Method for determining the geometric inlet angle of the inlet flow angle of the cascade blades of a counter thrust device

Abstract

The application provides a method for determining the inlet flow angle of a cascade blade of a reverse thrust device, which is based on the actuality of the outer bypass flow field where the cascade is located, comprehensively considers the influence of the outer wall of the outer bypass and the blocker door, fits the inlet flow angle of the blade as a first segmented function about the relative relationship between the distance from the blade to the front end of the cascade and the axial length of the cascade, and the included angle between the outer wall profile of the outer bypass and the axis, the included angle between the profile of the blocker door in the reverse thrust state and the axis, and each term has a clear meaning. The method for determining the inlet flow angle of the cascade blade of the reverse thrust device has high efficiency and high accuracy verified by tests and simulations, and can meet the requirements of rapid design and iteration. In addition, a method for determining the geometric inlet angle of the cascade blade of the reverse thrust device is provided, which is implemented based on the above method for determining the inlet flow angle of the cascade blade of the reverse thrust device.

Description

Technical Field

[0001] This application belongs to the field of science and technology, specifically relating to a method for determining the geometric inlet angle of the inlet airflow angle of the guide vane of a thrust reverser device. Background Technology

[0002] To shorten the landing roll distance of the aircraft, a thrust reverser device for the aero-engine is designed, mainly including a flow deflector and guide vanes. The flow deflector is hinged in a slot in the outer wall of the bypass and has the following characteristics:

[0003] In the forward thrust state, the flow obstruction gate blocks the slot on the outer wall of the outer bypass, forming part of the outer wall of the outer bypass, allowing the airflow of the aero-engine to be discharged normally and providing thrust to the aircraft.

[0004] In reverse thrust mode, the choke deflects inwards towards the outer wall of the bypass, blocking the aero-engine bypass. This forces the airflow through slots in the outer wall of the bypass to exit via guide vanes, providing reverse thrust to the aircraft and thus shortening the landing roll distance. Figure 1 As shown.

[0005] When the thrust reverser of an aero-engine is in reverse thrust mode, the guide vane accelerates and turns the airflow to generate reverse thrust. The aerodynamic performance of the guide vane directly determines the reverse thrust efficiency of the aircraft in reverse thrust mode. The wider the optimal angle of attack range of the guide vane, the smaller the flow loss in its channel, and the stronger its aerodynamic performance and adaptability to the angle of attack of the incoming flow.

[0006] The inlet airflow angle of the guide vane directly affects its aerodynamic performance. In practice, the inlet airflow angle of the guide vane varies greatly from front to back, and the working conditions of the blades are not the same. Simply arranging the blades in an array cannot guarantee that all blades are working within the optimal angle of attack range, which leads to separation and vortices in the vane passage, resulting in reduced flow capacity of the vane passage or even blockage. This reduces the deflection efficiency of the airflow, increases flow losses, and reduces the reverse thrust efficiency of the aircraft.

[0007] Because the components involved in aero-engine thrust reversers and their guide vanes are large and complex, and the flow is complex when in thrust reverse mode, the blade inlet airflow angle and aerodynamic performance are usually not strongly correlated. Currently, most designs are based on the results of three-dimensional flow field simulation analysis of the preliminary layout scheme, followed by optimization and adjustment, and then the design of the blade geometric inlet angle. This technical solution requires a large amount of numerical calculation and iterative design, which is time-consuming and labor-intensive, and cannot meet the needs of rapid design and iteration of aero-engine thrust reversers and their guide vanes.

[0008] This application is made in view of the aforementioned technical deficiencies.

[0009] It should be noted that the above background information is only used to assist in understanding the inventive concept and technical solution of this invention, and it does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0010] The purpose of this application is to provide a method for determining the geometric inlet angle of the inlet airflow angle of the guide vane of a thrust reverser device, so as to overcome or mitigate at least one of the known technical defects.

[0011] The technical solution of this application is:

[0012] One aspect provides a method for determining the inlet airflow angle of the guide vane cascade blades in a thrust reverser device, including:

[0013] When L = c1·L0, β1 = a1·β A -b1; where 0≤c1≤0.01, 0.99≤a1≤1.01, 1.99°≤b1≤2.01°;

[0014] When L = c²·L₀, β₁ = a²·β A -b2; where 0.05≤c2≤0.06, 0.65≤a2≤0.75, -0.01°≤b2≤0.01°;

[0015] When L = c3·L0, β1 = a3·β A -b3; where 0.80≤c3≤0.85, 1.15≤a3≤1.35, -0.01°≤b3≤0.01°;

[0016] When L = c4·L0, β1 = a4·β E -b4; where 0.90≤c4≤0.97, 1.2≤a4≤1.6, -0.01°≤b4≤0.01°;

[0017] When L = c5·L0, β1 = a5·β E -b5; where 0.99≤c5≤1, 0.99≤a5≤1.01, 20°≤b5≤30°;

[0018] in,

[0019] L is the distance from the blade to the leading edge of the guide vane;

[0020] L0 is the axial length of the guide vane cascade;

[0021] β1 is the inlet airflow angle of the blade;

[0022] β AThe angle between the outer wall profile of the culvert and the axis;

[0023] β E In the reverse state, the angle between the flow-blocking gate profile and the axis.

[0024] According to at least one embodiment of this application, in the above-described method for determining the inlet airflow angle of the guide vane cascade blades of the reverse thrust device, c1 = 0, a1 = 1, b1 = 2°;

[0025] c2=0.055, a2=0.70, b2=0°;

[0026] c3=0.825, a3=1.25, b3=0°;

[0027] c4=0.935, a4=1.40, b4=0°;

[0028] c5=1, a5=1, b5=25°.

[0029] On the other hand, a method for determining the geometric inlet angle of the guide vanes of a thrust reverser device is provided, including:

[0030] Based on any of the above-mentioned methods for determining the inlet airflow angle of the guide vane cascade of the reverse thrust device, the inlet airflow angle β1 of the vane is determined;

[0031] Calculate the blade geometric inlet angle β 1k =β1-i, i=-5°~-10°;

[0032] in,

[0033] i represents the blade angle of attack.

[0034] According to at least one embodiment of this application, in the above-described method for determining the geometric inlet angle of the guide vane of the thrust reverser device, i = -7.5°. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the aero-engine thrust reverser device provided in the embodiments of this application when it is in thrust reverser state;

[0036] Figure 2 yes Figure 1 A partial sectional view from AA direction;

[0037] Figure 3 This is a schematic diagram of the guide vane cascade provided in an embodiment of this application;

[0038] Figure 4 This is a schematic diagram showing the relationship between the blade geometry inlet angle, inlet airflow angle, and angle of attack provided in an embodiment of this application;

[0039] Figure 5This is a schematic diagram of the method for determining the inlet airflow angle of the guide vane cascade of the thrust reverser device provided in the embodiments of this application;

[0040] in:

[0041] β1 is the inlet airflow angle of the blade, which is the angle between the direction of the inlet airflow and the axis of the blade;

[0042] β 1k The blade geometric inlet angle is the angle between the tangent to the blade's geometric profile line and the axis.

[0043] i represents the blade angle of attack;

[0044] β1 is the inlet airflow angle of the blade;

[0045] β A The angle between the outer wall profile of the culvert and the axis;

[0046] β E In the reverse thrust state, the angle between the flow-blocking gate profile and the axis;

[0047] L is the distance from the blade to the leading edge of the guide vane;

[0048] L0 is the axial length of the guide vane cascade.

[0049] To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual size of the product. Furthermore, the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent. Detailed Implementation

[0050] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings. Other related parts can be referred to the general design. In the absence of conflict, the embodiments and technical features in the embodiments of this application can be combined with each other to obtain new embodiments.

[0051] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer," etc., used in this application description to indicate relative direction or positional relationship are used only to indicate relative orientation or positional relationship, and do not imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly, and therefore should not be construed as a limitation on this application. The terms "first," "second," "third," and similar terms used in this application description are used only for descriptive purposes to distinguish different components, and should not be construed as indicating or implying relative importance. The terms "a," "one," or "the," etc., used in this application description should not be construed as an absolute limitation on quantity, but should be construed as indicating the existence of at least one. The terms "including," "comprising," etc., used in this application description mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects.

[0052] Furthermore, it should be noted that, unless otherwise explicitly specified and limited, terms such as “installation,” “connection,” and “linkage” used in the description of this application should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can be a connection within two components. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0053] The following is in conjunction with the appendix Figures 1 to 5 This application will be described in further detail.

[0054] The inlet airflow angle β1 of the first few rows of guide vanes is mainly affected by the guiding and diffusion effects of the outer wall of the duct, and is the angle β1 between the duct outer wall profile and the axis. A Strong correlation; as the axial length changes, the guiding and diffuser effects of the outer wall of the culvert weaken, and the inlet airflow angle β1 gradually decreases.

[0055] When the guide vanes reach a certain distance, the inlet airflow angle β1 will drop to a minimum value and then gradually increase.

[0056] The airflow angle β1 at the inlet of the last few rows of channels behind the guide vane is mainly affected by the huge vortex in front of the flow barrier, and the angle is relatively large.

[0057] Based on the above, this application provides a method for determining the inlet airflow angle of the guide vane cascade of a thrust reverser device. Specifically, the inlet airflow angle of the blade from front to back is summarized as a piecewise linear function of the distance L from the blade to the leading edge of the guide vane cascade, as follows:

[0058] When L = c1·L0, β1 = a1·β A -b1; where c1 = 0, a1 = 1, b1 = 2°, see details. Figure 5 Location of point A in the middle;

[0059] When L = c²·L₀, β₁ = a²·β A -b2; where c2 = 0.055, a2 = 0.70, b2 = 0°, see details. Figure 5 Location of point B in the middle;

[0060] When L = c3·L0, β1 = a3·β A -b3; where c3 = 0.825, a3 = 1.25, b3 = 0°, see details. Figure 5 Location of point C;

[0061] When L = c4·L0, β1 = a4·β E -b4; where c4 = 0.935, a4 = 1.40, b4 = 0°, see details. Figure 5 Location of point D;

[0062] When L = c5·L0, β1 = a5·β E -b5; where c5 = 1, a5 = 1, b5 = 25°, see details. Figure 5 Location of point E in the middle.

[0063] The above-mentioned method for determining the inlet airflow angle of the guide vane cascade blades in the reverse thrust device is based on the actual flow field of the duct where the guide vane cascade is located, and comprehensively considers the influence of the duct outer wall and the flow barrier. The inlet airflow angle β1 of the blades is fitted as the angle β between the duct outer wall profile and the axis. A The angle β between the flow-blocking gate profile and the axis in the reverse state. E The first-order piecewise function relating the distance L from the blade to the front end of the guide vane cascade to the axial length L0 of the guide vane cascade has clear meanings for each term. It is highly efficient for determining the inlet airflow angle of the guide vane cascade blades in the thrust reverser device. Furthermore, it has been verified by experiments and simulations to have high accuracy, which can meet the needs of rapid design and iteration.

[0064] Since the guide vanes of the thrust reverser device of an aero-engine are convergent channels, the blades need to efficiently achieve large airflow deflection, minimize airflow separation and blockage, and ensure the flow capacity of the channel. The blades are typically designed to operate within a negative angle of attack range. Based on the method for determining the inlet airflow angle of the guide vanes of the thrust reverser device disclosed in the above embodiments, this application provides a method for determining the geometric inlet angle of the guide vanes of the thrust reverser device, as detailed below:

[0065] Based on the method for determining the inlet airflow angle of the guide vane cascade blade of the reverse thrust device disclosed in the above embodiments, the inlet airflow angle β1 of the blade is determined;

[0066] Calculate the blade geometric inlet angle β 1k =β1-i, i=-5°~-10°;

[0067] in,

[0068] i represents the blade angle of attack, the specific value of which can be determined by relevant technical personnel based on the actual situation when applying the technical solution disclosed in this application, and is usually -7.5°.

[0069] The method for determining the geometric inlet angle of the guide vane cascade blades of the thrust reverser disclosed in the above embodiments is based on the method for determining the inlet airflow angle of the guide vane cascade blades of the thrust reverser disclosed in the above embodiments. The description is relatively simple. For specific details, please refer to the relevant description in the section on determining the inlet airflow angle of the guide vane cascade blades of the thrust reverser. The technical effects can also be referred to the relevant part of the method for determining the inlet airflow angle of the guide vane cascade blades of the thrust reverser. It will not be repeated here.

[0070] The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0071] The technical solution of this application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A method for determining the inlet airflow angle of a thrust reverser device guide vane cascade, characterized in that, include: hour, ;in, , , ; hour, ;in, , , ; hour, ;in, , , ; hour, ;in, , , ; hour, ;in, , , ; in, This is the distance from the blade to the leading edge of the guide vane cascade. The axial length of the guide vane cascade; The inlet airflow angle of the blade; The angle between the outer wall profile of the culvert and the axis; In the reverse state, the angle between the flow-blocking gate profile and the axis.

2. The method for determining the inlet airflow angle of the guide vane cascade blades of the thrust reverser device according to claim 1, characterized in that, ， ， ； ， ， ； ， ， ； ， ， ； ， ， 。 3. A method for determining the geometric inlet angle of the guide vanes of a thrust reverser device, characterized in that, include: Based on the method for determining the inlet airflow angle of the guide vane cascade of the reverse thrust device according to any one of claims 1-2, the inlet airflow angle of the vane is determined. ; Calculate the blade geometric inlet angle , ; in, To improve the angle of attack of the blades.

4. The method for determining the geometric inlet angle of the guide vane cascade of the thrust reverser device according to claim 3, characterized in that, 。

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