A method for calculating the aerodynamic performance of an aircraft propeller under a wing and nacelle configuration

Abstract

The present invention discloses a method for calculating the aerodynamic performance of an aircraft propeller in a wing and nacelle configuration, belonging to the field of propeller aerodynamic performance calculation. First, a mathematical model for calculating the aerodynamic performance of the propeller in the wing and nacelle configuration is established; the flow at the propeller tip and root of the established mathematical model is corrected, and the interference effect of the wing and nacelle on the aerodynamic performance of the propeller is considered, and the angle of attack of the blade element is corrected. According to the corrected mathematical model, program development is carried out using Matlab software. This program can quickly and accurately predict the aerodynamic performance of the propeller under the aerodynamic interference of the wing and nacelle, and can provide certain guiding functions for evaluating the structural strength, overall design and performance optimization of the propeller aircraft. The present invention improves the calculation efficiency, saves the calculation cost, and increases the convenience of calculating the aerodynamic performance of the propeller in the installed state.

Description

Technical Field

[0001] The present invention belongs to the field of calculating the aerodynamic performance of propellers, and specifically relates to a method for calculating the aerodynamic performance of an aircraft propeller under the configuration of a wing and a nacelle. Background Art

[0002] Propeller aircraft still occupy a significant position in the current air transportation field due to their excellent economy. Especially in the context of the proposed and rapidly developing concept of "low-altitude economy", aircraft powered by propellers or ducted fans have attracted more attention and emphasis. However, the aerodynamic interference between the propeller and the wing and nacelle leads to a series of complex problems, and the wing and nacelle structures have a significant impact on the propeller performance. Therefore, in order to obtain the aerodynamic performance of propeller aircraft under complex configurations and improve the reliability of the aircraft, it is particularly important to quickly and reliably predict the aerodynamic performance of the propeller under the interference of the wing and nacelle. Summary of the Invention

[0003] To solve the problems in the prior art, the present invention proposes a method for calculating the aerodynamic performance of an aircraft propeller under the configuration of a wing and a nacelle, which improves the calculation efficiency, saves the calculation cost, and increases the convenience of calculating the aerodynamic performance of the propeller in the installed state. The present invention first establishes a mathematical model, corrects the lift coefficient at the tip and root positions of the propeller, and considers the interference effect of the wing and nacelle on the aerodynamic performance of the propeller, corrects the angle of attack of the blade element, and develops a program using Matlab software based on the corrected mathematical model. This program can quickly and accurately predict the aerodynamic performance of the propeller under the aerodynamic interference of the wing and nacelle, and can provide certain guidance for evaluating the structural strength, overall design, and performance optimization of propeller aircraft.

[0004] Technical Solution: A method for calculating the aerodynamic performance of a propeller considering the configuration of a wing and a nacelle includes the following steps:

[0005] Step 1. Establish a mathematical model for calculating the aerodynamic performance of the propeller under the configuration of the wing and the nacelle;

[0006] Step 2. Correct the flow at the tip and root of the established mathematical model;

[0007] Step 3. Based on the corrected mathematical model, use Matlab software to establish a program for calculating the aerodynamic performance of the propeller under the configuration of the wing and the nacelle.

[0008] Further, the specific steps of Step 1 are as follows:

[0009] Step 1.1. Establish the calculation formulas for the propeller thrust and torque, and the formulas are as follows;

[0010]

[0011] Where N is the number of propeller blades, ρ is the air density, c is the blade chord length, r is the radius at any position of the blade, V R is the composite velocity of airflow relative to blade element, C l is the lift coefficient, C d is the drag coefficient, φ is the resultant inflow angle, ψ represents the phase angle; dT represents the pull, and dQ represents the torque.

[0012] Step 1.2: According to the momentum theorem, the calculation formula of propeller thrust and torque is obtained;

[0013]

[0014]

[0015] Among them, V ia represents the blade axial induced distributed velocity, V disc represents the resultant flow velocity through the propeller, V yz⊥ represents the component velocity perpendicular to the leading edge of the blade; ω represents the propeller angular velocity.

[0016] Step 1.3: Combine the calculation formulas of the thrust and torque obtained in step 1.1 and step 1.2, perform iterative calculations, and obtain the thrust T and torque Q of the isolated propeller in the case of an incoming flow angle.

[0017] Step 1.4, calculate the bending moment B and tangential force F generated by the propeller according to the tension and torque obtained in step 1.3;

[0018]

[0019] Furthermore, the specific steps of step 2 are as follows:

[0020] Step 2.1, establish the blade tip correction coefficient, the formula is as follows:

[0021]

[0022] Among them, F Prandtl represents the tip correction coefficient, R represents the propeller radius, e is a constant, r is the radius of the blade at any position, φ is the resultant inflow angle, and B is the bending moment generated by the propeller.

[0023] Step 2.2, establish the propeller root flow correction coefficient, the formula is as follows:

[0024] F cl =1-12×e (-35×r)

[0025] Among them, F clrepresents the blade root flow correction coefficient, e is a constant, and r is the radius at any position of the blade.

[0026] Step 2.3: Multiply the correction coefficients obtained in Step 2.1 and Step 2.2 by the corresponding airfoil lift coefficients to obtain the corrected lift coefficient, and use the corrected lift coefficient for subsequent calculations; the calculation formula is as follows:

[0027] C l correct =C l ×F Prandtl ×F cl

[0028] where, C lcorrect is the corrected lift coefficient;

[0029] Step 2.4: Further correct the airfoil angle of attack under the wing and nacelle configurations. The calculation formula for the correction coefficient is as follows:

[0030]

[0031] where, f is the ratio of the hub diameter to the length, i is the ratio of the wing chord length to the thickness, and j is the ratio of the propeller diameter to the distance from the wing; F p-t. represents the angle of attack correction function at the peak and trough positions, F tra. represents the angle of attack correction function in the transition section, e is a constant, and ψ represents the phase angle; A1, A2, B1, B2, C1, C2 are related to the angle of incidence. Specifically:

[0032] A1 = 685×θ 2 +2.4×θ + 7.5, A2 = -2280×θ 2 +43×θ - 10

[0033] B1 = -0.02×θ 2 +0.003×θ - 0.0003, B2 = -0.01×θ 2 +0.002×θ - 0.0002

[0034] C1 = 38.5×θ 2 -2.9×θ + 0.2, C2 = -54.7×θ 2 +6.4×θ - 0.36

[0035] where, θ is the angle between the oncoming flow direction and the rotation axis of the propeller (in radians, i.e., the angle of incidence)

[0036] The corrected element angle of attack, the calculation formula is as follows:

[0037] α Correct =β - φ + F p-t +Ftra.

[0038] Among them, a Correct represents the corrected blade element angle of attack, φ is the resultant inflow angle, and β represents the blade angle.

[0039] Furthermore, the program calculation process in step three is as follows:

[0040] Step 3.1: Specify the propeller geometric parameters and calculation conditions.

[0041] The propeller geometric parameters include the number of propeller blades, propeller radius, hub radius, and pitch angle; the calculation conditions include the oncoming flow velocity, oncoming flow angle, and propeller rotational speed.

[0042] Step 3.2: Import the airfoil lift and drag database generated by Xfoil into the Matlab program, and obtain parameters such as the chord length and blade angle at any radius of the propeller blade through interpolation.

[0043] The chord length at any radius r is determined by linear interpolation during the aerodynamic design process. The blade angle β is also determined by linear interpolation during the aerodynamic design process.

[0044] Step 3.3: Solve the induced distribution velocity V on the propeller disk surface according to the inflow model established by Prter & Pitt ia .

[0045]

[0046] Among them, V ia，0 is the induced velocity at the center of the propeller disk, χ represents the wake deflection angle at the center of the propeller disk, r is the radius at any position of the propeller blade, ψ represents the phase angle, and R represents the propeller radius;

[0047] Step 3.4: Calculate the resultant inflow angle φ and the angle of attack correction functions F p-t. , F tra. , and obtain the corrected blade angle of attack a Correct according to the calculated parameters;

[0048] Calculate steps F according to the formula in step 2.4 p-t. , F tra. and a Correct .

[0049] Step 3.5: Call the lift and drag coefficients in the airfoil lift and drag database, and interpolate to solve the lift coefficient and drag coefficient corresponding to the corrected blade angle of attack;

[0050] The lift coefficient and drag coefficient are determined by linear interpolation using the data in the database.

[0051] Specifically, the Prandtl wingtip correction model is adopted to correct the lift coefficient at the wingtips of the propeller. Since there is separated flow at the propeller root, the lift coefficient is also corrected accordingly at the propeller root to obtain the corrected lift coefficient. The propeller wingtip correction coefficient F Prandtl and the propeller root flow correction coefficient F cl are the formulas in Step 2.1, and the corrected lift coefficient is calculated according to the formula in Step 2.3.

[0052] Step 3.6: Using the drag coefficient and the corrected lift coefficient, iterative solutions are carried out to obtain the aerodynamic performance parameters of the propeller blades affected by the wing and nacelle, such as thrust, torque, bending moment, and tangential force.

[0053] The calculation formulas for the thrust, torque, bending moment, and tangential force are calculated by the formulas in Steps 1.1 - 1.4.

[0054] Beneficial effects:

[0055] 1) The model established in the present invention has high calculation accuracy. The average error between the calculation results of the propeller aerodynamic performance parameters under the wing / nacelle configuration obtained based on the mathematical model in the present invention and the CFD simulation results is less than 11%. Moreover, within one rotation period, the aerodynamic performance of a single propeller blade shows serrated fluctuations; the aerodynamic performance of the entire propeller shows periodic changes, with three pairs of peaks and valleys appearing within one rotation period, which is the same as the number of propeller blades.

[0056] 2) The mathematical model established in the present invention is applicable to the study of the calculation of propeller aerodynamic performance in the installed state. For the propeller in the installed state, due to the interference of the wing and nacelle, the flow field around the propeller becomes more complex, which brings certain difficulties to accurately predicting the propeller aerodynamic performance. By adopting the wingtip, root, and blade element angle of attack correction methods, a new mathematical model is established. This improved model provides certain assistance for the aerodynamic design and performance prediction of the propeller and the aircraft. Description of the drawings

[0057] Figure 1 is the force diagram of the blade element;

[0058] Figure 2 is the schematic diagram of the geometric model of the propeller aircraft under the wing and nacelle configuration;

[0059] Figure 3 is the program flow chart for calculating the aerodynamic performance of the propeller under the wing and nacelle configuration;

[0060] Figure 4 is the schematic diagram of the phase angle (ψ) and the oncoming flow situation when the propeller under the wing and nacelle configuration rotates clockwise one week around the Z axis in the CFD simulation calculation.

[0061] Figure 5 When the angle of attack of the oncoming flow is 6 degrees, it shows the variation of the aerodynamic performance parameters of the propeller blade 1 under the wing and nacelle configurations. Among them, (a) shows the variation of the thrust coefficient and power coefficient of the propeller blade 1 with the phase angle, and (b) shows the variation of the bending moment coefficient and tangential force coefficient of the propeller blade 1 with the phase angle.

[0062] Figure 6 When the angle of attack of the oncoming flow is 6 degrees, it shows the variation of the aerodynamic performance parameters of the entire propeller under the wing and nacelle configurations. Among them, (a) shows the variation of the thrust coefficient and power coefficient of the entire propeller with the phase angle, and (b) shows the variation of the bending moment coefficient and tangential force coefficient of the entire propeller with the phase angle. Detailed implementation manners

[0063] The technical solution of the present invention will be described in detail below through embodiments, but the protection scope of the present invention is not limited to the described embodiments.

[0064] According to the flow characteristics of the propeller, the present invention corrects the flow at the blade tip and root, and also adopts corresponding correction methods for the blade element angle of attack, establishes a mathematical model of the aerodynamic performance of the propeller under the wing and nacelle configurations, develops a calculation program for the aerodynamic performance of the propeller in the installed state using Matlab software, calculates the aerodynamic performance of the propeller using the developed calculation program, and analyzes the calculation results to obtain the interference effect of the wing and nacelle on the aerodynamic performance of the propeller. Specifically, the present invention discloses a method for calculating the aerodynamic performance of an aircraft propeller under the wing and nacelle configurations, including the following steps:

[0065] Step 1: Based on the flow characteristics of the propeller, establish a mathematical model for calculating the aerodynamic performance of the propeller under the wing and nacelle configurations.

[0066] Figure 1 As shown in the blade element force diagram, by iteratively solving the calculation formulas for thrust and torque, the aerodynamic performance parameters of the propeller can be obtained.

[0067] The specific steps of Step 1 are as follows:

[0068] Step 1.1: Use the blade element theory to obtain the expressions for thrust and torque as:

[0069]

[0070] Step 1.2: Use the momentum theory to obtain the thrust and torque:

[0071]

[0072] Step 1.3: Integrate dT and dQ at each span position to obtain the propeller blade thrust T and torque Q.

[0073] Step 1.4. Through the tensile force and torque, the expressions for the propeller bending moment B and the tangential force F can be obtained as follows:

[0074] B = T × r (5)

[0075]

[0076] In the formula, N represents the number of propeller blades, ρ represents the air density, c represents the chord length of the blade, V R represents the resultant velocity of the air flow relative to the blade element, C l is the lift coefficient, C d is the drag coefficient, φ represents the resultant inflow angle, V ia represents the induced velocity, V disc represents the velocity of the air flow passing through the propeller disc, V yz⊥ represents the component velocity perpendicular to the blade, ω represents the angular velocity of the propeller, and r represents the radius at any position of the propeller blade.

[0077] Step Two. Modify the established mathematical model.

[0078] The specific steps of Step Two are as follows:

[0079] Step 2.1. Adopt the Prandtl tip correction method to establish a function of the correction coefficient F prandtl distributed in the spanwise position of the propeller blade, and the formula is as shown in (7).

[0080]

[0081] Step 2.2. Use the root flow correction method to establish a function of the correction coefficient F cl at different blade positions, and the formula is as shown in (8).

[0082] F cl = 1 - 12 × e (-35×r) (8)

[0083] Step 2.3. Multiply the correction coefficients obtained in Step 2.1 and Step 2.2 by the corresponding airfoil lift coefficient to obtain the corrected lift coefficient, and use the corrected lift coefficient for subsequent calculations; the calculation formula is as follows:

[0084]

[0085] Step 2.4. Establish the correction coefficients F p-t. and F tra. to correct the angle of attack of the blade element;

[0086] As Figure 2As shown in the figure, the propeller geometric model under the wing and nacelle configuration. After the propeller is installed on the wing, the wing will have a significant and complex impact on the propeller's flow field, changing the flow field environment where the propeller blades are located. Therefore, the forces and torques acting on the propeller blades will exhibit complex unsteady changes. The presence of the wing will cause a certain upwash phenomenon in the propeller's inflow. When the propeller blades rotate above the wing, the influence of the wing will cause the inflow direction of the propeller to deflect, resulting in a change in the inflow angle. The change in the inflow angle will directly affect the angle between the propeller blades and the oncoming flow, that is, the angle of attack. It directly determines the aerodynamic force and torque on the blades. Therefore, it is necessary to consider the influence of the change in the angle of attack on the aerodynamic performance of the propeller under the wing and nacelle configuration. The relative position of the propeller and the wing, as well as the shape and size of the wing and nacelle, will directly or indirectly affect the propeller's inflow angle, and thus cause a change in the angle of attack. When the relative position of the propeller and the wing is far away, the influence of the upwash airflow on the propeller's inflow angle will weaken. On the contrary, the influence of the upwash airflow will be more significant. The ratio of the chord length to the thickness of the wing, that is, the relative thickness of the airfoil, will also affect the intensity of the upwash airflow. The shape and size of the nacelle will directly affect the inflow conditions of the propeller, thereby affecting the angle of attack of the propeller.

[0087] Based on the above analysis, two correction functions F p-t. and F tra. affecting the blade element angle of attack of the propeller are established. p-t. Among them, F tra. is the angle of attack correction function at the peak and trough positions, and F Correct is the angle of attack correction function in the transition section. α

[0088]

[0089] is the corrected blade element angle of attack (also known as the corrected blade element angle of attack). Correct Step 2.5: Calculate the corrected blade element angle of attack α

[0090] α Correct = β - φ + F p-t. + F tra. (12)

[0091] Step 3: According to the corrected mathematical model, use Matlab software to establish a propeller aerodynamic performance calculation program under the wing / nacelle configuration. The program calculation process is as Figure 3 shown. The specific steps of Step 3 are as follows:

[0092] Step 3.1: Given that the number of propeller blades is 3, the propeller radius is 0.525 m, the hub radius is 0.0606 m, and the pitch angle at 70% is 56 degrees. Under the given calculation conditions, the oncoming flow velocity is 82 m / s, and the propeller rotational speed is 1396.9 min －1 , the oncoming flow angle, etc.

[0093] Step 3.2: Import the airfoil lift and drag database generated by Xfoil into the Matlab program, and obtain parameters such as the chord length r and blade angle at any radius of the propeller blade by interpolation.

[0094] Step 3.3: Solve the induced distribution velocity V on the propeller disk surface according to the inflow model established by Prter & Pitt ia .

[0095] Step 3.4: Calculate the synthetic inflow angle φ and the angle of attack correction angle F p-t. , F tra. , and obtain the corrected blade angle of attack α according to the calculated parameters Correct .

[0096] Calculation formula for the synthetic inflow angle φ:

[0097]

[0098] where V x is the axial component velocity of the oncoming flow;

[0099] According to formulas (10) and (11), the angle of attack correction function F p-t. , F tra .

[0100] Calculate the blade angle of attack α according to formula (12) Correct .

[0101] Step 3.5: Call the lift and drag coefficients in the database and interpolate to solve the lift and drag coefficients corresponding to the corrected angle of attack.

[0102] Adopt the Prandtl wing tip correction model to correct the lift coefficient at the propeller wing tip. Since there is separated flow at the propeller root, the lift coefficient is also corrected accordingly at the propeller root to obtain the corrected lift coefficient. Calculate according to steps 2.1 - 2.3.

[0103] Step 3.6: Use the drag coefficient and the corrected lift coefficient to perform iterative solution to obtain the aerodynamic parameters of the propeller blade affected by the wing and nacelle, such as thrust, torque, bending moment, and tangential force, etc.

[0104] The thrust, torque, bending moment, and tangential force are calculated according to formulas (1) - (6).

[0105] Figure 4 In the CFX calculation, it is a schematic diagram of the oncoming flow direction and rotation direction of the propeller.

[0106] By calculating the aerodynamic performance of the propeller with oncoming flow angles of 0°, 3°, 6°, and 9°, the average error between the program and the CFD calculation value is within 11%. Taking the example with an oncoming flow angle of 6° as an illustration, the results are as Figure 5 and Figure 6 shown.

[0107] Figure 5 It is the variation of the aerodynamic performance parameters of the propeller blade1 under the configuration of the wing and nacelle when the oncoming flow angle is 6°; among them, (a) is the variation of the thrust coefficient and power coefficient of the propeller blade1 with the phase angle, and (b) is the variation of the bending moment coefficient and tangential force coefficient of the propeller blade1 with the phase angle. Under the interference of the wing and nacelle, the aerodynamic parameters of the propeller show a zigzag fluctuation with the phase angle. Under the interference of the wing and nacelle, when the blade descends and is approximately in front of the wing, that is, at about the 80° phase angle position, the aerodynamic performance received by the propeller reaches the maximum value. On the contrary, when the blade ascends and is approximately in front of the wing, that is, at about the 290° phase angle position, the aerodynamic performance received by the blade reaches the minimum value. The program prediction value is close to the CFD calculation value. Within one rotation of the blade, the average deviation of C T is 0.22%, the average deviation of C P is -1.72%, the average deviation of C F is -3.14%, and the average deviation of C B is 1.27%.

[0108] C T C P C F C B respectively represent the thrust coefficient, power coefficient, tangential force coefficient, and bending moment coefficient.

[0109] Figure 6 It is the variation of the aerodynamic performance parameters of the entire propeller under the configuration of the wing / nacelle when the oncoming flow angle is 6°; among them, (a) is the variation of the thrust coefficient and power coefficient of the entire propeller with the phase angle, and (b) is the variation of the bending moment coefficient and tangential force coefficient of the entire propeller with the phase angle. Within a complete rotation cycle, the aerodynamic characteristic parameters of the entire propeller show periodic fluctuations. Since this propeller has three blades, there are three pairs of peaks and valleys in the aerodynamic characteristic parameters within one cycle, and the three peak values and valley values basically remain unchanged.

[0110] The present invention establishes a mathematical model for the aerodynamic performance of a propeller in the installed state, corrects the blade element angle of attack, constructs a calculation program for the aerodynamic performance of the propeller, calculates the aerodynamic performance of the propeller under different working conditions, and obtains the following conclusions:

[0111] (1) The aerodynamic performance parameters of a single blade under the wing and nacelle configurations show periodic sawtooth fluctuations with the azimuth angle within one rotation period. When the propeller blade descends and is roughly in front of the wing, the aerodynamic performance received by the blade is the largest; when the blade ascends and is roughly in front of the wing, the aerodynamic performance received by the blade is the smallest. And as the oblique incoming flow angle increases, the peak value increases and the trough value decreases.

[0112] (2) The overall propeller aerodynamic parameters show periodic fluctuations within the rotation period, and the number of fluctuations is the same as the number of propeller blades. And as the incidence angle increases, the fluctuation amplitude increases, the peak value increases, and the trough value also increases, but the increase amplitude of the trough value is relatively small.

[0113] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as a limitation of the present invention itself. Various changes in form and detail can be made without departing from the spirit and scope of the present invention.

Claims

1. A method for calculating the aerodynamic performance of an aviation propeller under a wing and nacelle configuration, characterized in that: The steps include: Step 1: Establish a mathematical model for calculating propeller aerodynamic performance under wing and nacelle configuration; Step 2: Modify the established mathematical model for the flow at the blade tip and blade root; Step 3: Based on the revised mathematical model, use Matlab software to establish a propeller aerodynamic performance calculation program under the wing and nacelle configuration; The specific steps of step 2 are as follows: Step 2.1, establish the blade tip correction coefficient, the formula is as follows: Among them, F Prandtl represents the tip correction factor, R represents the propeller radius, e is a constant, r is the radius of the blade at any position, φ is the resultant inflow angle, and B is the bending moment generated by the propeller; Step 2.2: Establish the propeller root flow correction coefficient. The formula is as follows: F cl =1-12×e (-35×r) Among them, F cl represents the blade root flow correction coefficient, e is a constant, and r is the radius of the blade at any position; Step 2.3: Multiply the correction coefficients obtained in step 2.1 and step 2.2 by the corresponding airfoil lift coefficient to obtain the corrected lift coefficient. The corrected lift coefficient is used for subsequent calculations. The calculation formula is as follows: C l correct =C l ×F Prandtl ×F cl Among them, C l correct is the corrected lift coefficient; Step 2.4: Correct the airfoil angle of attack under the wing and nacelle configuration. The correction coefficient calculation formula is as follows: Where f is the ratio of hub diameter to length, i is the ratio of wing chord to thickness, and j is the ratio of propeller diameter to distance from the wing; F p-t. The attack angle correction function representing the peak and trough position, F tra. represents the attack angle correction function of the transition section, ψ represents the phase angle; A1, A2, B1, B2, C1, C2 are related to the angle of incidence, specifically: A1 = 685 × θ 2 +2.4×θ+7.5, <h2 style=";text-align:left;direction:ltr">A2 = 2280×θ<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +43×θ-10,B1=-0.02×θ<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +0.003×θ-0.0003, <h2 style=";text-align:left;direction:ltr">B2 = -0.01×θ<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +0.002×θ-0.0002,C1=38.5×θ<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> -2.9×θ+0.2, C2=-54.7×θ 2 +6.4×θ-0.36, where θ is the angle between the incoming flow direction and the rotation axis, i.e. the incident angle; The corrected blade element angle of attack is calculated as follows: a Correct =β-φ+F p-t. +F tra. Among them, a Correct represents the corrected blade element angle of attack, φ is the resultant inflow angle, and β represents the blade angle.

2. The calculation method according to claim 1, characterized in that: The specific steps of step one are as follows: Step 1.1, establish the propeller thrust and torque calculation formula, the formula is as follows; Where N is the number of propeller blades, ρ is the air density, c is the blade chord length, r is the radius at any position of the blade, V R is the composite velocity of airflow relative to blade element, C l is the lift coefficient, C d is the drag coefficient, φ is the resultant inflow angle, ψ represents the phase angle; dT represents the pulling force, and dQ represents the torque; Step 1.2: According to the momentum theorem, the calculation formula of propeller thrust and torque is obtained; Among them, V ia represents the blade axial induced velocity, V disc represents the resultant flow velocity through the propeller, V yz⊥ represents the component velocity perpendicular to the leading edge of the blade; ω represents the propeller angular velocity; Step 1.3, combining the calculation formulas of the thrust and torque obtained in step 1.1 and step 1.2, and performing iterative calculation to obtain the thrust T and torque Q of the isolated propeller under the condition of an incoming flow angle; Step 1.4, calculate the bending moment B and tangential force F generated by the propeller according to the tension and torque obtained in step 1.3; B=T×r 3. The calculation method according to claim 1, characterized in that: The specific steps of step three are as follows: Step 3.1, given propeller geometric parameters and calculation conditions; The propeller geometric parameters include the number of propeller blades, propeller radius, hub radius and pitch angle; the calculation conditions include the incoming flow velocity, the incoming flow angle and the propeller speed; Step 3.2, import the airfoil lift and drag database generated by Xfoil into the Matlab program, and obtain the chord length and blade angle parameters of the propeller blade at any radius through interpolation; Step 3.3: Based on the inflow model established by Prter & Pitt, solve the induced distributed velocity V of the propeller disk ia ; Step 3.4: Calculate the synthetic inflow angle φ and the angle of attack correction function F p-t. 、F tra. , the corrected blade attack angle a is obtained based on the calculated parameters Correct ; Step 3.5, call the lift and drag coefficients in the airfoil lift and drag database, and interpolate to solve the corresponding lift coefficient and drag coefficient under the modified blade attack angle; Step 3.6: Use the drag coefficient and the corrected lift coefficient to iteratively solve the aerodynamic performance parameters of the propeller blades affected by the wing and nacelle, including thrust, torque, bending moment and tangential force.

Images