An air inlet channel turning section optimization design method and air inlet channel

Abstract

The application provides an air inlet channel turning section optimization design method and an air inlet channel, and the method comprises the following steps: establishing an internal flow channel turning section profile solving coordinate system XOY; constructing a sine function to solve an internal flow channel turning section first profile characteristic curve A0A n ; optimizing the internal flow channel turning section first profile characteristic curve A0A n ; discretizing the internal flow channel turning section first profile characteristic curve A0A n to solve an internal flow channel turning section second profile characteristic curve B0B n ; optimizing the internal flow channel turning section second profile characteristic curve B0B n ; performing coordinate conversion on the internal flow channel turning section first profile characteristic curve A0A n and the internal flow channel turning section second profile characteristic curve B0B n located in the coordinate system XOY to obtain the internal flow channel turning section first profile characteristic curve A0A n and the internal flow channel turning section second profile characteristic curve B0B n located in the air inlet channel global coordinate system X1O1Y1. The technical scheme of the application can alleviate the problems of large internal resistance, high outlet flow field distortion index and turning section airflow separation of the air inlet channel in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intake duct optimization design, in particular to an intake duct turning section optimization design method and an intake duct. BACKGROUND

[0002] As an important part of air-breathing power device, the function of supersonic / hypersonic intake duct is to use the velocity of the oncoming high-speed airflow to effectively convert its kinetic energy into potential energy, increase the pressure of the airflow, and provide the ramjet engine with the required uniform air flow as much as possible. In order to make the performance of the intake duct optimal, the compression surface optimization design, throat design and airflow flow passage design are needed, among which the turning section optimization design in the airflow flow passage design mainly involves the problems of internal flow passage resistance reduction, airflow separation and flow field distortion. How to realize the reduction of internal resistance, the improvement of airflow separation characteristics and the reduction of the flow field distortion index at the outlet of the intake duct through the optimization design of the turning section of the internal flow passage is the key and difficulty of the optimization design of the internal flow passage of the intake duct.

[0003] In the design of the turning section of the internal flow passage of the intake duct, the existing design method mainly uses two smooth transition arcs connected as the reference characteristic curve, and designs the turning section according to the variable pipe flow principle of aerodynamics. This design method focuses on the control of the equivalent expansion angle of the profile and the control of the airflow separation (the purpose is to reduce the flow field distortion index at the outlet of the intake duct), and generally does not take into account the influence of the internal flow passage resistance reduction and the structure load on the overall performance. The variable pipe flow differential formula in aerodynamics qualitatively gives the influence law of the airflow flow area variation on the airflow flow parameters, but in the precise design of the turning section of the internal flow passage of the intake duct, if the design parameters of the turning section are not properly selected, the following two serious consequences may occur: first, if the flow passage area discrete control method is improper, the internal flow passage after the throat may appear the form of expansion-constriction-expansion, which may produce a secondary throat after the throat of the intake duct, so that the mixed pressure intake duct does not start at the working Mach number, increases the aerodynamic external resistance of the aircraft, and greatly changes the flight moment, resulting in the failure of the flight task; second, the improper selection of the design parameters of the profile characteristic curve may increase the internal resistance of the intake duct, or cause airflow separation or secondary centrifugal flow in the turning section, which may cause the airflow flow quality of the intake duct to deteriorate sharply, increase the flow field distortion index at the outlet of the intake duct, and reduce the overall performance of the intake duct. SUMMARY

[0004] The present application provides an intake duct turning section optimization design method and an intake duct to solve the problems of large internal resistance of the turning section of the intake duct, high flow field distortion index at the outlet of the intake duct and airflow separation in the turning section in the prior art.

[0005] According to one aspect of the present invention, a method for optimizing the design of an air intake turn section is provided. The method comprises: establishing a coordinate system XOY for solving the profile of the inner flow channel turn section, wherein the coordinate origin O of the coordinate system XOY for solving the profile of the inner flow channel turn section is located at the first profile characteristic curve A0A of the inner flow channel turn section. n The OX axis is parallel to the O1X1 axis of the inlet duct global coordinate system X1O1Y1, and the OY axis is perpendicular to the OX axis. Among them, O1 is located at the vertex of the compression surface of the leading edge of the inlet duct, the O1X1 axis is in the same direction as the far front flow direction of zero attack angle, and the O1Y1 axis is perpendicular to the O1X1 axis. In the XOY coordinate system for solving the surface of the inner flow channel turning section, a sine function is constructed to solve the first surface characteristic curve A0A of the inner flow channel turning section. n Optimize the first profile characteristic curve A0A of the inner flow channel turning section with the goal of reducing inner flow channel drag (or preventing airflow separation) n ; The first profile characteristic curve A0A of the inner flow channel turning section n Discretize to solve the second profile characteristic curve B0B of the inner flow channel turning section n ; To prevent airflow separation (or reduce drag in the inner flow channel) as the goal, optimize the second profile characteristic curve B0B of the inner flow channel turning section n ; Solve the first profile characteristic curve A0A of the inner runner turning section under the coordinate system XOY for the profile of the inner runner turning section n And the second profile characteristic curve B0B of the inner channel turning section n Perform coordinate transformation to obtain the first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the inlet duct n And the second profile characteristic curve B0B of the inner channel turning section n According to the first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the inlet duct n And the second profile characteristic curve B0B of the inner channel turning section n The optimized design of the inlet turning section is achieved through the optimized design of the inlet turning section.

[0006] Furthermore, the first profile characteristic curve A0A of the inner flow channel turning section n Discretize to solve the second profile characteristic curve B0B of the inner flow channel turning section n Specifically including: the first profile characteristic curve A0A of the inner flow channel turning section n The projection length on the O1X1 axis of the inlet duct global coordinate system X1O1Y1 is 2b (b>0), and the first profile characteristic curve A0A of the inner flow channel turning section is n The projection length on the O1Y1 axis of the inlet duct global coordinate system X1O1Y1 is 2a (a>0), and the first profile characteristic curve A0A of the inner flow channel turning section is n The sine curve in the surface coordinate system XOY is

[0007] Furthermore, the optimization design method of the inlet turning section is based on Optimize the first profile characteristic curve A0A of the inner flow channel turning section n , where k A,max (k A,max >0) is the first profile characteristic curve A0A of the inner flow channel turning section for aerodynamic drag reduction (or preventing airflow separation) n The maximum slope value allowed at the coordinate origin O of the coordinate system XOY is solved in the inner channel turning section profile. A,max Under the premise of constraints, the values ​​of a and b are appropriately selected to meet the loading space requirements at the same time. Generally speaking, increasing the b value can achieve internal flow channel drag reduction (or prevent airflow separation); changes in the a value will have different effects on loading, and it is necessary to adjust the load according to the first profile characteristic curve A0A of the inner flow channel turning section. n It depends on your location.

[0008] Furthermore, in the inner channel turning section profile solving coordinate system XOY, the first profile characteristic curve A0A of the inner channel turning section is n The X-axis is evenly divided into n segments, and the nodes corresponding to the airflow direction are 0, 1, 2, ..., n, and the axial horizontal coordinates corresponding to each node are X0, X1, X2, ..., X n , the first profile characteristic curve A0A of the inner flow channel turning section n The coordinates of any discrete point on the XOY coordinate system are A i (x A,i ,y A,i ), A i (x A,i ,y A,i ) in the global coordinate system X1O1Y1 is Solve the corresponding coordinates of the origin O in the coordinate system XOY in the global coordinate system X1O1Y1 as (s, t). i (x A,i ,y A,i ) Tangent line A i T i The tangent of the angle with the X axis is k A,i , pass A i (x A,i ,y A,i ) Draw a straight line from point A i B i ⊥A i T i The second profile characteristic curve B0B of the inner channel turning section n Interchange at B i (x B,i ,yB,i ) point, pass A i (x A,i ,y A,i ) Draw a straight line from point A i C i / / X axis, pass B i (x B,i ,y B,i ) Draw a straight line from point B i C i / / Y axis, line A i C i 、B i C i Intersection at C i Point, let line segment A i C i =dx i , B i C i =dy i ,according to Calculate and obtain any discrete point A in the solution coordinate system XOY i (x A,i ,y A,i ) point B i Point coordinates (x B,i ,y B,i ) to obtain the second profile characteristic curve B0B of the inner flow channel turning section n , where S0 is the airflow channel area corresponding to the starting point 0 of the inner flow channel turning section, S n is the airflow channel area corresponding to the end point n of the inner flow channel turning section.

[0009] Furthermore, the optimization design method of the inlet turning section is based on k B,i <k B,max Optimize the second profile characteristic curve B0B of the inner flow channel turning section n ,in, k B,max (k B,max >0) To prevent airflow separation (or reduce drag in the inner flow channel), the second profile characteristic curve B0B of the inner flow channel turning section n The maximum slope value allowed. B,max Under the premise of constraints, the values ​​of a and b are appropriately selected again to meet the loading space requirements. Generally speaking, increasing the b value can prevent airflow separation (or achieve internal flow channel drag reduction); changes in the a value will have different effects on loading, and it is necessary to adjust the load according to the first profile characteristic curve A0A of the internal flow channel turning section. n It depends on your location.

[0010] Furthermore, the first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the air inlet duct is nAnd the second profile characteristic curve B0B of the inner channel turning section n According to Calculate and obtain, where the corresponding coordinates of the origin O in the inner flow channel turning section coordinate system XOY in the inlet duct global coordinate system X1O1Y1 are (s, t), A i (x A,i ,y A,i ) is the first profile characteristic curve A0A of the inner channel turning section under the coordinate system XOY of the inner channel turning section profile solution n Any discrete point on A0A is the first profile characteristic curve of the inner flow channel turning section under the global coordinate system X1O1Y1 of the inlet duct n Up and A i (x A,i ,y A,i ) corresponding discrete points, B i (x B,i ,y B,i ) is the second profile characteristic curve B0B of the inner runner turning section under the coordinate system XOY of the inner runner turning section profile solution n Any discrete point on The second profile characteristic curve B0B of the inner flow channel turning section under the global coordinate system X1O1Y1 of the inlet duct is n Up and B i (x B,i ,y B,i ) corresponding discrete points.

[0011] According to another aspect of the present invention, an air intake is provided, wherein the air intake uses the air intake turning section optimization design method as described above to design the air intake turning section.

[0012] The technical solution of the present invention provides an optimization design method for the turning section of an air intake duct. The optimization design method for the turning section of an air intake duct is to optimize the first profile characteristic curve A0A of the turning section of the inner flow channel. n Optimization can achieve the purpose of aerodynamic drag reduction (or prevent airflow separation) by adjusting the first profile characteristic curve A0A of the inner flow channel turning section. n Discretize to solve the second profile characteristic curve B0B of the inner flow channel turning section n To prevent the profile characteristic curve B0B n The second profile characteristic curve B0B of the inner flow channel turning section is designed for the purpose of airflow separation (or inner flow channel drag reduction) caused by the sharp turn. nThe optimization is performed in the manner that, compared with the prior art, the drag reduction design of the inlet passage or the internal flow passage of the engine can be realized by optimizing the design parameters under the premise of considering the structural loading requirement; the air flow separation of the turning section of the wide Mach number range working inlet passage can be prevented by optimizing the design parameters under the premise of considering the structural loading requirement; and the outlet flow field distortion index is reduced to improve the overall performance of the inlet passage under the premise of considering the structural loading requirement, the aerodynamic drag reduction design and the air flow separation characteristic improvement. BRIEF DESCRIPTION OF DRAWINGS

[0013] The accompanying drawings, which are included to provide a further understanding of the embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. It is readily apparent to one skilled in the art that the following description in the drawings merely illustrates the embodiments of the application and that numerous other embodiments can be derived from these drawings without creative work by one skilled in the art.

[0014] Figure 1 A schematic view of an axisymmetric supersonic inlet passage and a coordinate system provided by a specific embodiment of the application is shown;

[0015] Figure 2 A schematic view of an axisymmetric inlet passage turning section optimization design method provided by a first embodiment of the application is shown;

[0016] Figure 3 A schematic view of an axisymmetric inlet passage turning section optimization design method provided by a second embodiment of the application is shown. DETAILED DESCRIPTION

[0017] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by one of ordinary skill in the art without creative work are within the scope of protection of the present application.

[0018] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0019] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the examples are not intended to limit the scope of the application unless otherwise specifically stated. It is to be understood that the drawings are not necessarily to scale as the dimensions of the parts shown are for the purpose of illustration and description only and not intended to limit the scope of the application. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the description of the application. In all examples shown and discussed herein, any specific value is to be interpreted as merely an example and not a limitation. Thus, other examples of the exemplary embodiments can have different values. It is noted that like numbers and letters refer to like elements throughout the several views of the drawings and, as such, no further discussion with regard thereto is needed.

[0020] As shown in Figures 1 to 3 , the specific embodiments according to the present application provide an air inlet turning section optimization design method, which comprises: establishing an internal flow passage turning section profile solving coordinate system XOY, a coordinate origin O of the internal flow passage turning section profile solving coordinate system XOY is located at the center of a first profile feature curve A0A n of the internal flow passage turning section, an OX axis is parallel to an O1X1 axis of a global coordinate system X1O1Y1 (O1 is located at a vertex of a compression surface of a leading edge of the air inlet, the O1X1 axis is in the same direction as a far-upstream flow direction at zero angle of attack, for an axisymmetric air inlet, the O1X1 axis coincides with a central axis, and an O1Y1 axis is perpendicular to the O1X1 axis), and an OY axis is perpendicular to the OX axis; under the internal flow passage turning section profile solving coordinate system XOY, a sine function is constructed to solve the first profile feature curve A0A n of the internal flow passage turning section; the first profile feature curve A0A n of the internal flow passage turning section is optimized for the purpose of internal flow passage drag reduction (or preventing airflow separation); the first profile feature curve A0A n of the internal flow passage turning section is discretized to solve a second profile feature curve B0B n of the internal flow passage turning section; the second profile feature curve B0B n of the internal flow passage turning section is optimized for the purpose of preventing airflow separation (or internal flow passage drag reduction); the first profile feature curve A0An And the second profile characteristic curve B0B of the inner channel turning section n Perform coordinate transformation to obtain the first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the inlet duct n And the second profile characteristic curve B0B of the inner channel turning section n According to the first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the inlet duct n And the second profile characteristic curve B0B of the inner channel turning section n The optimized design of the inlet turning section is achieved through the optimized design of the inlet turning section.

[0021] By using this configuration, a method for optimizing the design of the turning section of the air intake duct is provided. The method for optimizing the design of the turning section of the air intake duct is based on the first profile characteristic curve A0A of the turning section of the inner flow channel. n Optimization can achieve the purpose of aerodynamic drag reduction (or prevent airflow separation) by adjusting the first profile characteristic curve A0A of the inner flow channel turning section. n Discretize to solve the second profile characteristic curve B0B of the inner flow channel turning section n , the second profile characteristic curve B0B of the inner flow channel turning section n Optimize to prevent the profile characteristic curve B0B n The purpose is to prevent airflow separation (or internal flow duct drag reduction) caused by sharp turns. Compared with the existing technology, this method can achieve drag reduction design of the air inlet or the engine internal flow duct by optimizing the design parameters while taking into account the structural loading requirements; it can prevent airflow separation in the turning section of the working air inlet in a wide Mach number range by optimizing the design parameters while taking into account the structural loading requirements; it can reduce the outlet flow field distortion index and achieve an improvement in the overall performance of the air inlet while taking into account the structural loading requirements, aerodynamic drag reduction design and improvement of airflow separation characteristics.

[0022] As a first embodiment of the present invention, Figure 2 As shown, the first profile characteristic curve A0A of the inner flow channel turning section is optimized with the inner flow channel drag reduction as the goal. n ; The first profile characteristic curve A0A of the inner flow channel turning section n Discretize to solve the second profile characteristic curve B0B of the inner flow channel turning section n ; To prevent airflow separation, optimize the second profile characteristic curve B0B of the inner flow channel turning section n ; Solve the first profile characteristic curve A0A of the inner runner turning section under the coordinate system XOY for the profile of the inner runner turning section n And the second profile characteristic curve B0B of the inner channel turning section nPerform coordinate transformation to obtain the first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the inlet duct n And the second profile characteristic curve B0B of the inner channel turning section n According to the first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the inlet duct n And the second profile characteristic curve B0B of the inner channel turning section n The optimized design of the inlet turning section is achieved through the optimized design of the inlet turning section.

[0023] Alternatively, as a second embodiment of the present invention, in the present invention, the curve close to the central axis of the central cone can also be used as the first profile characteristic curve. Figure 3 As shown, when the curve close to the central axis of the center cone is used as the first profile characteristic curve, the first profile characteristic curve A0A of the inner flow channel turning section is optimized with the goal of preventing airflow separation. n ; The first profile characteristic curve A0A of the inner flow channel turning section n Discretize to solve the second profile characteristic curve B0B of the inner flow channel turning section n ; Optimize the second profile characteristic curve B0B of the inner flow channel turning section with the goal of reducing the inner flow channel drag n ; Solve the first profile characteristic curve A0A of the inner runner turning section under the coordinate system XOY for the profile of the inner runner turning section n And the second profile characteristic curve B0B of the inner channel turning section n Perform coordinate transformation to obtain the first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the inlet duct n And the second profile characteristic curve B0B of the inner channel turning section n According to the first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the inlet duct n And the second profile characteristic curve B0B of the inner channel turning section n The optimized design of the inlet turning section is achieved through the optimized design of the inlet turning section.

[0024] Specifically, in the present invention, a supersonic axisymmetric inlet is taken as an example to illustrate the optimization design method of the inlet turning section based on a sine curve. A supersonic axisymmetric inlet and its global coordinate system X1O1Y1 (O1 is located at the vertex of the central cone, the O1X1 axis coincides with the central axis, and the O1Y1 axis is perpendicular to the O1X1 axis) are shown as follows: Figure 1 In the global coordinate system X1O1Y1, the starting point A0 of the inner channel turning section and its corresponding starting point B0 and ending point A n and its corresponding end point B nThe area of the annular passage corresponding to the rotation of the connecting line A0B0 of the starting point of the inner flow passage turning section around the central axis of the inlet passage by 360° is S0, and the connecting line A n B n The area of the circular passage corresponding to the rotation of the connecting line A0B0 of the starting point of the inner flow passage turning section around the central axis of the inlet passage by 360° is S n . In the solving of the first profile characteristic curve A0A n and the second profile characteristic curve B0B n of the inner flow passage turning section, the first profile characteristic curve A0A n is constructed as a sinusoidal curve to solve the corresponding second profile characteristic curve B0B n . Taking the first profile characteristic curve A0A n as an example, the length of the projection on the O1X1 axis is 2b (b>0), and the length of the projection on the O1Y1 axis is 2a (a>0), and the first profile characteristic curve A0A n and the second profile characteristic curve B0B n of the inner flow passage turning section are solved by the above known data.

[0025] As a first embodiment of the present application, as shown in Figure 2 , the first profile characteristic curve A0A n is taken as an example to solve the second profile characteristic curve B0B n of the inner flow passage turning section, and the modeling method for optimizing the profile of the inlet passage turning section based on a sinusoidal curve is described.

[0026] Step one, establish the coordinate system XOY for solving the profile of the inner flow passage turning section, the coordinate origin O of the coordinate system XOY for solving the profile of the inner flow passage turning section is located at the center of the first profile characteristic curve A0A n , the OX axis is parallel to the O1X1 axis of the global coordinate system X1O1Y1 (O1 is located at the center of the cone, the O1X1 axis is coincided with the central axis, and the O1Y1 axis is perpendicular to the O1X1 axis), and the OY is perpendicular to the OX axis, as shown in Figure 2 , the first profile characteristic curve A0A n and the second profile characteristic curve B0B n of the inner flow passage turning section are solved under the XOY coordinate system.

[0027] Step two, construct a sinusoidal function under the coordinate system XOY for solving the profile of the inner flow passage turning section to solve the first profile characteristic curve A0A n . The first profile characteristic curve A0A n is wherein the first profile characteristic curve A0An The projection length on the O1X1 axis of the inlet duct global coordinate system X1O1Y1 is 2b, and the first profile characteristic curve A0A of the inner flow channel turning section n The projection length on the O1Y1 axis of the intake duct global coordinate system X1O1Y1 is 2a.

[0028] Step 3: Optimize the first profile characteristic curve A0A of the inner flow channel turning section n To achieve the purpose of aerodynamic drag reduction, the values ​​of a and b should meet the following constraints: Among them, k A,max (k A,max >0) is the first profile characteristic curve A0A of the inner channel turning section n The maximum slope value allowed at the coordinate origin O of the coordinate system XOY is solved in the inner flow channel turning section profile. The maximum slope value is given by the designer based on actual loading requirements and design experience. As can be seen from the above formula, reducing a or increasing b can make the first profile characteristic curve A0A of the inner flow channel turning section n It becomes relaxed and the aerodynamic internal resistance is reduced, but it will compress the loading space of the internal structure of the projectile behind the center cone.

[0029] Step 4: First profile characteristic curve A0A of the inner flow channel turning section n Discretize to solve the second profile characteristic curve B0B of the inner flow channel turning section n .like Figure 2 As shown, the first profile characteristic curve A0A of the inner flow channel turning section n Discretize to solve the second profile characteristic curve B0B of the inner flow channel turning section n Specifically, the first profile characteristic curve A0A of the inner flow channel turning section is converted into the inner flow channel turning section profile characteristic curve A0A in the inner flow channel turning section profile solving coordinate system XOY. n Discrete space, assuming that the first profile characteristic curve A0A of the inner channel turning section n The X-axis is evenly divided into n segments, and the nodes corresponding to the airflow direction are 0, 1, 2, ..., n, and the axial coordinates corresponding to each node are X0, X1, X2, ..., X n , the first profile characteristic curve A0A of the inner flow channel turning section n The coordinates of any discrete point on the XOY coordinate system are A i (x A,i ,y A,i ), A i (x A,i ,y A,i ) in the global coordinate system X1O1Y1 is Solve the corresponding coordinates of the origin O in the coordinate system XOY in the global coordinate system X1O1Y1 as (s, t). i (x A,i,y A,i ) Tangent line A i T i The tangent of the angle with the X axis is k A,i , pass A i (x A,i ,y A,i ) Draw a straight line from point A i B i ⊥A i T i The second profile characteristic curve B0B of the inner channel turning section n Interchange at B i (x B,i ,y B,i ) point, pass A i (x A,i ,y A,i ) Draw a straight line from point A i C i / / X axis, pass B i (x B,i ,y B,i ) Draw a straight line from point B i C i / / Y axis, line A i C i 、B i C i Intersection at C i Point, let line segment A i C i =dx i , B i C i =dy i , then any discrete point A can be calculated as follows i (x A,i ,y A,i ) point B i Point coordinates (x B,i ,y B,i ) to obtain the second profile characteristic curve B0B of the inner flow channel turning section n .

[0030] according to Calculate and obtain any discrete point A in the solution coordinate system XOY i (x A,i ,y A,i ) point B i Point coordinates (x B,i ,y B,i ) to obtain the second profile characteristic curve B0B of the inner flow channel turning section n Among them, S0 is the airflow channel area corresponding to the line A0B0 connecting the starting point 0 of the inner flow channel turning section rotating 360° around the central axis of the air inlet channel, S nLine A is the end point n of the inner channel turning section n B n The area of ​​the airflow channel corresponding to a 360° rotation around the central axis of the air inlet.

[0031] In this step, the axial equal area expansion law is used as an example to illustrate the second profile characteristic curve B0B of the inner flow channel turning section. n The curve solution method can be selected according to the design needs in the actual design by using the multi-segment equal area expansion law or other area expansion laws. n The discrete solution method implies n = ΔX = X n -X0, that is, the X-axis discrete step length X step =X i+1 -X i =1, in the design, the step size can be appropriately selected according to the density of the discrete points, and the above solution formula should also be adjusted accordingly. In solving the characteristic curve of the inlet turning section, for the axisymmetric inlet, dy i The solution of the above-mentioned frustum area formula is used; for the two-dimensional air intake, this design method can also be used. In this case, dy i The solution can be obtained by using a rectangular or other area formula according to the cross-sectional configuration of the airflow, and the above-mentioned surface characteristic curve solution formula can be appropriately transformed.

[0032] Step 5: Optimize the second profile characteristic curve B0B of the inner flow channel turning section n . Assume profile curve B0B n Any coordinate B on i (x B,i ,y B,i ) is k B,i , then k can be calculated using the following formula B,i : To prevent the profile curve B0B n Airflow separation occurs due to a sharp turn, k B,i The following constraints should be met: B,i <k B,max , where k B,max (k B,max >0) To prevent airflow separation, the second profile characteristic curve B0B of the inner flow channel turning section n The maximum slope value allowed is given by the designer based on actual loading requirements and design experience. k can be optimized by adjusting the a value or b value or the channel area pressure diffusion law. B,i The value can prevent airflow separation while maximally meeting the structural loading requirements.

[0033] Step 6: Calculate the first profile characteristic curve A0A of the inner channel turning section under the coordinate system XOY for the inner channel turning section profile. nAnd the second profile characteristic curve B0B of the inner channel turning section n Perform coordinate transformation to obtain the first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the inlet duct n And the second profile characteristic curve B0B of the inner channel turning section n Assume that the coordinates of the origin O in the inner channel turning section surface solving coordinate system XOY in the inlet duct global coordinate system X1O1Y1 are (s, t), then the first surface characteristic curve A0A of the inner channel turning section is n Any discrete point A i (x A,i ,y A,i ) in the X1O1Y1 coordinate system It can be calculated as follows:

[0034]

[0035] Similarly, the second profile characteristic curve B0B of the inner channel turning section can be calculated n Any discrete point B i (x B,i ,y B,i ) in the X1O1Y1 coordinate system

[0036] Step 7: Based on the first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the air inlet n And the second profile characteristic curve B0B of the inner channel turning section n The optimized design of the inlet turning section is achieved through the optimized design of the inlet turning section.

[0037] As a second embodiment of the present invention, Figure 3 As shown, the first profile characteristic curve A0A of the inner flow channel turning section n Solve the second profile characteristic curve B0B of the inner flow channel turning section n Taking the example, the modeling method of the optimized design of the inlet turning section profile based on the sine curve is explained.

[0038] Step 1: Establish the inner runner turning section profile solution coordinate system XOY. The coordinate origin O of the inner runner turning section profile solution coordinate system XOY is located at the first profile characteristic curve A0A of the inner runner turning section. n The OX axis is parallel to the O1X1 axis of the inlet duct global coordinate system X1O1Y1 (O1 is located at the vertex of the central cone, the O1X1 axis coincides with the central axis, and the O1Y1 axis is perpendicular to the O1X1 axis), and OY is perpendicular to the OX axis. Figure 3 As shown, the first profile characteristic curve A0A of the inner flow channel turning section is solved in the XOY coordinate system. nAnd the second profile characteristic curve B0B of the inner channel turning section n .

[0039] Step 2: In the inner channel turning section profile solving coordinate system XOY, construct a sine function to solve the first profile characteristic curve A0A of the inner channel turning section n The first profile characteristic curve A0A of the inner channel turning section n for Among them, the first profile characteristic curve A0A of the inner flow channel turning section n The projection length on the O1X1 axis of the inlet duct global coordinate system X1O1Y1 is 2b, and the first profile characteristic curve A0A of the inner flow channel turning section n The projection length on the O1Y1 axis of the intake duct global coordinate system X1O1Y1 is 2a.

[0040] Step 3: Optimize the first profile characteristic curve A0A of the inner flow channel turning section n To prevent airflow separation, the values ​​of a and b should satisfy the following constraints: Among them, k A,max (k A,max >0) is the first profile characteristic curve A0A of the inner channel turning section n The maximum slope value allowed at the coordinate origin O of the coordinate system XOY is solved in the inner flow channel turning section profile. The maximum slope value is given by the designer based on actual loading requirements and design experience. As can be seen from the above formula, reducing a or increasing b can make the first profile characteristic curve A0A of the inner flow channel turning section n It becomes soothed, which prevents airflow separation, but compresses the internal structural loading space of the center cone.

[0041] Step 4: First profile characteristic curve A0A of the inner flow channel turning section n Discretize to solve the second profile characteristic curve B0B of the inner flow channel turning section n .like Figure 3 As shown, the first profile characteristic curve A0A of the inner flow channel turning section n Discretize to solve the second profile characteristic curve B0B of the inner flow channel turning section n Specifically, the first profile characteristic curve A0A of the inner flow channel turning section is converted into the inner flow channel turning section profile characteristic curve A0A in the inner flow channel turning section profile solving coordinate system XOY. n Discrete space, assuming that the first profile characteristic curve A0A of the inner channel turning section n The X-axis is evenly divided into n segments, and the nodes corresponding to the airflow direction are 0, 1, 2, ..., n, and the axial coordinates corresponding to each node are X0, X1, X2, ..., X n , the first profile characteristic curve A0A of the inner flow channel turning section n The coordinates of any discrete point on the XOY coordinate system are Ai (x A,i ,y A,i ), A i (x A,i ,y A,i ) in the global coordinate system X1O1Y1 is Solve the coordinates of the origin O in the coordinate system XOY and the corresponding coordinates in the global coordinate system X1O1Y1 are (s, t). i (x A,i ,y A,i ) Tangent line A i T i The tangent of the angle with the X axis is k A,i , pass A i (x A,i ,y A,i ) Draw a straight line from point A i B i ⊥A i T i The second profile characteristic curve B0B of the inner channel turning section n Interchange at B i (x B,i ,y B,i ) point, pass A i (x A,i ,y A,i ) Draw a straight line from point A i C i / / Y axis, pass B i (x B,i ,y B,i ) Draw a straight line from point B i C i / / X axis, line A i C i 、B i C i Intersection at C i Point, let line segment A i C i =dy i , B i C i =dx i , then any discrete point A can be calculated as follows i (x A,i ,y A,i ) point B i Point coordinates (x B,i ,y B,i ) to obtain the second profile characteristic curve B0B of the inner flow channel turning section n .

[0042] according to Calculate and obtain any discrete point A in the solution coordinate system XOYi (x A,i ,y A,i ) point B i Point coordinates (x B,i ,y B,i ) to obtain the second profile characteristic curve B0B of the inner flow channel turning section n Among them, S0 is the airflow channel area corresponding to the line A0B0 connecting the starting point 0 of the inner flow channel turning section rotating 360° around the central axis of the air inlet channel, S n Connect line A to the end point n of the inner channel turning section n B n The area of ​​the airflow channel corresponding to a 360° rotation around the central axis of the air inlet.

[0043] Step 5: Optimize the second profile characteristic curve B0B of the inner flow channel turning section n . Assume profile curve B0B n Any coordinate B on i (x B,i ,y B,i ) is k B,i , then k can be calculated using the following formula B,i : In order to realize the drag reduction design of the inner channel turning section, k B,i The following constraints should be met: B,i <k B,max , where k B,max (k B,max >0) is the second profile characteristic curve B0B of the inner flow channel turning section for drag reduction design n The maximum slope value allowed is given by the designer based on design experience. k can be optimized by adjusting the a value or b value or the channel area pressure diffusion law. B,i numerical value, which can realize the internal flow to profile drag reduction design while maximally meeting the structural loading requirements.

[0044] Step 6: Calculate the first profile characteristic curve A0A of the inner channel turning section under the coordinate system XOY for the inner channel turning section profile. n And the second profile characteristic curve B0B of the inner channel turning section n Perform coordinate transformation to obtain the first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the inlet duct n And the second profile characteristic curve B0B of the inner channel turning section n Assume that the coordinates of the origin O in the inner channel turning section surface solving coordinate system XOY in the inlet duct global coordinate system X1O1Y1 are (s, t), then the first surface characteristic curve A0A of the inner channel turning section is n Any discrete point A i (x A,i ,y A,i) in the X1O1Y1 coordinate system It can be calculated as follows:

[0045]

[0046] Similarly, the second profile characteristic curve B0B of the inner channel turning section can be calculated n Any discrete point B i (x B,i ,y B,i ) in the X1O1Y1 coordinate system

[0047] Step 7: Based on the first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the air inlet n And the second profile characteristic curve B0B of the inner channel turning section n The optimized design of the inlet turning section is achieved through the optimized design of the inlet turning section.

[0048] According to another aspect of the present invention, an air inlet is provided, which uses the above-mentioned air inlet turn section optimization design method to design the air inlet turn section. Since the air inlet turn section optimization design method provided by the present invention can achieve drag reduction design of the air inlet or the flow channel within the engine by optimizing design parameters while taking into account the structural loading requirements; can prevent airflow separation in the turn section of the air inlet operating in a wide Mach number range by optimizing design parameters while taking into account the structural loading requirements; can reduce the outlet flow field distortion index while taking into account the structural loading requirements, aerodynamic drag reduction design and improvement of airflow separation characteristics, and achieve improvement in the overall performance of the air inlet, therefore, using the air inlet turn section optimization design method provided by the present invention to design the air inlet turn section can reduce the internal flow resistance of the inlet turn section, prevent airflow separation in the turn section, and reduce the outlet flow field distortion index of the air inlet.

[0049] In summary, the present invention provides a method for optimizing the design of an inlet turn section. This method has been effectively verified by engineering practice and wind tunnel tests. The design method has the following advantages: 1) Under the premise of taking into account the structural loading requirements, the drag reduction design of the inlet or the engine inner flow duct can be achieved by optimizing the design parameters; 2) Under the premise of taking into account the structural loading requirements, the airflow separation in the working inlet turn section within a wide Mach number range can be prevented by optimizing the design parameters; 3) Under the premise of taking into account the structural loading requirements, the aerodynamic drag reduction design and the improvement of the airflow separation characteristics, the distortion index of the flow field at the inlet outlet is reduced, and the overall performance of the inlet is improved. The method for optimizing the design of the inlet turn section provided by the present invention is not only applicable to the design of the inner flow duct of the inlet, but also to the design of other inner flow ducts with higher requirements on the quality of the airflow field.

[0050] For purposes of the description hereinafter, spatial or directional terms, for example, "above", "below", "upper", "lower", and the like, can be used, and relate to the device as illustrated in the figures. However, it is to be understood that no absolute or relative orientation of the device is intended or implied, unless specifically described as such. Terms concerning attachments, coupling and the like, such as "connected" and "coupled" and the like, are to be construed in accordance with their normal meanings, that is, as referring to an indirect or direct connection or coupling. Any reference to "comprising" or "containing" is to be construed as meaning "comprising or containing, but not limited to". Any reference to "comprising" or "containing" is to be construed as meaning "comprising or containing, but not limited to".

[0051] In addition, it should be pointed out that the use of the terms "first", "second" and the like, to describe various elements, is merely intended to differentiate the elements from one another, and does not connote any special order or order of precedence, unless otherwise specifically indicated. Thus, the use of the terms "first", "second" and the like, is not intended to limit the scope of the present application, and is not intended to connote any special order or order of precedence.

[0052] The preferred embodiments herein disclosed are not intended to limit or restrict the scope of the application, but merely convey the best mode contemplated by the inventors of carrying out the claimed application. Any modifications, variations or changes within the spirit and scope of the application as disclosed herein will be considered to fall within the scope of the application.

Claims

1. A method for optimizing the design of an air intake turning section, characterized in that: The inlet turning section optimization design method includes: Establish the inner runner turning section profile solution coordinate system XOY, the coordinate origin O of the inner runner turning section profile solution coordinate system XOY is located at the first profile characteristic curve A0A of the inner runner turning section n The OX axis is parallel to the O1X1 axis of the inlet global coordinate system X1O1Y1, and OY is perpendicular to the OX axis, wherein O1 is located at the vertex of the compression surface at the leading edge of the inlet, the O1X1 axis is in the same direction as the far front flow direction at zero angle of attack, and the O1Y1 axis is perpendicular to the O1X1 axis; In the inner flow channel turning section profile solving coordinate system XOY, a sine function is constructed to solve the first profile characteristic curve A0A of the inner flow channel turning section. n ; Optimize the first profile characteristic curve A0A of the inner flow channel turning section with the goal of reducing the inner flow channel drag or preventing airflow separation n ; The first profile characteristic curve A0A of the inner flow channel turning section n Discretize to solve the second profile characteristic curve B0B of the inner flow channel turning section n ; The second profile characteristic curve B0B of the inner flow channel turning section is optimized with the goal of preventing airflow separation or reducing inner flow channel drag. n ; The first profile characteristic curve A0A of the inner flow channel turning section is solved in the coordinate system XOY for the inner flow channel turning section profile. n and the second profile characteristic curve B0B of the inner flow channel turning section n Perform coordinate transformation to obtain the first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the air inlet duct n and the second profile characteristic curve B0B of the inner flow channel turning section n ; According to the first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the air inlet n and the second profile characteristic curve B0B of the inner flow channel turning section n The optimized design of the inlet turning section is achieved through the optimized design of the inlet turning section.

2. The method for optimizing the design of an air intake turning section according to claim 1, characterized in that: The first profile characteristic curve A0A of the inner flow channel turning section n The sine curve in the surface coordinate system XOY is Among them, the first profile characteristic curve A0A of the inner flow channel turning section n The projection length on the O1X1 axis of the inlet duct global coordinate system X1O1Y1 is 2b, and the first profile characteristic curve A0A of the inner flow channel turning section n The projection length on the O1Y1 axis of the intake duct global coordinate system X1O1Y1 is 2a.

3. The method for optimizing the design of an air intake turning section according to claim 2, characterized in that: The first profile characteristic curve A0A of the inner flow channel turning section n Discretize to solve the second profile characteristic curve B0B of the inner flow channel turning section n Specifically, the first profile characteristic curve A0A of the inner flow channel turning section is converted into the profile characteristic curve A0A of the inner flow channel turning section in the inner flow channel turning section profile solving coordinate system XOY. n The X-axis is evenly divided into n segments, and the nodes corresponding to the airflow direction are 0, 1, 2, ..., n, and the axial horizontal coordinates corresponding to each node are X0, X1, X2, ..., X n , the first profile characteristic curve A0A of the inner flow channel turning section n The coordinates of any discrete point on the XOY coordinate system are A i (x A,i ,y A,i ), A i (x A,i ,y A,i ) in the global coordinate system X1O1Y1 is Solve the corresponding coordinates of the origin O in the coordinate system XOY in the global coordinate system X1O1Y1 as (s, t). i (x A,i ,y A,i ) Tangent line A i T i The tangent of the angle with the X axis is k A,i , pass A i (x A,i ,y A,i ) Draw a straight line from point A i B i ⊥A i T i and the second profile characteristic curve B0B of the inner flow channel turning section n Interchange at B i (x B,i ,y B,i ) point, pass A i (x A,i ,y A,i ) Draw a straight line from point A i C i / / X axis, pass B i (x B,i ,y B,i ) Draw a straight line from point B i C i / / Y axis, line A i C i 、B i C i Intersection at C i Point, let line segment A i C i =dx i , B i C i =dy i ,according to Calculate and obtain any discrete point A in the solution coordinate system XOY i (x A,i ,y A,i ) point B i Point coordinates (x B,i ,y B,i ) to obtain the second profile characteristic curve B0B of the inner flow channel turning section n , where S0 is the airflow channel area corresponding to the starting point 0 of the inner flow channel turning section, S n is the airflow channel area corresponding to the end point n of the inner flow channel turning section.

4. The method for optimizing the design of an air intake turning section according to claim 3, characterized in that: The optimization design method of the inlet turning section is based on Optimize the first profile characteristic curve A0A of the inner flow channel turning section n , where k A,max (k A,max >0) is the first profile characteristic curve A0A of the inner flow channel turning section for aerodynamic drag reduction or preventing airflow separation n The maximum allowable slope value at the coordinate origin O of the coordinate system XOY is solved for the inner flow channel turning section profile. By adjusting the a and b values, the aerodynamic drag reduction design of the inner flow channel turning section or the prevention of airflow separation can be achieved.

5. The method for optimizing the design of an air intake turning section according to claim 4, characterized in that: The optimization design method of the inlet turning section is based on the k B,i <k B,max Optimize the second profile characteristic curve B0B of the inner flow channel turning section n ,in, k B,max (k B,max >0) is to prevent airflow separation or reduce the drag of the inner flow channel. The second profile characteristic curve B0B of the inner flow channel turning section n The maximum allowable slope value is achieved by adjusting the a and b values ​​to prevent airflow separation or achieve aerodynamic drag reduction design in the inner flow channel turning section.

6. The method for optimizing the design of an air intake turning section according to claim 2 or 3, characterized in that: The first profile characteristic curve A0A of the inner flow channel turning section located in the global coordinate system X1O1Y1 of the air inlet n and the second profile characteristic curve B0B of the inner flow channel turning section n According to Calculation is performed, where the coordinate value of the origin O of the coordinate system XOY of the inner flow channel turning section surface solution in the inlet duct global coordinate system X1O1Y1 is (s, t), A i (x A,i ,y A,i ) is the first profile characteristic curve A0A of the inner channel turning section under the coordinate system XOY of the inner channel turning section profile solution n Any discrete point on A0A is the first profile characteristic curve of the inner flow channel turning section under the global coordinate system X1O1Y1 of the inlet duct n Up and A i (x A,i ,y A,i ) corresponding discrete points, B i (x B,i ,y B,i ) is the second profile characteristic curve B0B of the inner runner turning section under the coordinate system XOY of the inner runner turning section profile solution n Any discrete point on The second profile characteristic curve B0B of the inner flow channel turning section in the global coordinate system X1O1Y1 of the inlet duct is n Up and B i (x B,i ,y B,i ) corresponding discrete points.

7. An air intake duct, characterized in that: The air intake duct is designed using the air intake duct turning section optimization design method according to any one of claims 1 to 6.

Images