Non-axisymmetric end wall structure based on spline curved surface, compressor blade and application

Abstract

The invention relates to the field of pneumatic design of gas compressors, in particular to a non-axisymmetric end wall structure based on a spline curved surface, a gas compressor blade and application, and the modeling range of the non-axisymmetric end wall structure covers the area from 25% of the axial chord length of the upstream of the front edge of the blade to 25% of the axial chord length of the downstream of the tail edge of the blade in the axial direction. The axial chord length is the axial distance between the front edge and the tail edge of the blade; the end wall profile is obtained by lofting six tangential control lines, and each tangential control line is a cubic spline curve which is determined by six points and has tangential width equal to the pitch; the end wall molded surface obtained by lofting the six tangential control lines is characterized by comprising a concave pit close to a suction surface at the front section of the blade channel and a double-peak convex hull at the rear section of the blade channel in geometrical characteristics. The present disclosure is directed to improving flow in a compressor blade end region.

Description

Technical Field

[0001] The present disclosure relates to the field of compressor aerodynamic design, and in particular to a non-axisymmetric end wall structure based on a spline surface, a compressor blade, and applications. Background Art

[0002] Modern aviation compressor aerodynamic design no longer solely focuses on improving the load capacity of energy conversion stages. Instead, it requires balancing the contradictions between high load, high flow, high efficiency, and surge margin across the entire operating range. A major challenge in high-load compressor design is the difficulty in controlling the highly three-dimensional flow, resulting in severe secondary flow and flow separation issues. Flow losses caused by secondary flow can account for 30%-50% of the total aerodynamic losses within a blade row.

[0003] However, three-dimensional separation in compressors not only dramatically increases flow losses but can also deteriorate the inlet flow environment at the downstream blade row, potentially even inducing rotating stall. Consequently, secondary flow and three-dimensional separation are key factors limiting the performance of modern aviation compressors, making flow control a key area of ​​focus in compressor aerodynamic design. Summary of the Invention

[0004] To solve the above-mentioned problems mentioned in the background technology, the present disclosure proposes a non-axisymmetric end wall structure based on a spline surface, a compressor blade and an application, aiming to improve the flow in the end area of ​​the compressor blade.

[0005] According to one aspect of the present disclosure, a non-axisymmetric end wall structure based on a spline surface is provided, wherein the shaping range of the non-axisymmetric end wall structure covers an area in the axial direction from 25% of the axial chord length upstream of the leading edge of the blade to 25% of the axial chord length downstream of the trailing edge, wherein the axial chord length is the axial distance between the leading edge and the trailing edge of the blade; the end wall profile is obtained by lofting 6 tangential control lines, wherein each tangential control line is a cubic spline curve determined by 6 points and has a tangential width equal to the pitch; the end wall profile obtained by lofting the 6 tangential control lines includes, in terms of geometric features, a concave pit near the suction surface in the front section of the blade channel and a double-peak convex hull in the rear section of the blade channel.

[0006] Optionally, the six tangential control lines include the first tangential control line to the sixth tangential control line, the first tangential control line and the sixth tangential control line respectively determine the axial boundaries of the end wall profile, and the second tangential control line to the fifth tangential control line are equidistantly distributed between the leading edge and the trailing edge.

[0007] Optionally, the line connecting the endpoints on the same side of the first tangential control line and the second tangential control line is tangent to the center arc line at the leading edge; the line connecting the endpoints on the same side of the fifth tangential control line and the sixth tangential control line is tangent to the center arc line of the blade at the trailing edge of the blade; the two fixed points at both ends of the second tangential control line to the fifth tangential control line are respectively connected to the center arc lines of two adjacent blades, and the tangential distance between two adjacent points on each control line is equal, and is equal to one-fifth of the pitch, wherein the pitch is the tangential distance between the leading edges of two adjacent blades.

[0008] Optionally, the spanwise coordinates of the first tangential control line and the sixth tangential control line are both 0, forming a straight line whose spanwise coordinate is equal to 0.

[0009] Optionally, the second tangential control line to the fifth tangential control line are determined by fixed points at both ends with spanwise coordinates equal to 0 and four control points in the middle.

[0010] Optionally, the relative spanwise coordinates of the four control points between the second tangential control line and the fifth tangential control line are as follows: the relative spanwise coordinates of the points on the second tangential control line are: -0.0065, -0.0266, -0.0430 and -0.0434 respectively; the relative spanwise coordinates of the points on the third tangential control line are: -0.0033, -0.0290, -0.0692 and -0.0360 respectively; the relative spanwise coordinates of the points on the fourth tangential control line are: 0.0185, 0.0245, -0.0186 and -0.0193 respectively; the relative spanwise coordinates of the points on the fifth tangential control line are: 0.0022, 0.0168, 0.0353 and 0.0204 respectively; wherein, the relative spanwise coordinate is defined as the ratio of the spanwise coordinate value to the blade chord length.

[0011] According to another aspect of the present disclosure, a compressor blade is provided, having the non-axisymmetric end wall structure based on the spline surface.

[0012] According to another aspect of the present disclosure, there is provided an application of the compressor blade in an aircraft engine.

[0013] Compared with the prior art, the beneficial effects of the present disclosure are: 1) The present disclosure can reduce the total pressure loss of airflow through the blade channel by suppressing the corner separation of the compressor blade tip area; 2) The present disclosure can avoid stall under high angle of attack conditions by weakening compressor angular separation under high angle of attack conditions, thereby expanding the available angle of attack range of the compressor blades.

[0014] 3) The precise design of the end wall profile and the layout of the control lines disclosed in this disclosure significantly improve the flow in the end area of ​​the compressor blade. This improvement can optimize the aerodynamic performance of the compressor, including increasing flow rate and reducing noise, thereby improving overall performance.

[0015] 4) The non-axisymmetric endwall structure disclosed in the present invention expands the range of available angles of attack, enabling the compressor to adapt to more variable operating conditions. This improved adaptability enables the compressor to maintain efficient and stable operation within a wider operating range, enhancing its flexibility and reliability in practical applications.

[0016] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

[0017] Further features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings herein are incorporated into and constitute a part of the specification. These drawings illustrate embodiments consistent with the present disclosure and, together with the specification, are used to explain the technical solutions of the present disclosure.

[0019] Figure 1 A schematic diagram of parameterization of a non-axisymmetric end wall in an embodiment of the present disclosure is shown; Figure 2 shows a contour line cloud diagram of a non-axisymmetric end wall in an example of the present disclosure; Figure 3 A compressor blade having a non-axisymmetric endwall in an embodiment of the present disclosure is shown; Figure 4 A graph showing the variation of the total pressure loss coefficient with the angle of attack of the prototype blade cascade and the non-axisymmetric endwall blade cascade in the embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0020] Various exemplary embodiments, features, and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0021] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0022] In addition, numerous specific details are provided in the following detailed description to better illustrate the embodiments of the present disclosure. Those skilled in the art will appreciate that the present disclosure can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art are not described in detail in order to highlight the main points of the present disclosure.

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure.

[0024] The present disclosure provides a non-axisymmetric end wall structure based on a spline surface. The non-axisymmetric end wall structure includes an end wall profile formed by lofting six tangential control lines, wherein each control line is a cubic spline curve with a tangential width equal to the pitch, determined by six points. The blade parameters are shown in Table 1: Table 1 Blade parameters

[0025] In one embodiment, if Figure 1 The figure shows a schematic diagram of the parameterization of a non-axisymmetric end wall. The modeling range covers the area from 25% of the axial chord length upstream of the leading edge to 25% of the axial chord length downstream of the trailing edge in the axial direction. The end wall profile is obtained by lofting six tangential control lines. Each tangential control line is a cubic spline curve determined by six points. Among them, the first tangential control line ( Figure 1 The axial position of L1 in the figure is 25% of the axial chord length upstream of the leading edge of the blade. The second tangential control line ( Figure 1 The axial position of L2 in the figure is at the leading edge of the blade, and the third tangential control line ( Figure 1 L3 in) and the fourth tangential control line ( Figure 1 The axial positions of L4 in the figure are respectively at 33% and 67% of the axial chord length downstream of the leading edge of the blade. The fifth tangential control line ( Figure 1 The axial position of L5 in the figure is at the trailing edge of the blade, and the sixth tangential control line ( Figure 1 The axial position of L6 in FIG is 25% of the axial chord length downstream of the blade trailing edge.

[0026] In one embodiment, the geometric features of the end wall profile include a concave pit near the suction surface at the front section of the blade channel and a double-peak convex hull at the rear section of the blade channel, which can reduce the total pressure loss of the airflow through the blade channel by suppressing the corner area separation of the compressor blade end area.

[0027] In one embodiment, the line connecting the endpoints on the same side of the first tangential control line and the second tangential control line is tangent to the center arc line at the leading edge; the line connecting the endpoints on the same side of the fifth tangential control line and the sixth tangential control line is tangent to the center arc line of the blade at the trailing edge of the blade; the two fixed points at both ends of the second tangential control line to the fifth tangential control line are respectively connected to the center arc lines of two adjacent blades, and the tangential distance between two adjacent points on each control line is equal, which is equal to one-fifth of the pitch, wherein the pitch is the tangential distance between the leading edges of two adjacent blades.

[0028] In one embodiment, the spanwise coordinates of the first tangential control line and the sixth tangential control line are both 0, forming a straight line with a spanwise coordinate equal to 0. The second to fifth tangential control lines are defined by fixed points with spanwise coordinates equal to 0 at both ends and four control points in the middle.

[0029] In one embodiment, the relative spanwise coordinates of the four control points between the second tangential control line and the fifth tangential control line are as follows: the relative spanwise coordinates of the points on the second tangential control line are: -0.0065, -0.0266, -0.0430 and -0.0434 respectively; the relative spanwise coordinates of the points on the third tangential control line are: -0.0033, -0.0290, -0.0692 and -0.0360 respectively; the relative spanwise coordinates of the points on the fourth tangential control line are: 0.0185, 0.0245, -0.0186 and -0.0193 respectively; the relative spanwise coordinates of the points on the fifth tangential control line are: 0.0022, 0.0168, 0.0353 and 0.0204 respectively; wherein the relative spanwise coordinate is defined as the ratio of the spanwise coordinate value to the blade chord length. As shown in Table 2, the relative spanwise coordinates of each point on the tangential control lines L2 to L5 are given, where each point is named after the name of the tangential control line to which it belongs plus Figure 1 The point numbers are shown, for example, the second point of the second tangential control line L2 is called L22. The relative spanwise coordinates in Table 3 are defined as the ratio of the spanwise coordinate value to the blade chord length.

[0030] Table 2 Relative spanwise coordinates of points on the tangent control line

[0031] Obtained by the above 6 tangent control lines Figure 2 Non-axisymmetric end wall profile shown.

[0032] The embodiment of the present disclosure further provides a compressor blade, including the non-axisymmetric end wall structure based on the spline surface in the above embodiment, such as Figure 3 Shown is a compressor blade with a non-axisymmetric end wall in this embodiment.

[0033] in, Figure 4The variation of the total pressure loss coefficient of the prototype cascade and the non-axisymmetric endwall cascade with angle of attack is presented. The non-axisymmetric endwall reduces the total pressure loss of the compressor cascade at angles of attack ranging from -4 to +6 degrees. At +6 degrees, the non-axisymmetric endwall reduces the total pressure loss of the prototype cascade in a stalled state to that of a non-stalled state by weakening the angular separation, with a loss reduction of 47%.

[0034] Through the above analysis, it can be seen that the compressor blades in the embodiment of the present disclosure can achieve good results when applied to aircraft engines, that is, they can avoid stall under high angle of attack conditions by weakening the compressor angular zone separation under high angle of attack conditions, thereby expanding the available angle of attack range of the compressor blades.

[0035] The flow charts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems, methods and computer program products according to multiple embodiments of the present disclosure. In this regard, each box in the flow chart or block diagram can represent a part of a module, program segment or instruction, and the part of the module, program segment or instruction contains one or more executable instructions for realizing the prescribed logical function. In some alternative implementations, the functions marked in the box can also occur in a sequence different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs the prescribed function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0036] While various embodiments of the present disclosure have been described above, the above descriptions are illustrative, non-exhaustive, and not intended to be limiting of the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technical improvements to existing technologies, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A non-axisymmetric end wall structure based on a spline surface, characterized in that: The shaping range of the non-axisymmetric end wall structure covers the area from 25% of the axial chord length upstream of the leading edge of the blade to 25% of the axial chord length downstream of the trailing edge in the axial direction, where the axial chord length is the axial distance between the leading edge and the trailing edge of the blade; the end wall profile is obtained by lofting 6 tangential control lines, wherein each tangential control line is a cubic spline curve determined by 6 points and has a tangential width equal to the pitch; the end wall profile obtained by lofting the 6 tangential control lines includes a pit near the suction surface in the front section of the blade channel and a double-peak convex hull in the rear section of the blade channel in terms of geometric features.

2. The non-axisymmetric end wall structure based on spline surface according to claim 1, characterized in that: The six tangential control lines include the first tangential control line to the sixth tangential control line. The first tangential control line and the sixth tangential control line respectively determine the axial boundaries of the end wall profile. The second tangential control line to the fifth tangential control line are equidistantly distributed between the leading edge and the trailing edge.

3. The non-axisymmetric end wall structure based on spline surface according to claim 2, characterized in that: The line connecting the endpoints on the same side of the first tangential control line and the second tangential control line is tangent to the center arc line at the leading edge; the line connecting the endpoints on the same side of the fifth tangential control line and the sixth tangential control line is tangent to the center arc line of the blade at the trailing edge of the blade; the two fixed points at both ends of the second tangential control line to the fifth tangential control line are respectively connected to the center arc lines of two adjacent blades, and the tangential distance between two adjacent points on each control line is equal, which is equal to one-fifth of the pitch, wherein the pitch is the tangential distance between the leading edges of two adjacent blades.

4. The non-axisymmetric end wall structure based on spline surface according to claim 2, characterized in that: The spanwise coordinates of the first tangential control line and the sixth tangential control line are both 0, forming a straight line whose spanwise coordinate is equal to 0.

5. The non-axisymmetric end wall structure based on spline surface according to claim 2, characterized in that: The second tangential control line to the fifth tangential control line are determined by fixed points at both ends with spanwise coordinates equal to 0 and four control points in the middle.

6. The non-axisymmetric end wall structure based on spline surface according to claim 2, characterized in that: The relative spanwise coordinates of the four control points between the second tangent control line and the fifth tangent control line are as follows: the relative spanwise coordinates of the points on the second tangent control line are: -0.0065, -0.0266, -0.0430 and -0.0434 respectively; the relative spanwise coordinates of the points on the third tangent control line are: -0.0033, -0.0290, -0.0692 and -0.0360 respectively; the relative spanwise coordinates of the points on the fourth tangent control line are: 0.0185, 0.0245, -0.0186 and -0.0193 respectively; the relative spanwise coordinates of the points on the fifth tangent control line are: 0.0022, 0.0168, 0.0353 and 0.0204 respectively; among which, the relative spanwise coordinate is defined as the ratio of the spanwise coordinate value to the blade chord length.

7. A compressor blade, characterized in that: The invention has a non-axisymmetric end wall structure based on a spline surface as described in any one of claims 1 to 6.

8. Use of the compressor blade according to claim 7 in an aircraft engine.

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