A method, system and electronic device for determining flow field in computational fluid dynamics

Abstract

The present invention provides a method, system, and electronic device for determining a computational fluid dynamics (CFD) flow field, relating to the technical field of momentum source methods. The method includes determining a mapping relationship between a computational domain disk grid and a momentum source domain disk grid; determining a fluid control equation in the computational domain to obtain a first velocity of each blade at the blade radius in the computational domain coordinate system; and a second velocity in the momentum source domain coordinate system; equating the rotor blade structure to a Bernoulli-Euler beam to obtain the blade flapping velocity; using the flapping velocity to update the normal velocity component in the second velocity to obtain a momentum source term affected by the flapping deformation motion; and then determining the fluid dynamics flow field. The present invention takes into account the influence of the flapping deformation motion of the rotor blade structure on the CFD flow field, thereby improving the accuracy and rationality of determining the CFD flow field.

Description

Technical Field

[0001] The present invention relates to the technical field of momentum source methods, and in particular to a computational fluid dynamics flow field determination method, system and electronic equipment. Background Art

[0002] The momentum source method is used to determine the computational fluid dynamics flow field of an object and is widely used to simulate the perturbations of rotor blades on the flow field. This method offers the advantages of low computational resources and short computational cycles while meeting engineering accuracy requirements. Since its introduction by Rajagopalan and Chaffin in the last century, it has been widely used in engineering design. The traditional momentum source method simplifies the rotor into an infinitely thin disk and transforms the rotor's periodic influence on the flow field into a near-steady one through time averaging. The effect of the blades on the air is then added to the flow field as a source term, thus avoiding the generation of a large rotor mesh and improving computational efficiency. However, this method does not account for the rotor's elastic flapping deformation motion. In particular, for elastic rotors with large aspect ratios, which generate high flapping velocities at the blade tips, the computational accuracy of the traditional momentum source method is significantly reduced. Summary of the Invention

[0003] The purpose of the present invention is to provide a method, system and electronic equipment for determining the computational fluid dynamics flow field, which can take into account the influence of the flapping deformation motion of the rotor blade structure on the computational fluid dynamics flow field, thereby improving the accuracy and rationality of determining the computational fluid dynamics flow field.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] A method for determining a flow field in computational fluid dynamics, comprising:

[0006] According to the parameters of the rotor blade structure, the computational domain disk grid and the momentum source domain disk grid are constructed based on computational fluid dynamics, and the mapping relationship between the computational domain disk grid and the momentum source domain disk grid is determined;

[0007] Determine the grid where the blade is located in the disk grid of the momentum source domain as the blade grid;

[0008] Determine the blade radius and the azimuth angle of each blade based on the blade grid;

[0009] The fluid control equation is determined in the computational domain according to the size of the disk grid, and the velocity of each blade at the blade radius in the computational domain coordinate system is obtained as the first velocity;

[0010] Determining the velocity of each blade at the blade radius in the momentum source domain coordinate system as a second velocity based on the mapping relationship, the azimuth angle of each blade, and the first velocity of each blade at the blade radius;

[0011] determining an average rotor thrust of the plurality of blades at a blade radius based on the second speed of the plurality of blades;

[0012] Based on the average rotor thrust, the rotor blade structure is equivalent to a Bernoulli-Euler beam, and the equivalent flapping motion equation is determined to obtain the flapping velocity at the blade radius.

[0013] The normal velocity component of the second velocity is updated using the flapping velocity, so that the velocity of the blade affected by the flapping deformation motion in the momentum source domain coordinate system is obtained as a third velocity;

[0014] Determining, based on the mapping relationship and the third speed, an average rotor thrust of the blade grid affected by the flapping deformation motion at the blade radius as the average rotor thrust affected by flapping;

[0015] Determining, based on the mapping relationship and the third speed, an average rotor drag of the blade grid affected by the flapping deformation motion at the blade radius as an average rotor drag affected by flapping;

[0016] Determine the force on the blade grid affected by the flapping deformation motion based on the average flapping rotor pull and the average flapping rotor drag;

[0017] According to the forces on the blade mesh affected by the flapping deformation motion and Newton's third law, the momentum source term affected by the flapping deformation motion is determined;

[0018] The fluid dynamics flow field is determined according to the momentum source term affected by the flapping deformation motion and the fluid control equation.

[0019] Optionally, the second speed is:

[0020]

[0021] Among them, v τ represents the tangential component of the second velocity, v r represents the spanwise component of the second velocity, v n represents the normal component of the second velocity, represents the azimuth angle of the blade, u represents the X-axis component of the first velocity, v represents the Y-axis component of the first velocity, w represents the Z-axis component of the first velocity, Ω represents the rotor angular velocity, and r represents the blade radius.

[0022] Optionally, determining the average rotor thrust of the plurality of blades at the blade radius based on the second speeds of the plurality of blades includes:

[0023] Determine any blade as the current blade;

[0024] According to the second speed of the current blade, the formula β=aectan(v n / v r ) determines the inflow angle of the current blade; where β represents the inflow angle, v n represents the normal component of the second velocity, v r represents the spanwise component of the second velocity;

[0025] According to the inflow angle, the formula α=α g -β determines the aerodynamic angle of attack of the current blade; where α represents the aerodynamic angle of attack, α g represents the geometric installation angle at the blade radius r of the propeller disk;

[0026] According to the second speed of the current blade, use the lift formula Determine the cross-sectional lift of the current blade at the blade radius; where dL represents the cross-sectional lift, v F represents the incoming flow velocity of the blade profile, C l represents the lift coefficient under the aerodynamic angle of attack and Reynolds number; c represents the chord length of the profile blade;

[0027] According to the inflow angle and the cross-sectional lift, the formula dF is used. n =dLcosβ-dD sin β determines the rotor thrust of the current blade at blade radius r, and then determines the average rotor thrust of multiple blades at blade radius; dF n Indicates the rotor thrust of the current blade at the blade radius.

[0028] Optionally, the step of equating the rotor blade structure to a Bernoulli-Euler beam based on the average rotor thrust, and determining the equivalent flapping motion equation to obtain the flapping velocity at the blade radius includes:

[0029] According to the average rotor thrust, the rotor blade structure is equivalent to a Bernoulli-Euler beam, and the equivalent flapping motion equation is determined to obtain the blade flapping angular velocity; the flapping motion equation is: Where m represents the mass of the blade, represents the swing angular velocity; is the second-order derivative of the blade flapping displacement q with respect to time, E represents the blade elastic modulus, I represents the blade moment of inertia, q' represents the second-order derivative of the blade position x, q' represents the first-order derivative of the blade micro-segment x, Ω represents the rotor angular velocity, L represents the micro-end spacing, and f app (x,t) represents the force on the blade micro-segment x at time t;

[0030] According to the blade flapping angular velocity and blade radius, use the formula Determine the flapping velocity at the blade radius; v H represents the flapping speed and r represents the blade radius.

[0031] Optionally, the updating the normal velocity component in the second velocity by using the swinging velocity includes:

[0032] The sum of the normal component of the second velocity and the swing velocity is determined as the updated normal component of the second velocity.

[0033] Optionally, the momentum source term affected by the flapping deformation motion is determined according to the following formula:

[0034]

[0035]

[0036] Where dF represents the force on the blade mesh affected by the flapping deformation motion; dF J It indicates the force exerted on the air by the blades; represents the average flapping rotor pull, dF τH represents the average flapping rotor drag, dφ represents the circumferential spacing, Ω represents the rotor angular velocity, and dt represents the time step.

[0037] Optionally, determining the fluid dynamics flow field based on the momentum source term affected by the flapping deformation motion and the fluid control equation includes:

[0038] Substituting the momentum source term affected by the flapping deformation motion into the fluid control equation to determine the undetermined fluid dynamics flow field;

[0039] Determine whether the undetermined fluid dynamics flow field converges and obtain a determination result;

[0040] If the judgment result is yes, determining that the undetermined fluid dynamics flow field at the last iteration is a fluid dynamics flow field taking into account the flapping deformation motion;

[0041] If the judgment result is no, return to the step of "determining the fluid control equation in the calculation domain according to the size of the calculation domain propeller disk grid, and obtaining the speed of each blade at the blade radius in the calculation domain coordinate system as the first speed".

[0042] A computational fluid dynamics flow field determination system, comprising:

[0043] A grid construction module is used to construct a computational domain disk grid and a momentum source domain disk grid based on computational fluid dynamics according to the parameters of the rotor blade structure, and to determine the mapping relationship between the computational domain disk grid and the momentum source domain disk grid;

[0044] A blade grid determination module is used to determine the grid where the blade is located in the momentum source domain disk grid as the blade grid;

[0045] a radius and azimuth determination module, configured to determine the blade radius and the azimuth of each blade according to the blade grid;

[0046] A first speed determination module is used to determine the fluid control equation in the calculation domain according to the size of the disk grid in the calculation domain, and obtain the speed of each blade at the blade radius in the calculation domain coordinate system as the first speed;

[0047] a second speed determining module, configured to determine, based on the mapping relationship and the azimuth angle of each blade and the first speed of each blade at the blade radius, the speed of each blade at the blade radius in the momentum source domain coordinate system as a second speed;

[0048] an average rotor thrust determining module, configured to determine an average rotor thrust of the plurality of blades at a blade radius based on a second speed of the plurality of blades;

[0049] A flapping speed determination module is used to equate the rotor blade structure to a Bernoulli-Euler beam based on the average rotor thrust, and to determine the equivalent flapping motion equation to obtain the flapping speed at the blade radius;

[0050] a third velocity determination module, configured to update the normal velocity component of the second velocity using the flapping velocity, and obtain a velocity of the blade affected by the flapping deformation motion in a momentum source domain coordinate system as a third velocity;

[0051] an average flapping rotor pull determining module, configured to determine, based on the mapping relationship and a third speed, an average rotor pull of a blade grid affected by flapping deformation motion at a blade radius as the average flapping rotor pull;

[0052] an average flapping rotor drag determining module, configured to determine, based on the mapping relationship and a third speed, an average rotor drag of a blade grid affected by flapping deformation motion at a blade radius as the average flapping rotor drag;

[0053] A force determination module is used to determine the force of the blade grid affected by the flapping deformation motion based on the average flapping rotor pull and the average flapping rotor drag;

[0054] a momentum source term determination module, used for determining a momentum source term affected by the flapping deformation motion according to the forces on the blade mesh affected by the flapping deformation motion and Newton's third law;

[0055] The fluid dynamics flow field determination module is used to determine the fluid dynamics flow field according to the momentum source term affected by the flapping deformation motion and the fluid control equation.

[0056] An electronic device includes a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute a computational fluid dynamics flow field determination method.

[0057] Optionally, the memory is a readable storage medium.

[0058] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0059] The present invention provides a computational fluid dynamics flow field determination method, system and electronic device, the method comprising: constructing a computational domain disc grid and a momentum source domain disc grid based on computational fluid dynamics according to parameters of a rotor blade structure, and determining a mapping relationship between the computational domain disc grid and the momentum source domain disc grid; determining the grid where the blade is located in the momentum source domain disc grid as a blade grid; determining the blade radius and the azimuth angle of each blade according to the blade grid; determining a fluid control equation in the computational domain according to the size of the computational domain disc grid, and obtaining the speed of each blade at the blade radius in the computational domain coordinate system as a first speed; determining the speed of each blade at the blade radius in the momentum source domain coordinate system as a second speed according to the mapping relationship and the azimuth angle of each blade, and the first speed of each blade at the blade radius; determining the average rotor thrust of multiple blades at the blade radius according to the second speeds of multiple blades; and equivalentizing the rotor blade structure to a Bernoull equation according to the average rotor thrust. i-Euler beam, and determine the equivalent flapping motion equation to obtain the flapping velocity at the blade radius; use the flapping velocity to update the normal velocity component in the second velocity, and obtain the velocity of the blade affected by the flapping deformation motion in the momentum source domain coordinate system as the third velocity; according to the mapping relationship and the third velocity, determine the average rotor thrust of the blade grid affected by the flapping deformation motion at the blade radius as the average flapping rotor thrust; according to the mapping relationship and the third velocity, determine the average rotor drag of the blade grid affected by the flapping deformation motion at the blade radius as the average flapping rotor drag; according to the average flapping rotor thrust and the average flapping rotor drag, determine the force of the blade grid affected by the flapping deformation motion; according to the force of the blade grid affected by the flapping deformation motion and Newton's third law, determine the momentum source term affected by the flapping deformation motion; according to the momentum source term affected by the flapping deformation motion and the fluid control equation, determine the fluid dynamics flow field. The present invention takes into account the influence of the flapping deformation motion of the rotor blade structure on the computational fluid dynamics flow field, thereby improving the accuracy and rationality of determining the computational fluid dynamics flow field. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0061] Figure 1 This is a flow chart of the method for determining the flow field of computational fluid dynamics in Example 1 of the present invention;

[0062] Figure 2 This is a schematic diagram of the paddle disc grid in Example 1 of the present invention. DETAILED DESCRIPTION

[0063] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0064] The purpose of the present invention is to provide a method, system and electronic equipment for determining the computational fluid dynamics flow field, which can take into account the influence of the flapping deformation motion of the rotor blade structure on the computational fluid dynamics flow field, thereby improving the accuracy and rationality of determining the computational fluid dynamics flow field.

[0065] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0066] Example 1

[0067] like Figure 1 As shown, this embodiment provides a method for determining a computational fluid dynamics flow field, including:

[0068] Step 101: Based on the parameters of the rotor blade structure, a computational domain disk grid and a momentum source domain disk grid are constructed based on computational fluid dynamics, and a mapping relationship between the computational domain disk grid and the momentum source domain disk grid is determined.

[0069] like Figure 2As shown in the figure, with the disc center O as the circle center, the blade undercut Rq as the inner diameter, the rotor radius R as the outer diameter, the grid unit length dr and the circumferential spacing dφ, the disc grid MD is established in the CFD calculation domain, and the disc grid MR is established in the momentum source domain. In the CFD calculation domain, the left-hand rule is used to establish the CFD calculation domain coordinate system (X, Y, Z), in which the grid unit center coordinate is used as the grid unit coordinate; the grid unit coordinates in the divided disc grid MD are converted from the CFD calculation domain coordinate system (X, Y, Z) to the momentum source domain coordinate system (X S ,Y S ,Z S ), in order to facilitate the subsequent calculation of the radius position r and azimuth position of the propeller grid unit The grids at the same radius and azimuth in the two sets of grids are connected; in the propeller disk grid MR, the trailing edge point of the first blade is fixed in the positive direction of the X-axis of the momentum source domain coordinate system as a reference, and the actual blades are arranged respectively, and the leading edge azimuth and trailing edge azimuth of each blade are recorded. H ,φ Q ] The grid cells within the range are marked as blade grids MJ.

[0070] The calculation formula 1 for converting the CFD calculation domain coordinate system into the momentum source domain coordinate system is as follows:

[0071]

[0072] Among them, X represents the X-axis coordinate of the propeller disc grid unit in the CFD calculation domain coordinate system, Y represents the Y-axis coordinate of the propeller disc grid unit in the CFD calculation domain coordinate system, and Z represents the Z-axis coordinate of the propeller disc grid unit in the CFD calculation domain coordinate system. S represents the X-axis coordinate of the propeller disc grid unit in the momentum source domain coordinate system, Y S represents the Y-axis coordinate of the propeller disc grid unit in the momentum source domain coordinate system, Z S represents the Z-axis coordinate of the propeller disc grid unit in the momentum source domain coordinate system. A and B are the left tilt angle and forward tilt angle of the propeller disc, respectively. (x c ,y c ,z c ) is the O coordinate of the propeller disk center in the CFD calculation domain coordinate system.

[0073] Step 102: Determine the grid where the blade is located in the momentum source domain disk grid as the blade grid.

[0074] Step 103: Determine the blade radius and the azimuth angle of each blade according to the blade grid.

[0075] The calculation formula for the radial position r of the propeller disk grid unit is: Azimuth position of the disk grid unit The calculation formula is: φ=arctan(Y s / X s ), where X s Y is the X-axis coordinate of the propeller disc grid unit in the momentum source domain coordinate system. s is the Y-axis coordinate of the disk grid unit in the momentum source domain coordinate system.

[0076] Step 104: Determine the fluid control equation in the computational domain according to the size of the computational domain disk grid, and obtain the velocity of each blade at the blade radius in the computational domain coordinate system as the first velocity.

[0077] In the CFD calculation domain, the following fluid control equations are used for flow field calculation:

[0078]

[0079]

[0080]

[0081]

[0082]

[0083] Where t is the physical time, F c is the convection flux term, V is the volume of the grid unit, S is the area of the grid unit, W is the conserved variable, (n x ,n y ,n z ) is the normal vector of the grid element surface, ρ is the air density, e is the total energy of gas per unit mass, P is the pressure, u is the velocity component in the x-axis direction of the CFD calculation domain, v is the velocity component in the y-axis direction of the CFD calculation domain, w is the velocity component in the z-axis direction of the CFD calculation domain, τ xx is the viscous stress component acting on the plane perpendicular to the x-axis and along the x-axis, τ xy is the viscous stress component acting on the plane perpendicular to the x-axis and along the y-axis, τ xz is the viscous stress component acting on the plane perpendicular to the x-axis and along the z-axis, τ yy is the viscous stress component acting on the plane perpendicular to the y-axis and along the y-axis, τ yx is the viscous stress component acting on the plane perpendicular to the y-axis and along the x-axis, τ yz is the viscous stress component acting on the plane perpendicular to the y-axis and along the z-axis, τ zz is the viscous stress component acting on the plane perpendicular to the z-axis and along the z-axis, τzx is the viscous stress component acting on the plane perpendicular to the z-axis and along the x-axis, τ zy is the viscous stress component acting on the plane perpendicular to the z-axis and along the y-axis, Θ x is the heat flux along the x-axis, Θ y is the heat flux along the y-axis, Θ z is the heat flux along the z-axis; T is the momentum source term, T x is the component of the momentum source term T in the x-axis direction, T y is the component of the momentum source term T in the y-axis direction, T z is the component of the momentum source term T in the z-axis direction;

[0084] Solve the above fluid control equation, where the solution of the fluid control equation is

[0085] Step 105: Based on the mapping relationship, the azimuth angle of each blade, and the first velocity of each blade at the blade radius, the velocity of each blade at the blade radius in the momentum source domain coordinate system is determined as the second velocity; the second velocity is:

[0086]

[0087] Among them, v τ represents the tangential component of the second velocity, v r represents the spanwise component of the second velocity, v n represents the normal component of the second velocity, represents the azimuth angle of the blade, u represents the X-axis component of the first velocity, v represents the Y-axis component of the first velocity, w represents the Z-axis component of the first velocity, Ω represents the rotor angular velocity, and r represents the blade radius.

[0088] Step 106: Determine an average rotor thrust of the plurality of blades at a blade radius based on the second speeds of the plurality of blades. Step 106 includes:

[0089] Step 1061: Determine any blade as the current blade;

[0090] Step 1062: According to the second speed of the current blade, the formula β=arctan(v n / v r ) determines the inflow angle of the current blade; where β represents the inflow angle, v n represents the normal component of the second velocity, v r represents the spanwise component of the second velocity;

[0091] Step 1063: Based on the inflow angle, use the formula α=α g-β determines the aerodynamic angle of attack of the current blade; where α represents the aerodynamic angle of attack, α g represents the geometric installation angle at the blade radius r of the propeller disk;

[0092] Step 1064: Based on the second speed of the current blade, use the lift formula Determine the cross-sectional lift of the current blade at the blade radius; where dL represents the cross-sectional lift, v F represents the incoming flow velocity of the blade profile, C l represents the lift coefficient under the aerodynamic angle of attack and Reynolds number; c represents the chord length of the profile blade;

[0093] Step 1065: According to the inflow angle and the cross-sectional lift, according to the formula dF n =dL cosβ -dD sinβ determines the rotor thrust of the current blade at blade radius r, and then determines the average rotor thrust of multiple blades at blade radius; dF n Indicates the rotor thrust of the current blade at the blade radius.

[0094] Step 107: Equivalent the rotor blade structure to a Bernoulli-Euler beam based on the average rotor thrust, and determine the equivalent flapping motion equation to obtain the flapping velocity at the blade radius. Step 107 includes:

[0095] Step 1071: Equivalent the rotor blade structure to a Bernoulli-Euler beam based on the average rotor thrust, and determine the equivalent flapping motion equation to obtain the blade flapping angular velocity; the flapping motion equation is Where m represents the mass of the blade, represents the swing angular velocity; is the second-order derivative of the blade flapping displacement q with respect to time, E represents the blade elastic modulus, I represents the blade moment of inertia, q' represents the second-order derivative of the blade position x, q' represents the first-order derivative of the blade micro-segment x, Ω represents the rotor angular velocity, L represents the micro-end spacing, and f app (x, t) represents the force on the blade segment x at time t; the finite element method is used here to discretize each rotor blade into N blade units, where The calculated different radii Substituted into the flapping motion equation, the blade flapping angular velocity can be solved The angular velocity of the blade According to the formula The flapping speed v at the radial position r of the blade grid MJ can be calculated H .

[0096] Step 1072: Based on the blade flapping angular velocity and blade radius, use the formula Determine the flapping velocity at the blade radius; v H represents the flapping speed and r represents the blade radius.

[0097] Step 108: Use the flapping speed to update the normal velocity component in the second velocity, and obtain the velocity of the blade affected by the flapping deformation motion in the momentum source domain coordinate system as the third velocity; the updating process is to determine the sum of the normal component of the second velocity and the flapping speed as the normal component of the updated second velocity.

[0098] Step 109: Based on the mapping relationship and the third speed, determine the average rotor thrust of the blade mesh affected by flapping deformation at the blade radius as the average rotor thrust affected by flapping deformation. The formula for calculating the rotor thrust of the blade mesh affected by flapping deformation at the blade radius is the same as that in step 106.

[0099] Step 1010: According to the mapping relationship and the third speed, the average rotor drag of the blade mesh affected by the flapping deformation motion at the blade radius is determined as the average rotor drag affected by flapping.

[0100] Calculate the cross-sectional drag dD at the radial position r of the blade mesh MJ:

[0101]

[0102] Where c represents the chord length of the profile blade; v F represents the incoming flow velocity of the blade profile, C d The drag coefficient corresponding to the aerodynamic angle of attack and Reynolds number can generally be obtained by fitting and interpolating the aerodynamic characteristic data of the static airfoil calculated in advance; dr represents the grid unit length.

[0103] The rotor drag dF at the radial position r of the blade grid MJ τ as follows:

[0104] dF τ =dLsinβ+dD cosβ

[0105] Where dL represents the cross-sectional lift, dD represents the cross-sectional drag, and β represents the inflow angle.

[0106] Step 1011: Determine the force on the blade mesh affected by the flapping deformation motion based on the average flapping rotor pull and the average flapping rotor drag.

[0107] Step 1012: Determine the momentum source term affected by the flapping deformation motion based on the forces on the blade mesh affected by the flapping deformation motion and Newton's third law. The momentum source term affected by the flapping deformation motion is determined according to the following formula:

[0108]

[0109]

[0110] Where dF represents the force on the blade mesh affected by the flapping deformation motion; dF J It indicates the force exerted on the air by the blades; represents the average flapping rotor pull, dF τH represents the average flapping rotor drag, dφ represents the circumferential spacing, Ω represents the rotor angular velocity, and dt represents the time step.

[0111] Step 1013: Determine the fluid dynamics flow field based on the momentum source term affected by the flapping deformation motion and the fluid control equation. Step 1013 includes:

[0112] Step 10131: Substitute the momentum source term affected by the flapping deformation motion into the fluid control equation to determine the undetermined fluid dynamics flow field;

[0113] Step 10132: Determine whether the undetermined fluid dynamics flow field converges and obtain a determination result; if the determination result is yes, execute step 10133; if the determination result is no, execute step 104.

[0114] Step 10133: Determine that the undetermined fluid dynamics flow field at the last iteration is a fluid dynamics flow field that takes into account flapping deformation motion.

[0115] Example 2

[0116] In order to execute the method corresponding to the above embodiment 1 and achieve the corresponding functions and technical effects, a computational fluid dynamics flow field determination system is provided below, including:

[0117] The grid construction module is used to construct the computational domain disk grid and the momentum source domain disk grid based on computational fluid dynamics according to the parameters of the rotor blade structure, and to determine the mapping relationship between the computational domain disk grid and the momentum source domain disk grid.

[0118] The blade grid determination module is used to determine the grid where the blade is located in the momentum source domain disk grid as the blade grid.

[0119] The radius and azimuth angle determination module is used to determine the blade radius and the azimuth angle of each blade according to the blade grid.

[0120] The first speed determination module is used to determine the fluid control equation in the calculation domain according to the size of the calculation domain propeller disk grid, and obtain the speed of each blade at the blade radius in the calculation domain coordinate system as the first speed.

[0121] The second speed determination module is used to determine the speed of each blade at the blade radius in the momentum source domain coordinate system as the second speed according to the mapping relationship, the azimuth angle of each blade, and the first speed of each blade at the blade radius.

[0122] The average rotor thrust determination module is used to determine the average rotor thrust of the plurality of blades at the blade radius according to the second speed of the plurality of blades.

[0123] The flapping speed determination module is used to equate the rotor blade structure to a Bernoulli-Euler beam based on the average rotor thrust, determine the equivalent flapping motion equation, and obtain the flapping speed at the blade radius.

[0124] The third speed determination module is used to update the normal speed component in the second speed by using the flapping speed, and obtain the speed of the blade affected by the flapping deformation motion in the momentum source domain coordinate system as the third speed.

[0125] The average flapping rotor thrust determining module is used to determine, based on the mapping relationship and the third speed, the average rotor thrust of the blade grid at the blade radius affected by the flapping deformation motion as the average flapping rotor thrust.

[0126] The average flapping rotor drag determining module is used to determine, based on the mapping relationship and the third speed, the average rotor drag of the blade grid at the blade radius affected by the flapping deformation motion as the average flapping rotor drag.

[0127] The force determination module is used to determine the force of the blade grid affected by the flapping deformation motion according to the average flapping rotor pull and the average flapping rotor drag.

[0128] The momentum source term determination module is used to determine the momentum source term affected by the flapping deformation motion according to the force on the blade grid affected by the flapping deformation motion and Newton's third law.

[0129] The fluid dynamics flow field determination module is used to determine the fluid dynamics flow field based on the momentum source term and fluid control equation affected by the flapping deformation motion.

[0130] Example 3

[0131] This embodiment provides an electronic device, including a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the computational fluid dynamics flow field determination method described in Example 1.

[0132] The memory is a readable storage medium.

[0133] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0134] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A method for determining a flow field in computational fluid dynamics, characterized in that: include: According to the parameters of the rotor blade structure, the computational domain disk grid and the momentum source domain disk grid are constructed based on computational fluid dynamics, and the mapping relationship between the computational domain disk grid and the momentum source domain disk grid is determined; Determine the grid where the blade is located in the disk grid of the momentum source domain as the blade grid; Determine the blade radius and the azimuth angle of each blade based on the blade grid; The fluid control equation is determined in the computational domain according to the size of the disk grid, and the velocity of each blade at the blade radius in the computational domain coordinate system is obtained as the first velocity; Determining the velocity of each blade at the blade radius in the momentum source domain coordinate system as a second velocity based on the mapping relationship, the azimuth angle of each blade, and the first velocity of each blade at the blade radius; determining an average rotor thrust of the plurality of blades at a blade radius based on the second speed of the plurality of blades; Based on the average rotor thrust, the rotor blade structure is equivalent to a Bernoulli-Euler beam, and the equivalent flapping motion equation is determined to obtain the flapping velocity at the blade radius. The normal velocity component of the second velocity is updated using the flapping velocity, so that the velocity of the blade affected by the flapping deformation motion in the momentum source domain coordinate system is obtained as a third velocity; Determining, based on the mapping relationship and the third speed, an average rotor thrust of the blade grid affected by the flapping deformation motion at the blade radius as the average rotor thrust affected by flapping; Determining, based on the mapping relationship and the third speed, an average rotor drag of the blade grid affected by the flapping deformation motion at the blade radius as an average rotor drag affected by flapping; Determine the force on the blade grid affected by the flapping deformation motion based on the average flapping rotor pull and the average flapping rotor drag; According to the forces on the blade mesh affected by the flapping deformation motion and Newton's third law, the momentum source term affected by the flapping deformation motion is determined; The fluid dynamics flow field is determined according to the momentum source term affected by the flapping deformation motion and the fluid control equation.

2. A computational fluid dynamics flow field determination method according to claim 1, characterized in that: The second speed is: Among them, v τ represents the tangential component of the second velocity, v r represents the spanwise component of the second velocity, v n represents the normal component of the second velocity, represents the azimuth angle of the blade, u represents the X-axis component of the first velocity, v represents the Y-axis component of the first velocity, w represents the Z-axis component of the first velocity, Ω represents the rotor angular velocity, and r represents the blade radius.

3. The method for determining a computational fluid dynamics flow field according to claim 1, wherein: Determining the average rotor thrust of the plurality of blades at the blade radius according to the second speed of the plurality of blades includes: Determine any blade as the current blade; According to the second speed of the current blade, the formula β=arctan(v n / v r ) determines the inflow angle of the current blade; where β represents the inflow angle, v n represents the normal component of the second velocity, v r represents the spanwise component of the second velocity; According to the inflow angle, the formula α=α g -β determines the aerodynamic angle of attack of the current blade; where α represents the aerodynamic angle of attack, α g represents the geometric installation angle at the blade radius r of the propeller disk; According to the second speed of the current blade, use the lift formula Determine the cross-sectional lift of the current blade at the blade radius; where dL represents the cross-sectional lift, v F represents the incoming flow velocity of the blade profile, C l represents the lift coefficient under the aerodynamic angle of attack and Reynolds number; c represents the chord length of the profile blade; According to the inflow angle and the cross-sectional lift, the formula dF is used. n =dL cosβ -dD sinβ determines the rotor thrust of the current blade at blade radius r, and then determines the average rotor thrust of multiple blades at blade radius; dF n Indicates the rotor thrust of the current blade at the blade radius.

4. The method for determining a computational fluid dynamics flow field according to claim 1, wherein: The rotor blade structure is equivalent to a Bernoulli-Euler beam according to the average rotor thrust, and the equivalent flapping motion equation is determined to obtain the flapping velocity at the blade radius, including: According to the average rotor thrust, the rotor blade structure is equivalent to a Bernoulli-Euler beam, and the equivalent flapping motion equation is determined to obtain the blade flapping angular velocity; the flapping motion equation is: Where m represents the mass of the blade, represents the swing angular velocity; is the second-order derivative of the blade flapping displacement q with respect to time, E represents the blade elastic modulus, I represents the blade moment of inertia, q' represents the second-order derivative of the blade position x, q' represents the first-order derivative of the blade micro-segment x, Ω represents the rotor angular velocity, L represents the micro-end spacing, and f app (x,t) represents the force on the blade micro-segment x at time t; According to the blade flapping angular velocity and blade radius, use the formula Determine the flapping velocity at the blade radius; v H represents the flapping speed and r represents the blade radius.

5. The method for determining a computational fluid dynamics flow field according to claim 1, wherein: The updating of the normal velocity component in the second velocity by using the swinging velocity includes: The sum of the normal component of the second velocity and the swing velocity is determined as the updated normal component of the second velocity.

6. The method for determining a computational fluid dynamics flow field according to claim 1, wherein: The momentum source term affected by the flapping deformation motion is determined according to the following formula: Where dF represents the force on the blade mesh affected by the flapping deformation motion; dF J It indicates the force exerted on the air by the blades; represents the average flapping rotor pull, dF τH represents the average flapping rotor drag, dφ represents the circumferential spacing, Ω represents the rotor angular velocity, and dt represents the time step.

7. The method for determining a computational fluid dynamics flow field according to claim 1, wherein: Determining the fluid dynamics flow field according to the momentum source term affected by the flapping deformation motion and the fluid control equation includes: Substituting the momentum source term affected by the flapping deformation motion into the fluid control equation to determine the undetermined fluid dynamics flow field; Determine whether the undetermined fluid dynamics flow field converges and obtain a determination result; If the judgment result is yes, determining that the undetermined fluid dynamics flow field at the last iteration is a fluid dynamics flow field taking into account the flapping deformation motion; If the judgment result is no, return to step "determine the fluid control equation in the calculation domain according to the size of the calculation domain propeller disk grid, and obtain the speed of each blade at the blade radius in the calculation domain coordinate system as the first speed".

8. A computational fluid dynamics flow field determination system, characterized in that: include: A grid construction module is used to construct a computational domain disk grid and a momentum source domain disk grid based on computational fluid dynamics according to the parameters of the rotor blade structure, and to determine the mapping relationship between the computational domain disk grid and the momentum source domain disk grid; A blade grid determination module is used to determine the grid where the blade is located in the momentum source domain disk grid as the blade grid; a radius and azimuth determination module, for determining the blade radius and the azimuth of each blade according to the blade grid; A first speed determination module is used to determine the fluid control equation in the calculation domain according to the size of the disk grid in the calculation domain, and obtain the speed of each blade at the blade radius in the calculation domain coordinate system as the first speed; a second speed determining module, configured to determine, based on the mapping relationship and the azimuth angle of each blade and the first speed of each blade at the blade radius, the speed of each blade at the blade radius in the momentum source domain coordinate system as a second speed; an average rotor thrust determining module, configured to determine an average rotor thrust of the plurality of blades at a blade radius based on a second speed of the plurality of blades; A flapping speed determination module is used to equate the rotor blade structure to a Bernoulli-Euler beam based on the average rotor thrust, and to determine the equivalent flapping motion equation to obtain the flapping speed at the blade radius; a third velocity determination module, configured to update the normal velocity component of the second velocity using the flapping velocity, and obtain a velocity of the blade affected by the flapping deformation motion in a momentum source domain coordinate system as a third velocity; an average flapping rotor pull determining module, configured to determine, based on the mapping relationship and a third speed, an average rotor pull of a blade grid affected by flapping deformation motion at a blade radius as the average flapping rotor pull; an average flapping rotor drag determining module, configured to determine, based on the mapping relationship and a third speed, an average rotor drag of a blade grid affected by flapping deformation motion at a blade radius as the average flapping rotor drag; A force determination module is used to determine the force of the blade grid affected by the flapping deformation motion based on the average flapping rotor pull and the average flapping rotor drag; a momentum source term determination module, configured to determine a momentum source term affected by the flapping deformation motion according to the forces on the blade mesh affected by the flapping deformation motion and Newton's third law; The fluid dynamics flow field determination module is used to determine the fluid dynamics flow field according to the momentum source term affected by the flapping deformation motion and the fluid control equation.

9. An electronic device, characterized in that: The electronic device comprises a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to perform a computational fluid dynamics flow field determination method according to any one of claims 1 to 8.

10. The electronic device according to claim 9, characterized in that: The memory is a readable storage medium.

Images