced by the leading edge of the blade at the point of impact with the bird model. Specific steps include:
[0065] First, based on the axial velocity of the bird model The tangential linear velocity of the blade leading edge at the point of impact with the bird model ,pass The relative velocity of the bird block with respect to the leading edge of the blade and the impact point of the bird model was obtained through analysis. Then, combined with the geometric intake angle of the blade leading edge. The angle between the incident direction of the bird model and the direction of the engine axis Determine the normal velocity of the bird block relative to the chordal direction of the leading edge of the blade. normal velocity Determined by the following formula: It should be noted that during the actual cutting of the bird model by the blades, the blades will deform in the circumferential direction, resulting in a change in the geometric air intake angle. The analysis method in this embodiment assumes a change in the geometric intake angle. It remains unchanged.
[0066] Then, during the bird strike, the primary load on the blade comes from the dynamic impact force experienced when cutting the bird model. This dynamic impact force arises from the rheological changes (i.e., the change from a solid to a fluid state) caused by the bird model's inability to withstand the shock wave, and the stagnant pressure generated by the rigid wall of the blade further hinders the fluid motion. To determine the stagnant pressure of the bird fragment generated at the point of impact between the blade leading edge and the bird model... Based on the normal velocity of the bird block relative to the leading edge of the blade in the chord direction. Density of bird models The analysis yielded the bird block stagnant pressure at the impact point between the leading edge of the blade and the bird model. Bird block stagnant pressure Determined by the following formula:
[0067] .
[0068] Step 5: Based on the bird block stagnation pressure Maximum contact area with bird block Based on the fundamental relationship between pressure and force, the peak impact force experienced by the blade during the cutting of the bird model was determined. Specifically, during the cutting process of the bird model, the contact area between the bird piece and the blade continuously increases, and the impact force on the blade continuously increases. When the bird piece and the blade are in complete contact, i.e., when the contact area reaches its maximum, the impact force on the blade reaches its peak. Determined by the following formula:
[0069] .
[0070] Step Six: Measure the peak impact force experienced by the blade during the cutting of the bird model and the time it takes for the bird model to be cut by the blade. The product of these factors is used as the impact load of a bird strike on the leading edge of the blade. Specifically, since the impact damage to the blade is related not only to the magnitude of the impact force but also to the duration of the impact, the load of a bird strike on the blade is represented by the impact impulse. Moreover, during the cutting process of the bird model, the impact force acting on the blade changes continuously, and the impulse should be the integral of the impact force over the duration of the impact during this process. This embodiment uses a simplified calculation method, namely, using the peak impact force. Instead of the varying impact force during the cutting process, the impact load of the bird strike on the leading edge of the blade is determined by the following formula:
[0071] ;
[0072] in, The impact impulse of a bird strike at the leading edge of the blade is equal to the impact load of the bird strike at the leading edge of the blade.
[0073] This embodiment employs the aforementioned bird strike impact load analysis method for the leading edge of aero-engine blades. For the same engine, by changing the mass, axial velocity, blade rotational speed, and the radius of the impact point between the blade leading edge and the bird model, it can quickly analyze bird strike impact loads under different test conditions and at different locations. Furthermore, by comparing the analyzed impact load with a preset impact load threshold, if the analyzed impact load exceeds the preset threshold, the corresponding test condition and bird strike location are determined to be hazardous conditions and hazardous locations, providing support for the bird strike resistant design of the blades. It should be noted that the preset impact load threshold is determined based on the engine's bird strike resistant design requirements under the test conditions, or according to national military standards regarding the engine's bird strike resistant requirements under test conditions. It should also be noted that in the phrase "bird strike impact loads under different test conditions and at different locations," the location refers to the impact point between the blade leading edge and the bird model; multiple locations refer to impact points with different radii on the blade leading edge.
[0074] Based on the same inventive concept, see [link to inventive concept] Figure 3 This embodiment also provides a bird strike impact load analysis system for the leading edge of an aero-engine blade, including:
[0075] The bird strike simulation analysis module is used to conduct bird strike simulations of the leading edge of an aero-engine blade using a bird model. Based on the attribute parameters of the bird model, the structural parameters of the engine, and the state parameters of the engine under test conditions, the module analyzes and obtains the time when the bird model is cut off by the blade during a bird strike, the maximum contact area of the bird fragment acting on the blade surface, and the bird fragment stagnant pressure borne by the blade leading edge at the impact point with the bird model; the bird fragment is the piece cut off by the blade from the bird model.
[0076] The peak impact force analysis module is used to analyze and obtain the peak impact force borne by the blade during the cutting of the bird model based on the bird block stagnant pressure and the maximum contact area of the bird block.
[0077] The impact load analysis module is used to calculate the impact load of the bird strike on the leading edge of the blade as the product of the peak impact force experienced by the blade during the cutting of the bird model and the time it takes for the bird model to be cut by the blade.
[0078] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for analyzing bird strike impact loads on the leading edge of an aero-engine blade, characterized in that, include: Bird strike simulations of the leading edge of an aero-engine blade were conducted using a bird model. Based on the attribute parameters of the bird model, the structural parameters of the engine, and the state parameters of the engine under test conditions, the time it takes for the bird model to be cut off by the blade during the blade strike, the maximum contact area of the bird fragment acting on the blade surface, and the stabilizing pressure of the bird fragment at the impact point between the blade leading edge and the bird model were analyzed. The bird fragment refers to the piece cut off by the blade from the bird model. Based on the stabilizing pressure of the bird block and the maximum contact area of the bird block, the peak impact force borne by the blade during the cutting of the bird model was obtained. The product of the peak impact force experienced by the blade during the cutting of the bird model and the time it takes for the bird model to be cut off by the blade is taken as the impact load of the bird strike at the leading edge of the blade. The time when the bird model is cut off by the leaf is determined by the following formula: ； in: The time it takes for the bird model to be cut by the leaf; The diameter of the bird model; The tangential linear velocity at the point of impact between the leading edge of the blade and the bird model; The maximum contact area of the bird block acting on the blade surface is determined by the following formula: ； in: The maximum contact area of the bird block acting on the blade surface; The angle between the incident direction of the bird model and the direction of the engine axis; The stabilizing pressure of the bird block at the point of impact between the leading edge of the blade and the bird model is determined by the following formula: ； in: The stabilizing pressure of the bird block at the point of impact between the leading edge of the blade and the bird model; The density of the bird model; The axial velocity of the bird model; The rotational speed of the blades; The radius of the point of impact between the leading edge of the blade and the bird model; The geometric intake angle is the leading edge of the blade. The peak impact force experienced by the blade during the cutting of the bird model is determined by the following formula: ； in: This represents the peak impact force experienced by the blade during the cutting of the bird model; The expression for the impact load of the bird strike on the leading edge of the blade is: ； in: This represents the impact load from a bird strike on the leading edge of the blade.
2. The method for analyzing bird strike impact loads on the leading edge of aero-engine blades according to claim 1, characterized in that, The steps for analyzing and obtaining the time it takes for a bird model to be severed by a blade during a bird strike include: The tangential linear velocity at the point of impact between the blade leading edge and the bird model is determined based on the blade rotation speed and the radius of the point where the blade leading edge impacts the bird model. Based on the tangential linear velocity at the point of impact between the leading edge of the blade and the bird model, and the diameter of the bird model, the time it takes for the bird model to be cut off by the blade is analyzed.
3. The method for analyzing bird strike impact loads on the leading edge of aero-engine blades according to claim 2, characterized in that, The steps for analyzing and obtaining the maximum contact area of the bird fragments acting on the blade surface include: Based on the tangential linear velocity at the point of impact between the leading edge of the blade and the bird model and the axial velocity of the bird model, the angle between the incident direction of the bird model and the engine axis is analyzed and obtained. Based on the diameter of the bird model and the angle between the incident direction of the bird model and the direction of the engine axis, the maximum contact area of the bird block acting on the blade surface is obtained.
4. The method for analyzing bird strike impact loads on the leading edge of aero-engine blades according to claim 3, characterized in that, The steps for analyzing and obtaining the bird block stabilization pressure at the impact point between the leading edge of the blade and the bird model include: Based on the axial velocity of the bird model and the tangential linear velocity of the impact point between the blade leading edge and the bird model, the relative velocity of the bird block with respect to the impact point between the blade leading edge and the bird model is obtained. Then, combined with the geometric intake angle of the blade leading edge and the angle between the incident direction of the bird model and the engine axis, the normal velocity of the bird block relative to the chord direction of the blade leading edge is obtained. Based on the normal velocity of the bird block relative to the chordal direction of the blade leading edge and the density of the bird model, the stagnant pressure of the bird block at the impact point between the blade leading edge and the bird model is obtained.
5. A bird strike impact load analysis system for the leading edge of an aero-engine blade, implemented based on the bird strike impact load analysis method for the leading edge of an aero-engine blade according to any one of claims 1-4, characterized in that, include: The bird strike simulation analysis module is used to conduct bird strike simulations of the leading edge of an aero-engine blade using a bird model. Based on the attribute parameters of the bird model, the structural parameters of the engine, and the state parameters of the engine under test conditions, the module analyzes and obtains the time when the bird model is cut off by the blade during a bird strike, the maximum contact area of the bird fragment acting on the blade surface, and the bird fragment stagnant pressure borne by the blade leading edge at the impact point with the bird model; the bird fragment is the piece cut off by the blade from the bird model. The peak impact force analysis module is used to analyze and obtain the peak impact force borne by the blade during the cutting of the bird model based on the bird block stagnant pressure and the maximum contact area of the bird block. The impact load analysis module is used to calculate the impact load of the bird strike on the leading edge of the blade as the product of the peak impact force experienced by the blade during the cutting of the bird model and the time it takes for the bird model to be cut by the blade.