A low aspect ratio high pressure turbine end-bended guide vane and a turbine having the same

Abstract

The present invention relates to the technical field of turbine blades, and particularly relates to a low aspect ratio high-pressure turbine end-bent guide vane and a turbine having the same. The low aspect ratio high-pressure turbine end-bent guide vane has a blade body in a "J" shape. The concave surface of the blade body is the pressure surface, and the convex surface of the blade body is the suction surface. The bending angle of the blade body is 5° to 13°, and the height of the bending part of the blade body accounts for 30% to 90% of the entire blade height. The ratio of the height of the blade body to the chord length of the blade body is 0.4 to 0.6. The blade body adopts a hub end wall radially bent structure, which moves the saddle point position at the leading edge of the moving blade tip downstream, reduces the influence range of the suction surface horseshoe vortex branch, and makes the influence range of the suction surface horseshoe vortex branch concentrated near the suction surface of the blade. As a result, the interaction between the upper channel vortex and the surrounding fluid is reduced, the fluid flow loss is reduced, and the turbine efficiency can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of turbine blades, and in particular to a low aspect ratio high-pressure turbine end-bent guide vane and a turbine having the same. Background Art

[0002] With the increasing shortage of conventional energy and environmental problems, emerging energy conversion and utilization means such as industrial surplus pressure and waste heat, power generation from renewable energy, and compressed air energy storage technology have become important technologies that urgently need to be developed. Among these technologies, improving the turbine operating efficiency is the key link to improving the work capacity of the energy system and even the performance of the entire system.

[0003] Low aspect ratio turbines are commonly found in energy systems that utilize high-pressure gases to output work, such as compressed air energy storage and supercritical carbon dioxide cycles. Since the relative height of the turbine guide vanes is relatively low, the secondary flow at the blade end walls will cause uneven distributions of pressure, velocity, and flow angle in the guide vane channels, and have an adverse impact on the downstream rotor blade flow field. In the prior art, curved blades are usually used to improve the above problems. By shaping the blades into a curved shape, the distribution of the flow field pressure along the radial direction in the blade channels is adjusted, the vortex distribution in the blade channels is improved, and the secondary flow loss is reduced. However, the working medium density of high-pressure turbines is high, the aspect ratio of the guide vanes is low, the proportion of the end wall secondary flow and passage vortices in the guide vane channels in the blade height is large, and the influence on the flow field is high, resulting in chaotic distribution of the inlet air flow of the downstream rotor blades, large internal flow losses in the rotor blades, and low turbine efficiency. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects in the prior art that the inlet air flow distribution of the downstream rotor blades of the low chord ratio high-pressure turbine is chaotic, resulting in large internal flow losses in the rotor blades and low turbine efficiency, so as to provide a low aspect ratio high-pressure turbine end-bent guide vane and a turbine having the same.

[0005] To solve the above technical problem, the present invention provides a low aspect ratio high-pressure turbine end-bent guide vane,

[0006] The blade body is in a "J" shape, the concave surface of the blade body is the pressure surface, and the convex surface of the blade body is the suction surface;

[0007] The bending angle of the blade body is 5° to 13°, and the height of the bent part of the blade body accounts for 30% to 90% of the entire blade height;

[0008] The ratio of the height of the blade body to the chord length of the blade body is 0.4 to 0.6.

[0009] Optionally, the blade body is a positively bent blade, and the angles between the pressure surface and the two end faces are both acute angles;

[0010] Optionally, the blade body is radially bent near the hub end wall.

[0011] Optionally, the cross-section of the blade body is linearly invariant, and the height of the midpoint controlling the spline shape is at 50% of the height of the bending part.

[0012] Optionally, the bending pattern of the blade body adopts a B-spline curve.

[0013] Optionally, chamfers are provided at the tip and / or the root of the blade body.

[0014] The present invention also provides a turbine having the low aspect ratio high-pressure turbine end-bent guide vane described in the present invention.

[0015] The technical solution of the present invention has the following advantages:

[0016] 1. For the low aspect ratio high-pressure turbine end-bent guide vane provided by the present invention, the blade body is in a "J" shape, the concave surface of the blade body is the pressure surface, and the convex surface of the blade body is the suction surface; the bending angle of the blade body is 5° to 13°, and the height of the bending part of the blade body accounts for 30% to 90% of the entire blade height; the ratio of the height of the blade body to the chord length of the blade body is 0.4 to 0.6. The blade body adopts a radially bent structure at the hub end wall, which moves the saddle point position at the leading edge of the moving blade tip downstream, reduces the influence range of the suction surface horseshoe vortex branch, and makes the influence range of the suction surface horseshoe vortex branch concentrated near the suction surface of the blade. As a result, the interaction between the upper channel vortex and the surrounding fluid is reduced, the fluid flow loss is reduced, and the turbine efficiency can be effectively improved.

[0017] 2. For the low aspect ratio high-pressure turbine end-bent guide vane provided by the present invention, the blade body is a positively bent blade, and the angles between the pressure surface and the two end faces are both acute angles; the end-bent fairing vane is in a positively bent form. Without changing the stator pitch and the number of blades, the end-bent guide vane can change the inlet air flow angle of the moving blades near the hub and the casing, effectively eliminate the stagnation saddle point at the root of the leading edge of the moving blade, reduce the influence range of the horseshoe vortex and the action path and intensity of the secondary flow with the end wall, suppress the flow loss caused by the lower channel vortex of the moving blade, and improve the turbine efficiency. Description of the Drawings

[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1Schematic diagram of the low aspect ratio high pressure turbine end-bent guide vane provided in the embodiment of the present invention.

[0020] Figure 2 Front view of the low aspect ratio high pressure turbine end-bent guide vane provided in the embodiment of the present invention.

[0021] Figure 3 Left view of the low aspect ratio high pressure turbine end-bent guide vane provided in the embodiment of the present invention.

[0022] Figure 4 Top view of the low aspect ratio high pressure turbine end-bent guide vane provided in the embodiment of the present invention.

[0023] Figure 5 Distribution diagram of the energy loss coefficient along the blade height at the outlet of the low aspect ratio high pressure turbine end-bent guide vane provided in the embodiment of the present invention HA202208743

[0024] of the present invention. Detailed implementation manners

[0025] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0027] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0028] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] Embodiment 1

[0030] As Figures 1 to 4 shown is a low aspect ratio high pressure turbine end-bent guide vane provided by this embodiment. This vane is a stationary vane cascade in a turbine cascade.

[0031] The vane body is in a "J" shape. The concave surface of the vane body is the pressure surface, and the convex surface of the vane body is the suction surface. The bending angle of the vane body is 5° to 13°, and the height of the bending part of the vane body accounts for 30% to 90% of the entire vane height; the ratio of the height of the vane body to the chord length of the vane body is 0.4 to 0.6. Specifically, in this embodiment, the bending angle θ of the vane is 13°, and the bending height C1 accounts for 30% of the entire vane height H. The end-bent guide vane in this embodiment is applicable to a low aspect ratio turbine guide vane, and its aspect ratio range is 0.5, that is, the ratio of the height of the vane body to the chord length of the vane body is 0.5.

[0032] The vane body is a positively bent vane, and the angles between the pressure surface and both end faces are acute angles. The cross-section of the vane body is linearly invariant, and the vane body is radially bent near the hub end wall. The bending pattern of the vane body adopts a B-spline curve, and the height of the intermediate point controlling the spline shape is located at 50% of the bending part height. Chamfers are provided at both the tip and root of the vane body to facilitate machining and manufacturing.

[0033] Since the density of the working medium in a high pressure turbine is relatively high, when the aspect ratio of the guide vane is relatively low, the end wall secondary flow and passage vortex in the guide vane passage account for a large proportion of the vane height, have a relatively high influence on the flow field, and further have an adverse effect on the inlet air flow distribution of the downstream moving vane, resulting in a large fluid flow loss inside the moving vane and a low efficiency of the entire turbine.

[0034] The low aspect ratio high-pressure turbine end-bent guide vane provided in this embodiment adopts a radially bent structure of the hub end wall. Among them, the end-bent guide vane is a stationary vane cascade in the high-pressure turbine cascade; the end-bent guide vane is in a positive-bent form, and the angle between its pressure surface and the hub end surface is an acute angle. The blade body maintains the stationary blade profile unchanged. By radially bending the hub end wall of the turbine guide vane, without changing the pitch of the stationary blade and the number of blades, the end-bent guide vane changes the inlet flow angle of the moving blades near the hub and the casing, can effectively eliminate the stagnation saddle point at the root of the leading edge of the moving blade, reduce the influence range of the horseshoe vortex and the action path and intensity of the secondary flow with the end wall, and suppress the flow loss caused by the lower passage vortex of the moving blade; at the same time, the blade body is changed from the existing C shape to a J shape, which moves the saddle point position at the leading edge of the moving blade top downstream, reduces the influence range of the horseshoe vortex branch on the suction surface, and concentrates near the suction surface of the blade. As a result, the interaction between the upper passage vortex and the surrounding fluid is reduced, the static blade outlet velocity distribution can be changed, the inlet condition of the moving blade is improved, the flow loss inside the moving blade is reduced, and the turbine efficiency can be effectively improved.

[0035] The three-dimensional numerical analysis of a certain turbine stage with a low aspect ratio high-pressure turbine end-bent guide vane that realizes the efficiency increase of the moving blade by using computational fluid dynamics (CFD) software shows that the present invention can improve the turbine efficiency, as shown in the following table.

[0036]

[0037] The above table shows the comparison of the efficiency and flow rate between the low aspect ratio high-pressure turbine end-bent guide vane (end-bent guide vane) that realizes the efficiency increase of the moving blade and the prototype straight guide vane (prototype guide vane). For the turbine stage with a hub end wall positive-bent guide vane, the efficiency of the turbine is increased by 0.77%, the flow rate is increased by 0.1 kg / s, and the flow capacity of the turbine is also partially improved while the efficiency is increased.

[0038] As Figure 5 shown is the distribution of the energy loss coefficient along the blade height at the outlet of the moving blade. Figure 5 It can be seen that the low aspect ratio high-pressure turbine end-bent guide vane reduces the flow loss caused by the tip clearance leakage vortex and the lower passage vortex in the moving blade passage, and improves the efficiency of the turbine.

[0039] Embodiment 2

[0040] This embodiment provides a turbine having the low aspect ratio high-pressure turbine end-bent guide vane described in Embodiment 1. By installing the low aspect ratio high-pressure turbine end-bent guide vane in front of the moving blade guide vane, the saddle point position at the leading edge of the moving blade top moves downstream, the influence range of the horseshoe vortex branch on the suction surface is reduced, and it is concentrated near the suction surface of the blade. As a result, the interaction between the upper passage vortex and the surrounding fluid is reduced, the static blade outlet velocity distribution can be changed, the inlet condition of the moving blade is improved, the flow loss inside the moving blade is reduced, and the turbine efficiency can be effectively improved.

[0041] Obviously, the above-described embodiments are merely examples for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or alterations can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. And the obvious changes or alterations derived therefrom still fall within the protection scope of the present invention.

Claims

1. A low aspect ratio high-pressure turbine end-bent guide vane, characterized in that the blade body is in a "J" shape, the concave surface of the blade body is the pressure surface, the convex surface of the blade body is the suction surface, and the blade body is radially bent near the hub end wall; the bending angle of the blade body is 5°-13°, and the height of the bending part of the blade body accounts for 30% of the whole blade height; the ratio of the height of the blade body to the chord length of the blade body is 0.4-0.

6.

2. The low aspect ratio high pressure turbine tip bowed guide vane according to claim 1, characterized in that, The blade body is a positively bent blade, and the included angles between the pressure surface and the two end faces are both acute angles.

3. The low aspect ratio high pressure turbine tip bowed guide vane according to claim 1 or 2, characterized in that, The cross-section of the blade body is linearly invariant, and the height of the middle point controlling the spline shape is located at 50% of the height of the bending part.

4. The low aspect ratio high pressure turbine end-bent guide vane according to claim 3, characterized in that, The bending pattern of the blade body adopts a B-spline curve.

5. The low aspect ratio high pressure turbine end-bended guide vane according to claim 1 or 2, characterized in that, The blade body is provided with chamfers at the blade tip and / or the blade root.

6. A turbine, characterized in that, A low aspect ratio high-pressure turbine end-bent guide vane according to any one of claims 1 to 5.

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