Automated design method and apparatus of serpentine nozzle shape and grid

Abstract

The present invention relates to a method for designing a serpentine nozzle shape and a mesh, comprising the steps of inputting shape variables of a nozzle to be designed, generating a shape of the nozzle to be designed reflecting the shape variables, selecting an analysis domain for calculating the aerodynamic characteristics of the nozzle, and generating a mesh suitable for the shape of the nozzle and the analysis domain. According to the present invention, the fabrication of the serpentine nozzle shape and the mesh is easy, and parameter changes are easy, thereby enabling the generation of a more efficiently optimized mesh.

Description

Technology Field

[0001] The present invention relates to a method for designing a serpentine nozzle shape and a grid, and a design apparatus. Background Technology

[0002] As the nature of the battlefield changes, nations are developing precise detection and interception systems, and the need for detection evasion technology to counter this is growing. Stealth technology is one of the solutions to evade these threats and is essential for maximizing the survivability of friendly forces, particularly in areas with superior surface-to-air capabilities. Stealth technology focuses primarily on reducing infrared signals and radar cross-sections (RCS), enabling penetration deep into enemy territory by minimizing the enemy's radar detection range.

[0003] High-speed aircraft, particularly military aircraft such as stealth fighters, often adopt complex serpentine nozzle structures to reduce noise and enhance radar evasion performance. Unlike conventional straight nozzles, serpentine nozzles are designed with a serpentine shape, which is effective in lowering infrared signals at the Line of Sight (LOS) and reducing the Radar Cross Section (RCS), thereby reducing the likelihood of radar detection. However, due to the complex geometric structure of this type of nozzle, it is difficult to produce high-quality meshes. Furthermore, accurate and stable meshes are essential for analyzing the internal flow of serpentine nozzles, which is a critical factor in ensuring the reliability of Computational Fluid Dynamics (CFD) analysis.

[0004] There are several issues with the mesh generation process for serpentine nozzles using current commercial software. First, generating meshes for complex geometries requires significant time and effort, as well as being repetitive and heavily manual. Second, existing mesh generation tools lack flexible automation support for specialized geometries like serpentine nozzles, leading to the inconvenience of having to manually readjust parameters whenever the geometry is modified. Furthermore, the difficulty in generating meshes of consistent quality during the generation process can affect the reliability of CFD results.

[0005] Accordingly, an automated mesh generation method optimized for the serpentine nozzle shape is required. In particular, there is a need for a method to rapidly generate a mesh that fits the shape of the serpentine nozzle and maintain consistent quality using automation tools such as Pointwise's Glyph code.

[0006] The matters described in the background technology above are intended to aid in understanding the background of the invention and may include matters that are not prior art already known to those skilled in the art to which this technology belongs. Prior art literature

[0007] Korean Patent Publication No. 10-2012-0136283 The problem to be solved

[0008] The present invention has been devised to solve the aforementioned problems, and the purpose of the present invention is to provide a design method and design apparatus for a serpentine nozzle shape and a grid that facilitate the fabrication of the serpentine nozzle shape and the grid, and facilitate the modification of parameters, thereby enabling the generation of a more efficiently optimized grid. means of solving the problem

[0009] A method for designing a serpentine nozzle shape and a grid according to one aspect of the present invention comprises the steps of inputting shape variables of a nozzle to be designed, generating a shape of the nozzle to be designed that reflects the shape variables, selecting an analysis domain for calculating the aerodynamic characteristics of the nozzle, and generating a grid suitable for the shape of the nozzle and the analysis domain.

[0010] And, after the step of selecting the interpretation area, the method may further include a step of setting the size and number of the grid.

[0011] Furthermore, after the step of setting the size and number of the grids, the method further includes a step of setting boundary conditions of the grids, and the step of generating the grids is characterized by generating the grids by reflecting the size and number of the grids and the boundary conditions of the grids.

[0012] Meanwhile, the above shape variables include the inlet radius of the nozzle, the outlet aspect ratio of the nozzle, the height of the lowest point of the centerline curve from the nozzle inlet, the curvature of the nozzle centerline curve, the curvature of the eccentricity function, the curvature of the area function, and the location of the maximum area change rate.

[0013] In addition, the shape variables may further include the height of the nozzle exit from the lowest point of the centerline curve, the curvature of the centerline curve in the nozzle inlet direction, the curvature of the centerline curve in the nozzle exit direction, and the starting curvature of the centerline curve.

[0014] Next, a design device for a serpentine nozzle shape and a grid according to one aspect of the present invention includes an input unit for inputting shape variables of a nozzle to be designed and an analysis domain for calculating the aerodynamic characteristics of said nozzle, a nozzle shape generation unit for generating a shape of said nozzle to be designed reflecting said shape variables, and a grid generation unit for generating a grid suitable for said nozzle shape and said analysis domain.

[0015] In addition, the size and number of the grid and the boundary conditions of the grid are set through the input unit.

[0016] Furthermore, the grid generating unit is characterized by generating the grid by reflecting the size and number of the grids and the boundary conditions of the grids.

[0017] Meanwhile, the above shape variables include the inlet radius of the nozzle, the outlet aspect ratio of the nozzle, the height of the lowest point of the centerline curve from the nozzle inlet, the curvature of the nozzle centerline curve, the curvature of the eccentricity function, the curvature of the area function, and the location of the maximum area change rate.

[0018] In addition, the shape variables may further include the height of the nozzle exit from the lowest point of the centerline curve, the curvature of the centerline curve in the nozzle inlet direction, the curvature of the centerline curve in the nozzle exit direction, and the starting curvature of the centerline curve. Effects of the invention

[0019] The design method and design device for the serpentine nozzle shape and grid of the present invention provide technical advantages that effectively solve various problems occurring in the conventional serpentine nozzle grid generation process.

[0020] First, the present invention is equipped with the function to automatically generate high-quality grids tailored to the complex shape of a serpentine nozzle. This significantly improves the efficiency of grid production compared to existing methods that relied on manual labor, and reduces working time.

[0021] Second, the glyph code of the present invention increases the reliability of CFD analysis by maintaining consistent mesh quality. Through an automated mesh generation procedure, uniformity of mesh quality can be ensured even when repeated under the same shape and conditions, thereby guaranteeing consistency of analysis results.

[0022] Third, the present invention is designed to flexibly respond to changes in the shape of the serpentine nozzle. Since grids tailored to various shapes can be easily generated simply by adjusting parameters within the glyph code, it provides great flexibility in the process of design changes or optimization of the serpentine nozzle.

[0023] Fourth, the mesh produced through the present invention has a structure optimized to increase the accuracy of CFD analysis regarding noise reduction, drag reduction, and heat release characteristics of the serpentine nozzle, and provides improved analysis quality compared to existing methods.

[0024] In conclusion, the present invention provides a grid automation solution optimized for the shape of a serpentine nozzle, thereby having the effect of significantly improving the efficiency, reliability, flexibility, and accuracy of CFD analysis. Brief explanation of the drawing

[0025] Figure 1 is a pointwise glyph code flowchart for shape and grid fabrication in a serpentine nozzle. FIG. 2 is a flowchart of the design method for the serpentine nozzle shape and grid of the present invention. Figure 3 shows a glyph code GUI. Figures 4 and 5 further explain the input variable values. Specific details for implementing the invention

[0026] In order to fully understand the present invention, the operational advantages of the present invention, and the objectives achieved by the implementation of the present invention, reference must be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described therein.

[0027] In describing preferred embodiments of the present invention, known technologies or repetitive descriptions that may unnecessarily obscure the essence of the invention will be shortened or omitted.

[0028] FIG. 1 is a flowchart of pointwise glyph code for shape and grid fabrication for a serpentine nozzle, and FIG. 2 is a flowchart of the method for designing the shape and grid of a serpentine nozzle according to the present invention.

[0029] Hereinafter, a method for designing a serpentine nozzle shape and a grid and a design apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 and FIGS. 2.

[0030] The present invention is written in pointwise glyph code to generate a grid for designing the nozzle shape and the area for calculating the aerodynamic characteristics of the nozzle's interior and exterior. The nozzle shape is designed by inputting variable values ​​of various functions constituting the nozzle, such as the curvature of the nozzle centerline curve, the height and position of the lowest point of the centerline curve from the nozzle inlet, the curvature of the eccentricity function, the curvature of the area function, the position of the maximum rate of change of area, and the aspect ratio of the nozzle exit. Based on the designed nozzle exit, the size of the area for analyzing the nozzle's aerodynamic performance is set, and then a grid for the nozzle and the analysis area is generated to enable CFD analysis. After selecting commercial CFD software suitable for the analysis purpose and setting boundary conditions, the file is saved for CFD analysis. The variables required in the above process can be displayed and entered via the GUI.

[0031] The serpentine nozzle designed in the present invention is classified into a single serpentine nozzle and a double serpentine nozzle depending on whether the change in the curvature of the nozzle is one or two. When a GUI file corresponding to the code to be used to create a mesh is executed, variables for the nozzle shape and the analysis area can be entered as shown in Fig. 3.

[0032] Descriptions of nozzle variables are shown in Tables 1 and 2, and ΔY1 and ΔY2 can be referenced in Figures 4 and 5.

[0033] In the X, Y coordinates, L is the length of the serpentine nozzle, ΔY1 is the height of the lowest point of the centerline curve from the nozzle inlet, and ΔY2 is the height of the nozzle outlet from the lowest point of the centerline curve.

[0034] A single serpentine nozzle can be designed by inputting only the variables in Table 1, while a double serpentine nozzle can be designed by inputting both the variables in Table 1 and Table 2. Specifically, the variables for the nozzle shape to be analyzed are entered through the input section, and after selecting the radius and height of the cylindrical analysis region from the nozzle exit, clicking 'Input' executes the glyph code to generate a pointwise mesh file for the nozzle. The size of the cylindrical analysis region is created with a radius of approximately 5 to 10 times and a height of 50 to 100 times the nozzle length. Since the thickness and length of the plume vary depending on the nozzle shape to be analyzed and the output and thermal conditions applied to the nozzle, the variables in Table 1 are modified to match the analysis conditions. The input variables are reflected in the nozzle shape generation section and applied according to a polynomial that determines the x, y, and z coordinates of the centerline; subsequently, the nozzle shape is generated along the centerline curve, and an analysis region connected to the nozzle exit is created. Finally, a mesh is generated within the nozzle and the analysis region by the mesh generation section. Then, by selecting the CFD to be analyzed from the executed grid file and setting the boundary conditions, the preparation for computational analysis of the nozzle is complete.

[0035] User Input Variable note Inlet Radius Nozzle inlet radius Outlet AR Nozzle Exit Aspect Ratio ΔY1 Height of the lowest point of the centerline curve from the nozzle inlet b center curvature of the nozzle centerline curve c center The point where ΔY / 2 is located b ecc Curvature of the eccentricity function b area curvature of the area function c area Point where the compression ratio is halved / Location of maximum area change rate

[0036] User Input Variable note ΔY2 Height of the nozzle exit from the lowest point of the centerline curve b center,1 curvature of the centerline curve in the direction of the nozzle inlet c center,1 The point where ΔY1 / 2 is located b center,2 curvature of the centerline curve in the nozzle exit direction c center,2 The point where ΔY2 / 2 is located First Curve Ratio Starting curvature of the centerline curve

[0037] The specific process of generating nozzle shape and grid according to nozzle variable input (Input user variable) is as shown in Fig. 2.

[0038] Based on the eccentricity calculated according to variables, the nozzle type is classified as Straight / Single or Double, and the fillet parameter or center curve is calculated for each depending on whether it is elliptical.

[0039] Then, the tangent vector of the curve is calculated, and the section and grid are calculated.

[0040] As described above, according to the present invention, the serpentine nozzle shape and the mesh can be easily fabricated, and parameters can be easily changed, thereby enabling the generation of a more efficiently optimized mesh.

[0041] Although the present invention has been described above with reference to the illustrated drawings, it is obvious to those skilled in the art that it is not limited to the described embodiments and can be modified and varied in various ways without departing from the spirit and scope of the invention. Accordingly, such modifications or variations should be deemed to fall within the scope of the claims of the present invention, and the scope of rights of the present invention should be interpreted based on the appended claims.

Claims

Claim 1 delete Claim 2 delete Claim 3 delete Claim 4 A method for automated design of a serpentine nozzle shape and a grid, comprising: a step of inputting shape variables of a nozzle to be designed through an input unit; a step of generating the shape of the nozzle to be designed with the shape variables reflected by a nozzle shape generation unit; a step of selecting an analysis area for calculating the aerodynamic characteristics of the nozzle by the nozzle shape generation unit; a step of setting the size and number of grids; a step of setting boundary conditions of the grids; and a step of generating a glyph code by the grid generation unit to automatically generate a pointwise grid file suitable for the shape of the nozzle and the analysis area, wherein the step of automatically generating the grid file is characterized by generating it by reflecting the size and number of grids and the boundary conditions of the grids, and wherein the shape variables include the inlet radius of the nozzle, the outlet aspect ratio of the nozzle, the height of the lowest point of the centerline curve from the nozzle inlet, the curvature of the nozzle centerline curve, the curvature of the eccentricity function, the curvature of the area function, and the position of the maximum area change rate. Claim 5 A method for automated design of a serpentine nozzle shape and a grid according to claim 4, wherein the shape variables further include the height of the nozzle exit from the lowest point of the centerline curve, the curvature of the centerline curve in the nozzle inlet direction, the curvature of the centerline curve in the nozzle exit direction, and the starting curvature of the centerline curve. Claim 6 delete Claim 7 delete Claim 8 delete Claim 9 An automated design device for a serpentine nozzle shape and grid, comprising: an input unit for inputting shape variables of a nozzle to be designed and an analysis domain for calculating aerodynamic characteristics of said nozzle; a nozzle shape generation unit for generating the shape of said nozzle to be designed reflecting said shape variables; and a grid generation unit for generating a glyph code to automatically generate a pointwise grid file suitable for said nozzle shape and said analysis domain, wherein the size and number of said grids and boundary conditions of said grids are set through said input unit, and the grid generation unit is characterized by generating said grid file by reflecting said grid size and number and said grid boundary conditions, and said shape variables include the inlet radius of said nozzle, the outlet aspect ratio of said nozzle, the height of the lowest point of the centerline curve from said nozzle inlet, the curvature of said nozzle centerline curve, the curvature of the eccentricity function, the curvature of the area function, and the position of the maximum area change rate. Claim 10 An automated design device for a serpentine nozzle shape and grid according to claim 9, wherein the shape variables further include the height of the nozzle exit from the lowest point of the centerline curve, the curvature of the centerline curve in the nozzle inlet direction, the curvature of the centerline curve in the nozzle exit direction, and the starting curvature of the centerline curve.

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