Nacelle, aircraft, method for designing a nacelle

Abstract

The application discloses an aero-engine nacelle, an aircraft, and an aero-engine nacelle design method. The aero-engine nacelle design method comprises the following steps: S1, obtaining a first transition position distribution of an outer surface of an aero-engine nacelle; S2, arranging a plurality of grooves in front of the first transition position, analyzing the aero-engine nacelle with the plurality of grooves, and obtaining a second transition position distribution; S3, adjusting parameters of the grooves, repeating step S2, and obtaining transition position distributions under different groove parameters until an optimal aero-engine nacelle design scheme is obtained. By arranging grooves in front of the first transition position, laminar flow immersion area of the nacelle surface can be improved, thereby reducing frictional resistance of the nacelle surface, improving aerodynamic performance of the nacelle, and by continuously adjusting the parameters of the grooves, the transition position distribution is optimized, and it is ensured that the laminar flow area of the nacelle surface after the grooves are arranged can be increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of engine nacelles, in particular to an aero-engine nacelle, an aircraft, and a design method of an aero-engine nacelle. BACKGROUND

[0002] With the rapid development of high-bypass-ratio turbofan engine technology, the increase in its geometric size leads to a rapid increase in the proportion of engine nacelle drag in the total aircraft drag, and the skin friction drag of the nacelle is one of the main sources of nacelle drag. Therefore, it is necessary to reduce the frictional drag of the nacelle. SUMMARY

[0003] The present application aims to overcome the defect of large frictional drag of the nacelle in the prior art, and provides an aero-engine nacelle, an aircraft, and a design method of an aero-engine nacelle.

[0004] The present application solves the above technical problems by the following technical solutions:

[0005] A design method of an aero-engine nacelle, the design method of the aero-engine nacelle comprising the following steps:

[0006] S1, obtaining a first transition location distribution of an outer surface of an aero-engine nacelle;

[0007] S2, arranging a plurality of grooves in front of the first transition location, and analyzing the aero-engine nacelle with the plurality of grooves to obtain a second transition location distribution;

[0008] S3, adjusting the parameters of the grooves, repeating step S2, and obtaining the transition location distribution under different groove parameters until the optimal aero-engine nacelle design scheme is obtained.

[0009] In the present application, by arranging grooves in front of the first transition location, the second transition location distribution is more rearward relative to the first transition location distribution, which can increase the laminar flow immersion area of the nacelle surface, thereby reducing the frictional drag of the nacelle surface and improving the aerodynamic performance of the nacelle. By continuously adjusting the parameters of the grooves, the transition location distribution is optimized to ensure that the laminar flow area of the nacelle surface after arranging the grooves can be increased.

[0010] Preferably, the step S1 comprises:

[0011] S11, establishing a mathematical model of the aerodynamic shape of the aero-engine nacelle;

[0012] S12, performing numerical simulation analysis on the mathematical model of the aerodynamic shape of the aero-engine nacelle to obtain the transition location distribution of the surface of the aero-engine nacelle.

[0013] Preferably, after the step S12 and before the step S2, the nacelle design method comprises:

[0014] S13, processing the nacelle aerodynamic shape mathematical model into a scale test piece, carrying out a blowing test on the scale test piece, and obtaining a first transition position distribution on the surface of the scale test piece.

[0015] Preferably, the step S2 comprises:

[0016] S21, processing the nacelle aerodynamic shape mathematical model into a scale test piece;

[0017] S22, arranging a plurality of grooves on the scale test piece, carrying out a nacelle blowing test on the scale test piece with the plurality of grooves, and obtaining a second transition position distribution on the surface of the scale test piece.

[0018] Preferably, the extension direction of the grooves is parallel to the length direction of the nacelle.

[0019] Preferably, the length of the grooves is 5% to 30% of the length of the nacelle.

[0020] Preferably, the parameters of the grooves include groove width, groove depth, groove position and groove shape.

[0021] Preferably, the number of the grooves is not less than 3.

[0022] Preferably, the cross section of the grooves is any one or more of the following shapes: V-shaped, rectangular, triangular, trapezoidal.

[0023] A nacelle, which is designed by the nacelle design method as described above.

[0024] In this scheme, the nacelle designed by the nacelle design method as described above has a smaller surface friction resistance, so that the nacelle has better aerodynamic performance, which is conducive to improving the economy of the aircraft.

[0025] An aircraft, which comprises the nacelle as described above.

[0026] The positive progress effect of the present application is that the nacelle design method of the present application arranges grooves in front of the first transition position of the nacelle, so that the second transition position distribution is more rearward relative to the first transition position distribution, which can increase the laminar flow area on the surface of the nacelle, thereby reducing the friction resistance on the surface of the nacelle, improving the aerodynamic performance of the nacelle, and by continuously adjusting the parameters of the grooves, optimizing the transition position distribution, and ensuring that the laminar flow area on the surface of the nacelle after arranging the grooves can be increased. Attached Figure Description

[0027] Figure 1 This is a flowchart of an aircraft engine nacelle design method according to an embodiment of the present invention.

[0028] Figure 2 A schematic diagram of a mathematical model of an aircraft engine nacelle.

[0029] Figure 3 This is a diagram showing the distribution of the first transition position of an aircraft engine nacelle.

[0030] Figure 4 This is a partially enlarged schematic diagram of the surface of an aircraft engine nacelle according to an embodiment of the present invention.

[0031] Figure 5 This is a schematic diagram of the groove structure of an aircraft engine nacelle according to an embodiment of the present invention.

[0032] Figure 6 This is a diagram showing the distribution of the second transition position of an aircraft engine nacelle.

[0033] Explanation of reference numerals in the attached figures

[0034] Aircraft engine nacelle 1

[0035] Trench 2

[0036] First turning point 10

[0037] Second turning point 20 Detailed Implementation

[0038] The present invention will be further illustrated by way of embodiments below, but the present invention is not limited to the scope of the embodiments described herein.

[0039] This embodiment provides a method for designing an aircraft engine nacelle, such as... Figure 1 As shown, the design method for an aircraft engine nacelle includes the following steps:

[0040] S1, Obtain the first turning point 10 distribution on the outer surface of the aircraft engine nacelle;

[0041] S2. Arrange multiple grooves in front of the first transition position 10, and analyze the aircraft engine nacelle with the multiple grooves to obtain the distribution of the second transition position 20;

[0042] S3. Adjust the parameters of the groove, repeat step S2, and obtain the distribution of transition positions under different groove parameters until the optimal design scheme of the aircraft engine nacelle 1 is obtained.

[0043] The parameters of the groove 2 include groove width, groove depth, groove position and groove shape. After changing the parameters of the groove each time, the transition position distribution of the surface of the scale test piece is retested until the laminar flow distribution of the surface of the scale test piece reaches the maximum.

[0044] Preferably, the length of the groove is 5% to 30% of the length of the nacelle 1.

[0045] By arranging the groove in front of the first transition position 10, the second transition position 20 distribution is more backward relative to the first transition position distribution, which can increase the laminar flow area of the surface of the nacelle, thereby reducing the frictional resistance of the surface of the nacelle, improving the aerodynamic performance of the nacelle, and by continuously adjusting the parameters of the groove, optimizing the transition position distribution, and ensuring that the laminar flow area of the surface of the nacelle after arranging the groove can be increased.

[0046] Expanding the laminar flow area can have a beneficial effect on reducing frictional resistance. At the same Reynolds number, the turbulent boundary layer frictional resistance is about 10 times that of the laminar boundary layer. Therefore, it is an effective means of flow control and drag reduction to delay the occurrence of transition as much as possible, expand the laminar flow area on the surface of the model, and reduce the turbulent flow area, thereby reducing the turbulent frictional resistance.

[0047] Achieving a certain length of laminar flow on the outer surface of the nacelle is beneficial to reducing the surface friction of the aircraft and improving the economy of the aircraft. In addition, the nacelle does not pursue lift, moment and other aerodynamic performance, and has less constraints in aerodynamic design, and is not plagued by cross-flow instability and attachment line transition problems, so the nacelle laminar flow drag reduction is very practical.

[0048] In addition, in step S1, the transition position distribution can be obtained by numerical simulation, or the transition position distribution can be obtained by processing a scale test piece and using a blowing test.

[0049] Specifically, in the embodiment, the step S1 includes:

[0050] S11, establishing a mathematical model of the aerodynamic shape of the nacelle;

[0051] S12, performing numerical simulation analysis on the mathematical model of the aerodynamic shape of the nacelle to obtain the first transition position 10 distribution on the surface of the nacelle.

[0052] As a preferred embodiment, when the mathematical model is established, first, a four-order NURBS curve is used to generate a two-dimensional profile of the nacelle section, and the profile is determined by the following formula:

[0053]

[0054] In the above formula, w i is the weight factor of the NURBS curve; Pi is the control vertex of the NURBS curve; i is the number of the control vertex, weight factor, and spline basis function; n is the number of control vertices, weight factors, and spline basis functions; k is the order of the NURBS curve; u is the parameter of the NURBS curve, u i ≤u≤u i+1 basis function N i,k (u) is the k-th degree normalized B-spline basis function, usually derived from the "node vector" U = [u1, u2, ..., u n+k+1 (u0≤u1…≤u) n+k+1 The recursive definitions of de Boer and Cox are determined.

[0055] Secondly, third-order NURBS curves are used to generate the circumferential lines of the nacelle, forming the data framework for the nacelle's three-dimensional model. A schematic diagram of the nacelle's shape is shown below. Figure 2 As shown.

[0056] During simulation, A transition model coupled with a k-ωSST turbulence model was used for numerical simulation analysis of the nacelle model to obtain the distribution of transition locations on the nacelle surface, such as... Figure 3 As shown. Using a mathematical model, the distribution of the first transition position on the surface of the aero-engine nacelle 1 can be obtained through numerical simulation.

[0057] Preferably, after step S12 and before step S2, the nacelle design method includes:

[0058] S13. The aerodynamic shape mathematical model of the aero-engine nacelle is processed into a scaled-down test piece. A blowing test is carried out on the scaled-down test piece to obtain the distribution of transition positions on the surface of the scaled-down test piece, thereby verifying the first transition position distribution obtained in step S12.

[0059] Preferably, step S2 includes:

[0060] S21. The aerodynamic shape mathematical model of the aero-engine nacelle is processed into a scaled-down test piece;

[0061] S22. Multiple grooves are set on the scaled-down test piece. A nacelle blowing test is carried out on the scaled-down test piece with multiple grooves to obtain the distribution of the second transition position on the surface of the scaled-down test piece.

[0062] The distribution of the second transition points can be found in [reference needed]. Figure 6 As shown.

[0063] In other alternative implementations, step S13 may be set after step S21.

[0064] In a preferred embodiment, the groove extends along the length of the aircraft engine nacelle 1, or along the direction of airflow, i.e., substantially parallel to the direction of airflow.Figure 2 the extension direction of the X axis in the figure.

[0065] Referring to Figure 3 As shown in the figure, the grooves are provided in plurality, preferably, referring to Figure 4 As shown in the figure, the grooves are provided in parallel with each other. The number of the grooves is not less than 3. As a preferred embodiment, the depth and width of the grooves are both in the range of 10 microns to 1 millimeter.

[0066] Referring to Figure 5 As shown in the figure, the cross section of the groove 2 is preferably V-shaped, and the groove 2 can also be in any one or more of the following shapes: rectangular, triangular, trapezoidal. Preferably, the bottom of the groove 2 can be rounded to reduce stress concentration.

[0067] The embodiment also provides an aircraft engine nacelle 1, which is designed by the aircraft engine nacelle design method as described above.

[0068] The aircraft engine nacelle designed by the aircraft engine nacelle design method as described above has smaller surface friction resistance, so that the aerodynamic performance of the aircraft engine nacelle is better, which is conducive to improving the economy of the aircraft.

[0069] The short nacelle scheme obtained by the aircraft engine nacelle design method of the embodiment can improve the laminar flow wetting area ratio by more than 3%, which can effectively reduce the friction resistance of the surface of the short nacelle.

[0070] The embodiment also provides an aircraft, which comprises the aircraft engine nacelle as described above.

[0071] Although the specific embodiments of the present application are described above, those skilled in the art should understand that this is only an example, the protection scope of the present application is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present application, and these changes and modifications all fall within the protection scope of the present application.

Claims

1. A method for designing an aircraft engine nacelle, characterized in that, The aircraft engine nacelle design method includes the following steps: S1. Obtain the first transition position distribution on the outer surface of the aircraft engine nacelle; S2. Arrange multiple grooves in front of the first transition position, and analyze the aircraft engine nacelle with the multiple grooves to obtain the distribution of the second transition position; S3. Adjust the parameters of the groove, repeat step S2, and obtain the distribution of transition positions under different groove parameters until the design scheme of the aero-engine nacelle with the largest surface laminar flow area is obtained.

2. The aircraft engine nacelle design method as described in claim 1, characterized in that, Step S1 includes: S11. Establish a mathematical model of the aerodynamic shape of the aircraft engine nacelle; S12. Numerical simulation analysis is performed on the mathematical model of the aerodynamic shape of the aero-engine nacelle to obtain the distribution of the first transition position on the surface of the aero-engine nacelle.

3. The aircraft engine nacelle design method as described in claim 2, characterized in that, After step S12 and before step S2, the nacelle design method includes: S13. The aerodynamic shape mathematical model of the aero-engine nacelle is processed into a scaled-down test piece, and a wind test is carried out on the scaled-down test piece to obtain the distribution of transition positions on the surface of the scaled-down test piece.

4. The aircraft engine nacelle design method as described in claim 1, characterized in that, Step S2 includes: S21. The aerodynamic shape mathematical model of the aero-engine nacelle is processed into a scaled-down test piece; S22. Multiple grooves are set on the scaled-down test piece. A nacelle blowing test is carried out on the scaled-down test piece with multiple grooves to obtain the distribution of the second transition position on the surface of the scaled-down test piece.

5. The aircraft engine nacelle design method as described in claim 1, characterized in that, The groove extends along the length of the aircraft engine nacelle.

6. The aircraft engine nacelle design method as described in claim 5, characterized in that, The length of the groove is 5% to 30% of the length of the aircraft engine nacelle.

7. The aircraft engine nacelle design method as described in claim 1, characterized in that, The parameters of the trench include trench width, trench depth, trench location, and trench shape.

8. The aircraft engine nacelle design method as described in claim 1, characterized in that, The number of grooves shall not be less than 3.

9. The aircraft engine nacelle design method as described in claim 1, characterized in that, The cross-section of the groove is any one or more of the following shapes: V-shaped, rectangular, triangular, trapezoidal.

10. An aircraft engine nacelle, characterized in that, The aircraft engine nacelle is designed using the aircraft engine nacelle design method as described in any one of claims 1-9.

11. An aircraft, characterized in that, The aircraft includes an aircraft engine nacelle as described in claim 10.

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