Propeller performance calculation method and device, computer equipment and storage medium

Abstract

The application provides a propeller performance calculation method and device, computer equipment and a storage medium, and relates to the technical field of propellers. The method comprises the following steps: calculating the interference angles of a plurality of blade elements according to preset blade element parameters, calculation condition parameters and a preset initial interference angle of the blade elements when the propeller is in different states; calculating the angles of attack of the blade elements according to the interference angles; determining a plurality of groups of lift-drag characteristic parameters of the blade elements in a preset propeller airfoil database according to a preset Reynolds number, a preset Mach number and the angles of attack of the blade elements; calculating aerodynamic force data of the blade elements when the propeller is in a hovering or forward flight state according to the plurality of groups of lift-drag characteristic parameters; and calculating total aerodynamic force data of the propeller when the propeller is in different states according to blade parameters of the propeller and the aerodynamic force data of the blade elements. The application can improve the calculation accuracy of propeller performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the propeller technical field, in particular to a propeller performance calculation method and device, computer equipment and storage medium. BACKGROUND

[0002] With the development of science and technology, the aviation industry has also developed rapidly, and the design of the propeller is very important as the propulsive force of the aircraft.

[0003] In the design process of the propeller, it is crucial to calculate and analyze the performance of the propeller. The traditional propeller performance calculation is mostly solved by using momentum theory or blade element theory. Since the influence of the downwash effect generated by the blade on the blade element induced velocity and the interference between the blades is not considered, the calculated propeller performance error is large and the precision is low. SUMMARY

[0004] The present application relates to the propeller technical field, in particular to a propeller performance calculation method and device, computer equipment and storage medium.

[0005] To achieve the above-mentioned purpose, the technical solutions adopted by the embodiments of the present application are as follows:

[0006] In a first aspect, the embodiments of the present application provide a propeller performance calculation method, which comprises:

[0007] According to the preset blade element parameters, the calculation condition parameters and the preset initial interference angle of the plurality of blade elements in different states of the propeller, the interference angle of the plurality of blade elements is calculated;

[0008] According to the interference angle of the plurality of blade elements, the angle of attack of the plurality of blade elements is calculated;

[0009] According to the preset Reynolds number, the preset Mach number and the angle of attack of the plurality of blade elements, a plurality of groups of lift-drag characteristic parameters corresponding to the plurality of blade elements are determined in a preset propeller airfoil database, wherein the propeller airfoil database comprises a plurality of reference Reynolds numbers, a plurality of reference Mach numbers, a plurality of reference angles of attack and a plurality of groups of lift-drag characteristic parameters corresponding relationship;

[0010] According to the plurality of groups of lift-drag characteristic parameters and the preset blade element parameters of the plurality of blade elements, the aerodynamic force data of the plurality of blade elements in the different states of the propeller is calculated;

[0011] According to the blade parameters of the propeller and the aerodynamic force data of the plurality of blade elements, the total aerodynamic force data of the propeller in the different states of the propeller is calculated.

[0012] In a second aspect, the embodiments of the present application further provide a propeller performance calculation device, the device comprising:

[0013] An interference angle calculation module is configured to calculate interference angles of the plurality of blade elements according to preset blade element parameters of the plurality of blade elements in different states of the propeller, calculation condition parameters, and preset initial interference angles.

[0014] An angle of attack calculation module is configured to calculate angles of attack of the plurality of blade elements according to the interference angles of the plurality of blade elements.

[0015] A lift-drag characteristic parameter determination module is configured to determine a plurality of groups of lift-drag characteristic parameters corresponding to the plurality of blade elements in a preset propeller airfoil database according to a preset Reynolds number, a preset Mach number, and the angles of attack of the plurality of blade elements, wherein the propeller airfoil database comprises a correspondence between a plurality of reference Reynolds numbers, a plurality of reference Mach numbers, a plurality of reference angles of attack, and the plurality of groups of lift-drag characteristic parameters.

[0016] A blade element aerodynamic force calculation module is configured to calculate aerodynamic force data of the plurality of blade elements in the different states of the propeller according to the plurality of groups of lift-drag characteristic parameters and the preset blade element parameters of the plurality of blade elements.

[0017] A propeller aerodynamic force calculation module is configured to calculate total aerodynamic force data of the propeller in the different states of the propeller according to blade parameters of the propeller and the aerodynamic force data of the plurality of blade elements.

[0018] In a third aspect, the embodiments of the present application further provide a computer device, comprising a processor, a storage medium, and a bus, the storage medium storing program instructions executable by the processor, when the computer device is running, the processor and the storage medium communicate through the bus, and the processor executes the program instructions to perform the steps of the propeller performance calculation method according to any one of the first aspect.

[0019] In a fourth aspect, the embodiments of the present application further provide a computer readable storage medium, the storage medium storing a computer program, when the computer program is run by a processor, the steps of the propeller performance calculation method according to any one of the first aspect are performed.

[0020] The beneficial effects of the present application are as follows:

[0021] The application provides a propeller performance calculation method and device, computer equipment and a storage medium. The method comprises the following steps: determining the lift-drag characteristic parameter calculation of a plurality of blade elements corresponding to a propeller airfoil database; calculating the aerodynamic force data of the plurality of blade elements under different states of the propeller; and calculating the total aerodynamic force data of the propeller under different states from the aerodynamic force data of the plurality of blade elements, so as to realize the rapid calculation of the propeller performance. The influence of the downwash effect on the induced velocity at different blade elements on the angle of attack at different blade elements is fully considered, the angle of attack of the plurality of blade elements is determined by calculating the interference angle of the plurality of blade elements, and the total aerodynamic force data of the propeller is calculated according to the lift-drag characteristic parameters corresponding to the angle of attack of the plurality of blade elements, so that the calculation accuracy of the propeller performance is improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0023] Figure 1 A flowchart of a propeller performance calculation method provided by an embodiment of the present application is shown in the figure.

[0024] Figure 2 A schematic diagram of a blade element decomposition model provided by an embodiment of the present application is shown in the figure.

[0025] Figure 3 A flowchart of another propeller performance calculation method provided by an embodiment of the present application is shown in the figure.

[0026] Figure 4 A flowchart of another propeller performance calculation method provided by an embodiment of the present application is shown in the figure.

[0027] Figure 5 A flowchart of another propeller performance calculation method provided by an embodiment of the present application is shown in the figure.

[0028] Figure 6 A flowchart of another propeller performance calculation method provided by an embodiment of the present application is shown in the figure.

[0029] Figure 7 A flowchart of another propeller performance calculation method provided by an embodiment of the present application is shown in the figure.

[0030] Figure 8 A flowchart of another propeller performance calculation method provided by an embodiment of the present application is shown in the figure.

[0031] Figure 9A propeller performance calculation method provided by the embodiment of the application, as shown in

[0032] Figure 10 A structural schematic diagram of a propeller performance calculation device provided by the embodiment of the application.

[0033] Figure 11 A schematic diagram of a computer device provided by the embodiment of the application. DETAILED DESCRIPTION

[0034] In order to make the objects, technical solutions and advantages of the embodiments of the application clearer, the technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are some but not all of the embodiments of the application.

[0035] Therefore, the detailed description of the embodiments of the application provided in the drawings below is not intended to limit the scope of the claimed application, but only represents selected embodiments of the application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the application without creative labor are within the scope of protection of the application.

[0036] In addition, the terms "first", "second", and the like in the specification and claims of the application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0037] It should be noted that the features in the embodiments of the application can be combined with each other without conflict.

[0038] Reference should be made to Figure 1 A structural schematic diagram of a propeller performance calculation method provided by the embodiment of the application, as shown in Figure 1 The method comprises the following steps.

[0039] S10: According to the preset blade element parameters, calculation condition parameters and preset initial interference angle of a plurality of blade elements of the propeller in different states, the interference angle of the plurality of blade elements is calculated.

[0040] In this embodiment, the blade is divided into an infinite number of micro segments, and the infinite number of blade micro segments arranged continuously on the blade of the propeller are referred to as blade elements, and one blade micro segment is one blade element. The preset blade element parameters include a blade element radius r, a blade element chord length b, and a blade element installation angle θ. The calculation condition parameters include a flow velocity and an angular velocity Ω of the propeller. A tangential velocity in the disc plane is Ωr.

[0041] The interference angle is an angle at which a flow velocity has an influence on aerodynamic force of a blade element in the process that the propeller moves a certain mass of airflow at a certain speed downward to generate a reaction force in order to generate lift. Since the flow velocity has different influences on the force of the blade element when the propeller is in different states, the interference angle generated is also different. For example, refer to Figure 2 FIG. 1 is a schematic diagram of a blade element decomposition model provided by an embodiment of the present application, as shown in Figure 2 The β is the interference angle of the blade element.

[0042] In a possible implementation, the S10 includes: calculating the interference angles of the plurality of blade elements according to the preset blade element parameters of the plurality of blade elements, the calculation condition parameters, and the preset initial interference angle of the input when the propeller is in the forward flight state.

[0043] Specifically, when the propeller is in the forward flight state, the forward flight velocity of the blade is the given flow velocity V0. The interference angles β of the plurality of blade elements are calculated by the blade element pull force obtained from the momentum theorem and the blade element pull force derived from the blade element theory. The specific calculation method is as follows:

[0044] As shown in Figure 2 The blade element radius r, the blade element chord length b, the blade element installation angle θ, and the angular velocity Ω. The blade element momentum theory assumes that the disc is composed of an infinite number of blades. The torque and the pull force of each ring surface are constant. v a represents the axial induced velocity at the disc, and v t represents the ring induced velocity at the disc. The given flow velocity V0. According to the momentum theorem, the pull force at the blade element micro segment is as follows:

[0045] dT = 2πrdr(V0 + v a )ρ(V0 + 2v a -V0) = 4πrdrρ(V0 + v a )v a (1)

[0046] Let the axial induced velocity coefficient be a = v a / V0. Then, the following is obtained:

[0047] dT = 4πrdrρ(V0 + v a )v a = 4πrdrρV02 (1+a)a (2)

[0048] The tension at the micro-section of the blade element derived from the blade element theory is:

[0049]

[0050] The tension derived from the momentum theorem is equal to the tension derived from the blade element theory, and formula (2) and formula (3) can be obtained by being associated:

[0051]

[0052] Let the real degree be σ=N b b / (2πr), and formula (4) can be obtained by substituting formula (4):

[0053]

[0054] The torque at the micro-section of the blade element can be known from the angular momentum theorem:

[0055] dM=2πrdr(V0+v a )ρ(2v t -0)r=4πr 2 drρ(V0+v a )v t (6)

[0056] Let the ring-induced velocity coefficient be a'=v t / (Ωr), and then:

[0057] dM=4πr 2 drρ(V0+v a )v t =4πr 2 drρV0(1+a)(Ωr)a' (7)

[0058] The torque at the micro-section of the blade element derived from the blade element theory is:

[0059]

[0060] The torque derived from the angular momentum theorem is equal to the torque derived from the blade element theory, and formula (7) and formula (8) can be obtained by being associated:

[0061]

[0062] Formula (5) and formula (9) can be obtained by being associated:

[0063]

[0064] From , it can be obtained:

[0065]

[0066] From equation (10) and equation (11), we can get:

[0067]

[0068] From equation (5) and equation (12), we can get:

[0069]

[0070] By simplifying equation (13), we can get:

[0071]

[0072] Substitute into equation (14), we can get:

[0073]

[0074] When solving equation (15), Newton iteration method can be used, assuming the initial interference angle is β0, then the angle of attack of the airflow relative to the blade element is:

[0075]

[0076] The lift coefficient and the drag coefficient are both functions of the angle of attack, within a certain range, the larger the angle of attack, the larger the lift coefficient and the drag coefficient, calculate the lift coefficient C L (α) and the drag coefficient C D (α) of the blade element at the angle of attack α, the angle at which the ratio of the drag of the blade element to the lift is:

[0077]

[0078] Convert equation (15) to the following form:

[0079]

[0080] Where, g(β)=1-tanγtanβ, the derivative of equation (18) can be obtained as:

[0081]

[0082] Where,

[0083]

[0084]

[0085] Let β = β0 + Δβ, then we can obtain the iterative formula as follows:

[0086] f(β0+Δβ)=0 (22)

[0087] f(β0)+Δβf'(β0)=0 (23)

[0088]

[0089] If Δβ ​​satisfies the preset iteration error, then the interference angle β of the leaf element is determined as β = β0 + Δβ. Otherwise, by continuously iterating the initial interference angle β0 until Δβ satisfies the preset iteration error, the interference angle β of the leaf element is obtained.

[0090] In one possible implementation, if Δβ does not satisfy the preset iteration error, β0 + Δβ can be used as the new initial interference angle β0, and iteration can continue until Δβ satisfies the preset iteration error. For example, Table 1 shows the iteration results for one interference angle. As shown in Table 1, at a given Mach number M... a The initial interference angle β0 is determined, and the angle of attack α is determined based on the initial interference angle β0 and formula (16). The iteration can be stopped by using Δβ calculated by formula (24). If the condition for stopping the iteration is not met, the initial interference angle β0 and the angle of attack α are updated according to β0+Δβ.

[0091] Table 1 Iterative results of interference angles

[0092]

[0093]

[0094]

[0095] In another possible implementation, S10 includes: calculating the interference angle of multiple blade elements based on preset blade element parameters, calculation condition parameters, and preset input initial interference angles of multiple blade elements when the propeller is in a hovering state.

[0096] Specifically, when the propeller is in a hovering state, the forward velocity of the blades, i.e., the given airflow velocity V0 = 0, is used to calculate the interference angle β of multiple blade elements by combining the blade element thrust obtained from the momentum theorem and the blade element thrust derived from blade element theory. The specific calculation method is as follows:

[0097] The axial velocity is:

[0098] V = V0 + v a =v a (25)

[0099] From equation (1), it can be seen that when the propeller is in hover state, the drag force at the blade element section is:

[0100] dT = 4πrdrρV 2 (26)

[0101] From equation (3), it can be seen that when the propeller is in hover state, the drag force at the blade element section derived from the blade element theory is:

[0102]

[0103] The drag force derived from the momentum theory is equal to the drag force derived from the blade element theory, and by combining equation (26) and equation (27), it can be obtained that:

[0104]

[0105] Let the solidity be σ = (N b b) / (2πr), and substitute it into equation (28) to obtain:

[0106]

[0107] That is:

[0108]

[0109] As shown in Figure 2 , since there is no induced velocity caused by the given inflow velocity V0 in the hover state, then Substitute equation (30) into equation (31) to obtain:

[0110]

[0111] When solving equation (31), the Newton iteration method can be used, and assuming that the initial interference angle is β0, the angle of attack of the airflow relative to the blade element is:

[0112] α = θ - β0 (32)

[0113] Convert equation (31) to the following form:

[0114]

[0115] Where h(β) = 4sin 2 βcosγ, g(β) = cos(β+γ), and the derivative of equation (33) can be obtained as:

[0116]

[0117] Where

[0118] h' = 8cosγsinβcosβ (35)

[0119] g' = -sin(β+γ) (36)

[0120] The iteration formula such as formula (22)-formula (24) is used for iteration, if Δβ meets the preset iteration error, the interference angle β of the blade element is determined as β = β0+Δβ, otherwise, the initial interference angle β0is iterated continuously until Δβ meets the preset iteration error, and the interference angle β of the blade element is obtained.

[0121] It should be noted that for the blade elements at different positions of the paddle, the blade element radii r are different, and the interference angles calculated are also different.

[0122] S20: Calculate the attack angles of the plurality of blade elements according to the interference angles of the plurality of blade elements.

[0123] In this embodiment, the attack angle is the angle between the direction of the airflow (equivalent to the forward direction of the wing) and the chord, also known as the angle of attack, which is used as a reference to determine the attitude of the wing in the airflow. Since the interference angles generated by the airflow at different blade elements are different, the attack angles at different blade elements are also different. After the interference angles of the plurality of blade elements are calculated through the steps of S10, the attack angles of the plurality of blade elements can be calculated according to the relationship between the attack angle and the interference angle. For example, as shown in FIG. 2, when the propeller is in the forward flight state, the attack angle of the blade element can be represented as: Figure 2 When the propeller is in the hovering state, the attack angle of the blade element can be represented as: α = θ-β.

[0124] S30: Determine a plurality of groups of lift-drag characteristic parameters corresponding to the plurality of blade elements in a preset propeller airfoil database according to a preset Reynolds number, a preset Mach number, and the attack angles of the plurality of blade elements, wherein the propeller airfoil database comprises a plurality of reference Reynolds numbers R e , a plurality of reference Mach numbers M a , a plurality of reference attack angles α, and a corresponding relationship between the plurality of groups of lift-drag characteristic parameters.

[0125] In this embodiment, the Reynolds number is a dimensionless number used to characterize the flow of fluid, which can be used to determine the resistance of an object flowing in a fluid. The Mach number is the most important parameter for measuring air compressibility. The propeller airfoil database is a database of the corresponding relationship between a plurality of reference Reynolds numbers, a plurality of reference Mach numbers, a plurality of reference attack angles, and a plurality of groups of lift-drag characteristic parameters, which is constructed in advance. By inputting the preset Reynolds number, the preset Mach number, and the calculated attack angles of the plurality of blade elements, the plurality of groups of lift-drag characteristic parameters corresponding to the plurality of blade elements are determined from the propeller airfoil database. Each group of lift-drag characteristic parameters comprises a lift coefficient C L , a drag coefficient C D , and a moment coefficient C​M wherein the lift coefficient C L is the ratio of the lift experienced by a physical object to the dynamic pressure of the airflow and the reference area, and the drag coefficient is the ratio of the drag experienced by a physical object to the dynamic pressure of the airflow and the reference area.

[0126] S40: According to the multiple sets of lift-drag characteristic parameters, the aerodynamic force data of the multiple blade elements in different states of the propeller are calculated.

[0127] In this embodiment, the formula for calculating the aerodynamic force data of the blade element determined according to the blade element momentum theory is used, the multiple sets of lift-drag characteristic parameters and the preset blade element parameters of the multiple blade elements are substituted into the formula for calculating the aerodynamic force data of the blade element, and the aerodynamic force data of the multiple blade elements are obtained, wherein the aerodynamic force data of the blade element include: lift dL, drag dD, total aerodynamic force dR, tension dT, hoop force dF, blade element torque dM, blade element torque power dP w , blade element effective power dP e and blade element efficiency η.

[0128] In a possible implementation, in the forward flight state of the propeller, the formula for calculating the aerodynamic force data of the blade element determined according to the blade element momentum theory can include:

[0129] The preset blade element parameters include: blade element radius r, blade element chord length b, blade element installation angle θ, angular velocity Ω, and the tangential velocity in the propeller disc plane is Ωr, so the geometric resultant velocity of the airflow relative to the blade element is:

[0130]

[0131] The included angle between the geometric resultant velocity and the rotation plane is:

[0132]

[0133] However, due to the interference angle β generated by the blade vortex, the actual included angle is:

[0134]

[0135] Therefore, the actual airflow velocity is:

[0136]

[0137] Since the axial induced velocity v a and the hoop induced velocity v t are unknown, the angle of attack α of the airflow relative to the blade element needs to be inferred according to the interference angle β, that is, the angle of attack of the airflow relative to the blade element is:

[0138]

[0139] The formula for calculating the lift dL of the blade element can be expressed as:

[0140]

[0141] The formula for calculating the drag dD of the blade element can be expressed as:

[0142]

[0143] Let the drag-lift angle of the blade element be γ, then

[0144]

[0145] The formula for calculating the total aerodynamic force dR of the blade element can be expressed as:

[0146]

[0147] The formula for calculating the pull dT of the blade element is:

[0148]

[0149] The formula (29), formula (32) and formula (33) can be obtained by combining:

[0150]

[0151] Since Therefore:

[0152]

[0153] Let the simplified parameter be:

[0154]

[0155] Therefore, the formula for calculating the pull dT of the blade element can be expressed as:

[0156]

[0157] Similarly, the formula for calculating the circumferential force dF of the blade element can be expressed as:

[0158]

[0159] The formula for calculating the torque dM of the blade element can be expressed as:

[0160]

[0161] Let the simplified parameter in the formula be:

[0162] The formula for calculating the torque power dP of the blade element can be expressed as: w ​

[0163] dP w = ΩdM (52)

[0164] The formula for calculating the effective power dP of the blade element can be expressed as: e

[0165] dP e = dT·V0 (53)

[0166] The formula for calculating the efficiency of the blade element can be expressed as:

[0167]

[0168] According to formula (26) and formula (27), it can be known that:

[0169]

[0170] Therefore, the formula for calculating the efficiency of the blade element can be expressed as:

[0171]

[0172] In another possible implementation, in the hovering state of the propeller, the formula for calculating the aerodynamic force data of the blade element determined according to the blade momentum theory can include:

[0173] The included angle between the geometric resultant velocity and the rotation plane is:

[0174]

[0175] According to the axial velocity of formula (25) and the actual airflow velocity in the forward flight state in formula (40), the actual airflow velocity in the hovering state can be obtained as:

[0176]

[0177] According to the angle of attack α = θ - β of the airflow relative to the blade element, the tension of the blade element is determined as:

[0178]

[0179] Since then:

[0180]

[0181] Let the simplified parameter be:

[0182]

[0183] Therefore, the formula for calculating the tension dT of the blade element can be expressed as:

[0184] ​

[0185] Similarly, the formula for calculating the blade element circumferential force dF can be expressed as:

[0186]

[0187] The formula for calculating the blade element torque dM can be expressed as:

[0188]

[0189] Let the simplified parameters in the formula be:

[0190] The calculation method of the blade rotational power (blade absorbed power) in the hovering state is the same as the calculation method of the blade rotational power in the forward flight state in formula (52). Since the given flow velocity V0 = 0 in the hovering state, according to formula (53) and formula (54), the blade effective power and the blade efficiency in the hovering state are both 0.

[0191] S50: According to the blade parameters of the propeller and the aerodynamic force data of the plurality of blade elements, the total aerodynamic force data of the propeller in different states of the propeller is calculated.

[0192] In this embodiment, the blade parameters include: the number of propeller blades N b , the blade radius R and the hub radius r0. Since the blade element is a blade segment, after the aerodynamic force data of a plurality of blade elements on one blade is calculated, the total aerodynamic force data of the propeller can be obtained by integrating the aerodynamic force data of the plurality of blade elements and superimposing a plurality of blades. The total aerodynamic force data of the propeller includes: the total tension T of the propeller, the circumferential force F of the propeller, the propeller torque M, the propeller torque power P w , the propeller effective power P e and the propeller efficiency η zong .

[0193] In a possible implementation, in the forward flight state of the propeller, the formula for integrating the aerodynamic force data of the plurality of blade elements and superimposing the plurality of blades to obtain the total aerodynamic force data of the propeller can be respectively expressed as:

[0194] The formula for calculating the total tension T of the propeller can be expressed as:

[0195]

[0196] The formula for calculating the total circumferential force F of the propeller can be expressed as:

[0197]

[0198] The formula for calculating the propeller torque M can be expressed as:

[0199]

[0200] The formula for calculating the propeller torque power P w may be expressed as:

[0201] P w = ΩM (68)

[0202] The formula for calculating the propeller effective power P e may be expressed as:

[0203] P e = TV0 (69)

[0204] The formula for calculating the propeller efficiency η zong may be expressed as:

[0205]

[0206] For example, please refer to Table 2 for the calculation results of various parameters of the present embodiment, as shown in Table 2, the calculation results of various parameters include: at different blade element positions, at different Mach numbers, the simplified parameters T c , Q c , induced velocity V, lift coefficient C L , drag coefficient C D , interference angle β, blade installation angle θ, angle of attack α, and dimensionless parameter CLtl. Among them, the interference angle β is 0 because the blade element has no interference angle in this calculation condition, so it is 0 at this time.

[0207] Table 2 Calculation results of various parameters

[0208]

[0209]

[0210]

[0211] In one possible implementation, when the propeller is in a hovering state, the aerodynamic force data of the plurality of blade elements are integrated, and the plurality of blades are superimposed to obtain the formula of the total aerodynamic force data of the propeller, which can be respectively expressed as:

[0212] The formula for calculating the total drag T of the propeller can be expressed as:

[0213]

[0214] The formula for calculating the total circumferential force F of the propeller can be expressed as:

[0215]

[0216] The formula for calculating the propeller torque M can be expressed as:

[0217]

[0218] The calculation method of the propeller torque power (element absorbed power) in the hovering state is the same as the calculation method of the propeller rotation power in the forward flight state in formula (68). Since the given flow velocity V0 in the hovering state is 0, according to formula (69) and formula (70), the propeller effective power and the propeller efficiency in the hovering state are both 0.

[0219] It should be noted that the above formula (1) to formula (73) can be executed by the pre-programmed CFL3d_Prepare program. The program first iteratively calculates the interference angles β of a plurality of elements of the propeller in different states by formula (1) to formula (24) or formula (25) to formula (36), then determines the angle of attack according to the interference angle β, and then calls the propeller airfoil database according to the angle of attack to determine the lift-drag characteristic parameters. Then, according to the pre-input preset element parameters and the lift-drag characteristic parameters, the program calculates the aerodynamic force data of a plurality of elements of the propeller in different states by formula (37) to formula (56) or formula (57) to formula (64). Finally, according to the pre-input propeller blade parameters, the program calculates the total aerodynamic force data of the propeller by formula (65) to formula (70) or formula (71) to formula (73).

[0220] The propeller performance calculation method provided by the above embodiment quickly determines the lift-drag characteristic parameters corresponding to a plurality of elements through the propeller airfoil database, calculates the aerodynamic force data of a plurality of elements of the propeller in different states, and then calculates the total aerodynamic force data of the propeller in different states from the aerodynamic force data of a plurality of elements, thereby realizing the rapid calculation of the propeller performance. By fully considering the influence of the downwash effect on the induced velocity at different elements of the blade on the size of the angle of attack at different elements, the angle of attack of a plurality of elements is determined by calculating the interference angles of a plurality of elements of the blade, and the total aerodynamic force data of the propeller is calculated according to the lift-drag characteristic parameters corresponding to the angle of attack of a plurality of elements, thereby improving the calculation accuracy of the propeller performance.

[0221] In some embodiments, since the propeller is composed of a limited number of individual blades, some airflow can escape between the blade tips and be captured by the tip vortex, resulting in that the actual induced airflow received by the blade is less than the theoretically predicted value, and the actual force received by the element is smaller than the calculated value. This loss is called tip loss. The closer to the blade tip, the smaller the force received by the blade relative to the calculated value.

[0222] In the embodiment, the Prandtl tip loss function is used to correct the force of the blade element, and the specific correction method is: calculating the Prandtl tip loss function value of each blade element, and multiplying the force of each blade element calculated in the foregoing by the Prandtl tip loss function value to obtain the corrected force of the blade element.

[0223] For example, the Prandtl tip loss function is:

[0224]

[0225] wherein,

[0226]

[0227] N is the induced flow angle, and b r is the relative position of the micro-section in the span direction.

[0228] On the basis of the above-mentioned embodiment, the embodiment of the application further provides another propeller performance calculation method. Please refer to Figure 3 FIG. 2 is a flowchart of another propeller performance calculation method provided by the embodiment of the application, as shown in Figure 3 The step of calculating the interference angle of the plurality of blade elements according to the preset initial interference angle in S10 can include the following steps:

[0229] S11: According to the preset blade element parameter, the calculation condition parameter and the initial interference angle, a preset iterative algorithm is used to calculate the first interference angle change of the plurality of blade elements.

[0230] In the embodiment, the preset iterative algorithm is the Newton iteration method. When the interference angles of the plurality of blade elements are calculated according to the momentum theorem and the theoretical derivation result of the blade element, the initial interference angle is assumed to be β0. When the propeller is in the forward flight state, the first interference angle change of the plurality of blade elements is calculated by the above-mentioned formulas (1) to (24); when the propeller is in the hovering state, the first interference angle change of the plurality of blade elements is calculated by the formulas (25) to (36).

[0231] S12: If the first interference angle change does not satisfy the preset interference angle error, the second interference angle change of the plurality of blade elements is recalculated according to the initial interference angle, the first interference angle change and a preset relaxation factor by using the iterative algorithm until the second interference angle change of the plurality of blade elements satisfies the preset interference angle error. The relaxation factor is used to control the convergence state of the iterative algorithm.

[0232] In the embodiment, if the first interference angle change quantity does not satisfy the preset interference angle error, it is determined that the first interference angle change quantity does not converge. In order to accelerate the convergence speed of the Newton iteration method and quickly complete iteration to obtain the stable interference angle of the plurality of blade elements, the relaxation method is used to relax the first interference angle change quantity. The first interference angle change quantity after the relaxation processing and the initial interference angle are taken as new initial interference angles to continue iteration until the second interference angle change quantity satisfies the preset interference angle error, and then the iteration is stopped.

[0233] In a possible implementation, the first interference angle change quantity is relaxed by setting a relaxation factor. The iteration is continued according to the sum of the product of the first interference angle change quantity and the relaxation factor and the initial interference angle as the new initial interference angle until the second interference angle change quantity satisfies the preset interference angle error, and then the iteration is stopped.

[0234] It should be noted that the selection of the relaxation factor plays a crucial role in the convergence speed. When the relaxation factor is too small, the convergence speed will be slow. When the relaxation factor is too large, it is not easy to converge, and the program may fall into a dead loop. After multiple tests of the program, it is determined that the calculation can converge when the relaxation factor is less than or equal to 0.12. The relaxation factor selected in the embodiment is 0.05.

[0235] For example, if the first interference angle change quantity Δβ does not satisfy the preset interference angle error, Δβ is set to 0.05*Δβ, and β0 is set to β0+Δβ.

[0236] S13: The interference angle of the plurality of blade elements is calculated according to the initial interference angle and the second interference angle change quantity.

[0237] In the embodiment, when the second interference angle change quantity satisfies the preset interference angle error, the calculation process can stop iteration. The sum of the new initial interference angle and the second interference angle change quantity is taken as the interference angle of the blade element.

[0238] The propeller performance calculation method provided in the above embodiment can judge whether the first interference angle change quantity calculated by the preset iteration algorithm satisfies the preset interference angle error. When the first interference angle change quantity does not satisfy the preset interference angle error, the first interference angle change quantity is relaxed by using a preset relaxation factor. Then, the second interference angle change quantity is recalculated by using the iteration algorithm until the preset interference angle error is satisfied, and the interference angle of the blade element is calculated. By introducing the relaxation factor to relax the interference angle change quantity, the convergence speed of the iteration algorithm can be accelerated, the iteration of the program can be accelerated, and the calculation efficiency of the program can be improved.

[0239] On the basis of the above embodiment, the embodiment of the present application further provides another propeller performance calculation method. Please refer to Figure 4 The flowchart of another propeller performance calculation method provided in the embodiment of the present application is shown in FIG. 4. Figure 4As shown, before the step of determining the multiple sets of lift-drag characteristic parameters corresponding to the multiple blades in the preset propeller airfoil database according to the preset Reynolds number, the preset Mach number and the angles of attack of the multiple blades in S30, the method further comprises:

[0240] S61: calculating the multiple sets of lift-drag characteristic parameters according to the multiple reference Reynolds numbers, the multiple reference Mach numbers and the multiple reference angles of attack.

[0241] In this embodiment, the preset Computational Fluid Dynamics (CFD) calculation method is adopted, and the CFL3d structured grid of the Reynolds average method (RANS) and the finite volume method are combined to calculate the multiple sets of lift-drag characteristic parameters corresponding to the multiple reference Reynolds numbers, the multiple reference Mach numbers and the multiple reference angles of attack of the propeller two-dimensional airfoil.

[0242] S62: constructing the propeller airfoil database according to the correspondence between the multiple reference Reynolds numbers, the multiple reference Mach numbers, the multiple reference angles of attack and the multiple sets of lift-drag characteristic parameters.

[0243] In this embodiment, after the multiple sets of lift-drag characteristic parameters are calculated, the correspondence between each reference Reynolds number, each reference Mach number, each reference angle of attack and a set of lift-drag characteristic parameters is constructed, and the correspondence between the multiple reference Reynolds numbers, the multiple reference Mach numbers, the multiple reference angles of attack and the multiple sets of lift-drag characteristic parameters is stored in the propeller airfoil database.

[0244] The propeller performance calculation method provided in the above embodiments needs to perform multiple iterations in the process of calculating the lift-drag characteristic parameters. In order to improve the calculation efficiency, the propeller airfoil database is constructed in advance to store the correspondence between the multiple reference Reynolds numbers, the multiple reference Mach numbers, the multiple reference angles of attack and the multiple sets of lift-drag characteristic parameters, so that when the propeller performance is calculated, the corresponding lift-drag characteristic parameters can be directly determined from the propeller airfoil database according to the set Reynolds number, Mach number and calculated angle of attack, avoiding the consumption of calculation time in the iteration process of calculating the lift-drag characteristic parameters when the propeller performance is calculated, which is beneficial to improve the calculation efficiency of the propeller performance and reduce the calculation time.

[0245] On the basis of the above embodiments, another propeller performance calculation method is further provided in the embodiments of the present application. Please refer to Figure 5 The flowchart of another propeller performance calculation method provided in the embodiments of the present application is shown in Figure 5 As shown, the step of calculating the multiple sets of lift-drag characteristic parameters according to the multiple reference Reynolds numbers, the multiple reference Mach numbers and the multiple reference angles of attack in S61 comprises:

[0246] S611: calculating the maximum value and the minimum value of the lift-drag characteristic parameters according to each reference Reynolds number, each reference Mach number and each reference angle of attack.

[0247] S612: Determine whether the lift-drag characteristic parameter meets a preset convergence condition according to the maximum value and the minimum value.

[0248] S613: If the lift-drag characteristic parameter meets the preset convergence condition, determine the convergence value as the lift-drag characteristic parameter.

[0249] In this embodiment, in the CFD calculation process, in order to ensure that the calculated lift-drag characteristic parameter is real and reliable, a convergence standard needs to be added. Generally, there are multiple convergence standards in the CFD calculation for selection, so as to determine whether the lift-drag characteristic parameter meets the convergence standard. The convergence standard includes a residual curve, mass conservation, and a monitoring curve. The residual curve is whether the residual between the calculated lift-drag characteristic parameter and a preset lift-drag characteristic standard gradually converges. The mass conservation is whether the difference between the inflow and outflow mass at each time step fluctuates around 0 during the calculation of the lift-drag characteristic parameter. The monitoring curve is whether the fluctuation range of the maximum value and the minimum value of the lift-drag characteristic parameter during the calculation is within a preset range or whether it fluctuates periodically.

[0250] In a possible implementation, the monitoring curve is taken as an example to describe in detail the determination of whether the lift-drag characteristic parameter converges. Specifically, for each reference Reynolds number, each reference Mach number, and each reference angle of attack, the maximum value and the minimum value of the lift-drag characteristic parameter in the iteration process are calculated. According to the difference between the maximum value and the minimum value, it is determined whether the lift-drag characteristic parameter meets a preset convergence condition. Then, the convergence value of the last step of iteration is taken as the corresponding lift-drag characteristic parameter.

[0251] For example, if the absolute value of the difference between the maximum value and the minimum value is greater than or equal to a first preset value, it is determined that the convergence condition is divergence. If the absolute value of the difference between the maximum value and the minimum value is greater than or equal to a second preset value and less than the first preset value, it is determined that the convergence condition is not convergence. If the absolute value of the difference between the maximum value and the minimum value is less than the second preset value, it is determined that the convergence condition is convergence. The first preset value can be 10, and the second preset value can be 0.001. The specific settings of the first preset value and the second preset value are subject to actual needs, and this embodiment does not limit this.

[0252] Please refer to Table 3 for a convergence condition description provided in this embodiment. As shown in Table 3, under the fixed Reynolds number and the fixed Mach number, the convergence conditions under different angles of attack are shown. As shown in Table 3, when the lift-drag characteristic parameter fluctuates within a preset range, it is determined that the CFD calculation has converged, and the calculation can be exited. Otherwise, the calculation needs to be continued until the result converges or diverges.

[0253] Table 3: Convergence condition description

[0254]

[0255]

[0256] Please refer to Table 4, a lift-drag characteristic parameter result provided for the embodiment, as shown in Table 4, under the condition of fixed Reynolds number and fixed Mach number and different angles of attack, the lift-drag characteristic parameter result is calculated according to the convergence condition.

[0257] Table 4: A lift-drag characteristic parameter result

[0258]

[0259]

[0260] It should be noted that when the Mach number is large, the error of the lift-drag characteristic parameter will become larger and larger with the increase of the iteration step number, in this case, even if the iteration operation is continued, convergence cannot be achieved, and the calculation will fall into a wireless loop, therefore, before the iteration starts, the range of the Mach number needs to be limited to avoid the situation of non-convergence.

[0261] The propeller performance calculation method provided in the above embodiment judges whether the lift-drag characteristic meets the preset convergence condition, so as to ensure that the lift-drag characteristic parameter obtained by calculation is real and reliable, so that the aerodynamic force data of the blade element and the total aerodynamic force data of the propeller can be accurately calculated, and the accuracy of the propeller performance calculation result is improved.

[0262] On the basis of the above embodiment, another propeller performance calculation method is further provided in the embodiment of the application. Please refer to Figure 6 The flowchart of another propeller performance calculation method provided for the embodiment of the application is shown in Figure 6 The step of determining the multiple sets of lift-drag characteristic parameters corresponding to the multiple blade elements in the preset propeller airfoil database according to the preset Reynolds number, the preset Mach number and the angles of attack of the multiple blade elements in S30 can include:

[0263] S31: Determine multiple sets of reference lift-drag characteristic parameters corresponding to the preset Reynolds number, the preset Mach number and multiple reference angles of attack in the propeller airfoil database.

[0264] S32: Determine multiple interpolation angles of attack corresponding to the angle of attack of each blade element from the multiple reference angles of attack according to the angle of attack of each blade element.

[0265] S33: Calculate a set of lift-drag characteristic parameters of each blade element according to the multiple sets of reference lift-drag characteristic parameters corresponding to the multiple interpolation angles of attack.

[0266] In the embodiment, when the propeller airfoil database is constructed, in order to accelerate the convergence speed of the calculated lift-drag characteristic parameters, the selected reference attack angles are generally the standard attack angles, for example, between-18° and 18°, with a step of 1°. Since the calculated attack angles are not necessarily standard attack angles, the propeller airfoil database can not have the data corresponding to the calculated attack angles, and therefore, the reference characteristic parameters need to be selected according to the calculated attack angles.

[0267] To this end, first, a plurality of sets of reference lift-drag characteristic parameters corresponding to a plurality of reference attack angles at the preset Reynolds number and the preset Mach number are selected from the propeller airfoil database according to the preset Reynolds number and the preset Mach number, then, at least one interpolation attack angle closest to the attack angle of the blade element is selected from the plurality of reference attack angles according to the attack angle of the blade element, and a set of lift-drag characteristic parameters of each blade element is calculated according to the reference lift-drag characteristic parameters corresponding to the interpolation attack angle.

[0268] For example, in the propeller airfoil database, the Reynolds number ranges from 0.5*10^5 to 2.3*10^7, the Mach number ranges from 0.02 to 0.6, and the attack angle ranges from-18° to 18°. If the attack angle of the blade element is less than-18°, the interpolation attack angle is-18°, and the reference lift-drag characteristic parameters corresponding to-18° are the lift-drag characteristic parameters of the blade element. If the attack angle of the blade element is greater than-18° and less than 18°, the two attack angles closest to the attack angle of the blade element are selected as the interpolation attack angles, and the lift-drag characteristic parameters of the blade element are calculated according to the two sets of reference lift-drag characteristic parameters corresponding to the two interpolation attack angles. If the attack angle of the blade element is greater than 18°, the interpolation attack angle is 18°, and the reference lift-drag characteristic parameters corresponding to 18° are the lift-drag characteristic parameters of the blade element.

[0269] The propeller performance calculation method provided in the above embodiment selects the interpolation attack angle in the propeller airfoil database, and calculates the lift-drag characteristic parameters of the blade element according to the reference lift-drag characteristic parameters corresponding to the interpolation attack angle, thereby avoiding the long calculation time consumed when the lift-drag characteristic parameters are directly calculated, greatly shortening the program running time, reducing the calculation time, and improving the calculation efficiency of the propeller performance.

[0270] On the basis of the above embodiment, the present embodiment further provides another propeller performance calculation method. Please refer to Figure 7 The flowchart of the another propeller performance calculation method provided in the present embodiment is shown in Figure 7 The step S50 of calculating the total aerodynamic force data of the propeller in different states according to the blade parameters of the propeller and the aerodynamic force data of the plurality of blade elements can include the following steps.

[0271] S51: Selecting a plurality of target blade elements from the plurality of blade elements of each blade of the propeller.

[0272] S52: Calculate total aerodynamic force data of the propeller in different states of the propeller according to the aerodynamic force data of the plurality of target blade elements of the plurality of blades.

[0273] In the embodiment, each blade of the propeller is divided into a plurality of blade elements, and the aerodynamic force data of each blade element is calculated. If the aerodynamic force of each blade is calculated, a plurality of blade elements need to be integrated. Because the number of blade elements is large, the calculation time is relatively long in the integration process, and the calculation efficiency is low. In order to improve the calculation efficiency, a plurality of target blade elements are selected from the plurality of blade elements of each blade, and the total aerodynamic force data of the propeller is obtained by integrating and superimposing the aerodynamic force data of the plurality of target blade elements of the plurality of blades.

[0274] In a possible implementation, when the plurality of target blade elements are selected from the plurality of blade elements of each blade, the complex Kort formula is used, each blade containing a plurality of blade elements is divided into a plurality of segments from a preset position of the blade to the blade root, four blade elements in each segment are selected as target blade elements, the four blade elements in each segment are integrated, then the plurality of segments of each blade are integrated, and finally the integration results of the plurality of blades are superimposed to obtain the total aerodynamic force data of the propeller.

[0275] For example, the interval [a, b] from the preset position of the blade to the blade root is divided into a series of small intervals wherein the nodes satisfy the relationship a=x0 n <b, and the complex Kort formula is used for integration on each small interval, so as to obtain the total aerodynamic force data of the propeller. The complex Kort formula is used for integration, the error of the calculation result is smallest in the case of using the least number of interpolation points, and the accuracy of calculating the total aerodynamic force data of the propeller is improved.

[0276] For example, the following formula is used to obtain the total aerodynamic force data of the propeller by using the complex Kort formula for integration:

[0277]

[0278] In the formula, wherein N=16 is taken, and 65 interpolation points are required for integration.

[0279] On the basis of the above embodiment, the embodiment of the application further provides another propeller performance calculation method. Please refer to Figure 8 The flowchart of another propeller performance calculation method provided by the embodiment of the application is shown in Figure 8 The method can further include the following steps.

[0280] S71: According to the interference angle of the plurality of blade elements, the angle of attack of the plurality of blade elements, and the aerodynamic force data of the plurality of blade elements obtained when calculating the total aerodynamic force data of the fixed propeller thrust, analyze the distribution of the interference angle and the aerodynamic force data of the blade elements at different spanwise positions on each blade of the propeller.

[0281] In this embodiment, the interference angle of the plurality of blade elements, the angle of attack of the plurality of blade elements, and the aerodynamic force data of the plurality of blade elements calculated in advance are loaded by the preset analysis software to generate the distribution of the interference angle, the angle of attack, and the aerodynamic force data on the blade elements at different spanwise positions on the blade.

[0282] For example, as shown in Figure 9 , the abscissa is the position of the blade element on the blade, and the ordinate is the installation angle θ, the angle of attack α, and the included angle Figure 9 of the blade element. As the position of the blade element on the blade changes, the angle changes, and the distribution of the angle of the blade element on the blade can be obtained from Figure 9 It can be seen that when the propeller performance is calculated by the fixed propeller thrust, that is, the installation angle of the blade matches the preset installation angle, the installation angle θ, the angle of attack α, and the included angle of the blade element at different spanwise positions on the blade calculated by the present application also match the reference installation angle θ, the reference angle of attack α, and the reference included angle .

[0283] S72: Calculate the induced velocity of the plurality of blade elements according to the interference angle of the plurality of blade elements.

[0284] In this embodiment, the induced velocity includes the axial induced velocity v a and the circumferential induced velocity v t . According to formula (27), after the included angle is determined, the induced velocity of the plurality of blade elements can be calculated under the condition that the given airflow velocity V0 and the tangential velocity Ωr are known, wherein, as shown in Figure 2 , the included angle

[0285] S73: Analyze the distribution of the induced velocity on each blade of the propeller according to the induced velocity of the plurality of blade elements.

[0286] In this embodiment, the induced velocity of the plurality of blade elements is loaded by the preset analysis software to generate the distribution of the induced velocity on the blade elements. For example, the preset analysis software can be TECPLOT software, which is not limited by the present application.

[0287] The propeller performance calculation method provided in the above embodiments can analyze the interference angle, angle of attack, aerodynamic data, and induced velocity, and determine the distribution of the interference angle, angle of attack, aerodynamic data, and induced velocity along the spanwise direction of the blade, making it more suitable for propeller performance analysis.

[0288] Based on the propeller performance calculation method provided in the above embodiments, the propeller performance calculation is verified. Please refer to Table 5, which provides propeller parameters for this embodiment. According to the correspondence between propeller thrust and blade installation angle, the blade installation angle corresponding to a constant thrust under experimental conditions and the interference angle, angle of attack, and included angle of the blade element at different spanwise positions are determined. Using the propeller performance calculation method provided in this embodiment, the thrust calculated based on the initial blade installation angle is compared with the constant thrust under experimental conditions to determine the range of blade installation angles corresponding to the constant thrust. By continuously changing the initial blade installation angle through linear interpolation calculations, the thrust corresponding to the precise installation angle is determined as the constant thrust. Figure 9 As shown, by comparing the calculated interference angles, angles of attack, and included angles of the blade elements at different spanwise positions under a constant thrust with those measured under experimental conditions, it is confirmed that the propeller performance calculation method of this embodiment matches the experimental values. For example, when the blade installation angle θ = 17.21° is determined through constant thrust calculation, the calculated interference angles, angles of attack, and included angles (torsion angles) match the reference values ​​well, and the calculation results meet the accuracy requirements for engineering applications.

[0289] Table 5. Parameters of a Propeller

[0290] Total weight Rotor radius Rotor blade number Rotor rated speed Rotor solidity 9171.8 kg 9.144m 4 207 r / min 0.085 Tip speed Tip negative twist Airfoil Chord (rectangular) Blade root cut ratio 198.12 m / s -10° NACA0012 0.6096 0.15

[0291] Based on the above embodiments, this application also provides a propeller performance calculation device. Please refer to Figure 10, which is a structural schematic diagram of a propeller performance calculation device provided in this application embodiment. Figure 10 As shown, the device includes:

[0292] The interference angle calculation module 11 is used to calculate the interference angle of multiple blade elements based on the preset blade element parameters, calculation condition parameters and preset input initial interference angle of multiple blade elements in different states of the propeller.

[0293] Angle of attack calculation module 12 is used to calculate the angle of attack of multiple blade elements based on the interference angles of multiple blade elements;

[0294] The lift-drag characteristic parameter determination module 13 is configured to determine a plurality of groups of lift-drag characteristic parameters corresponding to the plurality of blades in the preset propeller airfoil database according to a preset Reynolds number, a preset Mach number, and angles of attack of the plurality of blades, wherein the propeller airfoil database comprises a correspondence between a plurality of reference Reynolds numbers, a plurality of reference Mach numbers, a plurality of reference angles of attack, and the plurality of groups of lift-drag characteristic parameters.

[0295] The blade aerodynamic force calculation module 14 is configured to calculate aerodynamic force data of the plurality of blades in different states of the propeller according to the plurality of groups of lift-drag characteristic parameters and preset blade parameters of the plurality of blades.

[0296] The propeller aerodynamic force calculation module 15 is configured to calculate total aerodynamic force data of the propeller in different states of the propeller according to blade parameters of the propeller and the aerodynamic force data of the plurality of blades.

[0297] Optionally, the interference angle calculation module 11 is specifically configured to calculate the interference angles of the plurality of blades according to the preset blade parameters of the plurality of blades, the calculation condition parameters, and the initial interference angle when the propeller is in the forward flight state, or to calculate the interference angles of the plurality of blades according to the preset blade parameters of the plurality of blades, the calculation condition parameters, and the initial interference angle when the propeller is in the hovering state.

[0298] Optionally, the interference angle calculation module 11 comprises:

[0299] The change amount calculation unit is configured to calculate a first interference angle change amount of the plurality of blades by using a preset iteration algorithm according to the preset blade parameters of the plurality of blades, the calculation condition parameters, and the initial interference angle when the propeller is in different states.

[0300] The iteration unit is configured to, if the first interference angle change amount does not satisfy a preset interference angle error, recalculate a second interference angle change amount of the plurality of blades by using an iteration algorithm according to the initial interference angle, the first interference angle change amount, and a preset relaxation factor until the second interference angle change amount of the plurality of blades satisfies the preset interference angle error, the relaxation factor being used to control a convergence state of the iteration algorithm.

[0301] The interference angle calculation unit is configured to calculate the interference angles of the plurality of blades according to the initial interference angle and the second interference angle change amount.

[0302] Optionally, before the lift-drag characteristic parameter determination module 13 determines the plurality of groups of lift-drag characteristic parameters corresponding to the plurality of blades in the preset propeller airfoil database, the device further comprises:

[0303] The lift-drag characteristic parameter calculation module is configured to calculate the plurality of groups of lift-drag characteristic parameters according to the plurality of reference Reynolds numbers, the plurality of reference Mach numbers, and the plurality of reference angles of attack.

[0304] An airfoil database construction module is configured to construct an airfoil database of the propeller according to a correspondence between a plurality of reference Reynolds numbers, a plurality of reference Mach numbers, a plurality of reference angles of attack, and a plurality of sets of lift-drag characteristic parameters.

[0305] Optionally, the lift-drag characteristic parameter calculation module comprises:

[0306] A calculation unit is configured to calculate a maximum value and a minimum value of the lift-drag characteristic parameter according to each reference Reynolds number, each reference Mach number, and each reference angle of attack.

[0307] A convergence judgment unit is configured to judge whether the lift-drag characteristic parameter satisfies a preset convergence condition according to the maximum value and the minimum value.

[0308] A convergence determination unit is configured to determine the convergence value as the lift-drag characteristic parameter if the lift-drag characteristic parameter satisfies the preset convergence condition.

[0309] Optionally, the lift-drag characteristic parameter determination module 13 comprises:

[0310] A lift-drag characteristic parameter determination unit is configured to determine a plurality of sets of reference lift-drag characteristic parameters corresponding to the preset Reynolds number, the preset Mach number, and the plurality of reference angles of attack in the airfoil database of the propeller.

[0311] An interpolation angle of attack determination unit is configured to determine a plurality of interpolation angles of attack corresponding to the angle of attack of each blade element from the plurality of reference angles of attack according to the angle of attack of each blade element.

[0312] A lift-drag characteristic parameter calculation unit is configured to calculate a set of lift-drag characteristic parameters of each blade element according to a plurality of sets of reference lift-drag characteristic parameters corresponding to the plurality of interpolation angles of attack.

[0313] Optionally, the propeller aerodynamic force calculation module 15 comprises:

[0314] A target blade element selection unit is configured to select a plurality of target blade elements from a plurality of blade elements of each blade of the propeller.

[0315] A propeller aerodynamic force calculation unit is configured to calculate total aerodynamic force data of the propeller according to aerodynamic force data of the plurality of target blade elements of the plurality of blades.

[0316] Optionally, the device further comprises:

[0317] A spanwise distribution module is configured to analyze distribution of interference angles, angles of attack, and aerodynamic force data of blade elements at different spanwise positions on each blade of the propeller according to the interference angles, the angles of attack, and the aerodynamic force data of the blade elements obtained when the performance of the propeller is calculated.

[0318] An induced velocity calculation module is configured to calculate induced velocities of the blade elements according to the interference angles of the blade elements.

[0319] The induced velocity distribution module is configured to analyze the distribution of the induced velocity of the blade element at different spanwise positions on each blade of the propeller according to the induced velocity of the plurality of blade elements.

[0320] The device is configured to execute the method provided by the foregoing embodiments, and has similar implementation principles and technical effects, which will not be described here again.

[0321] The modules can be one or more integrated circuits configured to implement the above method, for example, one or more application specific integrated circuits (ASICs), or one or more microprocessors, or one or more field programmable gate arrays (FPGAs), etc. For another example, when a certain module above is implemented in the form of a processing element scheduling code, the processing element can be a general-purpose processor, such as a central processing unit (CPU) or other processor that can invoke the code. For another example, the modules can be integrated together to implement in the form of a system on a chip (SOC).

[0322] For another example, the modules can be integrated together to implement in the form of a system on a chip (SOC). Figure 11 For another example, the modules can be integrated together to implement in the form of a system on a chip (SOC). Figure 11 As shown in FIG. 1, the computer device 100 includes a processor 101, a storage medium 102, and a bus. The storage medium 102 stores program instructions executable by the processor 101. When the computer device 100 is running, the processor 101 communicates with the storage medium 102 through the bus. The processor 101 executes the program instructions to execute the above method embodiments. The specific implementation manners and technical effects are similar, which will not be described here again.

[0323] Optionally, the present application also provides a program product, for example, a computer readable storage medium, including a program which, when executed by a processor, is configured to execute the above method embodiments.

[0324] In several embodiments provided by the present application, it should be understood that the disclosed apparatus and method can be implemented in other manners. For example, the described apparatus embodiments are merely schematic. The units as divided can be combined or integrated into another system, or some features can be ignored or not implemented. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be in electrical, mechanical or other forms.

[0325] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purposes of the embodiments.

[0326] In addition, each functional unit in the various embodiments of the present application can be integrated into a processing unit, or each unit can exist physically, or two or more units can be integrated into one unit. The integrated unit can be implemented in the form of hardware, or in the form of hardware plus software functional units.

[0327] The integrated unit implemented in the form of software functional units can be stored in a computer readable storage medium. The software functional units stored in the storage medium include a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (English: processor) to perform some steps of the method described in the various embodiments of the present application. The foregoing storage medium includes a U disk, a mobile hard disk, a read-only memory (English: Read-Only Memory, abbreviated as: ROM), a random access memory (English: Random Access Memory, abbreviated as: RAM), a magnetic disk or an optical disk, and various program code storage media.

[0328] The above is merely specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of calculating the performance of a propeller, characterized by, The method comprises: According to the preset blade element parameters of the plurality of blade elements under different states of the propeller, the initial interference angle of the preset input and the calculation condition parameters, the interference angle of the plurality of blade elements is calculated; According to the interference angle of the plurality of blade elements, the angle of attack of the plurality of blade elements is calculated; According to the preset Reynolds number, the preset Mach number and the angle of attack of the plurality of blade elements, a plurality of groups of lift-drag characteristic parameters corresponding to the plurality of blade elements are determined in a preset propeller airfoil database, wherein the propeller airfoil database comprises a plurality of reference Reynolds numbers, a plurality of reference Mach numbers, a plurality of reference angles of attack and a plurality of groups of lift-drag characteristic parameters corresponding relationship; According to the plurality of groups of lift-drag characteristic parameters, the aerodynamic force data of the plurality of blade elements under the different states of the propeller is calculated; According to the blade parameters of the propeller and the aerodynamic force data of the plurality of blade elements, the total aerodynamic force data of the propeller under the different states of the propeller is calculated.

2. The method of claim 1, wherein, The method comprises: According to the preset blade element parameters of the plurality of blade elements under different states of the propeller, the initial interference angle of the preset input and the calculation condition parameters, the interference angle of the plurality of blade elements is calculated; According to the preset blade element parameters of the plurality of blade elements under different states of the propeller, the initial interference angle of the preset input and the calculation condition parameters, the interference angle of the plurality of blade elements is calculated; 3. The method of claim 1, wherein, The method comprises: According to the preset blade element parameters of the plurality of blade elements under different states of the propeller, the initial interference angle of the preset input and the calculation condition parameters, the interference angle of the plurality of blade elements is calculated; According to the preset blade element parameters of the plurality of blade elements under different states of the propeller, the initial interference angle of the preset input and the calculation condition parameters, the interference angle of the plurality of blade elements is calculated; According to the preset Reynolds number, the preset Mach number and the angle of attack of the plurality of blade elements, a plurality of groups of lift-drag characteristic parameters corresponding to the plurality of blade elements are determined in a preset propeller airfoil database, wherein the propeller airfoil database comprises a plurality of reference Reynolds numbers, a plurality of reference Mach numbers, a plurality of reference angles of attack and a plurality of groups of lift-drag characteristic parameters corresponding relationship; 4. The method of claim 1, wherein, According to the plurality of groups of lift-drag characteristic parameters, the aerodynamic force data of the plurality of blade elements under the different states of the propeller is calculated; According to the blade parameters of the propeller and the aerodynamic force data of the plurality of blade elements, the total aerodynamic force data of the propeller under the different states of the propeller is calculated. The method comprises:

5. The method of claim 3, wherein, According to the preset blade element parameters of the plurality of blade elements under different states of the propeller, the initial interference angle of the preset input and the calculation condition parameters, the interference angle of the plurality of blade elements is calculated; According to the preset blade element parameters of the plurality of blade elements under different states of the propeller, the initial interference angle of the preset input and the calculation condition parameters, the interference angle of the plurality of blade elements is calculated; The method comprises: According to the preset blade element parameters of the plurality of blade elements under different states of the propeller, the initial interference angle of the preset input and the calculation condition parameters, the interference angle of the plurality of blade elements is calculated; According to the preset blade element parameters of the plurality of blade elements under different states of the propeller, the initial interference angle of the preset input and the calculation condition parameters, the interference angle of the plurality of blade elements is calculated; According to the preset Reynolds number, the preset Mach number and the angle of attack of the plurality of blade elements, a plurality of groups of lift-drag characteristic parameters corresponding to the plurality of blade elements are determined in a preset propeller airfoil database, wherein the propeller airfoil database comprises a plurality of reference Reynolds numbers, a plurality of reference Mach numbers, a plurality of reference angles of attack and a plurality of groups of lift-drag characteristic parameters corresponding relationship; According to the plurality of groups of lift-drag characteristic parameters, the aerodynamic force data of the plurality of blade elements under the different states of the propeller is calculated; According to the blade parameters of the propeller and the aerodynamic force data of the plurality of blade elements, the total aerodynamic force data of the propeller under the different states of the propeller is calculated. According to each reference Reynolds number, each reference Mach number and each reference angle of attack, the maximum and minimum values of the lift-drag characteristic parameters are calculated; According to the maximum and minimum values, it is judged whether the lift-drag characteristic parameters meet a preset convergence condition; If the lift-drag characteristic parameters meet the preset convergence condition, the convergence value is determined as the lift-drag characteristic parameters.

6. The method of claim 1, wherein, According to the preset Reynolds number, the preset Mach number and the angles of attack of the plurality of blades, a plurality of groups of lift-drag characteristic parameters corresponding to the plurality of blades are determined in a preset propeller airfoil database, including: In the propeller airfoil database, a plurality of groups of reference lift-drag characteristic parameters corresponding to the preset Reynolds number, the preset Mach number and the plurality of reference angles of attack are determined; According to the angle of attack of each blade, a plurality of interpolation angles of attack corresponding to the angle of attack of each blade are determined from the plurality of reference angles of attack; According to the plurality of groups of reference lift-drag characteristic parameters corresponding to the plurality of interpolation angles of attack, a group of lift-drag characteristic parameters of each blade is calculated.

7. The method of claim 1, wherein, According to the blade parameters of the propeller and the aerodynamic force data of the plurality of blades, total aerodynamic force data of the propeller in the different states is calculated, including: For each blade of the propeller, a plurality of target blades are selected from the plurality of blades of each blade; According to the aerodynamic force data of the plurality of target blades of the plurality of blades, total aerodynamic force data of the propeller in the different states is calculated.

8. A propeller performance calculation device, characterized by, The device comprises: An interference angle calculation module is configured to calculate interference angles of a plurality of blades according to preset blade parameters, calculation condition parameters and a preset input initial interference angle of the plurality of blades in different states of a propeller; An angle of attack calculation module is configured to calculate angles of attack of the plurality of blades according to the interference angles of the plurality of blades; A lift-drag characteristic parameter determination module is configured to determine a plurality of groups of lift-drag characteristic parameters corresponding to the plurality of blades in a preset propeller airfoil database according to a preset Reynolds number, a preset Mach number and the angles of attack of the plurality of blades, wherein the propeller airfoil database comprises a correspondence between a plurality of reference Reynolds numbers, a plurality of reference Mach numbers, a plurality of reference angles of attack and a plurality of groups of lift-drag characteristic parameters; A blade aerodynamic force calculation module is configured to calculate aerodynamic force data of the plurality of blades in the different states of the propeller according to the plurality of groups of lift-drag characteristic parameters and the preset blade parameters of the plurality of blades; A propeller aerodynamic force calculation module is configured to calculate total aerodynamic force data of the propeller in the different states according to blade parameters of the propeller and the aerodynamic force data of the plurality of blades.

9. A computer device, comprising: It comprises: A processor, a storage medium and a bus, the storage medium stores program instructions executable by the processor, when the computer device is running, the processor and the storage medium communicate through the bus, the processor executes the program instructions to execute the steps of the propeller performance calculation method in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, which is executed by the processor to execute the steps of the propeller performance calculation method in any one of claims 1 to 7.

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