An intelligent design system and method for an aero on-board multi-hole complex flow channel shell part

Abstract

The application discloses an intelligent design system and method for an aero multi-hole complex flow channel shell part, and relates to the technical field of intelligent design, comprising: a data acquisition module for acquiring a three-dimensional flow channel shell model, a working condition parameter set and manufacturing limits; a feature extraction and arrangement band generation module for generating a candidate arrangement band; a hole group design and optimization module for generating a circumferential shallow cavity communication scheme and hole group arrangement; an acoustic impedance synthesis module for constructing an equivalent surface complex impedance; a performance index calculation and correlation module for constructing system insertion loss and system additional pressure drop indexes; a multi-objective trade-off and solution verification module for obtaining a certain solution; and a design and manufacturing output module for taking the certain solution as parameterized computer-aided design data and formulating manufacturing points. The application can accurately select an arrangement area in a complex flow channel and construct a controlled hole group, and realizes the consideration of noise attenuation and flow loss.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intelligent design, and in particular to an intelligent design system for an aircraft-mounted multi-hole complex flow passage shell part. BACKGROUND

[0002] In the aircraft-mounted environment, the flow passage shell part generally bears complex aerodynamic and acoustic functions, both ensuring the stable delivery of high-speed airflow and realizing noise reduction and aerodynamic loss control in limited installation space. With more stringent requirements for cabin noise and structural weight of modern aircraft, the multi-hole lining has been widely concerned because it can utilize the hole group and back cavity structure to achieve wideband noise attenuation. However, the flow passage shell often has complex geometric characteristics such as sharp bends and slowly expanding cross sections, which leads to a significant static pressure difference distribution near the inner wall. When this static pressure difference is superimposed with the gas exchange of the hole group, it may cause serious imbalance of the hole group flow distribution, and then cause problems such as flow asymmetry, local noise amplification, and additional aerodynamic resistance increase. These phenomena not only weaken the noise reduction effect, but also may cause system-level performance degradation, such as engine noise exceeding the limit or overall aerodynamic efficiency decreasing.

[0003] In the prior art, the traditional design method usually relies on uniform distribution of hole groups or empirical formulas for arrangement, and this method cannot fully utilize the actual static pressure difference distribution in the flow passage. When the hole group is arranged only according to the geometric parameters without considering the local static pressure difference, it is easy to cause some areas of the hole group to bear excessive flow exchange, leading to local flow overload, while other areas of the hole group are in an inefficient state. This not only destroys the coordination between the overall flow and acoustics, but also significantly increases the additional pressure drop, thereby reducing the stability and reliability of the system in the actual flight state. Therefore, how to establish a design method that can balance the noise reduction performance and additional pressure drop control, and avoid flow distribution imbalance of the hole group in the complex flow passage, has become a core problem that needs to be solved in the design process of this type of part. SUMMARY

[0004] The purpose of the present application is to solve the problem in the prior art that in the complex flow passage environment, how to effectively control the additional flow resistance introduced by the hole group while ensuring noise attenuation, and a kind of intelligent design system and method for an aircraft-mounted multi-hole complex flow passage shell part are proposed.

[0005] In order to solve the problems existing in the prior art, the technical scheme adopted by the present application is as follows:

[0006] An intelligent design system for an aircraft-mounted multi-hole complex flow passage shell part, comprising:

[0007] A data acquisition module for acquiring a three-dimensional flow passage shell model, a working condition parameter set, and a manufacturing limit;

[0008] The feature extraction and layout strip generation module is used to extract the centerline arc length and determine the radius of curvature distribution from the three-dimensional flow channel shell model, and generate candidate layout strips based on the inner curved wall and the post-bend expansion section of the three-dimensional flow channel shell model.

[0009] The static pressure analysis and priority area screening module is used to determine the circumferential static pressure difference along the centerline arc length within the candidate layout zone based on the curvature radius distribution and the set of working parameters, and to screen out the priority layout zone based on the circumferential static pressure difference.

[0010] The orifice group design and optimization module is used to construct circumferentially connected shallow cavities in the priority arrangement area, group the orifices in the circumferentially connected shallow cavities, determine the single-orifice volumetric flow rate of each orifice based on the circumferential static pressure difference, and generate the circumferential shallow cavity connection scheme and orifice group arrangement based on the single-orifice volumetric flow rate.

[0011] The acoustic impedance synthesis module is used to calculate the aperture impedance and shallow cavity capacitive reactance based on the circumferential shallow cavity connectivity scheme and aperture group arrangement, and synthesize the aperture impedance and shallow cavity capacitive reactance into an equivalent surface complex impedance.

[0012] The performance index calculation and correlation module is used to calculate the system insertion loss based on the equivalent surface complex impedance, calculate the system additional pressure drop based on the single-hole volumetric flow rate, combine the system insertion loss and the system additional pressure drop into index pairs and correlate them with their corresponding design variable sets.

[0013] The multi-objective trade-off and solution verification module is used to form a trade-off curve on the index pair plane of system additional voltage drop and system insertion loss, and to use the curvature maxima of the geometric inflection point of the trade-off curve as candidate solutions, and to perform consistency verification on the candidate solutions to obtain the definite solution;

[0014] The design and manufacturing output module is used to take the determined solution as parametric computer-aided design data and formulate manufacturing points.

[0015] Preferably, obtaining the three-dimensional flow channel shell model, operating parameter set, and manufacturing limits includes:

[0016] The three-dimensional flow channel shell model, operating parameter set, and manufacturing limits are obtained. The operating parameter set includes gas density, dynamic viscosity, near-wall representative velocity, and sound velocity. The manufacturing limits include the range of hole radius and the range of base material wall thickness. The coordinates and units of the three-dimensional flow channel shell model are then unified.

[0017] Preferably, the centerline arc length is extracted from the three-dimensional flow channel shell model and the radius of curvature distribution is determined. Candidate arrangement zones are generated based on the inner curved wall and the post-bend gradual expansion section of the three-dimensional flow channel shell model, including:

[0018] The centerline of the inner cavity is extracted from the three-dimensional flow channel shell model, and the arc length is obtained by spline fitting and parameterization according to the arc length.

[0019] The curvature radius distribution is obtained based on the equidistant sampling calculation of the center line arc length curvature;

[0020] A local orthogonal system is established at each sampling section to determine the inner curved wall, and the radius difference of the inner and outer curved walls to the center line is recorded;

[0021] Under the condition of meeting the manufacturing limit, a strip area is formed at the inner curved wall, and a strip area is added as a post-bending slow expansion section at the section where the post-bending cross-sectional area increases gently;

[0022] The intersection area of the inner curved wall strip area and the post-bending slow expansion section is taken as a candidate arrangement strip.

[0023] Preferably, in the candidate arrangement strip, the circumferential static pressure difference along the center line arc length is determined based on the curvature radius distribution and the working condition parameter set, and the preferred arrangement area is screened according to the circumferential static pressure difference, including:

[0024] In the candidate arrangement strip, the circumferential static pressure difference is calculated by the curvature radius distribution, the near-wall representative velocity, the gas density, and the radius difference of the inner and outer curved walls of the section along the center line arc length position according to the centrifugal balance approximation;

[0025] The preferred arrangement area is obtained with the local maximum value of the circumferential static pressure difference as the center and the adjacent local minimum value as the interval boundary.

[0026] Preferably, in the preferred arrangement area, a circumferentially connected shallow cavity is constructed, the hole positions in the circumferentially connected shallow cavity are grouped, the single-hole volume flow rate of each hole is determined according to the circumferential static pressure difference, and the circumferential shallow cavity connection scheme and hole group arrangement are generated based on the single-hole volume flow rate, including:

[0027] A continuous circumferential shallow cavity ring is constructed along the flow passage circumferential direction according to the manufacturing limit in the preferred arrangement area;

[0028] According to the high-pressure side and the low-pressure side of the circumferential static pressure difference, the holes are arranged in groups from the high-pressure side to the low-pressure side;

[0029] The single-hole volume flow rate is calculated based on the hole radius, the orifice flow coefficient, and the circumferential static pressure difference;

[0030] The zero net mass exchange constraint is applied to each section of the flow passage in the shell, and the single-hole volume flow rate in the section is made to be zero by adjusting the number of holes and the position pairing mode of the holes, so as to obtain the circumferential shallow cavity connection scheme and hole group arrangement.

[0031] Preferably, the hole impedance and the shallow cavity capacitive impedance are calculated based on the circumferential shallow cavity connection scheme and the hole group arrangement, and the hole impedance and the shallow cavity capacitive impedance are combined into an equivalent surface complex impedance, including:

[0032] The opening rate is calculated based on the circumferential shallow cavity connection scheme and the hole group arrangement, and the hole axis inclination angle, the base material wall thickness, the hole radius, the shallow cavity volume, the liner surface area, the angular frequency, the gas density, the sound speed, and the dynamic viscosity are obtained.

[0033] Geometrically stretching the wall thickness of the base material according to the hole axis inclination angle and superimposing the end correction at both ends of the hole to obtain the equivalent thickness of the hole;

[0034] According to the Maa approximation and in combination with the equivalent thickness, the hole opening ratio, the hole radius, the dynamic viscosity, the gas density and the angular frequency to calculate the hole impedance;

[0035] According to the ratio of the shallow cavity volume to the liner surface area to obtain the unit area back cavity volume;

[0036] According to the gas density, the sound speed, the angular frequency and the unit area back cavity volume to calculate the shallow cavity capacitive reactance;

[0037] Superimpose the hole impedance and the shallow cavity capacitive reactance under the same centerline arc length and the same angular frequency to obtain the equivalent surface complex impedance.

[0038] Preferably, the system insertion loss is calculated based on the equivalent surface complex impedance, the system additional pressure drop is calculated according to the single-hole volume flow rate, the system insertion loss and the system additional pressure drop are combined into a pair of performance indicators and associated with a corresponding set of design variables, including:

[0039] Divide the equivalent surface complex impedance by the product of the gas density and the sound speed to obtain the dimensionless impedance;

[0040] Carry out the normal incidence sound absorption coefficient calculation on the dimensionless impedance to obtain the sound absorption coefficient;

[0041] Carry out the wide-band arithmetic average on the sound absorption coefficient to obtain the average sound absorption coefficient, carry out the insertion loss calculation on the average sound absorption coefficient and the centerline arc length weighted summation to obtain the system insertion loss;

[0042] Calculate the hole area according to the hole radius, divide the single-hole volume flow rate by the hole area to obtain the gas flow rate of the hole, and based on the gas flow rate and the gas density, obtain the local additional pressure drop of each hole;

[0043] Superimpose the local additional pressure drops of all holes to obtain the system additional pressure drop;

[0044] Combine the system insertion loss and the system additional pressure drop into a pair of performance indicators and associate them with a corresponding set of hole axis inclination angle, hole opening ratio, unit area back cavity volume, circumferential shallow cavity communication scheme and hole group arrangement.

[0045] Preferably, a trade-off curve is formed on the indicator pair plane of the system additional pressure drop and the system insertion loss, and the curvature maximum point of the geometric inflection point of the trade-off curve is taken as a candidate solution, the candidate solution is subjected to consistency checking to obtain a determined solution, including:

[0046] Draw the index point with the system additional pressure drop as the horizontal axis and the system insertion loss as the vertical axis, and screen the index point: the index point that does not exist another index pair and satisfies the index pair point with smaller system additional pressure drop and larger system insertion loss is reserved;

[0047] The reserved index pair point is sorted in ascending order of the system additional pressure drop, and a continuous trade-off curve is obtained by adopting cubic spline fitting;

[0048] The geometric inflection point of each point is obtained based on the discrete curvature of adjacent three points, and the point with the maximum curvature is taken as a candidate solution;

[0049] The single-hole volume flow rate of each section is calculated by substituting the corresponding circumferential static pressure difference of the candidate solution to verify the zero net mass exchange constraint, and the equivalent surface complex impedance, insertion loss and additional pressure drop of the design variable set associated with the candidate solution are recalculated, if the candidate solution is inconsistent with the inflection point index, only the hole axis inclination, opening rate, unit area back cavity volume or hole pairing relationship of the corresponding section are adjusted locally and recalculated until the inflection point index is satisfied, and a determined solution is obtained.

[0050] Preferably, the determined solution is taken as parameterized computer-aided design data and manufacturing points are formulated, including:

[0051] The design parameters in the determined solution are associated with the three-dimensional model of the flow channel shell to generate a fully parameterized three-dimensional CAD model;

[0052] Manufacturing points are given according to the characteristics of the additive manufacturing process and the geometric characteristics of the determined solution, including: construction direction, support and powder removal channel and unreachable area.

[0053] In order to solve the above problems, the present application also provides an intelligent design method for an aviation airborne multi-hole complex flow channel shell part, the method comprising:

[0054] S1, obtaining a three-dimensional flow channel shell model, a working condition parameter set and a manufacturing limit;

[0055] S2, extracting the centerline arc length from the three-dimensional flow channel shell model and determining the curvature radius distribution, and generating a candidate arrangement zone based on the inner curved wall and the curved expansion section after the three-dimensional flow channel shell model;

[0056] S3, in the candidate arrangement zone, determining the circumferential static pressure difference along the centerline arc length based on the curvature radius distribution and the working condition parameter set, and screening out a preferential arrangement area according to the circumferential static pressure difference;

[0057] S4, constructing a circumferentially connected shallow cavity in the preferential arrangement area, grouping the hole positions in the circumferentially connected shallow cavity, determining the single-hole volume flow rate of each hole according to the circumferential static pressure difference, and generating a circumferential shallow cavity connection scheme and hole group arrangement based on the single-hole volume flow rate;

[0058] S5, calculate the impedance of the hole and the capacity impedance of the shallow cavity based on the circumferential shallow cavity communication scheme and hole group arrangement, and combine the impedance of the hole and the capacity impedance of the shallow cavity into equivalent surface complex impedance;

[0059] S6, calculate the system insertion loss based on the equivalent surface complex impedance, calculate the system additional pressure drop according to the single-hole volume flow rate, combine the system insertion loss and the system additional pressure drop into an index pair and associate the corresponding design variable set of the index pair;

[0060] S7, form a trade-off curve on the index pair plane of the system additional pressure drop and the system insertion loss, and take the curvature maximum point of the geometric inflection point of the trade-off curve as a candidate solution, and perform consistency checking on the candidate solution to obtain a determined solution;

[0061] S8, take the determined solution as the parameterized computer-aided design data and formulate manufacturing points.

[0062] Compared with the prior art, the beneficial effects of the present application are:

[0063] 1. In the present application, the center line arc length is extracted in the complex flow channel shell, the curvature radius distribution is determined, the candidate arrangement zone is generated combining the inner curved wall and the slow expansion section after the bend, so that the hole group arrangement can accurately correspond to the local static pressure difference distribution, thereby avoiding the flow distribution imbalance caused by the traditional uniform hole arrangement method; through this method, the effective arrangement area can be limited at the initial design stage, so that the working state of the hole group is more stable, and the utilization efficiency of the noise attenuation structure is improved.

[0064] 2. In the present application, the circumferential static pressure difference is calculated in the candidate arrangement zone, and the circumferentially connected shallow back cavity is constructed according to the circumferential static pressure difference, and the cross-sectional zero net mass exchange constraint is applied, so that the algebraic sum of the volume flow rate of the hole group on each cross section is zero, and the problem of local hole group flow overload is eliminated; this design method not only controls the gas exchange distribution of the hole group, but also ensures the balance of the overall flow, thereby effectively reducing the adverse effects of additional pressure drop on the aerodynamic performance of the system.

[0065] 3. In the present application, the equivalent surface complex impedance model of the impedance of the hole and the capacity impedance of the shallow cavity is established, the system insertion loss is calculated based on the impedance model, and then the system additional pressure drop calculated from the single-hole volume flow rate is composed into an index pair, and finally a unique preferred solution is selected through the trade-off curve; this process enables the acoustic performance and the aerodynamic performance to be optimized in the same evaluation system, ensuring that the designed multi-hole system complex flow channel shell part has both wide-band noise attenuation capability and low flow loss in actual application, thereby significantly improving the overall system operation stability and reliability. BRIEF DESCRIPTION OF DRAWINGS

[0066] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

[0067] Figure 1 A functional module diagram of an intelligent design system of an aviation airborne multi-porous complex flow passage shell part provided by an embodiment of the application is shown in FIG. 1.

[0068] Figure 2 A flowchart of an intelligent design method of an aviation airborne multi-porous complex flow passage shell part provided by an embodiment of the application is shown in FIG. 2. DETAILED DESCRIPTION

[0069] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments of the application.

[0070] Embodiment: The embodiment provides an intelligent design system of an aviation airborne multi-porous complex flow passage shell part, as shown in FIG. 1. Figure 1 Specifically, the intelligent design system comprises:

[0071] a data acquisition module, configured to acquire a three-dimensional flow passage shell model, a working condition parameter set and a manufacturing limit;

[0072] In the embodiment of the application, the three-dimensional flow passage shell model, the working condition parameter set and the manufacturing limit are acquired, comprising:

[0073] acquiring the three-dimensional flow passage shell model, the working condition parameter set and the manufacturing limit, wherein the working condition parameter set comprises gas density, dynamic viscosity, near-wall representative velocity and sound speed, the manufacturing limit comprises a hole radius range and a base material wall thickness range, and the three-dimensional flow passage shell model is subjected to coordinate and unit unification;

[0074] Specifically, a three-dimensional flow passage shell model of an aircraft airborne multi-hole complex flow passage shell part is acquired, the model being an original three-dimensional model generated in the design stage of the flow passage shell, containing a complete flow passage inner cavity structure, and the model format adopting a STEP format commonly used in the engineering field; meanwhile, a working condition parameter set is acquired, wherein the gas density and dynamic viscosity parameters refer to typical working condition data of an aircraft airborne environment, are obtained according to relevant standards of the aviation industry, the near-wall representative velocity parameter is calculated by combining the design flow of the flow passage system with the flow passage section size, and the sound velocity parameter is calculated and acquired according to the temperature and composition of the working medium in the flow passage according to relevant formulas of gas dynamics; manufacturing limit parameters are acquired, the hole radius range parameter is determined according to the minimum hole diameter machining capability of the selected additive manufacturing equipment and the maximum hole diameter design constraint, and the base material wall thickness range parameter is determined according to the minimum wall thickness forming limit of the base material in the additive manufacturing process and the structural strength requirement; the acquired three-dimensional flow passage shell model is subjected to coordinate and unit unification processing, a right-handed rectangular coordinate system is established with the starting point of the flow passage center line as the coordinate origin, the tangent direction of the flow passage center line as the X axis, the radial direction of the flow passage section as the Y axis, and the circumferential direction of the flow passage section as the Z axis, the unit system is unified by adopting the international system of units derived system with the length unit being millimeter, the density unit being kilogram per cubic meter, the viscosity unit being pascal second, and the velocity unit being meter per second, and the three-dimensional flow passage shell model is adjusted to the unified coordinate system and unit system through the coordinate conversion function and unit conversion function of the three-dimensional modeling software, so that the data used in subsequent flow passage geometric feature extraction, circumferential static pressure difference calculation and other steps have consistent coordinate and unit bases.

[0075] The feature extraction and layout band generation module is configured to extract the center line arc length and determine the curvature radius distribution from the three-dimensional flow passage shell model, and generate a candidate layout band based on the curved wall and the slow expansion section after the bend in the three-dimensional flow passage shell model.

[0076] In the embodiments of the present application, the center line arc length is extracted from the three-dimensional flow passage shell model and the curvature radius distribution is determined, and the candidate layout band is generated based on the curved wall and the slow expansion section after the bend in the three-dimensional flow passage shell model, including:

[0077] The inner cavity center line is extracted from the three-dimensional flow passage shell model, and the arc length is obtained by spline fitting and arc length parameterization;

[0078] Specifically, a three-dimensional flow channel shell model with completed coordinates and unit uniformity is imported into a three-dimensional modeling software, the inner cavity area of the flow channel shell is selected through the inner cavity extraction function of the software, all curved surfaces constituting the inner cavity wall surface are screened out and a closed inner cavity boundary model is formed; a plurality of cross sections perpendicular to the flow channel direction are selected at an equal interval of 0.5 millimeters along the flow channel length direction, each cross section intersects with the inner cavity wall surface to form a closed cross section contour, the geometric center calculation function of the software is used to obtain the geometric center of each cross section contour respectively, the geometric centers of all cross sections are sequentially connected in the order of the flow channel direction to form an initial discrete point column of the inner cavity center line; a cubic spline fitting algorithm is used for curve fitting on the initial discrete point column, a smooth continuous curve is constructed by taking the coordinates of adjacent discrete points as constraint conditions, the deviation of the fitted curve from the initial point column is controlled within the flow channel design tolerance range, and the fitted curve is the inner cavity center line of the flow channel; the inner cavity center line obtained through fitting is subjected to arc length parameterization processing, one end point of the center line is taken as a starting point, the curve is discretized into a plurality of small line segment elements along the center line direction, the length of each line segment element is calculated through the numerical integration function of the software and is sequentially accumulated, the cumulative length from the starting point to an arbitrary point on the center line is obtained, and the cumulative length is the arc length of the corresponding point; meanwhile, a corresponding relationship table of the arc length and the coordinates of each point on the center line is generated.

[0079] The arc length curvature of the center line is calculated based on equidistant sampling, and the curvature radius distribution is obtained;

[0080] Specifically, based on the center line of the inner cavity and the generated arc length and coordinate correspondence table, the equidistant sampling interval is determined, which is set to 0.5 millimeters in combination with the total length of the flow channel and the accuracy requirement, which can ensure that the sampling points cover the entire center line and reflect the bending characteristics of the curve; sampling points are selected in turn along the arc length direction of the center line at the set interval, and the arc length value of each sampling point and its three-dimensional coordinates in the unified coordinate system are recorded to form an equidistant sampling point dataset containing arc length, X coordinate, Y coordinate and Z coordinate; the first and second derivatives of the curve at each sampling point are calculated using the five-point numerical differentiation method, and with any target sampling point as the center, two adjacent sampling points before and after it are selected, and the approximate function of the center line in this region is constructed through the Lagrange interpolation polynomial, and the first and second derivatives of the approximate function are calculated to obtain the tangent direction vector and the curvature rate vector at the target sampling point; then according to the spatial curve curvature calculation formula, the first derivative vector module length and the second derivative vector module length of the target sampling point are substituted into the formula to calculate the curvature value at the sampling point, wherein the curvature calculation formula is the ratio of the module length of the second derivative vector of the curve to the cube of the module length of the first derivative vector; the reciprocal of the curvature value calculated for each sampling point is taken to obtain the curvature radius corresponding to each sampling point, and for the section of the center line that is approximately a straight line, the curvature radius is set to infinity to meet the geometric characteristics of the straight line segment; finally, the arc length values and corresponding curvature radii of each sampling point are sorted in ascending order of arc length to form an arc length and curvature radius one-to-one correspondence table, which is the center line arc length curvature radius distribution table.

[0081] A local orthogonal system is established in each sampling section to determine the inner curved wall, and the radius difference of the inner and outer curved walls to the center line is recorded;

[0082] Specifically, the intersection point of each sampling section and the center line of the inner cavity is located by using the geometric analysis function of the three-dimensional modeling software, and the intersection point is the origin of the local orthogonal system of the corresponding sampling section; the X-axis of the local orthogonal system is determined based on the tangent direction of the center line at the intersection point, the tangent direction is calculated by the first derivative of the center line, the Y-axis of the local orthogonal system is determined in the direction perpendicular to the sampling section and passing through the origin, and finally the Z-axis of the local orthogonal system is obtained by the cross product of the X-axis and the Y-axis according to the right-hand screw rule, so as to complete the establishment of the local orthogonal system of each sampling section; in combination with the curvature radius distribution of the center line arc length, the curvature center direction of the center line at the sampling section is calculated, the curvature center direction is determined by the relationship between the second derivative and the first derivative of the center line, the sampling section wall surface close to the curvature center side is determined as the inner bending wall along the Y-axis direction of the local orthogonal system, and the sampling section wall surface away from the curvature center side is determined as the outer bending wall; according to the cross-sectional size, a plurality of measurement points are uniformly selected on the inner bending wall of the sampling section along the circumferential direction, the distance measurement function of the three-dimensional modeling software is used to calculate the distance from each measurement point to the origin of the local orthogonal system, and the arithmetic mean of these distances is taken as the radius from the inner bending wall to the center line; a plurality of measurement points are uniformly selected on the outer bending wall of the sampling section along the circumferential direction in the same way, the distance from each measurement point to the origin is calculated, and the arithmetic mean is taken as the radius from the outer bending wall to the center line; finally, the radius from the outer bending wall to the center line is subtracted from the radius from the inner bending wall to the center line, to obtain the radius difference from the inner bending wall to the center line of the sampling section, and the radius difference of each sampling section is recorded in sequence according to the arc length to form a corresponding data set of the inner and outer bending radius difference and the arc length.

[0083] A strip-shaped region is formed by expanding the inner bending wall under the condition of meeting the manufacturing limit, and a strip-shaped region is additionally arranged as a bending-after expansion section in the section where the bending-after cross-sectional area increases gently;

[0084] The intersection region of the inner bending wall strip-shaped region and the bending-after expansion section is taken as a candidate arrangement strip;

[0085] Specifically, the parameters of the range of the wall thickness of the base material and the hole radius in the manufacturing limit are obtained, and the geometric constraints that need to be met in the strip region expansion process are determined, that is, the minimum width of the strip region should not be less than twice the hole radius to ensure that there is enough space when the hole group is arranged, and the maximum width should not be greater than three times the wall thickness of the base material to avoid exceeding the material forming capacity and resulting in insufficient structural strength; based on the determined inner curved wall range and the local orthogonal system of each sampling section, the spatial profile of the inner curved wall is positioned in the three-dimensional modeling software, and the geometric center of the inner curved wall in each sampling section is taken as the reference, the strip region is expanded along the direction perpendicular to the inner curved wall surface in the local orthogonal system, and during the expansion process, the real-time size monitoring function of the software is used to ensure that the width of the strip region at each arc length position is within the range allowed by the manufacturing limit, and the interference checking function of the software is used to check whether the expanded strip region conflicts with other structures of the flow passage shell, such as the reinforcing ribs and the interface flanges, and if there is a conflict, the expansion width is adjusted locally until a continuous and conflict-free inner curved wall strip region is formed; then, the section where the cross-sectional area increases gently after bending is identified, the cross-sectional area of the adjacent sampling sections is calculated, the cross-sectional area is set to increase gently when the area growth rate of the adjacent sections is not more than 5%, and all arc length sections that meet the condition are selected, that is, the section where the cross-sectional area increases gently after bending; the same expansion principle as the inner curved wall strip region is used to expand to form an additional strip region along the normal direction of the wall surface in the section, the width of the additional strip region is kept consistent with that of the inner curved wall strip region during the expansion process, and the curve smoothing function of the software is used to make the two strip regions transition continuously at the junction; finally, the inner curved wall strip region and the additional strip region after bending are integrated to form a complete initial profile of the candidate arrangement strip, and the arc length range and three-dimensional coordinates of the profile are marked in the three-dimensional modeling software.

[0086] The static pressure analysis and priority area screening module is used to determine the circumferential static pressure difference along the arc length of the center line in the candidate arrangement strip based on the curvature radius distribution and the working condition parameter set, and to screen out the priority arrangement area according to the circumferential static pressure difference.

[0087] In the embodiments of the present application, the circumferential static pressure difference along the arc length of the center line is determined in the candidate arrangement strip based on the curvature radius distribution and the working condition parameter set, and the priority arrangement area is screened out according to the circumferential static pressure difference, which includes:

[0088] In the candidate arrangement strip, the circumferential static pressure difference is calculated along the arc length of the center line by the curvature radius distribution, the near-wall representative velocity, the gas density and the difference between the inner and outer bending radii of the section;

[0089] Specifically, within the arc length coverage area of ​​the candidate arrangement zone, sampling points are divided along the arc length direction of the corresponding centerline of the candidate arrangement zone at equidistant sampling intervals of 0.5 mm. Each sampling point corresponds to a unique arc length position, and the arc length value of each sampling point and its corresponding radius of curvature and the difference between the inner and outer bending radii of the cross section are recorded. For each sampling point, the circumferential static pressure difference calculation relationship is constructed using the centrifugal equilibrium approximation principle. The formula for calculating the circumferential static pressure difference is:

[0090]

[0091] In the formula, The arc length of the center line Circumferential static pressure difference at the location, For gas density, The near-wall representative velocity, The arc length of the center line The radius of curvature at that point The difference between the inner and outer bending radii of the cross section;

[0092] After calculating the circumferential static pressure difference for all sampling points, the calculation results are processed by the data smoothing module. Linear interpolation is used to fill the gaps in the circumferential static pressure difference data between adjacent sampling points to ensure the continuous distribution of the circumferential static pressure difference along the arc length of the centerline. At the same time, outliers exceeding the physically reasonable range are removed. The criteria for judging outliers is that the circumferential static pressure difference of a sampling point exceeds 20% of the average value of five adjacent sampling points. A correspondence table between the circumferential static pressure difference and the position of the arc length of the centerline is generated. In the 3D modeling software, the circumferential static pressure difference values ​​at each arc length position are associated and marked with the spatial position of the candidate arrangement zone to obtain the circumferential static pressure difference distribution covering the entire candidate arrangement zone.

[0093] The priority layout area is obtained by taking the local maximum value of the circumferential static pressure difference as the center and the adjacent local minimum values ​​as the interval boundary;

[0094] Specifically, the circumferential static pressure difference data is pre-processed, a moving average method is used to smooth the data, and the window size is 6 continuous sampling points, so as to eliminate high-frequency noise interference and ensure the continuous change trend of the static pressure difference; then, the circumferential static pressure difference data after smoothing is traversed along the center line arc length direction, and the local extreme value is determined through the sign change of the first derivative; when the first derivative of a sampling point changes from positive to negative, the point is determined as a local maximum point; when the first derivative changes from negative to positive, the point is determined as a local minimum point; the identified local maximum points are sorted in the order of arc length, and each local maximum point is taken as the center to find the first local minimum point adjacent to the front and rear of the local maximum point along the arc length direction; the forward adjacent local minimum point is taken as the interval starting boundary, and the backward adjacent local minimum point is taken as the interval ending boundary, to form a candidate interval with the local maximum value as the center; if the local maximum point is located at the starting end of the data, the arc length position corresponding to the starting end of the flow channel is taken as the interval starting boundary; if it is located at the end of the data, the arc length position corresponding to the end of the flow channel is taken as the interval ending boundary; for the case that the candidate intervals corresponding to adjacent local maximum points overlap, the union of the overlapping region is taken as the merged interval, and the center of the merged interval is the local maximum point with the maximum static pressure difference in the overlapping region; finally, all candidate intervals or merged intervals are mapped to the candidate arrangement zone of the three-dimensional flow channel shell model, and the space region corresponding to these intervals is marked as the priority arrangement region.

[0095] The hole group design and optimization module is used for constructing a circumferentially connected shallow cavity in the priority arrangement region, grouping the hole positions in the circumferentially connected shallow cavity, determining the single-hole volume flow rate of each hole according to the circumferential static pressure difference, and generating a circumferential shallow cavity connection scheme and hole group arrangement based on the single-hole volume flow rate.

[0096] In the embodiments of the present application, a circumferentially connected shallow cavity is constructed in the priority arrangement region based on the manufacturing limit, the hole positions in the circumferentially connected shallow cavity are grouped, the single-hole volume flow rate of each hole is determined according to the circumferential static pressure difference, and a circumferential shallow cavity connection scheme and hole group arrangement are generated based on the single-hole volume flow rate, which includes:

[0097] A continuous circumferential shallow cavity is constructed along the circumferential direction of the flow channel in the priority arrangement region according to the manufacturing limit.

[0098] According to the high-pressure side and the low-pressure side of the circumferential static pressure difference, the holes are arranged in groups from the high-pressure side to the low-pressure side.

[0099] Specifically, in the three-dimensional modeling software, the wall surface area of the priority arrangement area is positioned, and the cross-sectional profile line of the shallow cavity is drawn along the circumferential direction of the flow channel, limited by the circumferential boundary of the priority arrangement area. The cross-sectional shape adopts a rectangle, which is convenient for additive manufacturing. The cross-sectional depth is selected according to 40-60% of the base material wall thickness, and the specific value is dynamically adjusted according to the base material wall thickness at different arc length positions of the priority arrangement area to ensure that it does not exceed the manufacturing limit. The cross-sectional width is selected according to 3-5 times the hole radius to ensure that the circumferential range of the priority arrangement area is covered. The drawn cross-sectional profile line is swept along the arc length direction of the priority arrangement area by the sweeping function of the three-dimensional modeling software to form a continuous circumferential shallow cavity initial three-dimensional structure. The cross-sectional parameters of the shallow cavity are kept smooth in the arc length direction during the sweeping process, and the cross-sectional depth and width variation rate of adjacent positions are not more than 10%, so as to avoid stress concentration caused by sudden change. Then, the interference checking function of the software is enabled to check whether there is spatial overlap between the circumferential shallow cavity and other structures of the flow channel shell body, such as internal support and interface flange. If there is interference, the circumferential boundary of the shallow cavity is adjusted locally. After adjustment, it still needs to be located in the priority arrangement area or reduce the local cross-sectional size. After adjustment, it still meets the manufacturing limit until all interferences are eliminated. Finally, the inner wall of the circumferential shallow cavity is rounded with a radius not less than half of the hole radius to reduce stress concentration, and a three-dimensional model of the circumferential shallow cavity meeting the manufacturing limit and being continuous is generated. The model is integrated with the flow channel shell body base model by Boolean operation to output a flow channel shell body intermediate model containing the circumferential shallow cavity.

[0100] In detail, the high-pressure side and the low-pressure side boundaries at each arc length position are determined through the static pressure difference contour analysis, wherein the high-pressure side is the area with higher circumferential static pressure difference value, and the low-pressure side is the area with lower circumferential static pressure difference value. The division of the two is based on the static pressure difference gradient direction, that is, the direction from high gradient to low gradient is the direction from the high-pressure side to the low-pressure side. At the same time, the hole radius range parameter in the manufacturing limit is extracted, and it is clear that the minimum distance between holes should not be less than twice the hole radius to avoid insufficient structural strength between holes. The number of holes in a single group should not exceed the ratio of the circumferential width of the circumferential shallow cavity to the hole diameter to ensure that the hole groups are reasonably distributed in the shallow cavity. In the three-dimensional modeling software, the circumferential shallow cavity inner wall of the priority arrangement area is positioned, and the hole group arrangement axis is drawn along the direction from the high-pressure side to the low-pressure side of each arc length position. The axis length should not exceed the circumferential width of the circumferential shallow cavity to ensure that the hole is completely located in the shallow cavity. The hole spacing is set according to twice the hole radius, and the center coordinates of each hole in a single group are determined along the arrangement axis. The hole arrangement method adopts equal-interval linear arrangement, and the number of holes in a single group is an integer according to the ratio of the circumferential width of the shallow cavity to the hole diameter. The hole groups of adjacent arc length positions are checked for continuity, and the holes of adjacent groups are arranged continuously in the arc length direction by adjusting the starting position of the hole group to avoid obvious misplacement of the hole group in the arc length direction.

[0101] The single-hole volume flow rate is calculated based on the hole radius, orifice flow coefficient, and circumferential static pressure difference.

[0102] Specifically, the determined hole radius parameter and the orifice flow coefficient are obtained, wherein the orifice flow coefficient is selected according to the machining process characteristics of the hole, the coefficient value of 0.6 to 0.7 is taken for the unchamfered orifice formed by additive manufacturing, and the coefficient value of 0.7 to 0.8 is taken for the orifice chamfered after processing, the cross-sectional area of the hole is obtained according to the circular area calculation rule of the hole radius, the circumferential static pressure difference of the position of each hole is extracted, the three-dimensional coordinates of the hole are positioned in the circumferential static pressure difference distribution, the static pressure difference accurate value of the position is calculated by using the adjacent three-point interpolation method, wherein the static pressure difference of the corresponding position of the high-pressure side hole is recorded as the high-pressure value, the static pressure difference of the corresponding position of the low-pressure side hole is recorded as the low-pressure value, the static pressure difference driving value of the single hole is the difference value of the high-pressure value and the low-pressure value, the single hole volume flow rate is obtained by applying the orifice flow calculation rule, and the calculation process is the product of the orifice flow coefficient and the single hole cross-sectional area, multiplied by the square root of the ratio of twice the static pressure difference driving value and the gas density. According to this rule, the volume flow rate of each hole is calculated in turn.

[0103] The zero net mass exchange constraint is applied to each cross section of the flow channel in the shell, the single hole volume flow rate in the cross section is adjusted by adjusting the number of holes and the position pairing mode of the holes, so that the algebraic sum of the single hole volume flow rate in the cross section is zero, and the circumferential shallow cavity communication scheme and the hole group arrangement are obtained.

[0104] Specifically, along the arc length direction of the flow channel center line at a predetermined interval, the interval value is one-fifth to one-tenth of the flow channel diameter, and the flow channel cross section perpendicular to the center line is divided according to the flow channel size, each cross section intersects with the circumferential shallow cavity and the hole group, the hole identification contained in each cross section and the corresponding volume flow rate are recorded, the zero net mass exchange constraint is applied to each flow channel cross section, the algebraic sum of the volume flow rate of all holes in the cross section is calculated, the flow rate of the high-pressure side hole is positive, and the flow rate of the low-pressure side hole is negative. If the absolute value of the algebraic sum is greater than five percent of the maximum single hole volume flow rate in the cross section, the holes are adjusted. When adjusting the number of holes, the hole radius should be within the range allowed by the manufacturing limit. If the algebraic sum is positive, that is, the high-pressure side flow rate total is too large, then increase the number of holes on the low-pressure side or reduce the radius of part of the holes on the high-pressure side. If the algebraic sum is negative, that is, the low-pressure side flow rate total is too large, then increase the number of holes on the high-pressure side or reduce the radius of part of the holes on the low-pressure side. After each adjustment, the single hole volume flow rate and the cross section algebraic sum are recalculated until the absolute value of the algebraic sum is less than five percent of the maximum single hole volume flow rate in the cross section. When adjusting the position pairing mode of the holes, the hole group in the cross section is regrouped, the holes with larger high-pressure side flow rate are paired with the holes with larger low-pressure side flow rate, and the holes with smaller high-pressure side flow rate are paired with the holes with smaller low-pressure side flow rate, so that the absolute value deviation of the flow rate of each paired hole group is not more than ten percent, and the total flow rate in the cross section is balanced by adjusting the pairing combination. If the pairing adjustment still does not meet the constraint, the number of holes is adjusted until the absolute value of the volume flow rate algebraic sum in the cross section is close to zero. For the hole group in the same flow channel cross section that meets the zero net mass exchange constraint, the corresponding shallow cavity region is set as a communication structure.

[0105] An acoustic impedance synthesis module is configured to calculate hole impedance and shallow cavity reactance based on the circumferential shallow cavity communication scheme and the hole group arrangement, and to synthesize the hole impedance and the shallow cavity reactance into an equivalent surface complex impedance.

[0106] In an embodiment of the present application, the hole impedance and the shallow cavity reactance are calculated based on the circumferential shallow cavity communication scheme and the hole group arrangement, and are synthesized into an equivalent surface complex impedance, comprising:

[0107] The open hole ratio is counted based on the circumferential shallow cavity communication scheme and the hole group arrangement, and the hole axis inclination angle, the base material wall thickness, the hole radius, the shallow cavity volume, the liner surface area, the angular frequency, the gas density, the sound speed, and the dynamic viscosity are obtained.

[0108] The base material wall thickness is geometrically stretched according to the hole axis inclination angle, and an end correction at both ends of the hole is superimposed to obtain the equivalent thickness of the hole.

[0109] Specifically, the circumferential shallow cavity communication scheme three-dimensional model, the hole group arrangement three-dimensional model, and the liner surface area data of the preferential arrangement area are obtained, the total cross-sectional area of all holes in the hole group is calculated, and then the total cross-sectional area is divided by the liner surface area to obtain the open hole ratio value. Each parameter is obtained, wherein the hole axis inclination angle is obtained from the spatial posture data of the holes in the hole group arrangement, the base material wall thickness is obtained from the manufacturing limit parameters and the wall thickness analysis result of the flow channel shell model, the hole radius is obtained from the hole size parameters of the hole group arrangement, the shallow cavity volume is obtained through the volume measurement function of the circumferential shallow cavity communication scheme three-dimensional model, the liner surface area is the wall area of the preferential arrangement area, the angular frequency is calculated according to the acoustic analysis frequency range in the working condition parameters, the angular frequency is the product of the frequency and twice the circular frequency, and the gas density, the sound speed, and the dynamic viscosity are obtained from the working condition parameter set. The equivalent thickness of the hole is calculated, the base material wall thickness is geometrically stretched according to the hole axis inclination angle, the length after stretching is the base material wall thickness divided by the cosine value of the hole axis inclination angle, and then the end correction value at both ends of the hole is superimposed. The end correction value is an empirical value according to the hole flow characteristics, and is usually 1.6 times the hole radius, that is, 0.8 times the hole radius is corrected at both ends of the hole. The length after stretching and the end correction value are added to obtain the equivalent thickness of the hole.

[0110] The hole impedance is calculated according to the Maa approximation and in combination with the equivalent thickness, the open hole ratio, the hole radius, the dynamic viscosity, the gas density, and the angular frequency.

[0111] Specifically, the Maa approximation model is used to describe the acoustic impedance characteristics of the hole, the hole impedance is a complex number including a real part corresponding to viscous loss and an imaginary part corresponding to inertial effect, and the hole impedance calculation formula is:

[0112]

[0113] In the formula, represents the arc length position of the center line represents the acoustic impedance of the hole at the position of the center line and the angular frequency ω, and reflects the hindering ability of the hole to the sound wave propagation. The dynamic viscosity of the gas. Let be the equivalent thickness of the hole at position s along the centerline arc length. For open area ratio, Where is the radius of the hole. Angular frequency, For gas density, The imaginary unit; Corresponding energy loss, Corresponding phase change.

[0114] The volume of the back cavity per unit area is obtained by the ratio of the shallow cavity volume to the lining surface area.

[0115] Calculate the shallow cavity capacitive reactance based on gas density, sound velocity, angular frequency, and back cavity volume per unit area;

[0116] Specifically, the volume of the shallow cavity is divided by the surface area of ​​the lining to obtain the volume of the back cavity per unit area. This value reflects the size of the shallow cavity volume corresponding to a unit lining area. The acoustic response characteristics of the circumferential shallow cavity are described using acoustic capacitance theory. The formula for calculating the capacitance of the shallow cavity is as follows:

[0117]

[0118] In the formula, Position of the centerline arc length angular frequency The acoustic impedance of the lower aperture reflects the shallow cavity's ability to store acoustic energy; The imaginary unit, For gas density, The speed of sound in a gas. Angular frequency, Position of the centerline arc length The volume of the back cavity per unit area at that location.

[0119] The equivalent surface complex impedance is obtained by superimposing the aperture impedance and shallow cavity capacitive reactance at the same centerline arc length and the same angular frequency.

[0120] Specifically, the aperture impedance and shallow cavity capacitive reactance are matched with the same centerline arc length and the same angular frequency to form corresponding impedance and capacitive reactance data pairs. Complex superposition operation is performed on each set of matched data. According to the principle of acoustic impedance series superposition, the real part of the equivalent surface complex impedance is the real part of the aperture impedance, and the imaginary part is the algebraic sum of the imaginary parts of the aperture impedance and the imaginary parts of the shallow cavity capacitive reactance, thus obtaining the corresponding equivalent surface complex impedance value.

[0121] The performance index calculation and correlation module is used to calculate the system insertion loss based on the equivalent surface complex impedance, calculate the system additional pressure drop based on the single-hole volumetric flow rate, combine the system insertion loss and the system additional pressure drop into index pairs and correlate them with their corresponding design variable sets.

[0122] In embodiments of the present invention, the system insertion loss is calculated based on the equivalent surface complex impedance, and the system additional pressure drop is calculated based on the single-orifice volumetric flow rate. The system insertion loss and system additional pressure drop are combined into an index pair and associated with their corresponding set of design variables, including:

[0123] Dividing the equivalent surface complex impedance by the product of the gas density and the sound velocity yields the dimensionless impedance.

[0124] The absorption coefficient is obtained by calculating the normal incident absorption coefficient of the dimensionless impedance;

[0125] Specifically, the equivalent surface complex impedance is matched with the gas density and sound velocity corresponding to the same centerline arc length position and angular frequency. The dimensionless impedance is obtained by using the equivalent surface complex impedance as the dividend and the product of the gas density and sound velocity as the divisor. The complex division rule is that the real and imaginary parts are divided by the product of the gas density and sound velocity, respectively. The dimensionless impedance reflects the relative magnitude and phase characteristics of the impedance. The normal incident absorption coefficient is then calculated from the dimensionless impedance using the following formula:

[0126]

[0127] In the formula, Position of the centerline arc length angular frequency The sound absorption coefficient is below. This represents the real part of the dimensionless impedance. This is the imaginary part of the dimensionless impedance.

[0128] The sound absorption coefficient is obtained by wideband arithmetic mean. The average sound absorption coefficient is then calculated by inserting the average sound absorption coefficient and weighted and summed with the center line arc length to obtain the system insertion loss.

[0129] Specifically, based on the frequency range of acoustic interest, the broadband analysis range is determined to be from 20Hz to 20000Hz. This range is divided into multiple sub-bands with equal frequency intervals of 200Hz. Each sub-band corresponds to a unique angular frequency. For each centerline arc length position, the absorption coefficients of all sub-bands within the broadband are extracted. The average absorption coefficient at this position is calculated using the arithmetic mean method. Then, based on the correlation formula between insertion loss and average absorption coefficient, the insertion loss at each arc length position is calculated using the formula: [Formula omitted for brevity].

[0130]

[0131] In the formula, Position of the centerline arc length Insertion loss at that point, Position of the centerline arc length The average sound absorption coefficient of the position; the formula is based on the relationship between the sound absorption coefficient and the sound energy attenuation, and reflects the weakening ability of the position to the sound wave.

[0132] In detail, the arc length range is divided into a plurality of small arc segments along the center line of the flow passage, the length of each arc segment is not more than one tenth of the diameter of the flow passage, the weight of each arc segment is the actual length thereof, the weighted insertion loss of each arc segment is obtained by multiplying the corresponding insertion loss of the arc segment by the weight, and the system insertion loss of the entire flow passage is obtained by accumulating the weighted insertion losses of all the arc segments.

[0133] According to the hole radius, the hole area is calculated, the gas flow rate of the single hole is obtained by dividing the single hole volume flow rate by the hole area, and the local additional pressure drop of each hole is obtained based on the gas flow rate and the gas density;

[0134] The local additional pressure drops of all the holes are superimposed to obtain the system additional pressure drop;

[0135] Specifically, the hole area is calculated according to the circular area formula to obtain the single hole cross-sectional area, the gas flow rate of the hole is calculated by dividing the single hole volume flow rate by the corresponding hole cross-sectional area, the local additional pressure drop of the single hole is obtained by multiplying the square of the gas flow rate by the local resistance coefficient and then by 0.5 times the gas density, wherein the local resistance coefficient is determined according to the manufacturing process, the local additional pressure drops of all the holes are superimposed, and the system additional pressure drop is obtained by performing algebraic summation on all the local additional pressure drops of the single holes.

[0136] The system insertion loss and the system additional pressure drop are combined into a performance index pair, and the corresponding hole axis inclination angle, hole opening rate, unit area back cavity volume, circumferential shallow cavity communication scheme and hole group arrangement are associated;

[0137] Specifically, the system insertion loss and the system additional pressure drop are combined into an ordered performance index value pair in the form of (system insertion loss value, system additional pressure drop value), each performance index pair is marked with the corresponding calculation working condition parameter, and the corresponding hole axis inclination angle, hole opening rate, unit area back cavity volume, circumferential shallow cavity communication scheme identifier and hole group arrangement identifier are associated with the performance index pair as the core key value.

[0138] The multi-objective trade-off and solution verification module is configured to form a trade-off curve on the index pair plane of the system additional pressure drop and the system insertion loss, take the curvature maximum point of the geometric inflection point of the trade-off curve as a candidate solution, and perform consistency checking on the candidate solution to obtain a determined solution.

[0139] In the embodiments of the present application, a trade-off curve is formed on the index pair plane of the system additional pressure drop and the system insertion loss, the curvature maximum point of the geometric inflection point of the trade-off curve is taken as a candidate solution, consistency checking is performed on the candidate solution, and a determined solution is obtained, including:

[0140] Draw the index points with the system additional pressure drop as the horizontal axis and the system insertion loss as the vertical axis, and screen the index points: keep the index point that has smaller system additional pressure drop and has larger system insertion loss, and eliminate the abnormal index points that have negative system additional pressure drop or negative system insertion loss;

[0141] Specifically, the numerical pairs of the system additional pressure drop and the system insertion loss and the corresponding index point identifiers are extracted, the abnormal index points with negative system additional pressure drop or negative system insertion loss are eliminated, the coordinate axis scale range is determined according to the numerical range of the effective index points with the system additional pressure drop as the horizontal axis and the system insertion loss as the vertical axis, the index points are plotted in the coordinate system, and the all effective index points are evaluated by using the point-by-point comparison method. If there is an index point that has smaller system additional pressure drop and has larger system insertion loss, it is determined that the index point to be evaluated is non-optimal and is marked for elimination. If there is no such index point after the traversal, it is determined that the index point to be evaluated is optimal and is kept.

[0142] The retained index points are sorted in ascending order of the system additional pressure drop, and a continuous trade-off curve is obtained by using cubic spline fitting.

[0143] The geometric inflection points of each point are calculated based on the discrete curvatures of the adjacent three points, and the point with the maximum curvature is taken as the candidate solution.

[0144] Specifically, the retained index points are sorted in ascending order of the system additional pressure drop value, the sorted system additional pressure drop is taken as the horizontal axis data with the independent variable, and the corresponding system insertion loss is taken as the vertical axis data with the dependent variable, a continuous trade-off curve is constructed by using the cubic spline fitting method, the curve is ensured to satisfy the continuity of the first and second derivatives during fitting, a calculation unit is constructed by taking the adjacent three points as a group along the sorted index point sequence, for each group of three points, the coordinates (system additional pressure drop, system insertion loss) are applied to the discrete curvature formula to first calculate the center and radius of the circle formed by the three points, and then take the reciprocal of the radius as the discrete curvature of the middle point in the group. The curvature values of each middle index point are calculated in turn. For the first and last index points in the sequence, the three-point group is constructed by supplementing the adjacent two points and the adjacent points on the fitted curve to calculate the curvature. By comparing the curvature change trend of the adjacent index points, if the curvature values before and after a certain point present the change trend of first increasing and then decreasing or first decreasing and then increasing, it is determined as a geometric inflection point. The curvature values of all inflection points are compared, and the inflection point with the maximum curvature value is selected as the candidate solution.

[0145] The circumferential static pressure difference corresponding to the candidate solution is substituted into the calculation of the single-hole volume flow rate of each section to check the zero net mass exchange constraint, and the equivalent surface complex impedance, insertion loss and additional pressure drop of the design variable set associated with the candidate solution are recalculated. If it is inconsistent with the inflection point index, only the hole axis inclination, opening rate, unit area back cavity volume or hole pairing relationship of the corresponding section is adjusted locally and recalculated until the inflection point index is satisfied, and the determined solution is obtained.

[0146] Specifically, the circumferential static pressure difference distribution data corresponding to the candidate solution, the design variable set: hole axis inclination, opening rate, unit area back cavity volume, hole pairing relationship, and the inflection point index: system insertion loss and system additional pressure drop are retrieved. The circumferential static pressure difference is matched with the position of each section of the flow passage, the volume flow rate of all holes in each section is recalculated, and the zero net mass exchange constraint is checked for each section. If a section does not satisfy the zero net mass exchange constraint, mark the section as an area to be adjusted. Recalculate the equivalent surface complex impedance, system insertion loss and system additional pressure drop based on the design variable set of the candidate solution. Compare the recalculated results with the inflection point index. If the insertion loss deviation exceeds 0.5 decibels or the additional pressure drop deviation exceeds 50 pascals, it is determined to be inconsistent and adjustment is required. Focus on the adjustment section and the index deviation area during adjustment. Prioritize adjusting the hole axis inclination. The adjustment range is plus or minus five degrees of the original inclination, ensuring that it does not exceed the manufacturing limit. If the index is still inconsistent after adjustment, adjust the opening rate, with an increase or decrease of no more than 10% of the original opening rate, or adjust the unit area back cavity volume by changing the depth of the shallow cavity. The adjustment range is no more than 15% of the original volume. If necessary, re-pair the holes in the section, keeping the direction from the high-pressure side to the low-pressure side unchanged, and optimizing the absolute value deviation of the paired holes to within 5%. After each adjustment, repeat the single-hole volume flow rate calculation, zero net mass exchange constraint checking, and recalculation of the equivalent surface complex impedance, insertion loss and additional pressure drop. Until all sections satisfy the zero net mass exchange constraint and the recalculated index deviates from the inflection point index within the allowed range, output the design variable set and the corresponding structure parameters as the determined solution.

[0147] The design and manufacturing output module is used to output the determined solution as parametric computer-aided design data and formulate manufacturing points;

[0148] In the embodiments of the present application, the determined solution is output as parametric computer-aided design data and manufacturing points, which includes:

[0149] The design parameters in the determined solution are associated with the three-dimensional model of the flow passage shell to generate a fully parametric three-dimensional CAD model;

[0150] Manufacturing points are given according to the characteristics of the additive manufacturing process and the geometric characteristics of the determined solution, including: build direction, support and powder removal channel, and unreachable area.

[0151] Specifically, the design parameter set in the determined solution includes hole axis inclination, hole opening rate, hole radius, shallow cavity depth, hole group arrangement coordinates, and circumferential communication channel size, etc., and a basic three-dimensional model of the flow channel shell, and the association mapping between the design parameters and the model features is established through the parametric modeling module of the CAD software, the hole radius is associated with the diameter parameter of the hole feature, the shallow cavity depth is associated with the stretching depth parameter of the shallow cavity feature, the hole group arrangement coordinates are associated with the positioning parameter of the hole feature, the circumferential communication channel size is associated with the cross-section parameter of the channel feature, and a parameter-driven relationship chain is formed; then the parameter variable interval is set, the upper and lower limits of each parameter do not exceed the manufacturing limit, the model regeneration function is enabled to verify the parameter association, and the model features should be automatically updated without geometric conflicts after any parameter is modified, and a fully parameterized three-dimensional CAD model is generated; the geometric features of the determined solution are extracted according to the characteristics of the additive manufacturing process, including the depth-diameter ratio of the hole, the overhanging angle of the shallow cavity, and the density of the hole group, etc., and the construction direction is determined: taking the flow channel center line as the reference, the process adaptability of different directions such as the axial direction along the center line, the radial direction perpendicular to the center line, and the direction at an angle of 45 degrees with the center line is compared, and the direction that makes the angle between the hole axis and the construction direction not less than 30 degrees to reduce the forming deviation of the hole and the overhanging angle of the shallow cavity not greater than 45 degrees to reduce the support demand is preferentially selected, if there are multiple optional directions, the forming accuracy and material utilization rate are evaluated through the process simulation software, and the comprehensive optimal direction is selected; the support and powder removal channel is designed: for the overhanging structure at the bottom of the shallow cavity, if the overhanging length is greater than 2 mm, removable support is added, a grid-like structure is adopted, the support density increases with the increase of the overhanging length, and a 0.5 mm thick easy-to-peel layer is arranged on the connecting surface between the support and the base material; for the closed cavity formed by the circumferential shallow cavity and the hole group, if the volume is greater than 5 cubic centimeters, a powder removal channel is arranged at both ends of the cavity along the radial direction of the flow channel, the channel diameter is not less than 8 mm to ensure that the powder cleaning tool can be inserted, and the connecting round corner radius between the channel and the cavity is not less than 1 mm to avoid stress concentration; the unreachable area is identified: whether there is a blind hole with a diameter less than 3 mm and a depth exceeding 10 mm in the hole group and the shallow cavity corner is checked through the space analysis function of the CAD software, the laser is difficult to focus during additive manufacturing, or the angle of the narrow gap is less than 30 degrees, and the powder is difficult to spread, for such unreachable areas, the distribution density of the hole is adjusted, the distance between adjacent holes is increased to more than 5 mm, or the shallow cavity corner is modified to a round corner with a radius not less than 2 mm, and if necessary, the hole depth is locally reduced to ensure that the depth-diameter ratio is not greater than 5, and the reachability of the modified area is verified through process simulation, finally, the manufacturing points are integrated to form a process guidance file, including a three-dimensional schematic diagram of the construction direction, the position and size parameters of the support and powder removal channel, and the comparison diagram of the unreachable area before and after modification, the file is stored in association with the fully parameterized three-dimensional CAD model, and a data set directly used for additive manufacturing is output.

[0152] To solve the above problems, the present application further provides an intelligent design method for an aviation airborne multi-hole complex flow channel shell part, which comprises:

[0153] S1, obtaining a three-dimensional flow channel shell model, a working condition parameter set, and a manufacturing limit;

[0154] S2, extracting a centerline arc length from the three-dimensional flow channel shell model and determining a curvature radius distribution, and generating a candidate arrangement zone based on the inner curved wall and the curved rear slow expansion section in the three-dimensional flow channel shell model;

[0155] S3, in the candidate arrangement zone, determining a circumferential static pressure difference along the centerline arc length based on the curvature radius distribution and the working condition parameter set, and screening out a priority arrangement area according to the circumferential static pressure difference;

[0156] S4, constructing a circumferentially connected shallow cavity in the priority arrangement area, grouping the hole positions in the circumferentially connected shallow cavity, determining the single-hole volume flow rate of each hole according to the circumferential static pressure difference, and generating a circumferential shallow cavity connection scheme and hole group arrangement based on the single-hole volume flow rate;

[0157] S5, calculating the hole impedance and the shallow cavity capacitive impedance based on the circumferential shallow cavity connection scheme and the hole group arrangement, and synthesizing the hole impedance and the shallow cavity capacitive impedance into an equivalent surface complex impedance;

[0158] S6, calculating the system insertion loss based on the equivalent surface complex impedance, calculating the system additional pressure drop according to the single-hole volume flow rate, combining the system insertion loss and the system additional pressure drop into an index pair and associating the corresponding design variable set thereof;

[0159] S7, forming a trade-off curve on the index pair plane of the system additional pressure drop and the system insertion loss, and taking the curvature maximum point of the geometric inflection point of the trade-off curve as a candidate solution, performing consistency checking on the candidate solution, and obtaining a determined solution;

[0160] S8, taking the determined solution as parameterized computer-aided design data and formulating manufacturing points.

[0161] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. An intelligent design system for complex flow channel shell parts with porous systems for airborne applications, characterized in that, include: The data acquisition module is used to acquire the three-dimensional flow channel shell model, working condition parameter set, and manufacturing limits; The feature extraction and layout strip generation module is used to extract the centerline arc length and determine the radius of curvature distribution from the three-dimensional flow channel shell model, and generate candidate layout strips based on the inner curved wall and the post-bend expansion section of the three-dimensional flow channel shell model. The static pressure analysis and priority area screening module is used to determine the circumferential static pressure difference along the centerline arc length within the candidate layout zone based on the curvature radius distribution and the set of working parameters, and to screen out the priority layout zone based on the circumferential static pressure difference. The orifice group design and optimization module is used to construct circumferentially connected shallow cavities in the priority arrangement area, group the orifices in the circumferentially connected shallow cavities, determine the single-orifice volumetric flow rate of each orifice based on the circumferential static pressure difference, and generate the circumferential shallow cavity connection scheme and orifice group arrangement based on the single-orifice volumetric flow rate. The acoustic impedance synthesis module is used to calculate the aperture impedance and shallow cavity capacitive reactance based on the circumferential shallow cavity connectivity scheme and aperture group arrangement, and synthesize the aperture impedance and shallow cavity capacitive reactance into an equivalent surface complex impedance. The performance index calculation and correlation module is used to calculate the system insertion loss based on the equivalent surface complex impedance, calculate the system additional pressure drop based on the single-hole volumetric flow rate, combine the system insertion loss and the system additional pressure drop into index pairs and correlate them with their corresponding design variable sets. The multi-objective trade-off and solution verification module is used to form a trade-off curve on the index pair plane of system additional voltage drop and system insertion loss, and to use the curvature maxima of the geometric inflection point of the trade-off curve as candidate solutions, and to perform consistency verification on the candidate solutions to obtain the definite solution; The design and manufacturing output module is used to take the determined solution as parametric computer-aided design data and formulate manufacturing points.

2. The intelligent design system for complex flow channel shell parts with porous systems for airborne applications according to claim 1, characterized in that, Obtain the 3D flow channel shell model, operating parameter set, and manufacturing limits, including: The three-dimensional flow channel shell model, operating parameter set, and manufacturing limits are obtained. The operating parameter set includes gas density, dynamic viscosity, near-wall representative velocity, and sound velocity. The manufacturing limits include the range of hole radius and the range of base material wall thickness. The coordinates and units of the three-dimensional flow channel shell model are then unified.

3. The intelligent design system for complex flow channel shell parts with porous systems for airborne applications according to claim 2, characterized in that, The centerline arc length is extracted from the 3D flow channel shell model, and the radius of curvature distribution is determined. Candidate arrangement zones are generated based on the inner curved wall and the post-bend diffuser section of the 3D flow channel shell model, including: The centerline of the inner cavity is extracted from the three-dimensional flow channel shell model, and the arc length is obtained by spline fitting and parameterization according to the arc length. The curvature of the centerline arc length is calculated based on equidistant sampling to obtain the curvature radius distribution; Establish a local orthogonal system at each sampling section to determine the inner curved wall, and record the radius difference between the inner and outer curves to the center line; Under the condition of meeting the manufacturing limit, a strip-shaped region is formed by expanding the inner wall of the bend, and a strip-shaped region is added as a post-bend gradual expansion section in the section where the cross-sectional area increases gradually after the bend. The intersection of the inner curved wall strip and the post-bend widening section is considered as a candidate layout zone.

4. The intelligent design system for complex flow channel shell parts with porous systems for airborne applications according to claim 3, characterized in that, Within the candidate arrangement zone, the circumferential static pressure difference along the centerline arc length is determined based on the curvature radius distribution and the set of operating parameters. Preferred arrangement areas are then selected based on this circumferential static pressure difference, including: Within the candidate arrangement zone, the circumferential static pressure difference is approximately calculated by centrifugal equilibrium based on the curvature radius distribution, near-wall representative velocity, gas density, and the difference in the inner and outer bending radii of the cross section along the arc length of the centerline. The priority layout area is obtained by taking the local maximum value of the circumferential static pressure difference as the center and the adjacent local minimum values ​​as the interval boundary.

5. The intelligent design system for complex flow channel shell parts with porous systems for airborne applications according to claim 4, characterized in that, Within the priority layout area, construct circumferentially connected shallow cavities. Group the orifices within these circumferentially connected shallow cavities. Determine the single-orifice volumetric flow rate of each orifice based on the circumferential static pressure difference. Generate a circumferentially connected shallow cavity scheme and orifice group layout based on the single-orifice volumetric flow rate, including: Within the priority layout area, a continuous circumferential shallow cavity ring is constructed along the circumference of the flow channel according to manufacturing limits; Based on the high-pressure side and low-pressure side of the circumferential static pressure difference, the holes are arranged in groups from the high-pressure side to the low-pressure side. Calculate the volumetric flow rate of a single orifice based on orifice radius, orifice flow coefficient and circumferential static pressure difference; By applying zero net mass exchange constraints to each cross section of the flow channel inside the shell, and by adjusting the number of holes and the pairing method of the holes, the algebraic sum of the volumetric flow rate of a single hole in the cross section is made zero, thus obtaining the circumferential shallow cavity connection scheme and hole group arrangement.

6. The intelligent design system for complex flow channel shell parts with porous systems for airborne applications according to claim 1, characterized in that, Based on the circumferential shallow cavity connectivity scheme and the arrangement of the hole group, the hole impedance and shallow cavity capacitive reactance are calculated, and the hole impedance and shallow cavity capacitive reactance are combined into an equivalent surface complex impedance, including: Based on the circumferential shallow cavity connection scheme and the hole group arrangement, the opening ratio was statistically analyzed, and the hole axis inclination angle, base material wall thickness, hole radius, shallow cavity volume, lining surface area, angular frequency, gas density, sound velocity and dynamic viscosity were obtained. The base material wall thickness is geometrically stretched according to the hole axis inclination angle, and the end corrections at both ends of the hole are superimposed to obtain the equivalent thickness of the hole; The pore impedance is calculated based on the Maa approximation and in combination with equivalent thickness, porosity, pore radius, dynamic viscosity, gas density, and angular frequency. The volume of the back cavity per unit area is obtained by the ratio of the shallow cavity volume to the lining surface area. Calculate the shallow cavity capacitive reactance based on gas density, sound velocity, angular frequency, and back cavity volume per unit area; The equivalent surface complex impedance is obtained by superimposing the aperture impedance and shallow cavity capacitive reactance at the same centerline arc length and the same angular frequency.

7. The intelligent design system for complex flow channel shell parts with porous systems for airborne applications according to claim 6, characterized in that, The system insertion loss is calculated based on the equivalent surface complex impedance, and the system additional pressure drop is calculated based on the single-orifice volumetric flow rate. The system insertion loss and system additional pressure drop are combined into an index pair and associated with their corresponding set of design variables, including: Dividing the equivalent surface complex impedance by the product of the gas density and the sound velocity yields the dimensionless impedance. The absorption coefficient is obtained by calculating the normal incident absorption coefficient of the dimensionless impedance; The sound absorption coefficient is obtained by wideband arithmetic mean. The average sound absorption coefficient is then calculated by inserting the average sound absorption coefficient and weighted and summed with the center line arc length to obtain the system insertion loss. The orifice area is calculated based on the orifice radius. The gas flow rate of the orifice is obtained by dividing the volumetric flow rate of a single orifice by the orifice area. Based on the gas flow rate and gas density, the local additional pressure drop of each orifice is obtained. The additional pressure drop of the system is obtained by superimposing the local additional pressure drops of all the holes; The system insertion loss and system additional pressure drop are combined into a performance index pair, and their corresponding hole axis tilt angle, opening ratio, back cavity volume per unit area, circumferential shallow cavity connectivity scheme and hole group arrangement are associated.

8. The intelligent design system for complex flow channel shell parts with porous systems for airborne applications according to claim 7, characterized in that, A tradeoff curve is formed on the index pair plane of system additional pressure drop and system insertion loss. The curvature maxima of the geometric inflection point of the tradeoff curve are used as candidate solutions. The consistency of the candidate solutions is checked to obtain the definite solutions, including: Plot index points with the system additional voltage drop as the horizontal axis and the system insertion loss as the vertical axis, and filter the index points: retain index points that do not have another index pair that satisfy both a smaller system additional voltage drop and a larger system insertion loss; The retained indicators are sorted in ascending order of system additional pressure drop, and a continuous trade-off curve is obtained by cubic spline fitting. The geometric inflection point of each point is obtained based on the discrete curvature of three adjacent points, and the point with the maximum curvature is taken as a candidate solution. The circumferential static pressure difference corresponding to the candidate solution is used to back-calculate the single-hole volumetric flow rate of each section to verify the zero net mass exchange constraint. At the same time, the equivalent surface complex impedance, insertion loss and additional pressure drop are recalculated for the design variable set associated with the candidate solution. If they are inconsistent with the inflection point index, the hole axis inclination angle, opening ratio, back cavity volume per unit area or hole pairing relationship are adjusted locally in the corresponding section and the verification is repeated until the inflection point index is met to obtain the definite solution.

9. The intelligent design system for complex flow channel shell parts with porous systems for airborne applications according to claim 1, characterized in that, The determined solution is used as parametric computer-aided design data and manufacturing considerations are established, including: The design parameters in the determined solution are associated with the three-dimensional model of the flow channel shell to generate a fully parametric three-dimensional CAD model; Based on the characteristics of additive manufacturing processes and the geometric features of deterministic solutions, key manufacturing points are given, including: build direction, support and powder removal channels, and inaccessible areas.

10. A smart design method for complex flow channel shell parts with porous systems for airborne applications, characterized in that, The method includes: S1. Obtain the three-dimensional flow channel shell model, working condition parameter set, and manufacturing limits; S2. Extract the centerline arc length from the three-dimensional flow channel shell model and determine the radius of curvature distribution. Generate candidate arrangement zones based on the inner curved wall and the post-bend expansion section of the three-dimensional flow channel shell model. S3. Within the candidate arrangement zone, determine the circumferential static pressure difference along the arc length of the centerline based on the curvature radius distribution and the set of working parameters, and select the priority arrangement area based on the circumferential static pressure difference. S4. Construct circumferentially connected shallow cavities within the priority arrangement area, group the holes in the circumferentially connected shallow cavities, determine the single-hole volumetric flow rate of each hole based on the circumferential static pressure difference, and generate the circumferentially connected shallow cavity scheme and hole group arrangement based on the single-hole volumetric flow rate. S5. Based on the circumferential shallow cavity connection scheme and the arrangement of the hole group, calculate the hole impedance and shallow cavity capacitive reactance, and combine the hole impedance and shallow cavity capacitive reactance into an equivalent surface complex impedance. S6. Calculate the system insertion loss based on the equivalent surface complex impedance, calculate the system additional pressure drop based on the single-hole volumetric flow rate, combine the system insertion loss and the system additional pressure drop into an index pair and associate them with their corresponding set of design variables. S7. A trade-off curve is formed on the index pair plane of the system additional pressure drop and the system insertion loss. The curvature maxima of the geometric inflection point of the trade-off curve are used as candidate solutions. The consistency of the candidate solutions is checked to obtain the definite solution. S8. Use the determined solution as parametric computer-aided design data and formulate manufacturing points.

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