Noise reduction design method for propeller of eVTOL aircraft and related device

Abstract

The invention discloses a propeller noise reduction design method of an eVTOL aircraft and a related device. The method comprises the steps that according to spatial design parameter data, a plurality of spatial design parameter combinations meeting the design requirements of the total lift force requirement and the structural strength requirement of the eVTOL aircraft are obtained; performing distributed propeller system-level noise simulation processing on the propeller design corresponding to each spatial design parameter combination to obtain a system-level noise simulation result corresponding to each spatial design parameter combination; obtaining a first space design parameter combination with the lowest total noise according to a system-level noise simulation result; and performing noise reduction design processing on the propeller in the first space design parameter combination to obtain a propeller noise reduction design result. In the embodiment of the invention, the rapid reconstruction of the full-aircraft noise field is realized, compared with the complete modeling, the calculation amount is obviously reduced, and the time period of the distributed propeller multi-parameter design optimization is shortened.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of unmanned aerial vehicles, and particularly relates to a propeller noise reduction design method for an eVTOL aircraft and a related device. BACKGROUND

[0002] The eVTOL generally adopts a distributed electric propulsion (DEP) architecture, and generates lift through 8 to 16 electric motors driving propellers arranged on multiple power arms around the body; the overall noise of the machine mainly comes from two aspects: the noise generated by the rotation of multiple propellers, and the interference noise formed between the propellers or between the power arms supporting the propellers.

[0003] The propeller noise presents a superposition of broadband noise and discrete rotating noise in the frequency spectrum; the rotating noise can be divided into three core components according to the characteristics of the sound source: the periodic disturbance of the air medium with a limited thickness of the blade, which causes the unsteady motion of the gas clusters to form pressure pulsation, forming thickness noise; the load noise is driven by the periodic fluctuation of the lift and drag of the blade surface, and the essence is the unsteady change of the aerodynamic pressure field; the quadrupole noise is more significant only in the transonic or supersonic flow state at the blade tip region; in the propeller noise, the main component is the rotating noise, in which the thickness noise and the load noise contribute the main energy; for these two types of core noise, effective suppression can be achieved through optimization of the propeller design parameters: including reducing the blade tip relative Mach number, increasing the number of blades to improve the load dispersion, optimizing the aerodynamic load distribution along the span to reduce the local pulsation peak value, and fine design of the blade profile shape (such as optimization of chord length distribution and relative thickness) under the premise of ensuring structural strength.

[0004] The interference noise of the propeller and the power arm is caused by the unsteady flow field disturbance induced by the periodic sweeping of the blade on the static support structure, forming strong discrete noise (energy concentrated at the blade pass frequency BPF and its harmonics); for the core mechanism of this noise, the main noise reduction approaches are developed from two dimensions, including power arm aerodynamic profile optimization design and propeller-power arm spacing optimization; the interference noise between multiple propellers is mainly reduced by optimizing the spacing between the propellers.

[0005] In the traditional optimization design of helicopter propellers, high-precision CFD simulation is usually performed on a single propeller, and the large eddy simulation (LES) method is used to capture the pressure pulsation induced by micro-scale flow, and the grid resolution needs to be small enough; this method is still acceptable in terms of computational cost in the single propeller scenario, but when facing the distributed propulsion system of modern electric vertical take-off and landing aircraft (eVTOL) with 8-16 propellers, if a full-parameterized overall modeling strategy is used for multi-condition noise evaluation, the computational complexity will increase exponentially, especially when multiple design variables such as propeller spacing, axial spacing and power arm profile need to be optimized simultaneously, the traditional method almost loses its engineering feasibility. SUMMARY

[0006] The present application aims to overcome the deficiencies of the prior art, and provides a propeller noise reduction design method for an eVTOL aircraft and related devices, which realizes rapid reconstruction of the full-machine noise field, significantly reduces the calculation amount compared to complete modeling, and shortens the time period of distributed propeller multi-parameter design optimization.

[0007] To solve the above technical problems, the embodiments of the present application provide a propeller noise reduction design method for an eVTOL aircraft, which comprises:

[0008] Obtaining a plurality of spatial design parameter combinations under the design requirements of meeting the total lift demand and structural strength demand of the eVTOL aircraft according to spatial design parameter data, wherein the spatial design parameter data includes the number of propellers, propeller diameter, inter-blade spacing, power arm aerodynamic profile, and propeller-power arm spacing;

[0009] Performing system-level noise simulation processing on the propeller design corresponding to each of the plurality of spatial design parameter combinations to obtain system-level noise simulation results corresponding to each of the plurality of spatial design parameter combinations;

[0010] Obtaining a first spatial design parameter combination with the lowest total noise according to the system-level noise simulation results corresponding to each of the plurality of spatial design parameter combinations;

[0011] Performing noise reduction design processing on the propellers in the first spatial design parameter combination based on the blade profile thickness parameters and chord length parameters of the propellers to obtain propeller noise reduction design results.

[0012] Optionally, the obtaining a plurality of spatial design parameter combinations under the design requirements of meeting the total lift demand and structural strength demand of the eVTOL aircraft according to spatial design parameter data comprises:

[0013] Obtaining a plurality of combinations of the number of propellers and propeller diameter based on the coupling constraint condition between the number of propellers and propeller diameter in the spatial design parameters under the total lift demand of the eVTOL aircraft;

[0014] Obtaining a plurality of combinations of propeller diameter and inter-blade spacing based on the coupling constraint condition between the propeller diameter and inter-blade spacing in the spatial design parameters under the total length of the power arm;

[0015] Obtaining a plurality of combinations of power arm aerodynamic profile and propeller-power arm spacing based on the constraint condition that the selection of the power arm aerodynamic profile and propeller-power arm spacing in the spatial design parameters meets the structural strength demand;

[0016] According to a plurality of combinations of propeller numbers and propeller diameters, a plurality of combinations of propeller diameters and inter-blade distances, and a plurality of combinations of power arm aerodynamic profiles and propeller-power arm distances, a plurality of spatial design parameter combinations are formed.

[0017] Optionally, the system-level noise simulation processing of the corresponding propeller design of each of the plurality of spatial design parameter combinations is performed, and system-level noise simulation results corresponding to each of the plurality of spatial design parameter combinations are obtained, including:

[0018] The acoustic analogy noise source calculation processing is performed on each propeller of each of the plurality of spatial design parameter combinations, and an acoustic analogy noise source corresponding to each propeller is obtained, and a single propeller noise source database is formed;

[0019] According to the number of propellers corresponding to each of the plurality of spatial design parameter combinations and the distribution mode, a distributed propeller sound field network corresponding to each of the plurality of spatial design parameter combinations is constructed;

[0020] The single propeller noise source of each of the plurality of spatial design parameter combinations in the single propeller noise source database is imported into the distributed propeller sound field network according to the corresponding distribution mode for sound propagation simulation processing, and system-level noise simulation results of each of the plurality of spatial design parameter combinations at a far-field receiving point are obtained.

[0021] Optionally, the acoustic analogy noise source calculation processing of each propeller of each of the plurality of spatial design parameter combinations includes:

[0022] For the target propeller of each of the plurality of spatial design parameter combinations, the target propeller, the adjacent propeller, and the power arm are modeled as a power unit, and a power unit modeling result is obtained;

[0023] The flow field simulation processing of computational fluid dynamics is performed on the target propeller in the power unit modeling result, and a flow field simulation result of the target propeller is obtained, the flow field simulation is realized by large eddy simulation, and a sound source integration surface is set outside the target propeller;

[0024] The acoustic analogy noise source calculation processing of the corresponding propeller is performed according to the flow field simulation result of the target propeller.

[0025] Optionally, the first spatial design parameter combination with the lowest total noise is obtained according to the system-level noise simulation result corresponding to each of the plurality of spatial design parameter combinations, including:

[0026] Sort according to the total noise size in the system level noise simulation result corresponding to each spatial design parameter combination, and obtain the sorting result of the total noise size in the system level noise simulation result;

[0027] Select the spatial design parameter combination with the minimum total noise in the sorting result of the total noise size as the first spatial design parameter combination.

[0028] Optionally, the propeller noise reduction design processing is performed on the propeller in the first spatial design parameter combination based on the blade profile thickness parameter and the chord length parameter of the propeller, and a propeller noise reduction design result is obtained, including:

[0029] The lift coefficient proxy model and the noise proxy model of the propeller are constructed based on the blade profile thickness parameter and the chord length parameter of the propeller;

[0030] In the lift coefficient proxy model and the noise proxy model, multi-objective optimization processing is performed with the maximum lift coefficient and the minimum total sound pressure level as double objectives, and noise reduction design processing is performed according to the multi-objective optimization result, and a propeller noise reduction design result is obtained.

[0031] Optionally, the lift coefficient proxy model and the noise proxy model of the propeller are constructed based on the blade profile thickness parameter and the chord length parameter of the propeller, including:

[0032] Based on the blade profile thickness parameter and the chord length parameter of the propeller, a high-dimensional sampling point set is generated through Latin hypercube sampling, and large eddy simulation calculation is performed in a rotating coordinate system to obtain lift characteristic data;

[0033] The lift coefficient proxy model of the propeller is constructed based on the lift characteristic data;

[0034] When performing large eddy simulation calculation, the fluctuating pressure source term required by the FW-H acoustic analogy is extracted synchronously, and is imported into an acoustic propagation solver for noise calculation processing to obtain a noise calculation result;

[0035] The total sound pressure level is calculated at a far-field observation point defined by an aviation standard according to the noise calculation result, and a noise proxy model is established according to the total sound pressure level.

[0036] In addition, an embodiment of the present application also provides a propeller noise reduction design device of an eVTOL aircraft, the device comprising:

[0037] A first obtaining module is configured to obtain a plurality of spatial design parameter combinations under the design requirements of meeting the total lift demand and the structural strength demand of the eVTOL aircraft according to spatial design parameter data, wherein the spatial design parameter data includes the number of propellers, the diameter of the propeller, the inter-blade distance, the power arm aerodynamic profile, and the propeller-power arm distance.

[0038] a noise simulation module, configured to perform system-level noise simulation processing on the propeller corresponding to each of the plurality of combinations of spatial design parameters, to obtain a system-level noise simulation result corresponding to each of the plurality of combinations of spatial design parameters;

[0039] a second obtaining module, configured to obtain, according to the system-level noise simulation result corresponding to each of the plurality of combinations of spatial design parameters, a first combination of spatial design parameters with the lowest total noise;

[0040] a noise reduction design module, configured to perform noise reduction design processing on the propeller in the first combination of spatial design parameters based on a blade profile thickness parameter and a chord length parameter of the propeller, to obtain a noise reduction design result of the propeller.

[0041] In addition, an electronic device is also provided in an embodiment of the present application, which includes a processor and a memory, and the processor runs a computer program or code stored in the memory to implement the propeller noise reduction design method according to any one of the above.

[0042] In addition, a computer readable storage medium is also provided in an embodiment of the present application, which is used to store a computer program or code, and when the computer program or code is executed by a processor, the propeller noise reduction design method according to any one of the above is implemented.

[0043] In an embodiment of the present application, through system-level noise simulation processing and propeller-level noise reduction design processing, the LES (Large Eddy Simulation) flow field result of a single propeller unit is extracted to construct an equivalent sound source model, the full-aircraft noise field is quickly reconstructed in the acoustic model, and the calculation amount is significantly reduced compared to complete modeling; on the propeller level, the response surface technology is combined to establish a lift coefficient ΔC L and a proxy model of the far-field OASPL total sound pressure level, to drive the optimization iteration; this double-layer architecture shortens the time period of the distributed propeller multi-parameter design optimization; that is, the full-aircraft noise field is quickly reconstructed, the calculation amount is significantly reduced compared to complete modeling, and the time period of the distributed propeller multi-parameter design optimization is shortened. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0045] Figure 1 is a flowchart of the propeller noise reduction design method of the eVTOL aircraft in an embodiment of the present application;

[0046] Figure 2 is a flowchart of a propeller noise reduction design method of an eVTOL aircraft in another embodiment of the present application;

[0047] Figure 3 is a structural composition schematic diagram of a propeller noise reduction design device of an eVTOL aircraft in an embodiment of the present application;

[0048] Figure 4 is a structural composition schematic diagram of an electronic device in an embodiment of the present application. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0050] Embodiment one, please refer to Figure 1 , Figure 1 is a flowchart of a propeller noise reduction design method of an eVTOL aircraft in an embodiment of the present application.

[0051] As shown in Figure 1 , a propeller noise reduction design method of an eVTOL aircraft, the method comprising:

[0052] S101: obtaining a plurality of spatial design parameter combinations under the design requirements of meeting the total lift demand and structural strength demand of the eVTOL aircraft according to spatial design parameter data, wherein the spatial design parameter data includes the number of propellers, propeller diameter, inter-blade spacing, power arm aerodynamic profile, and propeller-power arm spacing;

[0053] In the implementation of the present application, the obtaining of the plurality of spatial design parameter combinations under the design requirements of meeting the total lift demand of the eVTOL aircraft and the structural strength demand according to the spatial design parameter data comprises: obtaining a plurality of combinations of the number of propellers and the propeller diameter based on the coupling constraint condition between the number of propellers and the propeller diameter in the spatial design parameters under the total lift demand of the eVTOL aircraft; obtaining a plurality of combinations of the propeller diameter and the inter-blade spacing based on the coupling constraint condition between the propeller diameter and the inter-blade spacing in the spatial design parameters under the total length of the power arm; obtaining a plurality of combinations of the power arm aerodynamic profile and the propeller-power arm spacing based on the constraint condition that the selection of the power arm aerodynamic profile and the propeller-power arm spacing meets the structural strength demand; and forming a plurality of spatial design parameter combinations according to the plurality of combinations of the number of propellers and the propeller diameter, the plurality of combinations of the propeller diameter and the inter-blade spacing, and the plurality of combinations of the power arm aerodynamic profile and the propeller-power arm spacing.

[0054] Specifically, in the eVTOL propeller noise reduction design, it sequentially includes system-level noise reduction design and propeller-level noise reduction design; the first thing to do is the system-level noise reduction design. In the system-level noise reduction design, the spatial design parameters need to be obtained first, which mainly include the number of propellers, the propeller diameter, the inter-blade spacing, the power arm aerodynamic profile, and the propeller-power arm spacing. Among these parameters, there are multiple coupling constraints. The number of propellers and the diameter are restricted by the total lift demand of the system, and the propeller disc diameter and the inter-blade spacing are limited by the total length of the power arm. The total lift and the structural length must be determined in advance through the aircraft overall design process, so several feasible configuration schemes designed by aerodynamic / structural collaboration need to be input. At the same time, the selection of the propeller airfoil profile parameters and the propeller-arm spacing must meet the composite material structural strength threshold, so the airfoil envelope and the installation distance range verified by the finite element method need to be provided as design inputs. These predefined parameter sets together constitute the basic design space for acoustic optimization.

[0055] At this time, a plurality of spatial design parameter combinations are formed by the plurality of combinations of the number of propellers and the propeller diameter, the plurality of combinations of the propeller diameter and the inter-blade spacing, and the plurality of combinations of the power arm aerodynamic profile and the propeller-power arm spacing.

[0056] S102: performing system-level noise simulation processing on the propeller design corresponding to each of the plurality of spatial design parameter combinations in a distributed manner to obtain system-level noise simulation results corresponding to each of the plurality of spatial design parameter combinations;

[0057] In the implementation of the present application, the system-level noise simulation of the distributed propeller corresponding to each of the plurality of spatial design parameter combinations is performed, and the system-level noise simulation result corresponding to each of the plurality of spatial design parameter combinations is obtained, including: performing acoustic analogy noise source calculation on each propeller of each of the plurality of spatial design parameter combinations to obtain the acoustic analogy noise source corresponding to each propeller and form a single propeller noise source database; constructing a distributed propeller sound field network corresponding to each of the plurality of spatial design parameter combinations according to the number and distribution of the propellers corresponding to each of the plurality of spatial design parameter combinations; and importing the single propeller noise source of each of the plurality of spatial design parameter combinations in the single propeller noise source database into the distributed propeller sound field network for sound propagation simulation according to the corresponding distribution to obtain the system-level noise simulation result of each of the plurality of spatial design parameter combinations at a far-field receiving point.

[0058] Further, the acoustic analogy noise source calculation on each propeller of each of the plurality of spatial design parameter combinations includes: modeling a target propeller of each of the plurality of spatial design parameter combinations as a power unit together with adjacent propellers and a power arm to obtain a power unit modeling result; performing computational fluid dynamics flow field simulation on the target propeller in the power unit modeling result to obtain a flow field simulation result of the target propeller, wherein the flow field simulation is realized by large eddy simulation, and an acoustic source integration surface is arranged outside the target propeller; and performing acoustic analogy noise source calculation on the target propeller according to the flow field simulation result of the target propeller.

[0059] Specifically, in the system-level noise reduction design, the flow field simulation of each propeller at different rotational speeds under different overall design parameters is performed to obtain the pressure fluctuation information of the integration surface of different propellers, and then a single propeller acoustic analogy noise source database is established; then, based on the number and geometric distribution of the propellers, a sound field network of all distributed propellers is established, and according to the rotational speed of each propeller under the calculated working condition, the corresponding propeller noise source is selected from the noise source database, and the noise at the noise receiving point is obtained by acoustic analogy method, and the design parameter combination with the lowest noise is taken as the overall design result of the distributed propeller.

[0060] The total noise of the eVTOL aircraft is determined by the total noise of each propeller, and the total noise of each propeller is determined by the noise of each propeller and the interference of adjacent propellers and power arms. The noise evaluation process first needs to calculate the acoustic analogy noise source of a single propeller. In order to consider the interference of adjacent propellers and power arms on the target calculation propeller, the target calculation propeller, adjacent propellers and power arms are modeled as a unit. The CFD (Computational Fluid Dynamics) flow field simulation is performed on the unit, and the large eddy simulation (LES) is used as the turbulence model to meet the capture accuracy of small scale vortex sound sources. The sound source integration surface is set outside the target propeller, and the size of the integration surface needs to ensure that most of the vortex sound sources are included, and at the same time cannot be too large that the vortex sound sources have been dissipated. The acoustic analogy noise source of each propeller in different design schemes is calculated to obtain the acoustic analogy noise source database of each propeller. The distributed propeller sound field grid of different propeller numbers and distribution modes is constructed, and the acoustic analogy noise source of each propeller is imported into the sound field grid according to the corresponding distribution mode to perform sound propagation calculation to obtain the noise of the far-field receiving point. That is, the acoustic analogy noise source of each single propeller in the noise source database of each single propeller is imported into the distributed propeller sound field network according to the corresponding distribution mode to perform sound propagation simulation and obtain the system-level noise simulation result of each spatial design parameter combination at the far-field receiving point.

[0061] S103: obtaining the first spatial design parameter combination with the lowest total noise according to the system-level noise simulation result corresponding to each spatial design parameter combination;

[0062] In the specific implementation process of the present application, obtaining the first spatial design parameter combination with the lowest total noise according to the system-level noise simulation result corresponding to each spatial design parameter combination includes: sorting the system-level noise simulation results according to the size of the total noise to obtain the sorting result of the total noise size in the system-level noise simulation results; and selecting the spatial design parameter combination with the smallest total noise in the sorting result of the total noise size as the first spatial design parameter combination.

[0063] Specifically, the system-level noise simulation result corresponding to each spatial design parameter combination is sorted according to the size of the total noise to obtain the sorting result of the total noise size in the system-level noise simulation results; and finally, the spatial design parameter combination with the smallest total noise in the sorting result of the total noise size is selected as the first spatial design parameter combination.

[0064] S104: Perform noise reduction design processing on the propeller in the first spatial design parameter combination based on the propeller blade profile thickness parameter and chord length parameter, and obtain a propeller noise reduction design result.

[0065] In the implementation of the present application, the noise reduction design processing on the propeller in the first spatial design parameter combination based on the propeller blade profile thickness parameter and chord length parameter to obtain a propeller noise reduction design result includes: constructing a lift coefficient proxy model and a noise proxy model of the propeller based on the propeller blade profile thickness parameter and chord length parameter; performing multi-objective optimization processing in the lift coefficient proxy model and the noise proxy model with the dual objectives of maximizing the lift coefficient and minimizing the overall sound pressure level, and performing noise reduction design processing according to the multi-objective optimization result to obtain a propeller noise reduction design result.

[0066] Further, the construction of the lift coefficient proxy model and the noise proxy model of the propeller based on the propeller blade profile thickness parameter and chord length parameter includes: generating a high-dimensional sampling point set through Latin hypercube sampling based on the propeller blade profile thickness parameter and chord length parameter, and performing large eddy simulation calculation in a rotating coordinate system to obtain lift characteristic data; constructing a lift coefficient proxy model of the propeller based on the lift characteristic data; synchronously extracting the fluctuating pressure source term required for FW-H acoustic analogy during the large eddy simulation calculation, and importing it into a sound propagation solver for noise calculation processing to obtain noise calculation results; calculating the overall sound pressure level at the far-field observation points defined by aviation standards according to the noise calculation results, and establishing a noise proxy model according to the overall sound pressure level.

[0067] Specifically, the propeller in the first spatial design parameter combination is taken as the input of single-propeller detailed design, and then the flow field simulation is performed according to the blade profile thickness parameter and chord length parameter of the input propeller to obtain the pressure fluctuation information of the propeller integral surface, and the sound analogy method is used to calculate the receiving point noise; the lift and noise prediction proxy model of the propeller is established based on the flow field and noise calculation results of the propeller; the multi-objective optimization algorithm of the propeller level is established, and the maximum lift and the minimum noise are taken as the optimization objectives, the calculation is performed based on the aforementioned lift and noise proxy model, the Pareto frontier is obtained through multi-objective optimization, and the final detailed design parameters are obtained.

[0068] Among them, the optimized propeller diameter is taken as the key input parameter to drive the propeller level noise optimization design, and the blade profile thickness distribution and chord length distribution parameter design are focused on; in the system level design, the total lift of each propeller has been ensured to meet the flight performance requirements through the whole machine aerodynamic matching, and the propeller level is turned to the acoustic / efficiency multi-objective optimization of single propeller; the lift-noise collaborative design for the blade profile has a clear objective function, and the lift coefficient increment ΔC LMaximize and minimize total sound pressure level OASPL are double objectives, the calculation module of the optimization algorithm is composed of lift and noise proxy model, and the optimal blade configuration is obtained by analyzing the Pareto frontier.

[0069] The lift and noise proxy model is constructed by using the response surface method; based on the parameterized design space of blade thickness and chord length, a high-dimensional sampling point set is generated by Latin hypercube sampling; the lift characteristic data is obtained by performing LES calculation in the rotating coordinate system, and the lift coefficient proxy model is established accordingly; the fluctuating pressure source term required by the FW-H acoustic analogy is extracted synchronously, and the noise is calculated by introducing the sound propagation solver, and finally the OASPL total sound pressure level is calculated at the far-field observation point defined in the relevant aviation standard, and the noise proxy model is established accordingly; based on the lift and noise proxy model, the maximum lift coefficient and the minimum OASPL sound pressure level are taken as double objectives to perform multi-objective optimization, and after generating the Pareto frontier solution set, the problem is converted into single objective optimization by using the weight coefficient method, and finally the optimal design point in the Pareto frontier is selected.

[0070] In the embodiment of the application, through system-level noise simulation processing and propeller-level noise reduction design processing, the equivalent sound source model is constructed by extracting the LES (large eddy simulation) flow field results of a single propeller unit to realize the rapid reconstruction of the full-machine noise field in the acoustic model, which significantly reduces the calculation amount compared with complete modeling; on the propeller level, the lift coefficient ΔC L and the proxy model of the far-field OASPL total sound pressure level are combined to drive the optimization iteration; this double-layer architecture shortens the time period of distributed propeller multi-parameter design optimization; that is, the rapid reconstruction of the full-machine noise field is realized, which significantly reduces the calculation amount compared with complete modeling, and shortens the time period of distributed propeller multi-parameter design optimization.

[0071] Embodiment two, please refer to Figure 2 , Figure 2 is a flowchart of a propeller noise reduction design method of an eVTOL aircraft in another embodiment of the application.

[0072] As Figure 2 shown, a propeller noise reduction design method of an eVTOL aircraft, the method comprises:

[0073] S201: Obtain a plurality of spatial design parameter combinations under the design requirements of meeting the total lift demand and structural strength demand of the eVTOL aircraft according to spatial design parameter data, wherein the spatial design parameter data includes the number of propellers, the diameter of the propeller, the inter-blade spacing, the power arm aerodynamic profile, and the propeller-power arm spacing;

[0074] S202: Perform acoustic analogy noise source calculation processing on each propeller of each of the plurality of spatial design parameter combinations, obtain the corresponding acoustic analogy noise source of each propeller, and form a single propeller noise source database;

[0075] S203: Construct a distributed propeller sound field network corresponding to each spatial design parameter combination according to the number, distribution mode of the propellers corresponding to each spatial design parameter combination;

[0076] S204: Import the single propeller noise source of each spatial design parameter combination in the single propeller noise source database into the distributed propeller sound field network according to the corresponding distribution mode for sound propagation simulation processing, and obtain the system-level noise simulation result of each spatial design parameter combination at the far-field receiving point;

[0077] S205: Obtain the first spatial design parameter combination with the lowest total noise according to the system-level noise simulation result corresponding to each spatial design parameter combination;

[0078] S206: Construct a lift coefficient proxy model and a noise proxy model of the propeller based on the blade profile thickness parameter and the chord length parameter of the propeller;

[0079] S207: In the lift coefficient proxy model and the noise proxy model, perform multi-objective optimization processing with the maximum lift coefficient and the minimum total sound pressure level as dual objectives, and perform noise reduction design processing according to the multi-objective optimization result to obtain a propeller noise reduction design result.

[0080] The specific implementation of the second embodiment can be referred to the above-mentioned embodiments, which will not be repeated here.

[0081] Embodiment three, please refer to Figure 3 , Figure 3 is a structural composition schematic diagram of the propeller noise reduction design device of the eVTOL aircraft in the embodiments of the present application.

[0082] As Figure 3 shown, a propeller noise reduction design device of an eVTOL aircraft, the device comprises:

[0083] The first obtaining module 301 is configured to obtain a plurality of spatial design parameter combinations under the design requirements of meeting the total lift demand and the structural strength demand of the eVTOL aircraft according to spatial design parameter data, wherein the spatial design parameter data includes the number of propellers, the diameter of the propeller, the inter-blade spacing, the power arm aerodynamic profile, and the propeller-power arm spacing.

[0084] In the implementation of the present application, the obtaining of the plurality of spatial design parameter combinations under the design requirements of meeting the total lift demand of the eVTOL aircraft and the structural strength demand according to the spatial design parameter data comprises: obtaining a plurality of combinations of the number of propellers and the propeller diameter based on the coupling constraint condition between the number of propellers and the propeller diameter in the spatial design parameters under the total lift demand of the eVTOL aircraft; obtaining a plurality of combinations of the propeller diameter and the inter-blade spacing based on the coupling constraint condition between the propeller diameter and the inter-blade spacing in the spatial design parameters under the total length of the power arm; obtaining a plurality of combinations of the power arm aerodynamic profile and the propeller-power arm spacing based on the constraint condition that the selection of the power arm aerodynamic profile and the propeller-power arm spacing meets the structural strength demand; and forming a plurality of spatial design parameter combinations according to the plurality of combinations of the number of propellers and the propeller diameter, the plurality of combinations of the propeller diameter and the inter-blade spacing, and the plurality of combinations of the power arm aerodynamic profile and the propeller-power arm spacing.

[0085] Specifically, in the eVTOL propeller noise reduction design, it sequentially includes system-level noise reduction design and propeller-level noise reduction design; the first thing to do is the system-level noise reduction design, and in the system-level noise reduction design, the spatial design parameters need to be obtained first, which mainly include the number of propellers, the propeller diameter, the inter-blade spacing, the power arm aerodynamic profile, and the propeller-power arm spacing; among these parameters, there are multiple coupling constraints, in which the number of propellers and the diameter are restricted by the total lift demand of the system, and the propeller disc diameter and the inter-blade spacing are limited by the total length of the power arm; the total lift and the structural length must be determined in advance through the aircraft overall design process, so a plurality of feasible configuration schemes designed by aerodynamic / structural collaboration need to be input; at the same time, the selection of the propeller airfoil profile parameters and the propeller-arm spacing must meet the composite material structural strength threshold, so the airfoil envelope and the installation distance range verified by the finite element method need to be provided as design inputs; these predefined parameter sets jointly constitute the basic design space for acoustic optimization.

[0086] At this time, a plurality of spatial design parameter combinations are formed by the plurality of combinations of the number of propellers and the propeller diameter, the plurality of combinations of the propeller diameter and the inter-blade spacing, and the plurality of combinations of the power arm aerodynamic profile and the propeller-power arm spacing.

[0087] The noise simulation module 302 is used for performing system-level noise simulation processing on the propeller design corresponding to each of the plurality of spatial design parameter combinations, and obtaining the system-level noise simulation result corresponding to each of the plurality of spatial design parameter combinations.

[0088] In the implementation of the present application, the system-level noise simulation of the distributed propeller corresponding to each of the plurality of spatial design parameter combinations is performed, and the system-level noise simulation result corresponding to each of the plurality of spatial design parameter combinations is obtained, including: performing acoustic analogy noise source calculation on each propeller of each of the plurality of spatial design parameter combinations to obtain the acoustic analogy noise source corresponding to each propeller and form a single propeller noise source database; constructing a distributed propeller sound field network corresponding to each of the plurality of spatial design parameter combinations according to the number and distribution of the propellers corresponding to each of the plurality of spatial design parameter combinations; and importing the single propeller noise source of each of the plurality of spatial design parameter combinations in the single propeller noise source database into the distributed propeller sound field network for sound propagation simulation according to the corresponding distribution to obtain the system-level noise simulation result of each of the plurality of spatial design parameter combinations at a far-field receiving point.

[0089] Further, the acoustic analogy noise source calculation on each propeller of each of the plurality of spatial design parameter combinations includes: modeling a target propeller of each of the plurality of spatial design parameter combinations as a power unit together with adjacent propellers and a power arm to obtain a power unit modeling result; performing computational fluid dynamics flow field simulation on the target propeller in the power unit modeling result to obtain a flow field simulation result of the target propeller, wherein the flow field simulation is realized by large eddy simulation, and an acoustic source integration surface is arranged outside the target propeller; and performing acoustic analogy noise source calculation on the target propeller according to the flow field simulation result of the target propeller.

[0090] Specifically, in the system-level noise reduction design, the flow field simulation of each propeller at different rotational speeds under different overall design parameters is performed to obtain the pressure fluctuation information of the integration surface corresponding to different propellers, and then a single propeller acoustic analogy noise source database is established; then, based on the number and geometric distribution of the propellers, a sound field network of all distributed propellers is established, and according to the rotational speed of each propeller under the calculated working condition, the corresponding propeller noise source is selected from the noise source database, and the noise at the noise receiving point is obtained by acoustic analogy method, and the design parameter combination with the lowest noise is taken as the overall design result of the distributed propeller.

[0091] The parameter design scheme determined in the overall design process of the eVTOL aircraft and meeting the design requirements of total lift, structural strength, etc. is taken as input, and noise evaluation is performed on each parameter design scheme to obtain the parameter design scheme with the lowest total noise, as follows: the noise evaluation process first needs to calculate the acoustic analogy noise source of a single propeller. In order to consider the interference of adjacent propellers and power arms on the target calculation propeller, the target calculation propeller, adjacent propellers and power arms are modeled as a unit. The CFD (Computational Fluid Dynamics) flow field simulation is performed on the unit, and the large eddy simulation (LES) is used for the turbulence model to meet the capture accuracy of small-scale vortex sound sources. An acoustic source integration surface is set outside the target propeller, and the size of the integration surface needs to ensure that most of the vortex sound sources are included, and at the same time, the integration surface cannot be too large so that the vortex sound sources have been dissipated. The acoustic analogy noise sources of single propellers of different design schemes are calculated to obtain a single propeller acoustic analogy noise source database. A distributed propeller sound field grid with different numbers and distribution modes of propellers is constructed, and the acoustic analogy noise sources of single propellers are imported into the sound field grid according to the corresponding distribution mode to perform sound propagation calculation to obtain the noise at the far-field receiving point. That is, the single propeller noise source of each spatial design parameter combination in the single propeller noise source database is imported into the distributed propeller sound field network according to the corresponding distribution mode to perform sound propagation simulation and obtain the system-level noise simulation result of each spatial design parameter combination at the far-field receiving point.

[0092] The second obtaining module 303 is configured to obtain a first spatial design parameter combination with the lowest total noise according to the system-level noise simulation result corresponding to each spatial design parameter combination.

[0093] In the implementation of the present application, the first spatial design parameter combination with the lowest total noise is obtained according to the system-level noise simulation result corresponding to each spatial design parameter combination, which includes: sorting the system-level noise simulation results according to the size of the total noise to obtain the sorting result of the total noise size in the system-level noise simulation results; and selecting the spatial design parameter combination with the smallest total noise in the sorting result of the total noise size as the first spatial design parameter combination.

[0094] Specifically, the system-level noise simulation result corresponding to each spatial design parameter combination is sorted according to the size of the total noise to obtain the sorting result of the total noise size in the system-level noise simulation results. Finally, the spatial design parameter combination with the smallest total noise in the sorting result of the total noise size is selected as the first spatial design parameter combination.

[0095] The noise reduction design module 304 is configured to perform noise reduction design processing on the propeller in the first spatial design parameter combination based on the propeller blade profile thickness parameter and the chord length parameter, and obtain a propeller noise reduction design result.

[0096] In the implementation of the present application, the noise reduction design processing on the propeller in the first spatial design parameter combination based on the propeller blade profile thickness parameter and the chord length parameter to obtain a propeller noise reduction design result comprises: constructing a lift coefficient proxy model and a noise proxy model of the propeller based on the propeller blade profile thickness parameter and the chord length parameter; performing multi-objective optimization processing in the lift coefficient proxy model and the noise proxy model with the dual objectives of maximizing the lift coefficient and minimizing the overall sound pressure level, and performing noise reduction design processing according to the multi-objective optimization result to obtain a propeller noise reduction design result.

[0097] Further, the construction of the lift coefficient proxy model and the noise proxy model of the propeller based on the propeller blade profile thickness parameter and the chord length parameter comprises: generating a high-dimensional sampling point set through Latin hypercube sampling based on the propeller blade profile thickness parameter and the chord length parameter, and performing large eddy simulation calculation in a rotating coordinate system to obtain lift characteristic data; constructing a lift coefficient proxy model of the propeller based on the lift characteristic data; synchronously extracting the fluctuating pressure source term required by the FW-H acoustic analogy during the large eddy simulation calculation, and importing it into a sound propagation solver for noise calculation processing to obtain noise calculation results; calculating the overall sound pressure level at the far-field observation points defined by the aviation standard according to the noise calculation results, and establishing a noise proxy model according to the overall sound pressure level.

[0098] Specifically, the propeller in the first spatial design parameter combination is taken as the input of the detailed design of a single propeller, and then the flow field simulation is performed according to the blade profile thickness parameter and the chord length parameter of the input propeller to obtain the pressure fluctuation information of the propeller integral surface, and the sound analogy method is used to calculate the noise at the receiving point; the lift and noise prediction proxy model of the propeller is established based on the flow field and noise calculation results of the propeller; a multi-objective optimization algorithm of the propeller level is established, and the maximum lift and the minimum noise are taken as the optimization objectives, the calculation is performed based on the aforementioned lift and noise proxy model, the Pareto frontier is obtained through multi-objective optimization, and the final detailed design parameters are obtained.

[0099] In the system level design, the total lift of each propeller is ensured to meet the flight performance requirements through the whole machine aerodynamic matching, and the propeller level is turned to the acoustic / efficiency multi-objective optimization of a single propeller; the lift-noise collaborative design of the blade profile has a clear objective function, and the lift coefficient increment ΔC LMaximize the total sound pressure level OASPL minimization is a double goal, the calculation module of the optimization algorithm is composed of lift and noise proxy model, and the optimal blade configuration is obtained by analyzing the Pareto frontier.

[0100] The lift and noise proxy model is constructed by response surface method; based on the parameterized design space of blade thickness and chord length, high-dimensional sampling point set is generated by Latin hypercube sampling; the lift characteristic data is obtained by performing LES calculation in the rotating coordinate system, and the lift coefficient proxy model is established accordingly; the fluctuating pressure source term required by the FW-H acoustic analogy is extracted synchronously, and the noise calculation is performed in the sound propagation solver, and finally the OASPL total sound pressure level is calculated at the far-field observation point defined in the relevant aviation standard, and the noise proxy model is established accordingly; based on the lift and noise proxy model, the maximum lift coefficient and the minimum OASPL sound pressure level are taken as the double target to perform multi-objective optimization, and after the Pareto frontier solution set is generated, the problem is converted into single objective optimization by weight coefficient method, and finally the optimal design point in the Pareto frontier is selected.

[0101] In the embodiment of the application, through system-level noise simulation processing and propeller-level noise reduction design processing, the equivalent sound source model is constructed by extracting the LES (large eddy simulation) flow field result of a single propeller unit to realize the rapid reconstruction of the full-machine noise field in the acoustic model, which significantly reduces the calculation amount compared with complete modeling; on the propeller level, the lift coefficient ΔC L The proxy model of the far-field OASPL total sound pressure level drives the optimization iteration; this double-layer architecture shortens the time period of distributed propeller multi-parameter design optimization; that is, the rapid reconstruction of the full-machine noise field is realized, which significantly reduces the calculation amount compared with complete modeling, and shortens the time period of distributed propeller multi-parameter design optimization.

[0102] The computer readable storage medium provided by the embodiment of the present application stores a computer program, and the program is executed by a processor to implement the propeller noise reduction design method of any one of the above embodiments. The computer readable storage medium includes, but is not limited to, any type of disk (including a floppy disk, a hard disk, an optical disk, a CD-ROM, and a magneto-optical disk), a ROM (Read-Only Memory), a RAM (Random Access Memory), an EPROM (Erasable Programmable Read-Only Memory), an EEPROM (Electrically Erasable Programmable Read-Only Memory), a flash memory, a magnetic card, or an optical card. That is, the storage device includes any medium that stores or transmits information in a form capable of being read by a device (for example, a computer, a mobile phone), and can be a read-only memory, a magnetic disk or an optical disk, etc.

[0103] The embodiment of the present application further provides a computer application program running on a computer, and the computer application program is used to execute the propeller noise reduction design method of any one of the above embodiments.

[0104] In addition, Figure 4 is a structural component diagram of an electronic device in the embodiment of the present application.

[0105] The embodiment of the present application further provides an electronic device, as shown in Figure 4 The electronic device includes a processor 402, a memory 403, an input unit 404, a display unit 405, and the like. Those skilled in the art can understand that the electronic device includes more or fewer components, or some components are combined, without departing from the scope of the present application. Figure 4 The structural components of the electronic device shown in the figure do not constitute a limitation on all devices, and can include more or fewer components than those shown in the figure, or some components can be combined. The memory 403 can be used to store an application program 401 and various function modules, and the processor 402 runs the application program 401 stored in the memory 403, thereby executing various function applications and data processing of the device. The memory can be an internal memory or an external memory, or include both the internal memory and the external memory. The internal memory can include a read-only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a flash memory, or a random memory. The external memory can include a hard disk, a floppy disk, a ZIP disk, a U disk, a magnetic tape, and the like. The memory disclosed in the present application includes, but is not limited to, these types of memory. The memory disclosed in the present application is only an example, not a limitation.

[0106] The input unit 404 is configured to receive input of signals and receive a keyword input by a user. The input unit 404 can include a touch panel and other input devices. The touch panel can collect a touch operation (e.g., an operation of a user using a finger, a stylus, or any suitable object or accessory near the touch panel) of the user on or near the touch panel and drive a corresponding connection device according to a preset program; the other input devices can include, but are not limited to, one or more of a physical keyboard, function keys (e.g., play control keys, switch keys, etc.), a trackball, a mouse, a joystick, etc. The display unit 405 can be configured to display information input by a user or information provided to the user and various menus of the terminal device. The display unit 405 can take the form of a liquid crystal display, an organic light-emitting diode, etc. The processor 402 is a control center of the terminal device, connects all parts of the entire device through various interfaces and lines, and performs various functions and processes data by running or executing software programs and / or modules stored in the memory 403 and calling data stored in the memory.

[0107] As an embodiment, the electronic device includes: one or more processors 402, a memory 403, and one or more application programs 401, wherein the one or more application programs 401 are stored in the memory 403 and configured to be executed by the one or more processors 402, and the one or more application programs 401 are configured to perform the corresponding propeller noise reduction design method in any one of the above embodiments.

[0108] In the embodiment of the present application, through system-level noise simulation processing and propeller-level noise reduction design processing, the equivalent sound source model is constructed by extracting the LES (Large Eddy Simulation) flow field result of a single propeller unit at the system level, the full-aircraft noise field is quickly reconstructed in the acoustic model, and the calculation amount is significantly reduced compared to complete modeling; at the propeller level, the response surface technology is combined to establish the lift coefficient ΔC L The proxy model of the far-field OASPL total sound pressure level drives the optimization iteration; this double-layer architecture shortens the time period of distributed propeller multi-parameter design optimization; that is, the full-aircraft noise field is quickly reconstructed, the calculation amount is significantly reduced compared to complete modeling, and the time period of distributed propeller multi-parameter design optimization is shortened.

[0109] In addition, the above describes in detail the propeller noise reduction design method and related device of the eVTOL aircraft provided by the embodiment of the application. The principle and implementation manner of the application are described by using specific examples in this paper. The above description of the embodiments is only used to help understand the method of the application and its core idea. Meanwhile, for those skilled in the art, according to the idea of the application, the specific implementation manner and application range will be changed. In summary, the content of the specification should not be understood as a limitation of the application.

Claims

1. A method of propeller noise reduction design for an eVTOL aircraft, characterized by, The method comprises: obtaining a plurality of spatial design parameter combinations under the design requirements of meeting the total lift demand and structural strength demand of the eVTOL aircraft according to spatial design parameter data, wherein the spatial design parameter data comprises the number of propellers, propeller diameter, inter-blade spacing, power arm aerodynamic profile and propeller-power arm spacing; performing system-level noise simulation processing on the propeller design corresponding to each of the plurality of spatial design parameter combinations to obtain system-level noise simulation results corresponding to each of the plurality of spatial design parameter combinations; obtaining a first spatial design parameter combination with the lowest total noise according to the system-level noise simulation results corresponding to each of the plurality of spatial design parameter combinations; performing noise reduction design processing on the propellers in the first spatial design parameter combination based on the blade profile thickness parameters and chord length parameters of the propellers to obtain propeller noise reduction design results.

2. The propeller noise reduction design method of claim 1, wherein, The method comprises: obtaining a plurality of spatial design parameter combinations under the design requirements of meeting the total lift demand and structural strength demand of the eVTOL aircraft according to spatial design parameter data, wherein the spatial design parameter data comprises the number of propellers, propeller diameter, inter-blade spacing, power arm aerodynamic profile and propeller-power arm spacing; obtaining a plurality of combinations of the number of propellers and propeller diameter based on the coupling constraint condition between the number of propellers and propeller diameter in the spatial design parameters under the total lift demand of the eVTOL aircraft; obtaining a plurality of combinations of the propeller diameter and inter-blade spacing based on the coupling constraint condition between the propeller diameter and inter-blade spacing in the spatial design parameters under the total length of the power arm; obtaining a plurality of combinations of the power arm aerodynamic profile and propeller-power arm spacing based on the constraint condition that the selection of the power arm aerodynamic profile and propeller-power arm spacing in the spatial design parameters meets the structural strength demand; 3. The propeller noise reduction design method of claim 1, wherein, forming a plurality of spatial design parameter combinations according to the plurality of combinations of the number of propellers and propeller diameter, the plurality of combinations of the propeller diameter and inter-blade spacing, and the plurality of combinations of the power arm aerodynamic profile and propeller-power arm spacing. The method comprises: performing acoustic analogy noise source calculation processing on each propeller of each of the plurality of spatial design parameter combinations to obtain a single propeller noise source corresponding to each propeller and form a single propeller noise source database; constructing a distributed propeller sound field network corresponding to each of the plurality of spatial design parameter combinations according to the number of propellers and distribution mode corresponding to each of the plurality of spatial design parameter combinations; 4. The propeller noise reduction design method of claim 3, wherein, importing the single propeller noise source of each of the plurality of spatial design parameter combinations in the single propeller noise source database into the distributed propeller sound field network according to the corresponding distribution mode to perform sound propagation simulation processing and obtain system-level noise simulation results of each of the plurality of spatial design parameter combinations at a far-field receiving point. The method comprises: For each of the target propellers in the plurality of spatial design parameter combinations, a power unit is modeled by taking the target propeller, an adjacent propeller, and a power arm as the power unit, and a power unit modeling result is obtained; A computational fluid dynamics flow field simulation is performed on the target propeller in the power unit modeling result, a flow field simulation result of the target propeller is obtained, the flow field simulation is implemented by large eddy simulation, and a sound source integral surface is arranged outside the target propeller; According to the flow field simulation result of the target propeller, a corresponding propeller acoustic analogy noise source is calculated.

5. The propeller noise reduction design method of claim 1, wherein, The first spatial design parameter combination with the lowest total noise is obtained according to the system-level noise simulation result corresponding to each spatial design parameter combination, comprising: According to the system-level noise simulation result corresponding to each spatial design parameter combination, a sorting result of the total noise size in the system-level noise simulation result is obtained by sorting according to the size of the total noise; In the sorting result of the total noise size, the spatial design parameter combination with the smallest total noise is selected as the first spatial design parameter combination.

6. The propeller noise reduction design method of claim 1, wherein, The first spatial design parameter combination is designed by reducing noise based on the blade profile thickness parameter and the chord length parameter of the propeller, and a propeller noise reduction design result is obtained, comprising: Based on the blade profile thickness parameter and the chord length parameter of the propeller, a lift coefficient proxy model and a noise proxy model of the propeller are constructed; In the lift coefficient proxy model and the noise proxy model, a multi-objective optimization is performed with the maximum lift coefficient and the minimum total sound pressure level as the dual objectives, and a noise reduction design is performed according to the multi-objective optimization result to obtain a propeller noise reduction design result.

7. The propeller noise reduction design method of claim 6, wherein, The lift coefficient proxy model and the noise proxy model of the propeller are constructed based on the blade profile thickness parameter and the chord length parameter of the propeller, comprising: Based on the blade profile thickness parameter and the chord length parameter of the propeller, a high-dimensional sampling point set is generated by Latin hypercube sampling, and large eddy simulation is performed in a rotating coordinate system to obtain lift characteristic data; Based on the lift characteristic data, a lift coefficient proxy model of the propeller is constructed; During the large eddy simulation calculation, the fluctuating pressure source term required for FW-H acoustic analogy is extracted synchronously, and is imported into a sound propagation solver for noise calculation to obtain a noise calculation result; According to the noise calculation result, the total sound pressure level is calculated at the far-field observation points defined by the aviation standard, and a noise proxy model is established according to the total sound pressure level.

8. A propeller noise reduction design apparatus for an eVTOL aircraft, characterized by, The device comprises: A first obtaining module is configured to obtain a plurality of spatial design parameter combinations under the design requirements of meeting the total lift demand and structural strength demand of the eVTOL aircraft according to spatial design parameter data, wherein the spatial design parameter data includes the number of propellers, the diameter of the propellers, the inter-propeller spacing, the power arm aerodynamic profile, and the propeller-power arm spacing; A noise simulation module is configured to perform system-level noise simulation on the distributed propellers corresponding to the propeller design of each of the plurality of spatial design parameter combinations, and obtain a system-level noise simulation result corresponding to each of the plurality of spatial design parameter combinations; The second obtaining module is configured to obtain a first spatial design parameter combination with the lowest total noise according to the system-level noise simulation result corresponding to each spatial design parameter combination. The noise reduction design module is configured to perform noise reduction design processing on the propeller in the first spatial design parameter combination based on the thickness parameter and the chord length parameter of the propeller blade profile to obtain a propeller noise reduction design result.

9. An electronic device comprising a processor and a memory, characterized in that The processor runs a computer program or code stored in the memory to implement the propeller noise reduction design method in any one of claims 1 to 7.

10. A computer readable storage medium for storing a computer program or code, characterized in that, The computer program or code, when executed by the processor, implements the propeller noise reduction design method in any one of claims 1 to 7.

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