Centrifugal impeller disk structure and centrifugal compressor

Abstract

The invention relates to the technical field of aviation power structures, in particular to a centrifugal impeller disc structure and a centrifugal compressor, and the centrifugal impeller disc structure comprises a wheel core, a wheel flange, an inner flow channel and a wheel back; the wheel core and the wheel flange are arranged oppositely, the inner flow channel and the wheel back are arranged oppositely, a wheel disc inlet is formed in the end, close to the wheel core, of the inner flow channel, and a wheel disc outlet is formed in the end, close to the wheel flange, of the inner flow channel. And the side, close to the wheel disc outlet, of the inner flow channel shrinks in the direction close to the wheel core, so that the radius of the wheel disc outlet is smaller than a preset wheel disc parameter. The design period is guaranteed, meanwhile, the strength and deformation problems are considered in advance, normal operation of the centrifugal impeller disc structure and the centrifugal compressor provided with the centrifugal impeller disc structure is guaranteed, and the corresponding operation requirements of aviation equipment are met.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation power structures, and in particular relates to a centrifugal impeller disc structure and a centrifugal compressor. Background Art

[0002] Centrifugal compressors are widely used in the power units of small and medium-sized aviation equipment. The core component of the centrifugal compressor is the centrifugal impeller. The centrifugal impeller works in a high temperature, high pressure and high speed environment, and is prone to deformation, resulting in changes in the working clearance. In severe cases, it can lead to deterioration of compressor performance and even friction causing engine damage.

[0003] There are many structural forms of existing centrifugal impeller discs. When making the initial design, it is difficult to fully consider the influence of the disc structure on deformation or wheel core stress, which leads to the need for multiple rounds of iterations to obtain a disc scheme with structural strength and deformation that meets the design requirements, resulting in a long design cycle. With the improvement of the power-to-weight ratio of aircraft engines, the pressure ratio of centrifugal compressors is also getting higher and higher, which also leads to higher and higher temperature loads, aerodynamic loads and centrifugal loads on centrifugal impellers. Especially when the pressure ratio of the centrifugal compressor exceeds 7.0, or the tangential speed of the centrifugal impeller disc outlet reaches the range of 600-680m / s, the strength and deformation problems of the centrifugal impeller are particularly prominent. Solving the strength and deformation problems of the centrifugal impeller is the key to whether the compressor can be used normally.

[0004] Therefore, it is difficult for existing centrifugal impeller discs to consider strength and deformation issues in advance while ensuring the design cycle. Summary of the invention

[0005] In view of the above problems, the present invention proposes a centrifugal impeller disc structure and a centrifugal compressor, wherein a centrifugal impeller disc structure comprises:

[0006] Wheel core, wheel rim, inner flow channel and wheel back;

[0007] The wheel core and the wheel rim are arranged opposite to each other, the inner flow channel and the wheel back are arranged opposite to each other, one end of the inner flow channel close to the wheel core forms a wheel disc inlet, and one end of the inner flow channel close to the wheel rim forms a wheel disc outlet;

[0008] The side of the inner flow channel close to the wheel disc outlet shrinks towards the wheel core so that the radius of the wheel disc outlet is smaller than a preset wheel disc parameter.

[0009] In some specific embodiments, a side of the inner flow channel close to the wheel disc inlet extends in a direction away from the wheel core, so that the radius of the wheel disc inlet is larger than a preset wheel disc parameter.

[0010] In some specific embodiments, one end of the wheel core close to the wheel disc inlet extends in the axial direction of the wheel core away from the wheel back;

[0011] One end of the inner flow channel close to the wheel disc inlet also extends in a direction away from the wheel back and connects with one end of the wheel core close to the wheel disc inlet, so that the axial length of the wheel disc inlet is greater than a preset wheel disc parameter.

[0012] In some specific embodiments, the outer wall of the inner flow channel on the side close to the wheel disk inlet extends radially away from the wheel core, so that the radius of the wheel disk inlet is larger than a preset wheel disk parameter.

[0013] In some specific embodiments, the outer wall of the inner flow channel on the side close to the wheel disk outlet shrinks along the radial direction of the wheel core toward the wheel core, so that the radius of the wheel disk inlet is smaller than the preset wheel disk parameter.

[0014] In some specific embodiments, the inner flow channel includes:

[0015] Control points, the number of the control points being nine, and the nine control points being connected end to end in sequence to form the inner flow channel;

[0016] The four control points arranged near the wheel disc inlet form an outer wall of the inner flow channel on a side near the wheel disc inlet;

[0017] The five control points close to the wheel outlet form the outer wall of the inner flow channel on a side close to the wheel outlet.

[0018] In some specific embodiments, the five control points close to the wheel outlet are spaced apart from the adjustment stop line;

[0019] Wherein, the adjustment stop line is a perpendicular line between the end of the wheel rim close to the control point and the wheel core.

[0020] In some specific embodiments, the four control points close to the roulette wheel outlet are spaced apart from the adjustment stop line.

[0021] In some specific embodiments, the corresponding maximum radius distances of the five control points close to the roulette exit are set in increments;

[0022] The maximum radius distance is the distance between the control point and the perpendicular line of the axis of the wheel core.

[0023] A centrifugal compressor based on the same concept includes: a centrifugal impeller disc structure as described in any of the above specific embodiments.

[0024] The centrifugal impeller disc structure of the present invention contracts toward the wheel core through the side of the inner flow channel close to the disc outlet. On the one hand, the center of gravity of the disc outlet area is offset toward the disc inlet, thereby controlling the axial deformation of the disc outlet. On the other hand, the weight of the disc area away from the wheel core is reduced, and the centrifugal load borne by the wheel core is weakened, thereby reducing the stress level of the wheel core. While ensuring the design cycle, the strength and deformation problems are considered in advance, ensuring the normal operation of the centrifugal impeller disc structure and the centrifugal compressor provided with the centrifugal impeller disc structure to meet the corresponding operating requirements of aviation equipment.

[0025] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A schematic diagram showing a centrifugal impeller disc structure in an embodiment of the present invention is shown;

[0028] Figure 2 A schematic diagram of a preset roulette wheel in an embodiment of the present invention is shown;

[0029] Figure 3 A comparison diagram of the centrifugal impeller disc structure in the embodiment of the present invention and a preset impeller disc is shown.

[0030] In the figure, 1, wheel core; 2, wheel rim; 3, inner flow channel; 31, control point; 4, wheel back. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Reference Figure 1The present invention provides a centrifugal impeller disc structure, including: a wheel core 1, a wheel rim 2, an inner flow channel 3 and a wheel back 4. The wheel core 1 and the wheel rim 2 are arranged opposite to each other, and the inner flow channel 3 and the wheel back 4 are arranged opposite to each other. The end of the inner flow channel 3 close to the wheel core 1 forms a wheel disc inlet. The end of the inner flow channel 3 close to the wheel rim 2 forms a wheel disc outlet. The side of the inner flow channel 3 close to the wheel disc outlet shrinks toward the direction close to the wheel core 1, so that the radius of the wheel disc outlet is smaller than the preset wheel disc parameters. Among them, the structure of the preset wheel disc refers to Figure 2 shown.

[0033] Specifically, one end of the wheel core 1 is connected to one end of the inner flow channel 3, the side of the inner flow channel 3 away from the wheel core 1 is connected to one side of the rim 2, the side of the rim 2 away from the inner flow channel 3 is connected to one end of the wheel back 4, and the end of the wheel back 4 away from the rim 2 is connected to the end of the wheel core 1 away from the inner flow channel 3, so that the wheel core 1 and the rim 2 are arranged opposite to each other, and the inner flow channel 3 and the wheel back 4 are arranged opposite to each other, thereby forming the centrifugal impeller disc structure. Among them, the end of the inner flow channel 3 close to the wheel core 1 forms the disc inlet, and the end of the inner flow channel 3 close to the rim 2 forms the disc outlet, and the side of the inner flow channel 3 close to the disc outlet shrinks toward the direction close to the wheel core 1, referring to Figure 3 That is, the curvature of the inner flow channel 3 on the side close to the disc outlet is increased, so that the radius of the inner flow channel 3 on the side close to the disc outlet will be smaller than the original preset disc parameters, which can significantly reduce the stress level and the axial deformation of the disc outlet during high-speed rotation, thereby improving the stability of the disc outlet and the overall high-speed rotation, and can greatly reduce the influence of high temperature, high pressure and high speed on the performance of the centrifugal compressor under high tangential speed conditions. When the compression ratio of the centrifugal compressor exceeds 7.0 or the tangential speed of the disc outlet of the centrifugal impeller disc structure reaches the range of 600-680m / s, the axial deformation of the centrifugal impeller disc structure can still be reduced, and the stress of the wheel core 1 can be reduced. In addition, the weight of the area of ​​the centrifugal impeller disc structure away from the wheel core is reduced, and the centrifugal load borne by the wheel core is weakened, thereby reducing the stress level of the wheel core. While ensuring the design period, the strength and deformation problems are considered in advance to ensure the normal operation of the centrifugal impeller disc structure and the centrifugal compressor provided with the centrifugal impeller disc structure to meet the corresponding operating requirements of aviation equipment.

[0034] Further, refer to Figure 1The structure of the wheel back 4 includes a first area segment, a second area segment, a third area segment, a fourth area segment and a fifth area segment which are connected in sequence. The first area segment is connected to the wheel rim 2, and the fifth area segment is connected to the wheel core 1. The first area segment and the second area segment are both linear structures, and the first area segment and the second area segment are connected in a circular arc transition manner. The third area segment is a circular arc structure with two tangent sections, and a circular arc structure of the third area segment close to the second area segment is tangent to the linear structure of the second area segment. The fourth area segment is a material removal setting, and the fourth area segment is a linear structure. The fifth area segment is a linear structure and two circular arc structures which are sequentially connected from the fourth area segment to the wheel core 1. The end of the circular arc structure of the fifth area segment close to the wheel core 1 is a horizontally arranged linear structure, so as to facilitate connection with the linear wheel core 1.

[0035] The maximum radius of the first area segment is R2, the minimum radius of the first area segment is 0.75R2 to 0.85R2, and the angle between the first area segment and the adjustment stop line is 2 degrees to 4 degrees.

[0036] The maximum radius of the second area segment is 0.75R2 to 0.85R2, the minimum radius of the second area segment is 0.65 to 0.7R2, and the angle with the adjustment stop line is 0 to 2 degrees. Area 3 Scheme 1 is represented by two arcs:

[0037] When the third area segment is composed of two arc structures, the radius of the arc structure arranged close to the second area segment is 0.2R2 to 0.3R2, and the radius of the other arc structure of the third area segment is 0.05R2 to 0.08R2. When the third area segment is composed of only a single arc structure, the radius of the entire third area segment is 0.1R2 to 0.15R2.

[0038] The maximum radius of the fourth area segment is 0.55R2 to 0.62R2, the minimum radius of the fourth area segment is 0.4R2 to 0.5R2, and the included angle with the adjustment stop line is 10 degrees to 14 degrees.

[0039] The maximum radius of a straight-line structure of the fifth section arranged near the fourth section is 0.45R2 to 0.55R2, and the angle with the adjustment stop line is 20 to 25 degrees. The radius of the first arc-shaped structure of the fifth section arranged near the fourth section is 0.1R2 to 0.15R2. The radius of the second arc-shaped structure of the fifth section arranged near the fourth section is 0.2R2 to 0.25R2. In addition, the second arc-shaped structure of the fifth section arranged near the fourth section is connected to the wheel core 1 through a smaller arc-shaped structure with a radius of 0.02R2 to 0.1R2.

[0040] The radius of the wheel core 1 is 0.165R2 to 0.25R2.

[0041] The average normal thickness of the blades at the outlet of the wheel disc is Tn, and the horizontal width of the rim 2 is 1.4Tn to 2.0Tn.

[0042] It should be noted that the adjustment stop line mentioned above is the perpendicular line between the end of the wheel rim 2 close to the inner flow channel 3 and the wheel core 1. The maximum radius of the linear structure of the first area segment, the second area segment, the fourth area segment and the fifth area segment arranged close to the fourth area segment is the distance between the end of the corresponding part away from the wheel core 1 and the perpendicular line of the axis of the wheel core 1. The maximum radius of the first area segment, the second area segment and the fourth area segment is the distance between the end of the corresponding part close to the wheel core 1 and the perpendicular line of the axis of the wheel core 1.

[0043] In some specific embodiments of the present invention, referring to Figure 1 The inner flow channel 3 extends from one side of the wheel disc inlet to the direction away from the wheel core 1, so that the radius of the wheel disc inlet is larger than the preset wheel disc parameters, thereby obtaining a centrifugal impeller with different inlet hub ratios.

[0044] Specifically, refer to Figure 3 , the side of the inner flow channel 3 close to the wheel inlet expands in the direction away from the wheel core 1, so that the radius of the side of the inner flow channel 3 close to the wheel inlet will be larger than the original preset wheel parameters, and the thickness of the wheel inlet, that is, the thickness of the side of the inner flow channel 3 close to the wheel core 1, is increased, so as to adapt to different interface sizes of the air intake casing and match different compressor shafts.

[0045] In some specific embodiments of the present invention, the end of the wheel core 1 close to the wheel disc inlet extends along the axial direction of the wheel core 1 away from the wheel back 4, thereby extending the length of the wheel core 1 and being able to be used to match centrifugal impellers of different lengths.

[0046] In some specific embodiments of the present invention, referring to Figure 3 The outer wall of the inner flow channel 3 on the side close to the disc outlet shrinks along the radial direction of the wheel core 1 toward the wheel core 1, so that the radius of the disc inlet is smaller than the preset disc parameter. The outer wall of the inner flow channel 3 on the side close to the disc outlet shrinks along the radial direction of the wheel core 1 toward the wheel core 1, and the curvature of the outer wall of the inner flow channel 3 on the side close to the disc inlet is increased, so that the radius of the inner flow channel 3 on the side close to the disc outlet is smaller than the original preset disc parameter, which can avoid excessive axial deformation of the centrifugal impeller disc structure under high tangential speed conditions and reduce the stress of the wheel core 1 at the same time.

[0047] In some specific embodiments of the present invention, referring to Figure 3, the inner flow channel 3 includes: control points 31. There are nine control points 31, and the nine control points 31 are connected end to end in sequence to form the inner flow channel 3. The inner flow channel 3 is represented by nine control points 31, so that it is easy to adjust the contraction or expansion of the inner flow channel 3. It is only necessary to adjust the setting position of the corresponding control points 31. Through the mutual cooperation of the nine control points 31, the overall adjustment of the inner flow channel 3 can be completed. Among them, four or more control points 31 can be set near the inlet of the roulette wheel to form the outer wall of the inner flow channel 3 on the side close to the inlet of the roulette wheel, that is, the four or more control points 31 set near the inlet of the roulette wheel need to expand in the radial direction of the wheel core 1 away from the wheel core 1. Five or more control points 31 near the outlet of the roulette wheel form the outer wall of the inner flow channel 3 on the side close to the outlet of the roulette wheel, that is, the five or more control points 31 near the outlet of the roulette wheel need to shrink in the radial direction of the wheel core 1 towards the wheel core 1.

[0048] In some specific embodiments of the present invention, referring to Figure 3 The five control points 31 near the outlet of the wheel disc are spaced from the adjustment stop line, that is, after the five control points 31 near the outlet of the wheel disc are contracted along the radial direction of the wheel core 1 toward the wheel core 1, it is not recommended that the outer wall of the five control points 31 near the outlet of the wheel disc exceed the position of the adjustment stop line, thereby reducing the axial displacement at the position of the wheel rim 2 and avoiding excessive axial deformation of the centrifugal impeller disc structure.

[0049] In some specific embodiments of the present invention, referring to Figure 3 , and the corresponding maximum radius distances of the five control points 31 near the outlet of the wheel disc are set to be increasing, and the thickness of the wheel disc between the area of ​​the inner flow channel 31 near the outlet of the wheel disc and the wheel back at the same radial position is increasing, thereby avoiding the situation where the centrifugal impeller disc structure strength reserve is insufficient. Among them, the maximum radius distance is the distance between the corresponding control point 31 and the perpendicular line of the axis of the wheel core 1.

[0050] Experimental comparison:

[0051] The inner flow channel 3 operates according to the preset wheel parameters, and the restrictions are:

[0052] Rotational angular velocity: 6051rad / s;

[0053] Roulette temperature: average temperature 370 degrees Celsius;

[0054] Axial preload: 97020N;

[0055] Roulette material: TC11;

[0056] Impeller radius: 108.5mm;

[0057] Tangential speed at wheel outlet: 656.5m / s.

[0058] Table 1. Preset roulette calculation results

[0059] parameter Preset Roulette Maximum comprehensive displacement (mm) 0.622 Maximum radial displacement (mm) 0.545 Axial displacement of wheel outlet (mm) -0.275 Maximum stress(Mpa) 718.3

[0060] The inner flow channel 3 is designed according to the centrifugal impeller disc structure of the present invention, and the radius of the centrifugal impeller disc is enlarged from 108.5 mm to 147.5 mm to obtain an initial disc, and then the optimized disc is obtained according to the adjustment method of the control point 31, wherein the restriction conditions are:

[0061] Rotational angular velocity: 4607rad / s;

[0062] Roulette temperature: average temperature 390 degrees Celsius;

[0063] Axial preload: 140000N;

[0064] Roulette material: TC11;

[0065] Impeller radius: 147.5mm;

[0066] Tangential speed at wheel outlet: 680m / s.

[0067] The parameters such as the maximum comprehensive displacement, maximum radial displacement, axial displacement at the disc outlet and maximum stress are predicted and compared.

[0068] Table 2. Comparison table of roulette parameter prediction results

[0069] parameter Initial Roulette Optimizing Roulette Contrast effect Maximum comprehensive displacement (mm) 0.9336 0.8039 -13.9％ Maximum radial displacement (mm) 0.8023 0.8030 0.1％ Axial displacement of wheel outlet (mm) -0.4825 0.0118 -102.4％ Maximum stress(Mpa) 771.7 690.1 -10.6％

[0070] It can be seen from Table 2 that when the wheel temperature, axial preload and wheel outlet tangential speed are increased, that is, the working environment of the wheel becomes more harsh, but the maximum comprehensive displacement of the optimized centrifugal impeller structure provided by the present invention is reduced by 13.9% compared with the initial wheel, the axial displacement of the wheel outlet is reduced by 102.4%, and the maximum stress is reduced by 10.6%, and the stress level and axial deformation control effect are extremely significant.

[0071] The present invention also provides a centrifugal compressor characterized by comprising: a centrifugal impeller disc structure as described in any of the above-mentioned specific embodiments. Because it includes the centrifugal impeller disc structure described above, it has the same beneficial effects as the centrifugal impeller disc structure described above. It can significantly reduce the stress level of the wheel core and the axial deformation of the wheel disc outlet, reduce the change in the working clearance of the centrifugal impeller, and weaken the impact of high temperature, high pressure and high speed on the performance of the centrifugal compressor under high tangential speed conditions. When the compression ratio of the centrifugal compressor exceeds 7.0 or the tangential speed of the wheel disc outlet of the centrifugal impeller disc structure reaches the range of 600 to 680 m / s, it is still possible to avoid excessive axial deformation of the centrifugal impeller disc structure, and at the same time reduce the stress of the wheel core 1, so as to ensure the normal operation of the centrifugal impeller disc structure and the centrifugal compressor provided with the centrifugal impeller disc structure to meet the corresponding operating requirements of aviation equipment.

[0072] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A centrifugal impeller disc structure, characterized in that: include: A wheel core (1), a wheel rim (2), an inner flow channel (3) and a wheel back (4); The wheel core (1) and the wheel rim (2) are arranged opposite to each other, the inner flow channel (3) and the wheel back (4) are arranged opposite to each other, one end of the inner flow channel (3) close to the wheel core (1) forms a wheel disc inlet, and one end of the inner flow channel (3) close to the wheel rim (2) forms a wheel disc outlet; The side of the inner flow channel (3) close to the wheel disc outlet shrinks in a direction close to the wheel core (1), so that the radius of the wheel disc outlet is smaller than a preset wheel disc parameter.

2. The centrifugal impeller disc structure according to claim 1, characterized in that: The inner flow channel (3) extends on a side close to the wheel disc inlet in a direction away from the wheel core (1), so that the radius of the wheel disc inlet is greater than a preset wheel disc parameter.

3. The centrifugal impeller disc structure according to claim 2, characterized in that: One end of the wheel core (1) close to the wheel disc inlet extends in the axial direction of the wheel core (1) in a direction away from the wheel back (4); An end of the inner flow channel (3) close to the wheel disc inlet also extends in a direction away from the wheel back (4) and is connected to an end of the wheel core (1) close to the wheel disc inlet, so that the axial length of the wheel disc inlet is greater than a preset wheel disc parameter.

4. The centrifugal impeller disc structure according to claim 3, characterized in that: The outer wall of the inner flow channel (3) on the side close to the wheel disc inlet extends in a radial direction of the wheel core (1) in a direction away from the wheel core (1), so that the radius of the wheel disc inlet is greater than a preset wheel disc parameter.

5. The centrifugal impeller disc structure according to claim 2, characterized in that: The outer wall of the inner flow channel (3) on the side close to the wheel disc outlet shrinks along the radial direction of the wheel core (1) towards the wheel core (1), so that the radius of the wheel disc inlet is smaller than a preset wheel disc parameter.

6. The centrifugal impeller disc structure according to claim 5, characterized in that: The inner flow channel (3) comprises: Control points (31), the number of the control points (31) being nine, and the nine control points (31) being connected end to end in sequence to form the inner flow channel (3); The four control points (31) arranged near the wheel disc inlet form an outer wall of the inner flow channel (3) on a side near the wheel disc inlet; The five control points (31) close to the wheel outlet form the outer wall of the inner flow channel (3) on a side close to the wheel outlet.

7. The centrifugal impeller disc structure according to claim 6, characterized in that: The five control points (31) close to the wheel outlet are spaced apart from the adjustment stop line; Wherein, the adjustment stop line is a perpendicular line between the end of the wheel rim (2) close to the control point (31) and the wheel core (1).

8. The centrifugal impeller disc structure according to claim 7, characterized in that: The four control points (31) close to the wheel outlet are spaced apart from the adjustment stop line.

9. The centrifugal impeller disc structure according to claim 6, characterized in that: The corresponding maximum radius distances of the five control points (31) close to the wheel exit are set in increasing order; The maximum radius distance is the distance between the control point (31) and the perpendicular line of the axis of the wheel core (1).

10. A centrifugal compressor, characterized in that: include: A centrifugal impeller disc structure as claimed in any one of claims 1 to 9.

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