A method for automatically generating a blocking domain for a turbine blade geometry

Abstract

This invention discloses a method for automatically generating block domains for turbine blade geometry. Based on the 2D blade profile of each radial section, an optimized 2D block is formed. These 2D blocks are then stacked radially using the same stacking lines as the blade stacking. Based on the geometric information of the 2D blade profile, O-blocks are constructed using shift-periodic topology. Finally, the optimized 2D blocks are stacked along the 3D blade stacking lines. This invention reduces mesh generation time; the use of shift-periodic topology to construct O-blocks avoids the high skewness caused by commonly used O-blocks; and the invention provides optimized 2D blocks, significantly improving mesh quality and reducing manual work involved in block generation.

Description

Technical Field

[0001] This invention relates to the field of turbine blade processing technology, and in particular to a method for automatically generating segmented domains of turbine blade geometry. Background Technology

[0002] In turbine-related research, ICEM CFD is frequently used as a mesh generation tool, thus requiring a block domain corresponding to the blade geometry. Since the optimization system involves extensive simulations, mesh generation is a significant workload. Therefore, to reduce mesh generation time, a block-based system / method was developed to automatically generate block domains. Summary of the Invention

[0003] The purpose of this invention is to provide a method for automatically generating block domains for turbine blade geometry, so as to solve the above-mentioned technical problems.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: a method for automatically generating block domains of turbine blade geometry, which forms an optimized two-dimensional block based on the two-dimensional blade profile of each radial section, and stacks the 2D blocks radially using the same stacking line as the blade stacking; constructs O-type blocks using shift periodic topology based on the geometric information of the 2D blade profile; and stacks the optimized 2D blocks along the 3D blade stacking line.

[0005] As a further optimization, the block region in the blade channel is bounded by the middle channel curve, which is formed by the midpoint of two adjacent blade profiles.

[0006] As a further optimization, an internal O-block is formed within the 2D blade profile for the radial portion at the blade tip.

[0007] As a further optimization, multiple vertices are designed to be movable to search for optimized blocks when generating blocks.

[0008] As a further optimization, parameterization of the tip groove is also included, whereby, given the tip clearance structure, the groove width w is parameterized. sq Axial cutoff percentage x sq and groove height h sq Control the geometry of the groove.

[0009] As a further optimization, the groove curve is generated by drawing a normal to the blade profile that is perpendicular to the groove width of a specified length.

[0010] As a further optimization, the curve is truncated along the blade axis by a percentage of axial cutoff.

[0011] As a further optimization, the trailing edge of the blade tip groove is drawn using a circular curve, and the radius of the circle is calculated to ensure a smooth connection between the groove profile and the circle. The groove cavity depth is controlled by the groove height.

[0012] As a further optimization, the groove width and groove height are designed to have different values ​​along the groove curve.

[0013] Compared with existing technologies, the beneficial effects of this invention are reflected in:

[0014] 1. This invention can reduce the time required for mesh generation;

[0015] 2. This invention can construct O-type blocks through shift periodic topology, avoiding the high skewness caused by commonly used O-type blocks.

[0016] 3. This invention can obtain optimized two-dimensional blocks, significantly improve mesh quality, and reduce manual work involved in block generation. Attached Figure Description

[0017] Figure 1 This invention uses a 2D block with shift period topology optimization.

[0018] Figure 2a This is the 3D static block of the present invention.

[0019] Figure 2b This is the 3D rotor block of the present invention.

[0020] Figure 3a This is a 2D schematic diagram of the blade tip groove of the present invention.

[0021] Figure 3b This is a 3D schematic diagram of the blade tip groove of the present invention. Detailed Implementation

[0022] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0023] Similar to the blade geometry generation system, the block system is also constructed in a 2D-3D manner. First, an optimized 2D block is formed based on the 2D blade profile of each radial section. Then, the 2D blocks are stacked radially using the same stacking lines as the blade stacking.

[0024] Based on the geometric information of the 2D blade profile, using, for example Figure 1The shifted periodic topology shown constructs an O-block. For high-steering blades, the commonly used O-block inevitably introduces high skewness to meet the periodicity requirement. This can be reduced by using a shifted periodic topology, as it exhibits corresponding periodicity at different index vertices. In the blade channel, the block domain is bounded by the middle channel curve, which is formed by the midpoint of two adjacent blade profiles, as shown. Figure 1 Curves v1-v2 and curves v3-v4 are shown in the figure. In addition, to generate the tip clearance grid, an extra internal O-block is formed within the blade profile for the radial portion at the top.

[0025] During block generation, multiple vertices are designed to move in search of an optimized block. Figure 1 Taking the vertices on the suction side of the rear edge as an example, vertex v5 moves on the O-shaped curve, and vertex v6 ​​moves along the tangent of the middle channel curve v1-v2. The block skewness is optimized by searching for the optimal combination of v5 and v6, i.e., obtaining the maximum value of the minimum angle among ∠1, ∠2, and ∠3, i.e., max[min(∠1, ∠2, ∠3)]. By applying a similar method to other moving vertices, optimized 2D blocks are obtained. This not only significantly improves mesh quality but also reduces the manual work involved in block generation. Figure 1 In the diagram, double-headed dashed arrows indicate how periodicity is applied to vertex pairs with different indices.

[0026] By stacking optimized 2D blocks along the 3D blade stacking line, the 3D blocks of the stator and rotor are formed as follows: Figure 2a and Figure 2b As shown, the 3D block is then imported into ICEM CFD, where a script is executed to automatically generate the mesh.

[0027] like Figure 3a and 3b As shown, several additional components are integrated into the parametric system to accommodate the design features of the turbine. These components are optional and depend on the designer's selection. To improve turbine tip performance, grooves can be added at the tip to block tip leakage flow and improve cooling performance. This design feature has been widely used in in-service engines such as the CFM56 and F100. The grooves are formed by the cavity at the tip, and under a given tip clearance structure, three parameters are used to control the groove geometry: groove width w sq Axial cutoff percentage x sq and groove height h sq .

[0028] By drawing a line perpendicular to the specified length w sq The groove curve is generated using the normal to the blade profile. This curve is along the blade axis at an x-axis. sqThe percentage cutoff was used to redraw the "trailing edge" of the blade tip groove using a circular curve. The radius of the circle was calculated to ensure a smooth connection between the groove profile and the circle. The groove cavity depth was determined by the groove height h. sq Control. To accommodate future design studies, the groove width and groove height can have different values ​​along the groove curve.

[0029] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A method for automatically generating block domains for turbine blade geometry, characterized in that, Includes the following steps: Based on the 2D blade profile of each radial section, an optimized 2D block is formed, which is bounded by the middle channel curve in the blade channel, which is formed by the midpoint of two adjacent blade profiles; 2D blocks are stacked radially using the same stacking line as the blade stack; O-blocks are constructed using a shift periodic topology based on the geometric information of the 2D blade profile, which has corresponding periodicity at different index vertices to reduce the high skewness caused by the commonly used O-blocks for high-steering blades; An internal O-shaped block is formed within the 2D blade profile for the radial portion of the blade tip to generate the tip clearance mesh. When generating the block, multiple vertices are designed to be movable to search for and optimize the block. By searching for combinations of movable vertices to optimize the block skewness, the maximum value of the minimum angle of each interior angle in the 2D block is obtained, i.e., max[min(∠1,∠2,∠3)]. The optimized 2D blocks are stacked along the 3D blade stacking line, and the 3D blocks are imported into ICEM CFD to execute the script to automatically generate the mesh. This also includes parameterizing the tip groove: given a tip clearance structure, using a parameterized groove width w sq Axial cutoff percentage x sq and groove height h sq Control the geometry of the groove; draw a groove width w perpendicular to the specified length. sq The normal to the blade profile generates a groove curve, which is cut off along the blade axis by an axial cutoff percentage x. sq Truncation; use a circular curve to draw the trailing edge of the blade tip groove, calculate the radius of the circle to ensure a smooth connection between the groove profile and the circle, and the groove cavity depth is determined by the groove height h. sq Control; along the groove curve, the groove width and groove height are designed to have different values.

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