Noise-controllable vertical take-off and landing aircraft propeller design method and implementation device

Abstract

The invention belongs to the technical field of vertical take-off and landing aircrafts, and particularly relates to a noise-controllable vertical take-off and landing aircraft propeller design method and an implementation device. The design method comprises the steps of selecting a blade spanwise key position and determining a basic airfoil profile, optimizing the airfoil profile at the key position, constructing a preliminary propeller configuration, exploring the influence of chord length, negative torque and blade number on noise, determining the basic configuration and optimization range of the propeller, optimizing the aerodynamic performance of the propeller and the like. According to the method, starting from airfoil optimization of key positions of blades, the influence of chord length, a negative torsion value and the number of the blades on propeller noise is gradually explored, a propeller basic configuration and an optimization range which are acceptable in noise are determined, multi-target pneumatic optimization is carried out on the basis, the pneumatic efficiency of the propeller is improved, the noise level is reduced, and the propeller noise is reduced. The trial and error cost and time are reduced, a high-performance and low-noise propeller design scheme can be provided for the vertical take-off and landing aircraft, and the application requirements of the vertical take-off and landing aircraft in complex environments such as urban air traffic are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of vertical take-off and landing aircraft, and in particular relates to a design method and an implementation device for a noise-controllable vertical take-off and landing aircraft propeller. Background Art

[0002] Vertical take-off and landing (VTOL) aircraft, capable of vertical take-off and landing without a runway, have broad application prospects in urban air mobility, search and rescue, patrol, and other fields. They are considered the core vehicles for future low-altitude urban flight. However, during operation, the high-speed rotating propellers of VTOL aircraft present a significant noise problem due to airflow disturbances, vortex effects, and blade vibration. On the one hand, propeller noise propagates directly into the cabin, resulting in poor passenger comfort. On the other hand, VTOL aircraft are widely deployed in densely populated areas, and the noise propagation distance is shorter when flying at low altitudes, exacerbating noise pollution in nearby residential areas. Therefore, propeller noise has become a bottleneck restricting the further promotion and application of VTOL aircraft.

[0003] Traditional propeller design methods for VTOL aircraft mostly prioritize aerodynamic performance, lacking systematic consideration of noise control. This results in excessive propeller noise in practical applications, or the need for passive noise reduction measures (such as soundproofing materials and structural shielding) later on. However, these methods often increase structural weight, impacting the overall performance of the aircraft. Therefore, comprehensively considering aerodynamic performance and noise control during the VTOL propeller design stage is key to resolving noise issues.

[0004] Therefore, the present invention aims to provide a noise-controllable vertical take-off and landing aircraft propeller design method and implementation device. By systematically and comprehensively considering aerodynamic performance and noise control in the design stage, active noise control can be achieved, thereby solving the problems in the prior art of excessive propeller noise or structural weight gain caused by passive noise reduction in the later stage. Summary of the Invention

[0005] In response to the above-mentioned deficiencies in the prior art, the present invention provides a noise-controllable vertical take-off and landing aircraft propeller design method and implementation device, which solves the problem of excessive propeller noise or structural weight increase caused by subsequent passive noise reduction in the prior art.

[0006] To achieve the above object, the technical solution adopted by the present invention is: A method for designing a noise-controllable vertical take-off and landing aircraft propeller is provided, comprising the following steps: S1: Select the key span positions of the blade and determine the basic airfoil: According to the design requirements of the aircraft, the key positions of the blade span are selected for subsequent wing profile optimization, and the basic wing profile for optimization is determined; S2: Determine the optimization target and constraint condition of the typical working condition, and optimize the wing profile of the key position of the blade span: According to the typical working conditions of hovering and cruising, the maximum lift coefficient and the minimum drag coefficient are taken as the target, and the basic wing profile is optimized under the constraint condition to determine the coordinate parameters of the optimized wing profile; S3: Preliminary arrangement of equal chord optimization wing profile along the blade span: The optimized wing profile is arranged along the span, and the equal chord design is adopted during the arrangement to form a preliminary propeller configuration; S4: According to the fixed specific negative twist value Twist and specific blade number Blade, adjust the chord value C to generate a test configuration set, and determine the chord length interval acceptable for noise ; S5: According to the fixed specific chord value C and specific blade number Blade, adjust the negative twist value Twist to generate a test configuration set, and determine the negative twist interval acceptable for noise ; S6: According to the fixed specific chord value C and specific negative twist value Twist, adjust the blade number Blade to generate a test configuration set, and determine the blade number interval acceptable for noise ; S7: Determine the basic configuration of the propeller and the optimization range: The optimization range of the chord value C is , the optimization range of the negative twist value Twist is , and the optimization range of the blade number Blade is ; From the noise acceptable chord length interval determined in S4, select a fixed value, from the noise acceptable negative twist interval determined in S5, select a fixed value, and from the noise acceptable blade number interval determined in S6, select a fixed value, which together constitute the noise acceptable basic configuration of the propeller; S8: Optimization of propeller configuration aerodynamic performance under corresponding working conditions: Under the typical working conditions, based on the basic configuration, multi-objective aerodynamic optimization is carried out within the parameter range of the chord value C, negative twist value Twist and blade number Blade determined in S7.

[0007] The beneficial effects of adopting the above technical solution are as follows: Step S1 selects the key position of the blade span and determines the basic airfoil, which can be used to determine the basic airfoil for subsequent optimization, providing a starting point and reference for subsequent airfoil optimization, avoiding blind exploration and deviation from the required characteristics, and improving the position that has the greatest impact on the performance of the aircraft, thereby improving the pertinence of the optimization effect; Step S2 optimizes the airfoil at the key position of the blade span by determining the optimization target and constraint conditions of the typical working condition to maximize the lift coefficient and minimize the drag coefficient As the goal, the basic airfoil is optimized under the constraints, which can make the optimized airfoil have better aerodynamic performance and flight performance under typical working conditions such as hovering and cruising; Step S3 forms a preliminary propeller configuration by preliminarily arranging the optimized airfoil with equal chord length along the span direction of the blade, which is conducive to the subsequent steps; Step S4 generates a test configuration set by selecting a specific negative torque value and the number of blades, adjusting the chord length value, so as to explore the influence law and range of the chord length value on the propeller noise, and clarify the chord length range with acceptable noise. , provides a clear range for subsequent parameter selection, avoids ineffective exploration within an unreasonable chord length range, and can screen out propeller configurations that meet noise requirements, helping to reduce the noise level during propeller operation; in step S5, based on the determined chord length value and number of blades, adjust the negative torque value to generate a test configuration set to explore the influence of the negative torque value on the propeller noise and further determine the negative torque range with acceptable noise. , narrowing the optimization range of the negative torque value and further optimizing the noise performance of the propeller; in step S6, based on the determined chord length value and negative torque value, the number of blades is adjusted to generate a test configuration to explore the influence of the number of blades on the propeller noise and determine the range of the number of blades with acceptable noise. , which provides a basis for finally determining the number of blades of the basic configuration of the propeller, avoiding the noise problem caused by unreasonable selection of the number of blades; in step S7, the basic configuration of the propeller with acceptable noise is constructed by selecting the chord length value, negative torque value and number of blades, providing a performance benchmark for subsequent aerodynamic performance optimization; in step S8, under typical working conditions, based on the basic configuration, multi-objective aerodynamic optimization is performed within the determined parameter range, comprehensively considering multiple factors such as hovering efficiency, cruising efficiency, and drag coefficient, so that the propeller has better aerodynamic performance while meeting the noise requirements, thereby improving the overall performance of the aircraft.

[0008] This design method combines aerodynamic performance with noise control. By optimizing the propeller's airfoil, chord length, negative torque value, number of blades and other parameters as well as the overall configuration of the propeller, the propeller's flight performance is improved while the noise level is effectively controlled. The various steps are interrelated and gradually advanced, which can quickly screen out propeller configurations that meet the requirements, improve design efficiency and shorten the R&D cycle.

[0009] Furthermore, in S1, the key positions include the main lift section, blade root and blade tip at 50% to 90% of the blade span.

[0010] The beneficial effects of adopting the above technical solution are as follows: the main lift section is at 50% to 90% of the blade span, with a moderate angle of attack, small induced drag and far away from hub interference, and the aerodynamic efficiency is the highest. By selecting an airfoil with good lift characteristics as the basic airfoil of the main lift section at 50% to 90% of the blade span and optimizing it, the comprehensive aerodynamic efficiency under hovering and cruising conditions can be further improved; a basic airfoil with high strength and large thickness is selected at the blade root. The rotation radius at the blade root is small, the linear speed is low, but the mass is concentrated. It needs to withstand the maximum centrifugal load and transmit torque and thrust at the same time. By optimizing the airfoil at the blade root, the loss of aerodynamic efficiency caused by the large thickness of the structure can be alleviated; a basic airfoil with a small maximum thickness, small leading edge radius, thin trailing edge, small curvature and high maximum lift coefficient is selected at the blade tip position. The linear speed at the blade tip is high, and the risk of airflow separation due to vortex interference is high. By optimizing the airfoil at the blade tip, the occurrence of airflow separation can be delayed.

[0011] Furthermore, in S2, the optimization objectives and constraints in the hovering state are:

[0012]

[0013] Where x is the airfoil parameterization vector, is the optimized airfoil lift coefficient in the hovering state, is the optimized airfoil drag coefficient in hovering state, is the drag coefficient of the basic airfoil in the hovering state, To optimize the maximum thickness of the airfoil, is the maximum thickness of the basic airfoil, UP is the upper boundary of the optimized airfoil parameterization vector, and LOW is the lower boundary of the optimized airfoil parameterization vector; The optimization objectives and constraints under the cruising state are:

[0014]

[0015] Where x is the airfoil parameterization vector, For the optimized airfoil drag coefficient in cruise state, is the optimized airfoil lift coefficient in cruise state, is the lift coefficient of the basic airfoil in the cruise state, UP is the upper boundary of the optimized airfoil parameterization vector, and LOW is the lower boundary of the optimized airfoil parameterization vector.

[0016] The beneficial effects of adopting the above technical solution are: the optimization constraint condition in the hovering state is the drag coefficient Does not exceed the drag coefficient of the basic airfoil , which ensures that the optimized airfoil has lower drag in the hovering state, thereby reducing energy loss; and the maximum thickness of the optimized airfoil in the hovering state and the maximum thickness of the basic airfoil The same can ensure that the optimized airfoil can maintain structural strength and meet loading requirements, and by optimizing the upper boundary UP and lower boundary LOW of the airfoil parameterization vector, extreme changes in the airfoil shape can be avoided, ensuring the performance stability of the aircraft under multiple working conditions. The optimization constraint condition in the cruise state is the lift coefficient Higher lift coefficient than the basic airfoil , which can ensure high cruising efficiency in the cruising state; and the cruise state has the same maximum thickness constraint and upper and lower boundary restrictions of the optimized airfoil parameterization vector as in the hovering state, in order to ensure that the multi-design point optimization composed of the two states produces a unique optimization solution.

[0017] Furthermore, in S2, the coordinate parameters of the optimized airfoil are determined by using the Hicks-Henne function, which is used to transform the airfoil parameterization vector into Converted into airfoil coordinate parameters, the formula is:

[0018] in, is the chord-wise horizontal coordinate of the airfoil, To optimize the vertical coordinate of the upper surface of the airfoil, To optimize the lower surface ordinate of the airfoil, is the upper surface ordinate of the basic airfoil, is the ordinate of the lower surface of the basic airfoil, is the coefficient of the disturbance component applied to the upper surface, is the coefficient of the disturbance component applied to the lower surface, ; The shape function formula is:

[0019] in, , are the n-1 specific airfoil chord-wise coordinates.

[0020] The beneficial effect of adopting the above technical solution is: by applying linear perturbations to the surface of the basic airfoil using the Hicks-Henne function, accurate optimization of the airfoil can be achieved, and the controllability of the optimized airfoil can be increased.

[0021] Furthermore, in S3, the preliminary propeller configuration arrangement includes arranging the optimized airfoil at the root and the optimized airfoil at the corresponding positions in the blade span direction, and preliminarily arranging the optimized airfoil of the main lift section within the corresponding blade span position range, and smoothly connecting the middle sections of the three airfoils.

[0022] The beneficial effects of adopting the above technical solution are: by optimizing the layout of the blade root, the structural stability and aerodynamic efficiency of the blade root area can be ensured; by optimizing the layout of the blade tip, the airflow separation can be delayed and the aerodynamic efficiency of the tip can be improved; by optimizing the layout of the main lift section, the overall aerodynamic performance of the propeller can be further improved; and the propeller is arranged using an equal chord length design method, which facilitates the exploration of noise influencing factors and range.

[0023] Furthermore, in S4, the fixed specific negative torque value Twist and the specific number of blades Blade are the empirical values ​​of the propeller aerodynamic design; the chord length value C is adjusted to generate a test configuration set based on the chord length empirical value, and multiple discrete values ​​of the chord length value C are selected to form a test configuration set for exploring the influence law and range of the chord length value on the propeller noise.

[0024] The beneficial effects of adopting the above technical solution are: in step S4, the negative torque value Twist and the number of blades Blade are fixed to verified aerodynamic design empirical values, and a number of chord length values ​​C are discretely selected based on the chord length empirical value to form a test configuration set. This can quickly lock the influence of chord length on propeller noise and its acceptable range, avoiding blind testing and providing a clear noise boundary for subsequent multi-objective aerodynamic optimization of propeller configuration, effectively improving test efficiency.

[0025] Furthermore, in S5, the specific chord length value C is the noise acceptable chord length range determined in S4. In the test, the chord length value with the best hovering efficiency and cruising efficiency of the obtained propeller configuration is selected; the specific number of blades Blade is the specific number of blades fixed in S4; the negative torque value Twist is adjusted to generate a test configuration set. Taking the negative torque value Twist fixed in S4 as the benchmark, multiple discrete values ​​of the negative torque value Twist are selected to form a test configuration set, which is used to explore the influence law and range of the negative torque value on the propeller noise.

[0026] The beneficial effects of adopting the above technical solution are: in step S5, the chord length value C is fixed to the best aerodynamic performance value within the noise acceptable chord length range determined in S4, the number of blades Blade maintains the specific value in S4, and then multiple negative torque values ​​Twist are discretely selected based on the negative torque value Twist to form a test configuration set. While maintaining the aerodynamic efficiency constraint, the influence range of negative torque on propeller noise can be obtained, which is beneficial to subsequent optimization and avoids the inefficiency problem caused by blind adjustment.

[0027] Furthermore, in S6, the specific chord length value C is the noise acceptable chord length range determined in S4. The chord length value with the best hovering efficiency and cruise efficiency of the obtained propeller configuration is selected; the specific negative torque value Twist is the acceptable negative torque range of noise determined by S5 In the test, the negative torque value with the best hovering efficiency and cruising efficiency of the obtained propeller configuration is selected; the number of blades Blade is adjusted to generate a test configuration set. Based on the fixed number of blades Blade in S4 or S5, multiple discrete values ​​of the number of blades Blade are selected to form a test configuration set for exploring the influence of the number of blades on the propeller noise and its range.

[0028] The beneficial effect of adopting the above technical solution is: step S6, based on the verified chord length value C in S5 and the negative twist value Twist with acceptable noise and best aerodynamic performance in S5, discretely samples multiple blade number Blade values ​​with the established blade number Blade as the benchmark to form a test configuration set, thereby quickly locking the impact range of the blade number Blade change on propeller noise within a locally optimal range.

[0029] Furthermore, in S8, the mathematical description of the propeller aerodynamic performance optimization is:

[0030]

[0031] Among them, FM is the hovering efficiency, ETA is the cruising efficiency, CT is the thrust coefficient, R is the propeller radius, Optimize the airfoil starting position for the main lift section, Optimize the end position of the airfoil for the main lift section, Twist is a negative twist value, is the lower limit of the acceptable negative torsion value of the noise determined in S5, is the upper limit of the acceptable negative torsion value of the noise determined in S5, is the average chord length of the blade, is the lower limit of the acceptable chord length of noise determined in S4, is the upper limit of the acceptable chord length of noise determined in S4, Blade is the number of blades, is the lower limit of the acceptable number of blades for noise determined in S6, is the upper limit of the number of blades with acceptable noise determined in S6, is the blade swept position, is the lower boundary of the swept position, is the upper boundary of the swept position, is the blade sweep angle, is the lower boundary of the sweep angle, is the upper boundary of the sweep angle.

[0032] The beneficial effects of adopting the above technical solution are: mainly optimizing the three aerodynamic performance indicators of hovering efficiency FM, cruise efficiency ETA and tension coefficient CT, and the optimization process is subject to the negative torque range of acceptable noise ( ), chord length interval ( ), blade number range ( ) and the range of sweep position and sweep angle ( 、 ) constraints, through this multi-objective optimization, the aerodynamic performance of the propeller in hovering and cruising states can be improved simultaneously, ensuring that the aircraft can achieve better flight efficiency in different flight modes. At the same time, the noise can be controlled within an acceptable range, avoiding aircraft usage restrictions caused by noise problems.

[0033] The present invention provides a device for designing a propeller for a vertical take-off and landing aircraft that achieves the above-mentioned noise control, comprising an aerodynamic optimization module, an aerodynamic evaluation module, and a noise evaluation module. The aerodynamic evaluation module is bidirectionally data-connected to the aerodynamic optimization module, the output of the aerodynamic evaluation module is connected to the input of the noise evaluation module, and the output of the noise evaluation module is connected to the input of the aerodynamic optimization module. Aerodynamic optimization module, used to maximize lift coefficient in typical hover and cruise conditions and minimize the drag coefficient For the purpose of basic airfoil optimization under constraints, the evaluated intermediate airfoil aerodynamic data is received as a reference for the optimization process and to guide the optimization direction of the airfoil; it is used for the basic propeller configuration with acceptable noise under typical working conditions and at a certain chord length value. , negative torque value and number of blades Multi-objective aerodynamic optimization within the parameter range of the propeller, receiving the evaluated intermediate propeller configuration aerodynamic data as a reference for the optimization process and guiding the propeller configuration optimization direction; The aerodynamic evaluation module is used to receive the intermediate airfoil parameters of the key position airfoil optimization under typical hovering and cruising working conditions generated by the aerodynamic optimization module, realize the two-dimensional coordinate calculation and aerodynamic numerical simulation of the intermediate airfoil parameters, and transmit the aerodynamic data to the aerodynamic optimization module; it is used to realize the three-dimensional coordinate calculation and aerodynamic numerical simulation of the propeller test configuration set in the propeller basic configuration and optimization range determination stage, and transmit the propeller surface pressure distribution data to the noise evaluation module as a basis for determining the propeller basic configuration and optimization range; it is used to receive the intermediate propeller configuration parameters of the multi-objective aerodynamic optimization based on the propeller basic configuration under typical working conditions generated by the aerodynamic optimization module, realize the three-dimensional coordinate calculation and aerodynamic numerical simulation of the intermediate propeller configuration parameters, and transmit the aerodynamic data to the aerodynamic optimization module; The noise assessment module is used to receive the surface pressure distribution data of the propeller test configuration set output by the aerodynamic assessment module during the propeller basic configuration and optimization range determination stage, realize acoustic numerical simulation, and finally select the chord length value C, negative twist value Twist and blade number Blade to form the propeller basic configuration with acceptable noise, and determine the chord length range with acceptable noise. , negative torsion range and blade number range , and sent to the aerodynamic optimization module for propeller configuration optimization.

[0034] The beneficial effects of adopting the above technical solution are as follows: the aerodynamic optimization module is used to perform airfoil parameter optimization and propeller configuration optimization, and can perform multi-objective aerodynamic optimization based on the aerodynamic data provided by the aerodynamic evaluation module and the basic configuration and optimization range provided by the noise evaluation module; the aerodynamic evaluation module can realize the aerodynamic performance evaluation of the blade airfoil and propeller configuration, and provide aerodynamic data for the aerodynamic optimization module; the noise evaluation module can realize the noise level evaluation of different propeller configurations, determine the acceptable design parameter range of noise, and provide noise control constraints for the aerodynamic optimization module. Through the feedback of the noise evaluation module, the aerodynamic optimization module can consider noise control while meeting the aerodynamic performance requirements, and achieve a balance between aerodynamic performance and noise level; in addition, the two-way data connection between the aerodynamic evaluation module and the aerodynamic optimization module ensures information flow and data update during the design process, thereby improving the accuracy and iteration efficiency of the design.

[0035] In summary, the noise-controllable vertical take-off and landing aircraft propeller design method and implementation device provided by the present invention have the following beneficial effects: (1) The noise-controllable propeller design method for a vertical take-off and landing aircraft in the present invention adopts the method of "first reducing the noise boundary, then aerodynamic improvement", which brings noise control to the aerodynamic design stage, thereby eliminating the need to add sound insulation structures or shielding devices in the later stages of aircraft development, and significantly avoiding the weight, complexity and cost costs caused by passive noise reduction.

[0036] (2) The noise-controllable vertical take-off and landing aircraft propeller design method in the application starts from the optimization of the airfoil of the key position of the blade, quickly obtains a high-performance airfoil considering the hovering efficiency and cruising efficiency by optimizing the airfoil of the main lift section, the blade root and the blade tip, and then sequentially locks the influence law of the chord length value, the negative torsion value and the number of blades on the propeller noise by using the single variable method, so as to quickly determine the noise-acceptable parameter interval, which not only narrows the range of subsequent multi-objective aerodynamic optimization, but also avoids a large number of noise calculations with high time consumption in the continuous design range, effectively reduces the trial and error cost, and finally performs multi-objective aerodynamic optimization in the determined noise constraint range, so that the propeller meets the low noise demand in complex scenarios such as urban air traffic while maintaining the optimal hovering efficiency and cruising efficiency, thereby providing a high-performance, low-noise and quickly iterative propeller design scheme for the vertical take-off and landing aircraft.

[0037] (3) The implementation device of the noise-controllable vertical take-off and landing aircraft propeller design method in the application forms an efficient and cooperative closed-loop optimization system by integrating the aerodynamic optimization module, the aerodynamic evaluation module and the noise evaluation module, wherein the aerodynamic optimization module is used to perform airfoil parameter optimization and propeller configuration optimization, and can perform multi-objective aerodynamic optimization according to the aerodynamic data provided by the aerodynamic evaluation module and the basic configuration and optimization range provided by the noise evaluation module; the aerodynamic evaluation module can realize the aerodynamic performance evaluation of the blade airfoil and the propeller configuration, and provide the aerodynamic data for the aerodynamic optimization module; the noise evaluation module can realize the noise level evaluation of different propeller configurations, determine the noise-acceptable design parameter range, and provide the noise control constraint condition for the aerodynamic optimization module, and through the feedback of the noise evaluation module, the aerodynamic optimization module can consider noise control while meeting the aerodynamic performance requirements, realize the balance between the aerodynamic performance and the noise level, not only improve the automation degree of the design process, but also ensure the reliability of the design result.

[0038] (4) The implementation device of the noise-controllable vertical take-off and landing aircraft propeller design method in the application can flexibly set typical working conditions according to different vertical take-off and landing aircraft use scenarios, and can set corresponding noise acceptability according to different standards to adjust the propeller configuration optimization range, meet diversified design requirements, and realize efficient noise reduction and aerodynamic performance collaborative optimization in a wide range of scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The flowchart of the design method of the application is shown in the figure; Figure 2 The composition and input-output relationship between the devices of the application are shown in the figure; DETAILED DESCRIPTION The specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations utilizing the concepts of the present invention are protected.

[0040] Example 1 like Figure 1 As shown, the noise-controllable vertical take-off and landing aircraft propeller design method provided by the present invention includes the following steps: S1: Select the key span positions of the blade and determine the basic airfoil: Based on the design requirements of the aircraft, key span-wise positions of the blades are selected for subsequent airfoil optimization, and the basic airfoil for optimization is determined. S2: Determine the optimization objectives and constraints for typical operating conditions, and optimize the airfoil at key spanwise locations: According to the typical working conditions of hovering and cruising, the lift coefficient is maximized. and minimize the drag coefficient As the goal, the basic airfoil is optimized under the constraint conditions and the coordinate parameters of the optimized airfoil are determined; S3: Preliminary arrangement of optimized airfoils with equal chord length along the span of the blades: Arrange the optimized airfoils along the span direction, using a constant chord length design to form a preliminary propeller configuration. S4: Based on the fixed specific negative twist value Twist and the specific number of blades Blade, adjust the chord length value C to generate a test configuration set and determine the chord length range with acceptable noise. ; S5: Based on the fixed specific chord length C and the specific number of blades Blade, adjust the negative twist value Twist to generate a test configuration set and determine the negative twist range with acceptable noise. ; S6: Based on the fixed specific chord length value C and the specific negative twist value Twist, adjust the number of blades Blade to generate a test configuration set and determine the range of blade numbers with acceptable noise. ; S7: Determine the basic propeller configuration and optimization scope: The optimal range of the chord length C is set to , the optimization range of negative twist value Twist is The optimization range of the number of blades is ;Acceptable chord length range of noise determined from S4 Select a fixed value from S5 to determine the acceptable negative torsion range of noise Select the fixed value and the acceptable noise blade number range determined from S6 Select fixed values ​​from them to form a basic propeller configuration with acceptable noise; S8: Optimize propeller configuration aerodynamic performance under corresponding working conditions: Under typical working conditions, based on the basic configuration, multi-objective aerodynamic optimization is performed within the parameter range of chord length C, negative twist value Twist and blade number Blade determined by S7.

[0041] In step S1, key locations include the main lift section at 50% to 90% of the blade span, the high-structural-strength blade root, and the high-speed blade tip. The main lift section has a moderate angle of attack, low induced drag, and is far from hub interference, resulting in the highest aerodynamic efficiency. By selecting and optimizing an airfoil with good lift characteristics as the basic airfoil for the main lift section at 50% to 90% of the blade span, the overall aerodynamic performance of the propeller can be further improved, thereby enhancing the efficiency and economy of the aircraft. A basic airfoil with high strength and thickness is selected at the blade root. The blade root has a small rotation radius and low linear velocity, but its mass is concentrated. It must withstand the maximum centrifugal load while also transmitting torque and thrust. By optimizing the airfoil at the blade root, the loss of aerodynamic efficiency caused by the large structural thickness can be alleviated. A basic airfoil with a small maximum thickness, a small leading edge radius, a thin trailing edge, a small camber, and a high maximum lift coefficient is selected at the blade tip. The blade tip has a high linear velocity and a high risk of airflow separation due to vortex interference. By optimizing the airfoil at the blade tip, the occurrence of airflow separation can be delayed.

[0042] In step S2, the optimization objectives and constraints in the hovering state are:

[0043]

[0044] Where x is the airfoil parameterization vector, is the optimized airfoil lift coefficient in the hovering state, is the optimized airfoil drag coefficient in hovering state, is the drag coefficient of the basic airfoil in the hovering state, To optimize the maximum thickness of the airfoil, is the maximum thickness of the basic airfoil, UP is the upper boundary of the optimized airfoil parameterization vector, and LOW is the lower boundary of the optimized airfoil parameterization vector; The optimization objectives and constraints under the cruising state are:

[0045]

[0046] Where x is the airfoil parameterization vector, For the optimized airfoil drag coefficient in cruise state, is the optimized airfoil lift coefficient in cruise state, is the lift coefficient of the basic airfoil in the cruise state, UP is the upper boundary of the optimized airfoil parameterization vector, and LOW is the lower boundary of the optimized airfoil parameterization vector.

[0047] The Hicks-Henne function is used to determine the coordinate parameters of the optimized airfoil. By applying linear perturbations on the surface of the basic airfoil, the airfoil parameterization vector Converted into airfoil coordinate parameters, the formula is:

[0048] in, is the chord-wise horizontal coordinate of the airfoil, To optimize the vertical coordinate of the upper surface of the airfoil, To optimize the lower surface ordinate of the airfoil, is the upper surface ordinate of the basic airfoil, is the ordinate of the lower surface of the basic airfoil, is the coefficient of the disturbance component applied to the upper surface, is the coefficient of the disturbance component applied to the lower surface, ; The shape function formula is:

[0049] in, , are the n-1 specific airfoil chord-wise coordinates.

[0050] The optimization constraint in the hovering state is the drag coefficient Does not exceed the drag coefficient of the basic airfoil , which ensures that the optimized airfoil has lower drag in the hovering state, thereby reducing energy loss; and the maximum thickness of the optimized airfoil in the hovering state and the maximum thickness of the basic airfoil The same can ensure that the optimized airfoil can maintain structural strength and meet loading requirements, and by optimizing the upper boundary UP and lower boundary LOW of the airfoil parameterization vector, extreme changes in the airfoil shape can be avoided, ensuring the performance stability of the aircraft under multiple working conditions. The optimization constraint condition in the cruise state is the lift coefficient Higher lift coefficient than the basic airfoil , which can ensure high cruising efficiency in the cruising state; and the cruise state has the same maximum thickness constraint and upper and lower boundary restrictions of the optimized airfoil parameterization vector as in the hovering state, in order to ensure that the multi-design point optimization composed of the two states produces a unique optimization solution.

[0051] In step S3, the preliminary propeller configuration layout includes arranging the optimized airfoil at the root and the optimized airfoil at corresponding positions in the blade span direction, and preliminarily arranging the optimized airfoil of the main lift section within the corresponding span direction position range of the blade. The middle sections of the three airfoils are smoothly connected. By optimizing the layout of the root, the structural stability and aerodynamic efficiency of the root area can be ensured. By optimizing the layout of the tip, the airflow separation can be delayed and the aerodynamic efficiency of the tip can be improved. By optimizing the layout of the main lift section, the overall aerodynamic performance of the propeller can be further improved. The use of a constant chord length design method to configure the propeller facilitates the exploration of noise influencing factors and ranges.

[0052] In step S4, the specific negative torque value Twist and the specific number of blades Blade are fixed as empirical values ​​for propeller aerodynamic design; the chord length value C is adjusted to generate a test configuration set based on the empirical chord length value, and multiple discrete values ​​of the chord length value C are selected to form a test configuration set for exploring the influence of the chord length value on propeller noise and its range. By fixing the negative torque value Twist and the number of blades Blade to verified empirical values ​​for aerodynamic design, and discretely selecting a number of chord length values ​​C based on the empirical chord length value to form a test configuration set, the influence of the chord length on propeller noise and its acceptable range can be quickly identified, avoiding blind testing while providing a clear noise boundary for subsequent multi-objective aerodynamic optimization of the propeller configuration, effectively improving test efficiency.

[0053] In step S5, the specific chord length value C is the noise acceptable chord length range determined in S4 In the above example, the chord length value that achieves the best hover and cruise efficiency for the resulting propeller configuration is selected; the specific number of blades, Blade, is the specific number of blades fixed in S4; the negative torque value, Twist, is adjusted to generate a test configuration set. Taking the negative torque value, Twist, fixed in S4 as a benchmark, multiple discrete values ​​of Twist are selected to form a test configuration set. This is used to explore the influence of negative torque on propeller noise and its range. By fixing the chord length, C, to the optimal aerodynamic performance value within the noise-acceptable chord length range determined in S4, maintaining the number of blades, Blade, at the specific value in S4, and then discretely selecting multiple negative torque values, Twist, based on Twist, to form a test configuration set, the influence range of negative torque on propeller noise can be determined while maintaining aerodynamic efficiency constraints. This facilitates subsequent optimization and avoids the inefficiency caused by blind adjustments.

[0054] In step S6, the specific chord length value C is the noise acceptable chord length interval determined in S4 The chord length value with the best hovering efficiency and cruise efficiency of the obtained propeller configuration is selected; the specific negative torque value Twist is the acceptable negative torque range of noise determined by S5 In the test, the negative torque value with the best hovering efficiency and cruising efficiency of the obtained propeller configuration is selected; the number of blades Blade is adjusted to generate a test configuration set based on the fixed number of blades Blade in S4 or S5. Multiple discrete values ​​of the number of blades Blade are selected to form a test configuration set, which is used to explore the influence law and range of the number of blades on propeller noise, so as to quickly lock the influence range of the change of the number of blades Blade on the propeller noise within a local optimal range.

[0055] In step S7, the optimization range of the chord length value C is set to , the optimization range of negative twist value Twist is The optimization range of the number of blades is ;Acceptable chord length range of noise determined from S4 Select a fixed value from S5 and determine the acceptable negative torsion range of the noise Select the fixed value and the acceptable noise blade number range determined from S6 Fixed values ​​are selected from them to form a basic propeller configuration with acceptable noise, providing a performance benchmark for subsequent aerodynamic performance optimization.

[0056] In step S8, under typical operating conditions, based on the basic configuration, multi-objective aerodynamic optimization of the propeller is performed within a determined parameter range. The mathematical description of the propeller aerodynamic performance optimization is:

[0057]

[0058] Among them, FM is the hovering efficiency, ETA is the cruising efficiency, CT is the thrust coefficient, R is the propeller radius, Optimize the airfoil starting position for the main lift section, Optimize the end position of the airfoil for the main lift section, Twist is a negative twist value, is the lower limit of the acceptable negative torsion value of the noise determined in S5, is the upper limit of the acceptable negative torsion value of the noise determined in S5, is the average chord length of the blade, is the lower limit of the acceptable chord length of noise determined in S4, is the upper limit of the acceptable chord length of noise determined in S4, Blade is the number of blades, is the lower limit of the acceptable number of blades for noise determined in S6, is the upper limit of the number of blades with acceptable noise determined in S6, is the blade swept position, is the lower boundary of the swept position, is the upper boundary of the swept position, is the blade sweep angle, is the lower boundary of the sweep angle, is the upper boundary of the sweep angle.

[0059] In step S8, the three aerodynamic performance indicators of hovering efficiency FM, cruise efficiency ETA and tension coefficient CT are optimized. The optimization process is subject to the negative torque range ( ), chord length interval ( ), blade number range ( ) and the range of sweep position and sweep angle ( 、 ) constraints, through this multi-objective optimization, the aerodynamic performance of the propeller in hovering and cruising states can be improved simultaneously, ensuring that the aircraft can achieve better flight efficiency in different flight modes. At the same time, the noise can be controlled within an acceptable range, avoiding aircraft usage restrictions caused by noise problems.

[0060] The noise-controllable vertical take-off and landing aircraft propeller design method provided by the present invention starts with the optimization of the airfoil at the key position of the blade, gradually explores the influence of chord length, negative torque value and number of blades on propeller noise, determines the basic configuration and optimization range of the propeller with acceptable noise, and performs multi-objective aerodynamic optimization based on this. It not only improves the aerodynamic efficiency of the propeller, but also significantly reduces the noise level, while reducing the trial and error cost and time in the design process. At the same time, it can provide a high-performance, low-noise propeller design solution for vertical take-off and landing aircraft to meet its application needs in complex environments such as urban air traffic.

[0061] Example 2 like Figure 2 As shown, to implement the above-mentioned design method, the present invention provides an implementation device of the noise-controllable vertical take-off and landing aircraft propeller design method, comprising an aerodynamic optimization module, an aerodynamic evaluation module, and a noise evaluation module. The aerodynamic evaluation module is bidirectionally data-connected to the aerodynamic optimization module, the output end of the aerodynamic evaluation module is connected to the input end of the noise evaluation module, and the output end of the noise evaluation module is connected to the input end of the aerodynamic optimization module. Among them, the aerodynamic optimization module is used to maximize the lift coefficient under typical hovering and cruising conditions. and minimize the drag coefficient For the purpose of basic airfoil optimization under constraints, the evaluated intermediate airfoil aerodynamic data is received as a reference for the optimization process and to guide the optimization direction of the airfoil; it is used for the basic propeller configuration with acceptable noise under typical working conditions and at a certain chord length value. , negative torque value and number of blades Multi-objective aerodynamic optimization within the parameter range of the propeller, receiving the evaluated intermediate propeller configuration aerodynamic data as a reference for the optimization process and guiding the propeller configuration optimization direction; The aerodynamic evaluation module is used to receive the intermediate airfoil parameters of the key position airfoil optimization under typical hovering and cruising working conditions generated by the aerodynamic optimization module, realize the two-dimensional coordinate calculation and aerodynamic numerical simulation of the intermediate airfoil parameters, and transmit the aerodynamic data to the aerodynamic optimization module; it is used to realize the three-dimensional coordinate calculation and aerodynamic numerical simulation of the propeller test configuration set in the propeller basic configuration and optimization range determination stage, and transmit the propeller surface pressure distribution data to the noise evaluation module as a basis for determining the propeller basic configuration and optimization range; it is used to receive the intermediate propeller configuration parameters of the multi-objective aerodynamic optimization based on the propeller basic configuration under typical working conditions generated by the aerodynamic optimization module, realize the three-dimensional coordinate calculation and aerodynamic numerical simulation of the intermediate propeller configuration parameters, and transmit the aerodynamic data to the aerodynamic optimization module; The noise assessment module is used to receive the surface pressure distribution data of the propeller test configuration set output by the aerodynamic assessment module during the propeller basic configuration and optimization range determination stage, realize acoustic numerical simulation, and finally select the chord length value C, negative twist value Twist and blade number Blade to form the propeller basic configuration with acceptable noise, and determine the chord length range with acceptable noise. , negative torsion range and blade number range , and sent to the aerodynamic optimization module for propeller configuration optimization.

[0062] The implementation device of the noise-controllable vertical take-off and landing aircraft propeller design method in the present invention forms an efficient and coordinated closed-loop optimization system by integrating an aerodynamic optimization module, an aerodynamic evaluation module and a noise evaluation module, wherein the aerodynamic optimization module is used to perform airfoil parameter optimization and propeller configuration optimization, and can perform multi-objective aerodynamic optimization based on the aerodynamic data provided by the aerodynamic evaluation module and the basic configuration and optimization range provided by the noise evaluation module; the aerodynamic evaluation module can realize the aerodynamic performance evaluation of the blade airfoil and propeller configuration, and provide aerodynamic data for the aerodynamic optimization module; the noise evaluation module can realize the noise level evaluation of different propeller configurations, determine the acceptable design parameter range of noise, and provide noise control constraints for the aerodynamic optimization module. Moreover, through the feedback of the noise evaluation module, the aerodynamic optimization module can consider noise control while meeting the aerodynamic performance requirements, and achieve a balance between aerodynamic performance and noise level, which not only improves the degree of automation of the design process, but also ensures the reliability of the design results.

[0063] In summary, the noise-controllable VTOL aircraft propeller design method and implementation device provided by the application comprehensively considers aerodynamic performance and noise control in the design stage, actively controls noise, ensures that the designed propeller achieves the best balance in aerodynamic performance and noise control, and provides strong guarantee for the implementation of the method through efficient cooperation of the device. Through the combination of the design method and the implementation device, the design efficiency is improved, the research and development cost is reduced, the comprehensive performance and environmental friendliness of the aircraft are improved, the noise pollution to the environment is reduced, important technical support and guarantee are provided for the development of future urban low-altitude flight.

Claims

1. A method for designing a noise-controllable vertical take-off and landing aircraft propeller, characterized in that: The following steps are involved: S1: Select the key span positions of the blade and determine the basic airfoil: Based on the design requirements of the aircraft, key span-wise positions of the blades are selected for subsequent airfoil optimization, and the basic airfoil for optimization is determined. S2: Determine the optimization objectives and constraints for typical operating conditions, and optimize the airfoil at key spanwise locations: According to the typical working conditions of hovering and cruising, the lift coefficient is maximized. and minimize the drag coefficient As the goal, the basic airfoil is optimized under the constraint conditions and the coordinate parameters of the optimized airfoil are determined; S3: Preliminary arrangement of optimized airfoils with equal chord length along the span of the blades: Arrange the optimized airfoils along the span direction, using a constant chord length design to form a preliminary propeller configuration. S4: Based on the fixed specific negative twist value Twist and the specific number of blades Blade, adjust the chord length value C to generate a test configuration set and determine the chord length range with acceptable noise. ; S5: Based on the fixed specific chord length C and the specific number of blades Blade, adjust the negative twist value Twist to generate a test configuration set and determine the negative twist range with acceptable noise. ; S6: Based on the fixed specific chord length value C and the specific negative twist value Twist, adjust the number of blades Blade to generate a test configuration set and determine the range of blade numbers with acceptable noise. ; S7: Determine the basic propeller configuration and optimization scope: The optimal range of the chord length C is set to , the optimization range of negative twist value Twist is The optimization range of the number of blades is ; Noise acceptable chord length range determined from S4 Select a fixed value from S5 to determine the acceptable negative torsion range of the noise Select the fixed value and the acceptable noise blade number range determined from S6 Select fixed values ​​from them to form a basic propeller configuration with acceptable noise; S8: Optimize propeller configuration aerodynamic performance under corresponding working conditions: Under typical working conditions, based on the basic configuration, multi-objective aerodynamic optimization is performed within the parameter range of chord length C, negative twist value Twist and blade number Blade determined by S7.

2. The noise-controllable vertical take-off and landing aircraft propeller design method according to claim 1, characterized in that: In S1, the key positions include the main lift section, the blade root and the blade tip at 50% to 90% of the blade length.

3. The noise-controllable vertical take-off and landing aircraft propeller design method according to claim 1, characterized in that: In S2, the optimization objectives and constraints in the hovering state are: Where x is the airfoil parameterization vector, is the optimized airfoil lift coefficient in the hovering state, is the optimized airfoil drag coefficient in hovering state, is the drag coefficient of the basic airfoil in the hovering state, To optimize the maximum thickness of the airfoil, is the maximum thickness of the basic airfoil, UP is the upper boundary of the optimized airfoil parameterization vector, and LOW is the lower boundary of the optimized airfoil parameterization vector; The optimization objectives and constraints under the cruising state are: Where x is the airfoil parameterization vector, For the optimized airfoil drag coefficient in cruise state, is the optimized airfoil lift coefficient in cruise state, is the lift coefficient of the basic airfoil in the cruise state, UP is the upper boundary of the optimized airfoil parameterization vector, and LOW is the lower boundary of the optimized airfoil parameterization vector.

4. The noise-controllable vertical take-off and landing aircraft propeller design method according to claim 1, characterized in that: In S2, the coordinate parameters of the optimized airfoil are determined by using the Hicks-Henne function, and the airfoil parameterization vector is converted to Converted into airfoil coordinate parameters, the formula is: in, is the chord-wise horizontal coordinate of the airfoil, To optimize the vertical coordinate of the upper surface of the airfoil, To optimize the lower surface ordinate of the airfoil, is the upper surface ordinate of the basic airfoil, is the ordinate of the lower surface of the basic airfoil, is the coefficient of the disturbance component applied to the upper surface, is the coefficient of the disturbance component applied to the lower surface, ; The shape function formula is: in, , are the n-1 specific airfoil chord-wise abscissas.

5. The noise-controllable vertical take-off and landing aircraft propeller design method according to claim 1, characterized in that: In S3, the preliminary propeller configuration arrangement includes arranging the optimized airfoil at the root and the optimized airfoil at the tip at corresponding positions in the blade span direction, and preliminarily arranging the optimized airfoil of the main lift section within the corresponding blade span direction position range, and smoothly connecting the middle sections of the three airfoils.

6. The noise-controllable vertical take-off and landing aircraft propeller design method according to claim 1 is characterized in that: in S4, the fixed specific negative torque value Twist and the specific number of blades Blade are empirical values ​​for propeller aerodynamic design; the chord length value C is adjusted to generate a test configuration set, and multiple discrete values ​​of the chord length value C are selected based on the empirical chord length value to form a test configuration set for exploring the influence of the chord length value on the propeller noise and the range thereof.

7. The noise-controllable vertical take-off and landing aircraft propeller design method according to claim 1, characterized in that: In S5, the specific chord length value C is the noise acceptable chord length range determined in S4. In the test, the chord length value with the best hovering efficiency and cruising efficiency of the obtained propeller configuration is selected; the specific number of blades Blade is the specific number of blades fixed in S4; the negative torque value Twist is adjusted to generate a test configuration set. Taking the negative torque value Twist fixed in S4 as the benchmark, multiple discrete values ​​of the negative torque value Twist are selected to form a test configuration set, which is used to explore the influence law and range of the negative torque value on the propeller noise.

8. The noise-controllable vertical take-off and landing aircraft propeller design method according to claim 1, characterized in that: In S6, the specific chord length value C is the noise acceptable chord length range determined in S4. The chord length value with the best hovering efficiency and cruise efficiency of the obtained propeller configuration is selected; the specific negative torque value Twist is the acceptable negative torque range of noise determined by S5 In the test, the negative torque value with the best hovering efficiency and cruising efficiency of the obtained propeller configuration is selected; the number of blades Blade is adjusted to generate a test configuration set. Based on the fixed number of blades Blade in S4 or S5, multiple discrete values ​​of the number of blades Blade are selected to form a test configuration set for exploring the influence of the number of blades on the propeller noise and its range.

9. The noise-controllable vertical take-off and landing aircraft propeller design method according to claim 1, characterized in that: In S8, the mathematical description of the propeller aerodynamic performance optimization is: Among them, FM is the hovering efficiency, ETA is the cruising efficiency, CT is the thrust coefficient, R is the propeller radius, Optimize the airfoil starting position for the main lift section, Optimize the end position of the airfoil for the main lift section, Twist is a negative twist value, is the lower limit of the acceptable negative torsion value of the noise determined in S5, is the upper limit of the acceptable negative torsion value of the noise determined in S5, is the average chord length of the blade, is the lower limit of the acceptable chord length of noise determined in S4, is the upper limit of the acceptable chord length of noise determined in S4, Blade is the number of blades, is the lower limit of the acceptable number of blades for noise determined in S6, is the upper limit of the number of blades with acceptable noise determined in S6, is the blade swept position, is the lower boundary of the swept position, is the upper boundary of the swept position, is the blade sweep angle, is the lower boundary of the sweep angle, is the upper boundary of the sweep angle.

10. A device for implementing a method for designing a noise-controlled vertical take-off and landing aircraft propeller, characterized in that: It includes an aerodynamic optimization module, an aerodynamic evaluation module and a noise evaluation module. The aerodynamic evaluation module is bidirectionally data-connected with the aerodynamic optimization module. The output end of the aerodynamic evaluation module is connected to the input end of the noise evaluation module, and the output end of the noise evaluation module is connected to the input end of the aerodynamic optimization module. The aerodynamic optimization module is used to maximize the lift coefficient under typical hovering and cruising conditions. and minimize the drag coefficient For the purpose of basic airfoil optimization under constraints, the evaluated intermediate airfoil aerodynamic data is received as a reference for the optimization process and to guide the optimization direction of the airfoil; it is used for the basic propeller configuration with acceptable noise under typical working conditions and at a certain chord length value. , negative torque value and number of blades Multi-objective aerodynamic optimization within the parameter range of the propeller, receiving the evaluated intermediate propeller configuration aerodynamic data as a reference for the optimization process and guiding the propeller configuration optimization direction; The aerodynamic evaluation module is used to receive the intermediate airfoil parameters of the key position airfoil optimization under typical hovering and cruising working conditions generated by the aerodynamic optimization module, realize the two-dimensional coordinate calculation and aerodynamic numerical simulation of the intermediate airfoil parameters, and transmit the aerodynamic data to the aerodynamic optimization module; is used to realize the three-dimensional coordinate calculation and aerodynamic numerical simulation of the propeller test configuration set in the propeller basic configuration and optimization range determination stage, and transmit the propeller surface pressure distribution data to the noise evaluation module as a basis for determining the propeller basic configuration and optimization range; is used to receive the intermediate propeller configuration parameters of the multi-objective aerodynamic optimization based on the propeller basic configuration under typical working conditions generated by the aerodynamic optimization module, realize the three-dimensional coordinate calculation and aerodynamic numerical simulation of the intermediate propeller configuration parameters, and transmit the aerodynamic data to the aerodynamic optimization module; The noise assessment module is used to receive the surface pressure distribution data of the propeller test configuration set output by the aerodynamic assessment module during the propeller basic configuration and optimization range determination stage, realize acoustic numerical simulation, and finally select the chord length value C, negative twist value Twist and blade number Blade to form the propeller basic configuration with acceptable noise, and determine the chord length range with acceptable noise. , negative torsion range and blade number range , and sent to the aerodynamic optimization module for propeller configuration optimization.

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