Turbine rotor blade tip

Abstract

A turbine moving blade tip can reduce leakage loss and improve turbine efficiency and comprises wing-shaped side ribs, and the side ribs comprise a suction side rib extending from the front edge side of a turbine moving blade along the suction side and a pressure side rib extending from the front edge side of the turbine moving blade along the pressure side. The suction side rib comprises a first part close to the front edge side and a second part close to the rear edge side of the turbine movable blade, the first part is connected with the second part, the first part is provided with a thickening part relative to the second part, and the thickening part is located on the inner side of the suction side rib.

Description

Technical Field

[0001] The invention relates to a turbine rotor blade tip. Background Art

[0002] Economy, reliability, safety and maintainability are important bases for evaluating commercial aircraft engines. A gas turbine is a rotating machine that converts the internal energy in high-temperature and high-pressure combustion gas into mechanical energy. It is one of the most critical components in an aircraft gas turbine, and its performance has a direct impact on the performance of the aircraft gas turbine. The high-pressure turbine blades of aircraft engines work in a high-temperature, high-pressure, and high-speed environment. They are subject to very large thermal and mechanical loads, and the temperature and speed vary in a wide range. The blades have a certain elongation, and the tip clearance has a certain range of variation. Tip leakage losses account for about 30% of the total loss of the turbine stage. The tip temperature is high, difficult to cool, and prone to ablation. Therefore, the high-pressure turbine tip greatly affects the economy, reliability, safety, and maintainability of commercial aircraft engines.

[0003] There is a circumferential and axial pressure difference in the blade tip area of ​​the turbine rotor blade. The circumferential pressure difference causes the high-pressure gas on the pressure surface to flow to the suction surface through the blade tip gap, forming a tip gap leakage flow. The leakage flow seriously deviates from the magnitude and direction of the mainstream velocity of the flow channel, which has a very large impact on the turbine gas thermal performance:

[0004] First, the leakage flow reduces the mainstream flow rate, and the leakage flow basically does no useful work, which reduces the work done by the gas on the blades;

[0005] Second, the leakage flow mixes with the mainstream to form a leakage vortex, which dissipates and affects the airflow angle at the blade outlet. At the same time, the leakage flow and the leakage vortex block the mainstream channel. These aspects increase the aerodynamic loss of the turbine. The tip leakage loss accounts for as much as 30% of the total turbine loss.

[0006] Third, the leakage flow and leakage vortex also increase the difficulty of heat transfer cooling near the turbine blade tip and greatly affect the unsteadiness of the downstream flow field.

[0007] In order to reduce the sensitivity of turbine blade tip clearance to turbine performance during the flight mission cycle, reduce leakage flow, improve turbine efficiency, improve blade tip thermal environment, increase blade tip life, and maximize high-pressure turbine efficiency, various new turbine tip configurations have emerged. Summary of the invention

[0008] The object of the present invention is to provide a turbine rotor blade tip which can reduce leakage loss and improve turbine efficiency.

[0009] According to the present invention, the tip of the turbine blade includes airfoil-shaped side ribs, and the side ribs include suction side ribs extending from the leading edge side of the turbine blade along the suction side and pressure side ribs extending from the leading edge side of the turbine blade along the pressure side, wherein the suction side ribs include a first part close to the leading edge side and a second part close to the trailing edge side of the turbine blade, the first part is connected to the second part, the first part has a thickened portion relative to the second part, and the thickened portion is located on the inner side of the suction side ribs.

[0010] In one embodiment, the thickness of the first portion gradually increases from the leading edge side and then gradually decreases.

[0011] In one embodiment, the starting point of the first portion is 0% to 30% of the arc length of the suction side rib from the leading edge side, and the ending point of the first portion is 20% to 60% of the arc length of the suction side rib from the leading edge side.

[0012] In one embodiment, an angle between an inner side surface of the first portion and a bottom surface of the groove extending between the suction side rib and the pressure side rib is an acute angle.

[0013] In one embodiment, an included angle between an inner side surface of the first portion and a bottom surface of the groove extending between the suction side rib and the pressure side rib is an obtuse angle.

[0014] In one embodiment, an angle between an inner side surface of the first portion and a bottom surface of the groove extending between the suction side rib and the pressure side rib is a right angle.

[0015] In one embodiment, a starting point and an ending point of the profile line of the inner side surface of the first portion smoothly transition with the profile lines of the inner side surfaces of other portions of the suction side rib.

[0016] In one embodiment, the curvatures of the inner profile of the first portion and the outer profile of the suction side rib are one positive and one negative, so that the thickened portion is convex toward the pressure side rib.

[0017] In one embodiment, the thickened portion includes a plurality of protrusions protruding toward the pressure-side rib.

[0018] In one embodiment, the thickness X of the bump is in the range of d<X≤0.6D, where D is the maximum thickness of the blade tip section blade profile, and d is the thickness of the pressure side rib or the second portion.

[0019] In one embodiment, the interval t between adjacent bumps is in the range of d≤t≤0.8D.

[0020] By setting a thickening block in the front of the suction side rib of the turbine blade tip toward the groove direction, the thickening block makes the rib in the front of the suction side rib thickened, and the tip clearance between the upper surface of the thickened rib and the outer ring changes in length along the rib thickness direction (first increases and then decreases), resulting in a redistribution of the pressure field and velocity in the area. This feature causes the tip flow flowing from the front of the suction side rib to the gap to flow more directly along the upper surface and outer surface of the suction side to the rear and end of the thickened area, forming a certain degree of obstruction for the leakage flow flowing from the groove to the suction side, reducing the leakage source, delaying the leakage starting point, and inhibiting the development of the leakage vortex system along the way. When the negative angle of attack range of the tip flow increases, the effect of this technology is more significant, reducing the sensitivity of the tip angle of attack. In this way, the sensitivity of the tip clearance and the inlet angle of attack of the turbine blades to the turbine performance in the flight mission cycle is reduced, the leakage flow is reduced, and the reduction of the leakage flow allows more gas to do useful work, and effectively reduces the leakage vortex intensity, thereby reducing leakage losses, improving turbine efficiency, improving the tip thermal environment, and increasing the tip life. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0022] Figure 1 is a schematic diagram of a turbine rotor;

[0023] Figure 2 is a schematic diagram of a turbine blade;

[0024] Figure 3 is another schematic diagram of the turbine blades;

[0025] Figure 4 It is a schematic diagram of a pair of proportional turbine rotor blade tips;

[0026] Figure 5 is a schematic diagram of a turbine rotor blade tip according to an embodiment;

[0027] Figure 6 is a partially enlarged schematic diagram of a turbine rotor blade tip according to an embodiment;

[0028] Figure 7 It is a schematic diagram comparing the tips of two turbine rotor blades;

[0029] Figure 8 is a schematic diagram of a turbine rotor blade tip according to an embodiment;

[0030] Fig.9A correspond Figure 6 Schematic diagram of a comparative example of the EE cross section

[0031] FIG. 9B to FIG. 9D It corresponds to Figure 6Schematic diagrams of different embodiments of EE cross sections;

[0032] Fig.10 is a schematic diagram of a turbine rotor blade tip according to another embodiment;

[0033] Fig.11 is a schematic diagram of a turbine rotor blade tip according to yet another embodiment;

[0034] Fig.12 A comparison diagram of the streamlines of the starting position of the tip leakage flow out of the groove according to the embodiment of the present invention and the comparative example;

[0035] Fig.13 yes Fig.11 A partial enlarged view of the box. DETAILED DESCRIPTION

[0036] Reference will now be made in detail to embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided to explain the present invention, not to limit the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made in the present invention without departing from the scope or spirit of the present invention. For example, a feature illustrated or described as part of one embodiment may be used together with another embodiment to produce yet another embodiment. Therefore, the present invention is intended to cover these modifications and variations within the scope of the appended claims and their equivalents.

[0037] Figure 1 The turbine rotor 100 of the gas turbine engine is shown. The turbine rotor 100 includes a plurality of turbine rotor blades 00, and the turbine rotor blades 00 include a tenon 01, a lip plate 02, and a blade body 03. Figure 2 and Figure 3 As shown, the blade body 03 includes a concave pressure surface 031 and a convex suction surface 032. The pressure surface 031 and the suction surface 032 extend between the leading edge 035 and the trailing edge 036 of the blade and between the root 04 and the tip 05 of the blade. The pressure surface is also called the blade basin and the suction surface is also called the blade back. The blade profile is similar to a dolphin, a crescent, etc. Its thickness gradually increases from the leading edge to the maximum thickness, and then gradually decreases to the trailing edge. The blade body 03 can be formed by stacking blades of different design cross sections according to a certain linear rule. The surface of the blade body 03 is a spatial curved surface with three-dimensional characteristics. The pressure surface 031 and the suction surface 032 make the fluid flowing through its surface produce different speed and pressure distributions. The pressure difference on the blade surface drives the turbine rotor blades, and the turbine rotor blades 00 drive the turbine rotor 100, which realizes the conversion from internal energy to kinetic energy.

[0038] Figure 4 A schematic diagram of a turbine rotor blade tip is shown as a pair of ratios, Figure 5FIG. 2 shows a schematic diagram of a turbine rotor blade tip according to an embodiment of the present invention. Figure 4 and Figure 5 It can be understood that what is the same between the two is that the tip of the turbine blade includes airfoil-shaped side ribs, and the side ribs include suction side ribs extending from the leading edge side of the turbine blade along the suction side and pressure side ribs extending from the leading edge side of the turbine blade along the pressure side. Different from the comparative example, the suction side ribs according to the embodiment of the present invention include a first part 521 close to the leading edge side and a second part close to the trailing edge side of the turbine blade, the first part is connected to the second part, the first part 521 has a thickened portion relative to the second part, and the thickened portion is located on the inner side of the suction side ribs. In other words, the rib width of the first part 521 of the suction side rib of the tip of the turbine blade according to the present invention is thicker than the rib width of the front part 521' of the suction side rib of the comparative example. In the embodiment shown in the figure, the part of the suction side rib other than the first part 521 is its second part.

[0039] Combination Figure 6 , more detailed features can be observed. The turbine impeller tip 05 has a double-rib tip structure, including a pressure side rib 51 and a suction side rib 52. The pressure side rib 51 and the suction side rib 52 intersect at the tip leading edge 50. There is a gap between the pressure side rib 51 and the tip trailing edge 53. The tip is shaped like a groove 54.

[0040] Combined with Figures 6 to 8 ,exist Figure 7 The dashed line 521b in the figure shows the inner profile of the front part 521' of the suction side rib in the comparative example. According to an embodiment of the present invention, the starting point A of the first part 521 is close to the leading edge 50 of the blade tip, and the ending point B of the first part 521 is approximately located in the middle of the suction side rib. Optionally, the distance between the starting point A of the first part 521 and the leading edge of the blade tip is 0% to 30% of the arc length of the suction side rib of the blade tip. The distance between the end point B of the first part 521 and the leading edge of the blade tip is 20% to 60% of the blade tip suction side rib arc length.

[0041] For comparison, in the comparative example, the pressure side rib 51 and the suction side rib 52 of the blade tip 05 have a nearly equal thickness d, while in the embodiment of the present invention, the thickness X of the first portion 521 of the suction side rib 52 on the blade tip 05 is greater than the thickness d of the remaining portions of the pressure side rib 51 and the suction side rib 52. The thickness X of the first portion 521 refers to the maximum thickness of the first portion 521. The thickness of the first portion 521 is gradually changing as a whole, gradually decreasing from the maximum thickness until the thickness at the junction with the remaining portions of the suction side rib 52 is the same. In one embodiment, as Figure 8As shown, the thickness X of the first part 521 of the suction side rib 52 of the blade tip 05 is the maximum diameter of the inscribed circle 801 on the inner and outer surfaces of the first part, and its value range is d<X≤0.6D (D is the maximum thickness of the blade tip cross-section blade). The thickness X of the first part 521 increases first and then decreases along the suction side rib direction.

[0042] In each embodiment as shown in the figure, the outer profile line 521c of the first portion 521 according to the embodiment of the present invention is consistent with the outer profile line of the front portion 521' of the suction side rib of the comparative example. Figure 6 As shown, the inner profile 521a of the first portion 521 deviates toward the groove, thereby forming a thickened portion 522 facing the pressure side rib 51. The curvature of the inner profile 521a of the first portion 521 and the outer profile 521c of the first portion are both positive or negative.

[0043] 9A to 9C Corresponding to Figure 6 Schematic diagram of the location of the E-E section. Fig.9A As shown, in the comparative example, the widths of the suction side rib 52 and the pressure side rib 51 are equal (X=d). Fig. 9B As shown, according to the embodiment of the present invention, the width of the first portion 521 of the suction side rib 52 is greater than the width of the pressure side rib 51 (X>d), and the angle α between the first portion 521 and the bottom of the groove 54 is an obtuse angle, as shown in FIG. Fig. 9C As shown, the angle α between the first portion 521 and the bottom of the groove 54 is an acute angle. Fig. 9C As shown, the angle α between the first portion 521 and the groove bottom of the groove 54 is a right angle.

[0044] like Fig.10 , which is a schematic diagram of another embodiment of the thickened portion of the first portion 521. The outer profile 521c of the first portion 521 is consistent with the outer profile of the front portion 521' of the suction side rib in the comparative example. The inner profile 521a of the first portion 521 protrudes into the inside of the groove, thereby forming a thickened portion 522 facing the pressure side rib 51. The two ends of the inner profile 521a of the front portion of the suction side rib smoothly transition with the suction side rib 52 (such as rounding, multiple arcs, etc.), and the curvature of the inner profile 521a of the first portion 521 and the outer profile 521c of the first portion 521 are positive and negative.

[0045] like Fig.11 and Fig.13, which is a schematic diagram of another embodiment of the thickened portion of the first part 521. The outer profile 521c of the front part 521 of the suction side rib is consistent with the outer profile 521' of the front part 521 of the suction side rib in the comparative example. The front part 521 of the suction side rib is provided with a plurality of thickened portions 522 toward the pressure side rib 51. The thickness X of the front part 521 of the suction side rib on the blade tip 05 of this embodiment is the diameter of the inscribed circle 801 on its upper or lower surface, and its value range is d<X≤0.6D (D is the maximum thickness of the blade profile of the blade tip cross section), and the spacing between the plurality of thickened portions 522 is d≤t≤0.8D.

[0046] Fig.12 The figure is a streamline comparison diagram of the starting position of the flow direction of the tip leakage flow out of the groove according to the embodiment of the present invention and the comparative example. In the comparative example, the tip region inflow 80 flows to the front part 521' of the suction side rib, and the quasi-leakage flow 81' that partially flows into the groove flows out of the groove on the suction side rib at a starting position P1. The leakage flow of the tip clearance of the high-pressure turbine is a converging and diverging high-speed jet, and the leakage source and leakage starting point of the front part of the tip suction side rib are difficult to control. More leakage sources and earlier leakage starting points increase the leakage vortex intensity, which interacts with the channel vortex and the mainstream to produce greater leakage losses. For the embodiment of the present invention, the tip region inflow 80 flows to the front part 521 of the suction side rib, and the quasi-leakage flow 81 that partially flows into the groove flows out of the groove on the suction side rib at a starting position P2, and the thickened portion 522 causes the tip inflow 83 that fails to flow into the groove to flow directly to the end of the thickened region along the upper surface and outer surface of the suction side. The thickened portion 522 blocks the leakage flow from the groove to the suction side to a certain extent, reduces the leakage source, delays the leakage starting point, and inhibits the development of the leakage vortex along the way. When the negative angle of attack range θ of the blade tip flow increases, the effect of this technology is more significant, and the sensitivity of the blade tip angle of attack can be effectively reduced.

[0047] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A turbine blade tip, comprising airfoil-shaped side ribs, wherein the side ribs include a suction side rib extending from the leading edge side of the turbine blade along the suction side and a pressure side rib extending from the leading edge side of the turbine blade along the pressure side, characterized in that: The suction side rib includes a first portion close to the leading edge and a second portion close to the trailing edge of the turbine blade, the first portion is connected to the second portion, the first portion has a thickened portion relative to the second portion, and the thickened portion is located inside the suction side rib.

2. The turbine rotor blade tip according to claim 1, characterized in that: The thickness of the first portion gradually increases from the leading edge side and then gradually decreases.

3. The turbine rotor blade tip according to claim 1 or 2, characterized in that: The distance between the starting point of the first part and the leading edge side is 0% to 30% of the arc length of the suction side rib, and the distance between the ending point of the first part and the leading edge side is 20% to 60% of the arc length of the suction side rib.

4. The turbine rotor blade tip according to claim 1 or 2, characterized in that: An angle between an inner side surface of the first portion and a bottom surface of the groove extending between the suction side rib and the pressure side rib is an acute angle.

5. The turbine rotor blade tip according to claim 1 or 2, characterized in that: An included angle between an inner side surface of the first portion and a bottom surface of a groove extending between the suction side rib and the pressure side rib is an obtuse angle.

6. The turbine rotor blade tip according to claim 1 or 2, characterized in that: The included angle between the inner side surface of the first portion and the bottom surface of the groove extending between the suction side rib and the pressure side rib is a right angle.

7. The turbine rotor blade tip according to claim 1 or 2, characterized in that: The starting point and the ending point of the profile line of the inner side surface of the first portion smoothly transition with the profile lines of the inner side surfaces of other portions of the suction side rib.

8. The turbine rotor blade tip according to claim 1 or 2, characterized in that: The curvatures of the inner profile of the first portion and the outer profile of the suction side rib are one positive and one negative, so that the thickened portion is convex toward the pressure side rib.

9. The turbine rotor blade tip according to claim 1 or 2, characterized in that: The thickened portion includes a plurality of protrusions protruding toward the pressure side rib.

10. The turbine rotor blade tip according to claim 9, characterized in that: The range of the thickness X of the bump is d<X≤0.6D, where D is the maximum thickness of the blade tip section blade profile, and d is the thickness of the pressure side rib or the second portion.

11. The turbine rotor blade tip according to claim 9, characterized in that: The range of the interval t between adjacent bumps is d≤t≤0.8D.

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