Nacelle acoustic liner architecture design method based on flow partition

Abstract

The invention provides a nacelle acoustic liner architecture design method based on flow partition, and the method comprises the following steps: A1, determining a nacelle outer culvert aerodynamic profile and an outer culvert flow channel, and determining an acoustic liner laying area; a2, numerical calculation of the flow field of the outer culvert flow channel is conducted through a computational fluid mechanics method, and aerodynamic parameter distribution of the outer culvert flow channel is obtained; a3, partitioning an acoustic liner laying area on the basis of the aerodynamic parameters obtained in the step A2; and A4, respectively establishing a plurality of agent models in each partition, running a multi-target optimization program on each agent model in parallel, and solving optimal acoustic liner structure design parameters of each partition. According to the method, the architecture design of the nacelle acoustic liner can be guided more quickly and accurately.

Description

Technical Field

[0001] The present invention relates to the field of aero engines, and in particular to the field of aerodynamic and acoustic design of engine nacelles. Background Art

[0002] Acoustic lining is the most effective technical means to reduce aircraft engine noise. It is mainly laid on the walls of the nacelle inlet, nacelle culvert, and fan casing. Its working principle is to convert the sound field energy into vortex field energy, thereby reducing the sound wave amplitude and enhancing the sound wave dissipation. For a long time, the loss of nacelle aerodynamic performance caused by acoustic lining resistance has only been passively accepted. It is a widely accepted fact that the total pressure loss of the nacelle caused by the laying of noise reduction lining is second only to the friction loss of the smooth solid wall. Among them, the nacelle culvert acoustic lining has the largest laying area, and the airflow velocity change is high, and the engine thrust loss caused by the acoustic lining is also more serious. In engineering estimates, it is generally believed that the performance loss caused by acoustic lining resistance accounts for about 50% of the performance of the smooth flow channel.

[0003] The traditional design of the outer duct sound liner structure is mainly considered from the aspect of acoustic performance. The design purpose is to maximize the noise reduction of the fan back-transmitted noise within the limitations of the reverse thrust structure layout. The typical nacelle sound liner structure is limited by the acoustic characteristics of the Helmholtz resonance cavity, and has the limitations of a narrow sound absorption frequency band and a rapid attenuation of noise reduction performance under non-noise reduction conditions. In order to broaden the noise reduction frequency band of the sound liner and the noise reduction amount at non-design operating points, the nacelle outer duct usually adopts a partitioned or multi-section sound liner design to effectively reduce noise at different frequencies and different operating conditions. The existing zoning design method of the outer duct sound liner only considers the influence of the noise source characteristics between different sections and the limitations of the structural parameters, but does not consider the difference in the flow characteristics of different partitions on the impedance characteristics of the sound liner, and also does not consider the sound liner resistance problem caused by the outer duct sound liner.

[0004] In recent years, research institutions at home and abroad have successively carried out numerical simulation and experimental research on acoustic liner resistance, mainly targeting simplified flat acoustic liner models. In terms of numerical research, high-precision numerical simulation is mainly used to study the small hole structure of flat acoustic liner and the microscale flow phenomenon in the cavity, and explain the mechanism of resistance generation. In terms of experimental research, the wind blowing experiment is mainly carried out on the flat acoustic liner test piece model, based on high-precision force balance or boundary layer thickness measurement, etc., to obtain the influence of the flat acoustic liner drag coefficient with the acoustic liner structure design parameters and flow field parameters. The relevant research results are rarely applied at the whole machine level, lacking the acoustic liner resistance calculation method and low resistance optimization design method that can support the nacelle product, and no set of nacelle noise reduction and drag reduction comprehensive optimization design methods with high precision and high efficiency characteristics have been proposed. Summary of the invention

[0005] An object of the present invention is to provide a nacelle acoustic liner architecture design method based on flow partitioning, which can guide the architecture design of the nacelle acoustic liner more quickly and accurately.

[0006] The design method for achieving the above-mentioned purpose comprises the following steps: A1. determining the aerodynamic profile of the nacelle duct and the duct flow passage, and determining the acoustic lining installation area; A2. using computational fluid dynamics methods to perform numerical calculations on the flow field of the duct flow passage, and obtaining the aerodynamic parameter distribution of the duct flow passage; A3. partitioning the acoustic lining installation area based on the aerodynamic parameters obtained in A2; A4. establishing multiple proxy models in each zone, and running a multi-objective optimization program on each proxy model in parallel to solve the optimal acoustic lining structure design parameters of each zone.

[0007] In one or more embodiments, in step A1, the range of the culvert outer wall sound lining laying area and the range of the culvert inner wall sound lining laying area are determined; wherein, the range of the outer wall sound lining laying area is such that the axial distance from the end of the outer wall sound lining laying interval of the culvert to the culvert throat is greater than the axial distance from the culvert throat to the culvert outlet, and the range of the culvert inner wall sound lining laying area is such that the axial position from the end of the outer wall sound lining laying interval of the culvert to the culvert outlet does not exceed one sound wave length downstream of the culvert outlet.

[0008] In one or more embodiments, in step A3, the culvert outer wall acoustic lining laying area and the culvert inner wall acoustic lining laying area are divided into zones based on the culvert isothermal lines or Mach number lines.

[0009] In one or more embodiments, acoustic linings with different structural design parameters are laid in each zone.

[0010] In one or more embodiments, in step A4, a performance response surface proxy model from the sound liner structure design parameters to the total pressure recovery coefficient of the nacelle culvert and a noise response surface proxy model from the sound liner structure design parameters to the cumulative noise reduction of the nacelle culvert are established in parallel in each partition.

[0011] In one or more embodiments, the steps of establishing a performance response surface proxy model from the sound liner structure design parameters to the total pressure recovery coefficient of the nacelle culvert in each partition are as follows: A4-1-1 taking the perforation rate and aperture of the perforated plate of the sound liner in each partition as optimization design variables, fixing the cavity depth and wall thickness of the perforated plate of the sound liner honeycomb cavity in each partition, and selecting sample points of the perforation rate and aperture of the sound liner within the range of the sound liner structure design parameters; A4-1-2 calculating the performance response surface proxy model of the sound liner structure design parameters of each partition under the flow Mach number through the sound liner resistance prediction model; The drag coefficient of the acoustic liner is obtained, and the equivalent roughness of the solid wall surface corresponding to the value of the drag coefficient of the acoustic liner is obtained; A4-1-3 assigns the equivalent roughness of the solid wall surface to the wall surface where the acoustic liner is laid, performs numerical calculations of the flow field of the nacelle outer duct, and solves the total pressure recovery coefficient of the nacelle outer duct under different combinations of acoustic liner structural design parameters in each partition; A4-1-4 establishes a performance response surface proxy model from the acoustic liner structural design parameters to the total pressure recovery coefficient of the nacelle outer duct based on the sample points obtained in step A4-1-1 and the solution results obtained in step A4-1-3.

[0012] In one or more embodiments, the acoustic liner resistance prediction model in step A4-1-2 is a relationship function between acoustic liner structural parameters, airflow parameters and acoustic liner resistance coefficient fitted based on an acoustic liner resistance test database, wherein the acoustic liner resistance test database includes test values ​​of acoustic liner resistance coefficient and corresponding equivalent roughness of nacelle acoustic liners with different structural design parameters under different tangential flow velocities and different incident sound intensities.

[0013] In one or more embodiments, the steps of establishing a noise response surface proxy model from the design parameters of the sound liner structure to the cumulative noise reduction of the nacelle culvert in each partition are as follows: A4-2-1 taking the perforation rate and aperture of the perforated plate of the sound liner in each partition as the optimization design variables, fixing the cavity depth and wall thickness of the perforated plate of the sound liner honeycomb cavity in each partition, and selecting sample points of the perforation rate and aperture of the sound liner within the range of the sound liner structure design parameters; A4-2-2 calculating the sound liner structure design parameters of each partition in the corresponding flow through the sound liner acoustic impedance prediction model; The acoustic impedance under the static temperature number; A4-2-3 sets the acoustic lining wall surface of the outer culvert acoustic lining laying area in the partition as the acoustic admittance boundary with the acoustic impedance obtained in A4-2-2, calculates the cumulative noise reduction of the nacelle outer culvert, and solves the cumulative noise reduction of the nacelle outer culvert under different combinations of acoustic lining structural design parameters of each partition; A4-2-4 establishes a noise response surface proxy model from the acoustic lining structural design parameters to the cumulative noise reduction of the nacelle outer culvert based on the sample points obtained in step A4-2-1 and the solution results obtained in step A4-2-3.

[0014] In one or more embodiments, the acoustic impedance prediction model of the acoustic liner in step A4-2-2 is a relationship function between the acoustic liner structural parameters, airflow parameters and the acoustic impedance value of the acoustic liner fitted based on the acoustic liner acoustic impedance test database, and the acoustic liner acoustic impedance test database includes the acoustic liner acoustic impedance test values ​​of nacelle acoustic liners with different structural design parameters under different tangential flow velocities and different incident sound intensities.

[0015] In one or more embodiments, a Latin hypercube sampling method is used to select acoustic liner perforation rate and aperture sample points on each partition within the acoustic liner structure design parameter range, and the total number of sample points is not less than 200.

[0016] In one or more embodiments, in step A2, the culvert inlet airflow parameters, the inlet boundary layer thickness, the fan back-transmitted sound source and the ambient airflow parameters are determined, the flow field calculation domain of the culvert flow passage is meshed, the culvert inlet boundary and the free flow boundary are assigned, and the flow field of the culvert flow passage is numerically calculated.

[0017] The above-mentioned nacelle acoustic liner architecture design method based on flow partitioning performs zoning design on the acoustic liner laying area according to the airflow characteristics of the duct, and establishes different corresponding models of the acoustic liner structural design parameters in each partition for solution design, and solves the optimal acoustic liner structural design parameters in each partition in parallel. Compared with the traditional nacelle acoustic liner architecture, the nacelle acoustic liner architecture design based on flow partitioning can ensure that the tangential flow velocity on the acoustic liner surface of each partition, the local airflow temperature and other parameters are approximately consistent within the partition range, and the nacelle aerodynamic performance design and acoustic liner noise reduction characteristic design can be carried out according to the airflow characteristics and sound source characteristics of different partitions, thereby taking into account the aerodynamic design and acoustic design of the nacelle acoustic liner, so that the method has the characteristics of high precision and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0019] Figure 1 This is a schematic diagram of the location of the nacelle culvert;

[0020] Figure 2 is a schematic diagram of an embodiment of a noise reduction liner;

[0021] Figure 3 It is a schematic diagram of the traditional sound liner architecture;

[0022] Figure 4 is a schematic diagram of an embodiment of a nacelle outer duct sound liner structure;

[0023] Figure 5 It is a schematic diagram of an embodiment of grid division for calculation of flow field outside the nacelle;

[0024] Figure 6 It is a schematic diagram of an embodiment of computational meshing of a nacelle outer culvert acoustic lining;

[0025] Figure 7 It is a flow chart of the design method of nacelle acoustic liner architecture based on flow partitioning;

[0026] Figure 8 It is a specific flow chart of an embodiment of a method for designing a sound liner structure. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with specific embodiments and drawings. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description herein. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0028] It should be noted that these and other subsequent drawings are only examples and are not drawn to scale, and should not be used to limit the actual scope of protection required by the present invention.

[0029] Figure 1 The nacelle culvert structure located downstream of the engine fan is shown, including the culvert outer wall and the culvert inner wall. The main functions of the nacelle culvert include: guiding the fan airflow to accelerate expansion and discharge it into the ambient atmosphere, while generating forward thrust. Figure 2 The acoustic liner shown in the figure includes a honeycomb core 11, a bottom plate 12 and a perforated plate 12, which is used to reduce the fan back-transmitted noise. Due to the special perforated plate characteristics of the nacelle acoustic liner surface, when the airflow flows through the acoustic liner surface, the flow resistance generated is greater than the resistance when flowing through a smooth solid surface, thereby causing additional aerodynamic losses.

[0030] In view of the increasingly stringent requirements of the civil aviation market for engine fuel economy, the performance indicators of various components have become more refined, and the resistance of the nacelle acoustic liner has gradually been taken seriously. The nacelle acoustic liner architecture design method based on flow partitioning disclosed in the present invention takes into account the aerodynamic design and acoustic design of the nacelle culvert acoustic liner, obtains a more refined acoustic liner setting scheme, optimizes the nacelle culvert acoustic liner laying architecture, and further performs multi-objective optimization on the nacelle culvert acoustic liner structural design parameters, thereby designing a nacelle culvert with both high aerodynamic performance and low noise characteristics.

[0031] Reference Figure 4 and Figure 7It is understood that the method includes the following steps: A1. Determine the aerodynamic profile of the nacelle outer duct and the outer duct flow channel, and determine the outer duct acoustic lining laying area; A2. Use the computational fluid dynamics method to perform numerical calculations on the flow field of the outer duct flow channel to obtain the aerodynamic parameter distribution of the nacelle outer duct flow channel area; A3. Based on the aerodynamic parameters obtained in A2, divide the acoustic lining laying area into zones; A4. Establish multiple proxy models in each zone, run the multi-objective optimization program on each proxy model in parallel, and solve the optimal acoustic lining structure design parameters of each zone.

[0032] That is, the above method includes two main parts: the design of the nacelle outer duct sound liner structure based on flow partitioning involving steps A1-A3 and the noise reduction and drag reduction design of the nacelle outer duct sound liner in step A4, and the acquisition of optimal parameters.

[0033] Specifically, in step A1, it is necessary to determine the scope of the acoustic lining laying area of ​​the outer wall of the nacelle culvert and the scope of the acoustic lining laying area of ​​the inner wall of the culvert. Figure 4 As shown, after obtaining the aerodynamic profile of the nacelle culvert, the nacelle culvert outer wall acoustic lining laying area range Zone1 and the culvert inner wall acoustic lining laying area range Zone2 are determined. Preferably, when determining the culvert outer wall acoustic lining laying area range and the culvert inner wall acoustic lining laying area range, the outer wall acoustic lining laying area range meets the requirement that the axial distance L1 from the end of the culvert outer wall acoustic lining laying interval to the culvert throat is greater than the axial distance L2 from the culvert throat to the culvert outlet, and the culvert inner wall acoustic lining laying area range meets the requirement that the axial position L3 from the end of the culvert inner wall acoustic lining laying interval to the culvert outlet does not exceed one acoustic wavelength λ downstream of the culvert outlet.

[0034] After the acoustic lining installation area is determined, in step A2, the culvert inlet airflow parameters, the inlet boundary layer thickness, the fan back-transmitted sound source, and the ambient airflow parameters are determined. The nacelle culvert aerodynamic surface and culvert flow passage, as well as the external ambient atmosphere, are used as the calculation domains to perform mesh division of the flow field calculation domain, such as Figure 5 The term "external duct inlet airflow parameters" in the above embodiment includes the total pressure and total temperature of the external duct inlet airflow, and the term "fan rear sound source" in the above embodiment includes the duct sound pressure level spectrum and sound source modal information.

[0035] exist Figure 5 In the figure, area A is the extension section of the culvert inlet, area B is the calculation domain of the environmental flow field, area C is the calculation domain of the nacelle culvert flow field, and area D is the calculation domain of the nozzle flow field. Figure 6 In the schematic diagram of the computational grid division of the nacelle culvert acoustic lining shown, area E refers to the inlet of the culvert acoustic field computational domain, area F refers to the extension section of the culvert inlet, area G refers to the area range of the culvert outer wall acoustic lining installation, area H refers to the culvert flow channel length range, area I refers to the area range of the culvert inner wall acoustic lining installation, area J refers to the extension section of the culvert outlet, and area K refers to the outlet of the culvert acoustic field computational domain.

[0036] When meshing the flow field calculation domain, it is necessary to extend the outer duct inlet boundary of the nacelle outer duct flow field calculation model upstream to obtain a boundary layer thickness similar to that in step A-1.

[0037] The culvert inlet boundary and free flow boundary are assigned, and the flow field of the nacelle culvert flow passage is numerically calculated to obtain the aerodynamic parameter distribution results such as the static temperature distribution cloud diagram in the culvert flow passage.

[0038] According to the distribution cloud diagram of the airflow parameters of the nacelle, the lining laying area of ​​the nacelle is decomposed according to a certain aerodynamic parameter, such as the isothermal line or the isomach number line, and the lining laying area is divided into several zones, such as Figure 4 As shown, according to aerodynamic parameter lines such as isothermal lines or equal Mach number lines, the outer wall acoustic lining laying area Zone1 of the culvert is divided into m partitions, and the inner wall acoustic lining laying area Zone2 of the culvert is divided into n partitions, and each partition is laid with an acoustic lining with different structural design parameters.

[0039] Compared to Figure 3 The traditional acoustic liner architecture shown in the figure can ensure that the tangential flow velocity of the acoustic liner surface and the local airflow temperature of each partition are approximately consistent within the partition range, which is conducive to the relatively accurate assignment of the equivalent roughness boundary of the acoustic liner wall surface during the calculation of the nacelle outer duct flow field and the acoustic admittance boundary of the acoustic liner wall surface during the calculation of the acoustic field, thereby improving the calculation accuracy of the nacelle outer duct flow field and the acoustic field. Since the airflow parameters (temperature, velocity, pressure, etc.) of the nacelle outer duct are constantly changing along the way. Figure 3 Under this architectural design, the tangential flow velocity, local air flow temperature and other parameters of the acoustic lining surface of each partition may vary. If the average air flow velocity or temperature of the partition surface is used to assign the resistance boundary of the flow field calculation or the acoustic admittance boundary of the sound field calculation, large errors and uncertainties will be introduced.

[0040] On the basis of completing the design and zoning of the nacelle outer culvert sound liner structure, the nacelle outer culvert noise reduction and drag reduction design can be further carried out. Compared with the traditional nacelle outer culvert sound liner structure, the nacelle outer culvert sound liner structure design based on flow zoning can ensure that the parameters such as the tangential flow velocity on the sound liner surface of each partition and the local airflow temperature are approximately consistent within the partition range, and the nacelle outer culvert aerodynamic performance design and sound liner noise reduction characteristic design can be carried out according to the airflow characteristics and sound source characteristics of different partitions.

[0041] In step A4, a performance response surface proxy model from the sound liner structure design parameters to the total pressure recovery coefficient of the nacelle outer culvert and a noise response surface proxy model from the sound liner structure design parameters to the nacelle outer culvert cumulative noise reduction are established in parallel in each partition, and a multi-objective optimization program is run in parallel to solve the optimal sound liner structure design parameters for each partition.

[0042] The total pressure recovery coefficient refers to the ratio of the total pressure at the pipeline outlet to the total pressure at the pipeline inlet, which represents the mechanical energy loss of the fluid flowing through the pipeline. The quantity of noise reduction refers to the degree of noise reduction. The response surface refers to the functional relationship between the output variable and the input variable. The surrogate model refers to the mathematical model that describes the relationship between the output variable and the input variable.

[0043] The steps of establishing the performance response surface proxy model from the sound liner structure design parameters to the total pressure recovery coefficient of the nacelle culvert in each partition are as follows: A4-1-1 The perforation rate and aperture of the perforated plate of the sound liner in each partition are used as optimization design variables, the cavity depth of the honeycomb cavity of the sound liner in each partition and the wall thickness of the perforated plate are fixed, and the perforation rate and aperture sample points of the sound liner are selected within the given range of the sound liner structure design parameters through the DOE software module; A4-1-2 The sound liner drag coefficient of the sound liner structure design parameters under the corresponding flow Mach number is calculated through the sound liner drag prediction model, and the solid wall equivalent roughness equivalent to the sound liner drag coefficient value is obtained; A4-1-3 Adopt Figure 5 The calculation domain grid of the nacelle culvert flow field is shown, and the culvert inlet boundary and the ambient free flow boundary are assigned. The acoustic liner laying wall surface of all partitions is set to the rough solid wall surface with the equivalent roughness obtained in A4-1-2, that is, the equivalent roughness of the solid wall surface is assigned to the acoustic liner laying wall surface, and the nacelle culvert flow field is numerically calculated to solve the nacelle culvert total pressure recovery coefficient under different acoustic liner structural design parameter combinations of each partition; A4-1-4 is a performance response surface proxy model from the acoustic liner structural design parameters to the nacelle culvert total pressure recovery coefficient based on the sample points obtained in step A4-1-1 and the solution results obtained in step A4-1-3.

[0044] The acoustic liner resistance prediction model in step A4-1-2 is a function of the relationship between the acoustic liner structural parameters, airflow parameters and the acoustic liner resistance coefficient, which is fitted based on the acoustic liner resistance test database. The independent variables of the function include: airflow Mach number, acoustic liner perforation rate, perforated plate thickness, perforated plate aperture, and acoustic liner honeycomb cavity depth. The contents of the acoustic liner resistance test database include the acoustic liner resistance coefficient test values ​​and equivalent roughness of nacelle acoustic liners with different structural design parameters under different tangential flow velocities and different incident sound intensities.

[0045] The steps of establishing the noise response surface proxy model from the design parameters of the acoustic liner structure to the cumulative noise reduction of the nacelle culvert in each partition are as follows: A4-2-1 Take the perforation rate and aperture of the perforated plate of the acoustic liner in each partition as the optimization design variables, fix the cavity depth of the honeycomb cavity of the acoustic liner in each partition and the wall thickness of the perforated plate, select the sample points of the perforation rate and aperture of the acoustic liner within the range of the acoustic liner structure design parameters, and obtain the sample points of the perforation rate and aperture of the acoustic liner in each partition consistent with step A4-4-1-1; A4-2-2 Calculate the acoustic impedance of the acoustic liner structure design parameters of each partition under the corresponding flow static temperature number through the acoustic liner acoustic impedance prediction model, acoustic impedance (Acoustic Impedance) refers to the ratio of the pressure of the medium on a certain area of ​​the wavefront to the volume velocity passing through this area; A4-2-3 meshes the acoustic field calculation domain of the nacelle culvert aerodynamic surface, sets the culvert flow channel inlet and outlet as annular modal duct boundaries, sets the acoustic liner wall surface of the acoustic liner laying area in the partition as the acoustic admittance boundary with the acoustic impedance obtained in A4-2-2, calculates the cumulative noise reduction of the nacelle culvert, and solves the cumulative noise reduction of the nacelle culvert under different combinations of acoustic liner structure design parameters in each partition; A4-2-4 establishes a noise response surface proxy model from the acoustic liner structure design parameters to the cumulative noise reduction of the nacelle culvert based on the sample points obtained in step A4-2-1 and the solution results obtained in step A4-1-3.

[0046] The acoustic impedance prediction model of the acoustic liner in step A4-2-2 is a function of the relationship between the acoustic liner structural parameters, airflow parameters and the acoustic impedance value of the acoustic liner, which is fitted based on the acoustic liner acoustic impedance test database, and the independent variables include: flow Mach number, sound speed, density, boundary layer thickness, sound pressure level, and frequency. The acoustic liner acoustic impedance test database includes acoustic liner acoustic impedance test values ​​of nacelle acoustic liners with different structural design parameters under different tangential flow velocities and different incident sound intensities.

[0047] In the above response surface proxy model, a DOE software module is used, and a Latin hypercube sampling method is adopted to select the sound liner perforation rate and aperture sample points on each partition within the given sound liner structure design parameter range, and the total number of sample points is not less than 200.

[0048] Since the parameters such as the tangential flow velocity on the acoustic liner surface and the local airflow temperature in each partition are approximately consistent within the partition range, the interpolation of the acoustic liner resistance boundary and the acoustic admittance boundary in different flow areas is avoided, which is conducive to the relatively accurate assignment of the equivalent roughness boundary of the acoustic liner wall surface in the calculation of the nacelle outer duct flow field and the acoustic admittance boundary of the acoustic liner wall surface in the calculation of the acoustic field; two corresponding surface proxy models are run in parallel in each partition to obtain the optimal design scheme in each partition, and the accurate calculation of the nacelle outer duct flow field and acoustic field considering the laying of the acoustic liner is realized.

[0049] In the case where the computational efficiency and cost of real modeling and simulation calculation of the actual acoustic liner structure of the product nacelle are relatively high and the requirements for the acoustic liner structure are gradually increased, the above method uses the acoustic liner resistance database and the acoustic liner resistance prediction model to assign the resistance effect of the acoustic liner on the nacelle outer culvert airflow to the nacelle outer culvert aerodynamic performance calculation through equivalent roughness, so that the nacelle outer culvert aerodynamic performance calculation under different acoustic liner laying schemes can be effectively, quickly and accurately carried out; and by establishing a performance response surface model from the acoustic liner structure design parameters to the nacelle outer culvert total pressure recovery coefficient, an agent model from the acoustic liner structure design parameters to the nacelle outer culvert cumulative noise reduction, a DOE software module, and a multi-objective optimization program, the aerodynamic and acoustic multi-objective optimization of the nacelle outer culvert acoustic liner is realized, and the program has high optimization efficiency and good convergence.

[0050] Combine the following Figure 8 , the specific process of an embodiment of the sound lining structure design method is described.

[0051] First, step A101 is performed to determine the aerodynamic profile of the nacelle culvert, and then the culvert flow passage is determined, and the nacelle culvert acoustic lining laying area is determined.

[0052] Then, steps A102 and A103 are performed to obtain the airflow parameters of the duct inlet, the thickness of the inlet boundary layer, the fan back-transmitted sound source and the ambient airflow parameters under the design state, and the nacelle duct and the external ambient atmosphere are used as the calculation domain, and the calculation domain is meshed for the flow field calculation domain, and the numerical calculation of the nacelle duct flow field is performed. After obtaining the numerical calculation results, step 104 is performed to extract the duct static temperature distribution cloud map, or select other aerodynamic parameters, such as the Mach number distribution cloud map or the static pressure distribution cloud map, etc., and divide the nacelle duct acoustic lining laying area into several partitions according to the isothermal line, or the isomach number line, the isostatic pressure line, etc., and each partition is laid with acoustic linings of different structural design parameters.

[0053] Subsequently, two types of models, namely, a performance response surface model and a noise response surface proxy model, are established in parallel in each partition, from the design parameters of the sound liner structure to the total pressure recovery coefficient of the nacelle culvert, as shown in steps A120 and A110 respectively.

[0054] When establishing the performance response surface model of the total pressure recovery coefficient, firstly, step A121 is performed, and the experimental design is performed through the DOE software module, and the sample points of the design parameters of the acoustic liner structure of each partition are established within the given range of the acoustic liner structure design parameters; then step A122 is performed, and the equivalent roughness of the solid wall corresponding to the acoustic liner drag coefficient is obtained through the acoustic liner resistance prediction model, so that the surface of the nacelle culvert acoustic liner under different structural design parameters and different flow parameters is approximated as a rough wall with the same resistance; then step A123 is performed, and the numerical calculation of the nacelle culvert flow field is performed to solve the aerodynamic performance of the nacelle culvert (total pressure recovery coefficient) under each sample point. Under the above step of converting the acoustic liner drag coefficient into the equivalent solid wall roughness, the resistance boundary of the acoustic liner wall is loaded in the numerical calculation of the aerodynamics of the nacelle culvert, so as to realize the rapid calculation of the aerodynamic performance of the nacelle culvert considering the influence of the acoustic liner laying. Finally, step A124 is performed to establish the performance response surface model from the acoustic liner structure design parameters to the total pressure recovery coefficient of the nacelle culvert.

[0055] Similarly, for establishing a noise response surface proxy model, firstly, step A111 is performed, and the design of experiments is performed through DOE to establish sample points of the design parameters of the acoustic lining structure of each partition; then, step A112 is performed, and the acoustic impedance of the acoustic lining wall of each partition is obtained through the acoustic impedance prediction model of the acoustic lining. Then, step A113 is performed to perform numerical calculation of the acoustic field of the nacelle culvert, and solve the noise reduction performance (cumulative noise reduction amount) of the nacelle culvert at each sample point; finally, step A114 is performed to establish a noise response surface proxy model from the design parameters of the acoustic lining structure to the cumulative noise reduction amount of the nacelle culvert.

[0056] After obtaining the two proxy models in parallel, proceed to step A105 to run a multi-objective optimization program to solve the optimal acoustic liner structural design parameters of all partitions and solve the comprehensive optimization design problem of aerodynamics and acoustics of the nacelle outer liner.

[0057] The present application uses specific words to describe the embodiments of the present application, such as "one embodiment", "an embodiment", and / or "some embodiments" to refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0058] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A nacelle acoustic liner architecture design method based on flow partitioning, characterized in that: The steps include: A1. Determine the aerodynamic profile of the nacelle culvert, the culvert flow passage, and the acoustic lining laying area; A2. numerically calculate the flow field of the outer duct using a computational fluid dynamics method to obtain the aerodynamic parameter distribution of the outer duct; A3. Based on the aerodynamic parameters obtained in A2, the acoustic lining installation area is divided into zones; A4. Establish multiple proxy models in each zone, run the multi-objective optimization program in parallel on each proxy model, and solve the optimal sound lining structure design parameters of each zone.

2. The nacelle acoustic liner structure design method according to claim 1, characterized in that: In step A1, the scope of the sound lining installation area of ​​the outer wall of the culvert and the scope of the sound lining installation area of ​​the inner wall of the culvert are determined; Among them, the range of the outer wall sound lining laying area is made to meet the requirement that the axial distance from the end of the outer wall sound lining laying section of the outer culvert to the outer culvert throat is greater than the axial distance from the outer culvert throat to the outer culvert outlet, and the range of the outer culvert inner wall sound lining laying area is made to meet the requirement that the axial position from the end of the outer wall sound lining laying section of the outer culvert to the outer culvert outlet is no more than one sound wave length downstream of the outer culvert outlet.

3. The nacelle acoustic liner structure design method according to claim 2, characterized in that: In step A3, the culvert outer wall acoustic lining laying area and the culvert inner wall acoustic lining laying area are divided into zones based on the culvert isothermal lines or Mach number lines.

4. The nacelle acoustic liner structure design method according to any one of claims 1 to 3, characterized in that: Acoustic lining with different structural design parameters is laid in each partition.

5. The nacelle acoustic liner structure design method according to claim 1, characterized in that: In step A4, a performance response surface proxy model from the sound liner structure design parameters to the total pressure recovery coefficient of the nacelle culvert and a noise response surface proxy model from the sound liner structure design parameters to the cumulative noise reduction of the nacelle culvert are established in parallel in each partition.

6. The nacelle acoustic liner structure design method according to claim 5, characterized in that: The steps to establish the performance response surface proxy model from the sound liner structure design parameters to the total pressure recovery coefficient of the nacelle culvert in each partition are as follows: A4-1-1 Take the perforation rate and aperture of the perforated plate of each partitioned acoustic liner as optimization design variables, fix the cavity depth of the honeycomb cavity of each partitioned acoustic liner and the wall thickness of the perforated plate, and select sample points of the perforation rate and aperture of the acoustic liner within the range of the acoustic liner structure design parameters; A4-1-2 The acoustic liner drag prediction model is used to calculate the acoustic liner drag coefficient of each partition acoustic liner structure design parameter under the flow Mach number, and the equivalent roughness of the solid wall surface equivalent to the acoustic liner drag coefficient value is obtained; A4-1-3 Assign the equivalent roughness of the solid wall surface to the wall surface where the acoustic liner is laid, perform numerical calculations on the flow field of the nacelle duct, and solve the total pressure recovery coefficient of the nacelle duct under different combinations of acoustic liner structural design parameters in each partition; A4-1-4 Based on the sample points obtained in step A4-1-1 and the solution results obtained in step A4-1-3, a performance response surface proxy model from the sound liner structure design parameters to the total pressure recovery coefficient of the nacelle culvert is established.

7. The nacelle acoustic liner structure design method according to claim 6, characterized in that: The acoustic liner resistance prediction model in step A4-1-2 is a relationship function between the acoustic liner structural parameters, airflow parameters and the acoustic liner resistance coefficient, which is fitted based on the acoustic liner resistance test database. The acoustic liner resistance test database includes the test values ​​of the acoustic liner resistance coefficient and the corresponding equivalent roughness of the nacelle acoustic liner with different structural design parameters under different tangential flow velocities and different incident sound intensities.

8. The nacelle acoustic liner structure design method according to claim 5, characterized in that: The steps to establish the noise response surface proxy model from the design parameters of the sound liner structure to the cumulative noise reduction of the nacelle culvert in each partition are as follows: A4-2-1 The perforation rate and aperture of the perforated plate of each partition acoustic liner are taken as optimization design variables, the cavity depth of the honeycomb cavity of each partition acoustic liner and the wall thickness of the perforated plate are fixed, and the perforation rate and aperture of the acoustic liner are selected within the range of the acoustic liner structure design parameters; A4-2-2 The acoustic impedance prediction model of the acoustic liner is used to calculate the acoustic impedance of each partition acoustic liner structure design parameter under the corresponding flow static temperature number; A4-2-3 Set the acoustic liner wall surface of the acoustic liner laying area in the partition as the acoustic admittance boundary with the acoustic impedance obtained in A4-2-2, calculate the cumulative noise reduction of the nacelle culvert, and solve the cumulative noise reduction of the nacelle culvert under different acoustic liner structure design parameter combinations in each partition; A4-2-4 Based on the sample points obtained in step A4-2-1 and the solution results obtained in step A4-2-3, a noise response surface proxy model is established from the design parameters of the sound liner structure to the cumulative noise reduction of the nacelle culvert.

9. The nacelle acoustic liner structure design method according to claim 8, characterized in that: The acoustic impedance prediction model of the acoustic liner in step A4-2-2 is a function of the relationship between the acoustic liner structural parameters, airflow parameters and the acoustic impedance value of the acoustic liner, which is fitted based on the acoustic liner acoustic impedance test database. The acoustic liner acoustic impedance test database includes the acoustic liner acoustic impedance test values ​​of nacelle acoustic liners with different structural design parameters under different tangential flow velocities and different incident sound intensities.

10. The nacelle acoustic liner structure design method according to any one of claims 6 to 9, characterized in that: The Latin hypercube sampling method is used to select the sound liner perforation rate and aperture sample points on each partition within the design parameter range of the sound liner structure, and the total number of sample points is not less than 200.

11. The nacelle acoustic liner structure design method according to claim 1, characterized in that: In step A2, the culvert inlet airflow parameters, inlet boundary layer thickness, fan back-transmitted sound source and ambient airflow parameters are determined, the flow field calculation domain of the culvert flow passage is meshed, the culvert inlet boundary and free flow boundary are assigned, and the flow field of the culvert flow passage is numerically calculated.

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