Method and system for constructing a flying wing inlet aerodynamic model based on boundary layer height on a mark analysis

Abstract

The present application relates to the technical field of aero-engine whole machine test design, and discloses a flying wing inlet aerodynamic model construction method and system based on boundary layer height analysis, which constructs a side edge cutting line for cutting the two sides of the flying wing inlet and an axial cutting line for cutting the axial direction of the fuselage, cuts the fuselage together along the normal direction of the fuselage, obtains an aerodynamic structure containing the inlet and the front fuselage, and builds a corresponding simulation analysis model. The method can complete the aerodynamic cutting of the flying wing inlet fuselage under the premise of retaining the real internal and external flow aerodynamic characteristics of the inlet and ensuring the consistency of the flow field characteristics and the installed state, thereby simplifying the double-engine inlet model for the inlet and engine matching test, adapting the size constraint of the ground test site without losing the aerodynamic characteristics of the inlet, widening the large-scale inlet test capability, and avoiding the problems of high difficulty and cost in the trial manufacture and assembly of the full-size test piece.

Description

Technical Field

[0001] This invention relates to the field of aero-engine whole-engine test design technology, and discloses a method and system for constructing an aerodynamic model of a flying wing inlet based on boundary layer height benchmark analysis. Background Technology

[0002] Existing inlet stability tests are generally slab tests or simulated slab tests, which are difficult to fully simulate the inlet conditions under actual flight. In some stability verification tests, the air intake and engine of a real aircraft are tested together. For twin-engine aircraft, due to the large size of the air intake, only a single-engine, single-side air intake cut-down model is generally used for testing and verification, which is difficult to simulate the test conditions where the two engines influence each other. If twin-engine tests are conducted, due to the high degree of integration between the aircraft forebody and the air intake, most twin-engine air intake test pieces need to consider the aerodynamic effects of the local fuselage and wings, resulting in excessively large test piece sizes and difficulties in selecting test sites, high requirements for prototype manufacturing and assembly, and high costs. Summary of the Invention

[0003] The purpose of this invention is to provide a method and system for constructing aerodynamic models of flying wing inlets based on boundary layer height benchmarking analysis. This method can complete the aerodynamic tailoring of the flying wing inlet fuselage while preserving the actual internal and external aerodynamic characteristics of the inlet and ensuring that the flow field characteristics are consistent with the installed state. This simplifies the dual-engine inlet model used for engine matching tests, adapts to the size constraints of ground test sites, and avoids the problems of high difficulty and cost in the trial production and assembly of full-size test parts.

[0004] To achieve the above-mentioned technical effects, the technical solution adopted by the present invention is as follows:

[0005] A method for constructing aerodynamic models of flying wing inlets based on boundary layer height benchmarking analysis includes: Based on the design structure of the flying wing air intake, the straight lines passing through the two sides of the air intake lip and parallel to the air intake axis are used as reference lines. The reference lines are offset along the wingspan direction on both sides to form side trimming lines that trim the sides of the fuselage. Using any straight line located at the air intake outlet plane and passing through the fuselage as the axial cutting line, the fuselage is cut along the fuselage normal direction by the side cutting line and the axial cutting line to form an aerodynamic structure including the air intake and the front fuselage. Based on the aerodynamic structure obtained by cutting, a simulation analysis model of the aerodynamic structure is constructed.

[0006] Furthermore, under given flight conditions and boundary conditions, a three-dimensional simulation of internal and external flows is performed on the constructed aerodynamic structure simulation analysis model to obtain the boundary layer thickness at the cut surfaces on both sides of the fuselage. If the average boundary layer thickness at the cut surfaces on both sides of the fuselage is less than or equal to a preset thickness threshold, the cutting scheme meets the requirements. Otherwise, the offset distance of the side cut lines on both sides of the fuselage is adjusted until the average boundary layer thickness at the cut surfaces on both sides of the fuselage is less than or equal to the preset thickness threshold, thus completing the optimization of the simulation analysis model.

[0007] Furthermore, the preset thickness threshold ,in The distance from the initial incoming flow to the leading edge point of the simulation analysis model of the aerodynamic structure under given flight conditions is denoted as . Let be the Reynolds number of the initial incoming flow.

[0008] Furthermore, if the average thickness of the boundary layer at the cut surfaces on both sides of the fuselage is greater than a preset thickness threshold, the offset distance of the side cut lines will be adjusted to... ,in To adjust the offset distance of the side cutting lines mentioned before the cutting width, , The diameter of the intake lip is [missing information]. This represents the average thickness of the boundary layer at the cut surfaces on both sides of the fuselage.

[0009] To achieve the above-mentioned technical effects, the present invention also provides a flying wing inlet aerodynamic model construction system based on boundary layer height benchmarking analysis, used to implement the aforementioned flying wing inlet aerodynamic model construction method based on boundary layer height benchmarking analysis, including: The side trimming line determination module is used to determine the side trimming lines for the fuselage by taking the straight lines that pass through the two sides of the air intake lip and are parallel to the air intake axis as reference lines, and offsetting the reference lines along the wingspan direction on both sides, according to the design structure of the flying wing air intake. The axial cutting line determination module is used to take any straight line located on the air intake outlet plane and passing through the fuselage as the axial cutting line, and cut the fuselage along the fuselage normal with the side cutting line and the axial cutting line to form an aerodynamic structure including the air intake and the front fuselage. The aerodynamic model building module is used to build a simulation analysis model of the aerodynamic structure based on the aerodynamic structure obtained by cutting.

[0010] Furthermore, it also includes an optimization and adjustment module, which is used to conduct three-dimensional simulation of internal and external flows on the constructed aerodynamic structure simulation analysis model under given flight conditions and boundary conditions, and obtain the boundary layer thickness at the cut surfaces on both sides of the fuselage; if the average boundary layer thickness at the cut surfaces on both sides of the fuselage is less than or equal to a preset thickness threshold, the cutting scheme meets the requirements; otherwise, the offset distance of the side cut lines on both sides of the fuselage is adjusted until the average boundary layer thickness at the cut surfaces on both sides of the fuselage is less than or equal to the preset thickness threshold, thus completing the optimization of the simulation analysis model.

[0011] Furthermore, in the optimization and adjustment module, the preset thickness threshold... ,in The distance from the initial incoming flow to the leading edge point of the simulation analysis model of the aerodynamic structure under given flight conditions is denoted as . Let be the Reynolds number of the initial incoming flow.

[0012] Furthermore, in the optimization and adjustment module, if the average thickness of the boundary layer at the cutting surfaces on both sides of the fuselage is greater than a preset thickness threshold, the offset distance of the side cutting lines is adjusted to... ,in To adjust the offset distance of the side cutting lines mentioned before the cutting width, , The diameter of the intake lip is [missing information]. This represents the average thickness of the boundary layer at the cut surfaces on both sides of the fuselage.

[0013] Compared with the prior art, the beneficial effects of this invention are: 1. This invention can complete the aerodynamic tailoring of the fuselage of the flying wing air intake while preserving the true internal and external aerodynamic characteristics of the air intake and ensuring that the flow field characteristics are consistent with the installed state, thereby simplifying the twin-engine air intake model for the air intake matching test; it can take into account the influence of internal and external flow on the aerodynamic characteristics of the air intake, and is especially suitable for the test design of the air intake of the flying wing configuration aircraft.

[0014] 2. When conducting full-scale air intake-related tests using the aerodynamic model of the flying wing constructed using this invention, the test site and space are saved to the greatest extent without being affected by the scaling effect; compared with traditional air intake wind tunnel tests, the full-scale air intake test piece obtained by this invention can be used to conduct air intake matching tests and verification in real environment. Attached Figure Description

[0015] Figure 1 This is a flowchart of the aerodynamic model construction method for the flying wing inlet based on boundary layer height benchmarking analysis in Example 1; Figure 2 This is a block diagram of the system structure for constructing the aerodynamic model of the flying wing inlet based on boundary layer height benchmarking analysis in Example 1; Figure 3This is a flowchart of the aerodynamic model construction method for the flying wing inlet based on boundary layer height benchmarking analysis in Example 2; Figure 4 This is a schematic diagram of the two side cutting lines on both sides of the fuselage in Example 2; Figure 5 This is a schematic diagram of the axial cutting line in Example 2; Figure 6 This is an aerodynamic structure diagram of the air intake and the front fuselage formed in step two of Example 2; The module includes: 1. Air intake; 2. Side trimming line determination module; 3. Axial trimming line determination module; 4. Aerodynamic model construction module; and 5. Optimization and adjustment module. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the above-described subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0017] Example 1 See Figures 1 to 2 A method for constructing an aerodynamic model of a flying wing inlet based on boundary layer height benchmarking analysis includes: According to the design structure of the flying wing air intake 1, the straight lines passing through the two sides of the lip of the air intake 1 and parallel to the axis of the air intake 1 are used as reference lines. The reference lines are offset along the wingspan direction on both sides to form side trimming lines that trim the sides of the fuselage. Take any straight line located at the outlet plane of the air intake 1 and passing through the fuselage as the axial cutting line, and cut the fuselage along the fuselage normal with the side cutting line and the axial cutting line to form an aerodynamic structure including the air intake 1 and the front fuselage. Based on the aerodynamic structure obtained by cutting, a simulation analysis model of the aerodynamic structure is constructed.

[0018] In this embodiment, by constructing side trimming lines that trim both sides of the flying wing air intake duct 1 and axial trimming lines that trim the fuselage axis, the fuselage is trimmed along the fuselage normal to obtain an aerodynamic structure including the air intake duct 1 and the forward fuselage, and a corresponding simulation analysis model is built accordingly. This method can complete the aerodynamic trimming of the flying wing air intake duct 1 fuselage while preserving the actual internal and external aerodynamic characteristics of the air intake duct 1 and ensuring that the flow field characteristics are consistent with the installed state. This simplifies the dual-engine air intake duct 1 model used for engine matching tests. It can adapt to the size constraints of the ground test site without losing the aerodynamic characteristics of the air intake duct 1, expand the testing capability of large-scale air intake duct 1, and avoid the problems of high difficulty and cost in the final assembly of full-size test parts.

[0019] Based on the same inventive concept, this embodiment also provides an aerodynamic model construction system for a flying wing inlet 1 based on boundary layer height benchmarking analysis, used to implement the aforementioned aerodynamic model construction method for a flying wing inlet 1 based on boundary layer height benchmarking analysis, including: The side trimming line determination module 2 is used to determine the side trimming lines for the fuselage by taking the straight lines that pass through the two sides of the lip of the air intake 1 and are parallel to the axis of the air intake 1 as reference lines, and offsetting the reference lines along the wingspan direction on both sides to form side trimming lines for the fuselage on both sides, according to the design structure of the flying wing air intake 1. The axial cutting line determination module 3 is used to take any straight line located at the outlet plane of the air intake duct 1 and passing through the fuselage as the axial cutting line, and cut the fuselage along the fuselage normal with the side cutting line and the axial cutting line to form an aerodynamic structure including the air intake duct 1 and the front fuselage. The aerodynamic model construction module 4 is used to construct a simulation analysis model of the aerodynamic structure based on the aerodynamic structure obtained by cutting.

[0020] The aerodynamic model construction system for the flying wing air intake 1 in this embodiment also includes an optimization and adjustment module 5, which is used to conduct three-dimensional simulations of the internal and external flows of the constructed aerodynamic structure simulation analysis model under given flight conditions and boundary conditions, and obtain the boundary layer thickness at the cut surfaces on both sides of the fuselage. If the average boundary layer thickness at the cut surfaces on both sides of the fuselage is less than or equal to a preset thickness threshold, the cutting scheme meets the requirements; otherwise, the offset distance of the side cut lines on both sides of the fuselage is adjusted until the average boundary layer thickness at the cut surfaces on both sides of the fuselage is less than or equal to the preset thickness threshold, thus completing the optimization of the simulation analysis model. The constructed simulation analysis model can be verified, and the size cutting of the air intake 1 test piece in the limited space can be optimized. This achieves high-precision capture of the internal and external spatial flow field characteristics of the air intake 1 test piece based on the real airflow distribution, ensuring the consistency between the internal flow field of the air intake 1 and the installed state.

[0021] Example 2 See Figures 3 to 6 A method for constructing an aerodynamic model of a flying wing inlet based on boundary layer height benchmarking analysis includes: Step 1: Based on the design structure of the flying wing air intake 1, take the straight lines that pass through the two sides of the lip of the air intake 1 and are parallel to the axis of the air intake 1 as the reference lines, and offset the reference lines along the wingspan direction on both sides to form the side trimming lines that trim the two sides of the fuselage. Because it is 1.5 meters away from the centerline of the intake section D The cross-section is crucial for the termination of near-field disturbances at the lip and the stabilization of the mainstream. Furthermore, the near-wall thin boundary layer thickens slightly due to shock compression, and most localized small separation bubbles are around 1.5 mm. D The section is closed and reattached before the current flow occurs, and there is no large-scale backflow separation at this section. Therefore, an offset of 0.5 is applied. D This is an optimal suggested value. Therefore, as... Figure 4 As shown, in this embodiment, a straight line passing through both sides of the lip of the intake duct 1 and parallel to the axis of the intake duct 1 is first drawn. Set the offset distance as the baseline. By applying an offset, two side cutting lines are obtained on both sides of the fuselage. and .

[0022] Step 2: Take any straight line located at the outlet plane of the air intake duct 1 and passing through the fuselage as the axial cutting line, and cut the fuselage along the fuselage normal with the side cutting line and the axial cutting line to form an aerodynamic structure including the air intake duct 1 and the front fuselage. In this embodiment, the axial cutting line like Figure 5 As shown. After cutting, the resulting aerodynamic structure, including the air intake duct 1 and the forward fuselage, is as follows. Figure 6 As shown.

[0023] Step 3: Based on the aerodynamic structure obtained by cutting, construct a simulation analysis model of the aerodynamic structure.

[0024] Step 4: Based on the simulation analysis model obtained in Step 3, under the given flight conditions and boundary conditions, conduct three-dimensional simulation of internal and external flows on the constructed aerodynamic structure simulation analysis model to obtain the boundary layer thickness at the cut surfaces on both sides of the fuselage; if the average boundary layer thickness at the cut surfaces on both sides of the fuselage is less than or equal to the preset thickness threshold, then the cutting scheme meets the requirements. In this embodiment, the preset thickness threshold ,in The distance from the initial incoming flow to the leading edge point of the simulation analysis model of the aerodynamic structure under given flight conditions is denoted as . The Reilly number of the initial incoming flow is the local boundary layer thickness, used as a reference value.

[0025] In this embodiment, if the average thickness of the boundary layer at the cut surfaces on both sides of the fuselage is greater than a preset thickness threshold, the offset distance of the side cut lines is adjusted to... ,in To adjust the offset distance of the side cutting lines mentioned before the cutting width, The diameter of the lip of the air intake duct 1 is [missing information]. This represents the average thickness of the boundary layer at the cut surfaces on both sides of the fuselage. The advantage of using this thickness offset is that the influence of the local boundary layer can be eliminated in the adjustment value.

[0026] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for constructing an aerodynamic model of a flying wing inlet based on boundary layer height benchmarking analysis, characterized in that, include: Based on the design structure of the flying wing air intake, the straight lines passing through the two sides of the air intake lip and parallel to the air intake axis are used as reference lines. The reference lines are offset along the wingspan direction on both sides to form side trimming lines that trim the sides of the fuselage. Using any straight line located at the air intake outlet plane and passing through the fuselage as the axial cutting line, the fuselage is cut along the fuselage normal direction by the side cutting line and the axial cutting line to form an aerodynamic structure including the air intake and the front fuselage. Based on the aerodynamic structure obtained by cutting, a simulation analysis model of the aerodynamic structure is constructed; Under given flight conditions and boundary conditions, a three-dimensional simulation of internal and external flows is carried out on the constructed aerodynamic structure simulation analysis model to obtain the boundary layer thickness at the cut surfaces on both sides of the fuselage. If the average boundary layer thickness at the cut surfaces on both sides of the fuselage is less than or equal to a preset thickness threshold, the cutting scheme meets the requirements. Otherwise, the offset distance of the side cut lines on both sides of the fuselage is adjusted until the average boundary layer thickness at the cut surfaces on both sides of the fuselage is less than or equal to the preset thickness threshold, thus completing the optimization of the simulation analysis model. If the average thickness of the boundary layer at the cut surfaces on both sides of the fuselage is greater than the preset thickness threshold, then adjust the offset distance of the side cut lines to: ,in To adjust the offset distance of the side cutting lines mentioned before the cutting width, , The diameter of the intake lip is [missing information]. This represents the average thickness of the boundary layer at the cut surfaces on both sides of the fuselage.

2. The method for constructing an aerodynamic model of a flying wing inlet based on boundary layer height benchmarking analysis according to claim 1, characterized in that, The preset thickness threshold ,in The distance from the initial incoming flow to the leading edge point of the simulation analysis model of the aerodynamic structure under given flight conditions is denoted as . Let be the Reynolds number of the initial incoming flow.

3. A flying wing inlet aerodynamic model construction system based on boundary layer height benchmarking analysis, used to implement the flying wing inlet aerodynamic model construction method based on boundary layer height benchmarking analysis as described in any one of claims 1 to 2, characterized in that, include: The side trimming line determination module is used to determine the side trimming lines for the fuselage by taking the straight lines that pass through the two sides of the air intake lip and are parallel to the air intake axis as reference lines, and offsetting the reference lines along the wingspan direction on both sides, according to the design structure of the flying wing air intake. The axial cutting line determination module is used to take any straight line located on the air intake outlet plane and passing through the fuselage as the axial cutting line, and cut the fuselage along the fuselage normal with the side cutting line and the axial cutting line to form an aerodynamic structure including the air intake and the front fuselage. The aerodynamic model building module is used to build a simulation analysis model of the aerodynamic structure based on the aerodynamic structure obtained by cutting.

4. The flying wing inlet aerodynamic model construction system based on boundary layer height benchmarking analysis according to claim 3, characterized in that, It also includes an optimization and adjustment module, which is used to perform three-dimensional simulation of internal and external flows on the constructed aerodynamic structure simulation analysis model under given flight conditions and boundary conditions, and obtain the boundary layer thickness at the cut surfaces on both sides of the fuselage; if the average boundary layer thickness at the cut surfaces on both sides of the fuselage is less than or equal to a preset thickness threshold, the cutting scheme meets the requirements; otherwise, the offset distance of the side cut lines on both sides of the fuselage is adjusted until the average boundary layer thickness at the cut surfaces on both sides of the fuselage is less than or equal to the preset thickness threshold, thus completing the optimization of the simulation analysis model.

5. The flying wing inlet aerodynamic model construction system based on boundary layer height benchmarking analysis according to claim 4, characterized in that, In the optimization and adjustment module, the preset thickness threshold ,in The distance from the initial incoming flow to the leading edge point of the simulation analysis model of the aerodynamic structure under given flight conditions is denoted as . Let be the Reynolds number of the initial incoming flow.

6. The flying wing inlet aerodynamic model construction system based on boundary layer height benchmarking analysis according to claim 4, characterized in that, In the optimization and adjustment module, if the average thickness of the boundary layer at the cutting surfaces on both sides of the fuselage is greater than a preset thickness threshold, the offset distance of the side cutting lines is adjusted to... ,in To adjust the offset distance of the side cutting lines mentioned before the cutting width, , The diameter of the intake lip is [missing information]. This represents the average thickness of the boundary layer at the cut surfaces on both sides of the fuselage.

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