Turbine guider and throat area adjusting method thereof

Abstract

The invention discloses a turbine guider and a throat area adjusting method thereof. Turbine guider blades are divided into the fixed guide blades and the adjustable guide blades at intervals, the fixed guide blades are fixedly connected with the inner and outer casings, and the adjustable guide blades can be driven by inner and outer sliding blocks at the two ends of the blades to move along sliding grooves in the inner and outer casings, so that the axial and / or circumferential positions of the blades are changed; therefore, the throat area of the turbine guider can be adjusted.

Description

Technical Field

[0001] The invention relates to the field of engines, and in particular to a turbine guide vane and a throat area adjustment method thereof. Background Art

[0002] The turbine guide nozzle is also called the nozzle ring. The blades on the turbine guide nozzle are called guide blades or stator blades, or guide vanes for short. The throat area refers to the minimum flow area in the blade channel.

[0003] Traditional fixed geometry turbines have high working efficiency near the design point, but their efficiency drops seriously when the working conditions are far from the design point. Variable geometry turbines change the geometry of blades or flow channels adaptively under different working conditions to change the turbine flow without adjusting the speed, so as to improve or adjust the working relationship between the engine compression components and turbine components, so that both the compressor and turbine are in a better working state, thereby improving the turbine's adaptability to variable working conditions and improving the overall performance of the engine.

[0004] The purpose of turbine variable geometry is to change the guide vane throat area and control the turbine flow rate. In the prior art, a rotary adjustable guide vane is generally used. By rotating the turbine guide vane and changing the blade installation angle, the flow area of ​​the turbine guide vane can be changed. In order to prevent the blades from scraping or getting stuck with the end wall and the casing wall when rotating, a large gap is generally left between the rotary adjustable guide vane and the upper and lower edge plates. Under the action of the pressure difference, the airflow flows from the pressure surface to the suction surface through the gap, causing leakage loss, thereby reducing the turbine efficiency. It is estimated that the efficiency of a single-stage rotary variable geometry turbine decreases by 1.5% to 2.0% due to the gap in the guide vane end area. It can be seen that the gap leakage loss has a significant impact on the turbine efficiency and is an important reason for the decrease in the efficiency of existing rotary variable geometry turbines.

[0005] Therefore, there is a need in the art for an improved turbine guide vane and a method for adjusting the throat area thereof. Summary of the invention

[0006] The present invention aims at the problem that the leakage loss at the end of the existing rotary variable geometry turbine guide vane is large and the turbine efficiency is significantly reduced. A novel translational turbine guide vane and throat area adjustment method thereof are proposed. The throat area of ​​the turbine guide vane is adjusted by translation of part of the adjustable guide vane. The present technology can greatly reduce or even eliminate the gap between the adjustable guide vane and the upper and lower edge plates, reduce the gap leakage loss, and improve the efficiency of the variable geometry turbine. Preferably, the present invention can adopt a conventional flat flow channel without special design of the flow channel profile.

[0007] In one embodiment of the present invention, a turbine guide vane is provided, which includes: an inner casing and an outer casing, the inner casing and the outer casing having corresponding slide grooves; a group of fixed guide vanes fixed between the inner casing and the outer casing; a group of adjustable guide vanes located between the inner casing and the outer casing and installed in the slide grooves on the inner casing and the slide grooves of the outer casing, wherein the adjustable guide vanes and the fixed guide vanes are distributed alternately with each other along the circumference of the turbine guide vane, and the adjustable guide vanes are configured to be able to move in the slide grooves on the inner casing and the slide grooves of the outer casing.

[0008] In one aspect, the slide groove on the inner casing and the slide groove on the outer casing are linear, curved or spiral, and when the adjustable guide vane moves in the slide groove on the inner casing and the slide groove on the outer casing, the adjustable guide vane moves in the axial direction and / or circumferential direction of the turbine guide vane.

[0009] In one aspect, the inner and outer ends of the adjustable guide vane are respectively provided with sliders for installation in the slide grooves on the inner casing and the slide grooves on the outer casing.

[0010] In one aspect, an angle between an extension direction of the slide groove on the inner casing and the slide groove on the outer casing and a blade direction of the adjustable guide vane is smaller than a threshold value.

[0011] In one aspect, a gap between inner and outer ends of the adjustable guide vane and walls of the inner casing and the outer casing is smaller than a threshold value.

[0012] In one aspect, one or more fixed guide vanes are arranged between two adjacent adjustable guide vanes among the adjustable guide vanes, or one or more adjustable guide vanes are arranged between two adjacent fixed guide vanes among the fixed guide vanes.

[0013] In one aspect, the fixed guide vanes are evenly and equidistantly arranged along the circumference of the turbine guide vane, and the slide grooves on the inner casing and the slide grooves on the outer casing are evenly and equidistantly arranged along the circumference of the turbine guide vane.

[0014] In one aspect, the adjustable guide vane can be adjusted by an axial distance S less than or equal to 0.3b, where b is the axial chord length of the adjustable guide vane.

[0015] In one embodiment of the present invention, an engine is provided, the engine comprising a turbine guide vane as described in any one of the above items.

[0016] In one embodiment of the present invention, a method for adjusting the throat area of ​​a turbine guide vane is provided, wherein the turbine guide vane includes a turbine guide vane as described in any one of the above items, and the method for adjusting the throat area of ​​the turbine guide vane includes: moving the adjustable guide vane in a slide groove on the inner casing and a slide groove on the outer casing to change the throat area of ​​the turbine guide vane.

[0017] The turbine guide vane and throat area adjustment method proposed in the present invention divide the guide vane blades into two groups of fixed guide vanes and adjustable guide vanes according to the interval method, and adjust the throat area of ​​the turbine guide vane by changing the axial / circumferential position of the adjustable guide vane. The throat area adjustment capacity of the guide vane can reach more than 20%. Preferably, when adjusting the throat area of ​​the turbine guide vane, there is no need to leave a large gap between the two ends of the adjustable guide vane and the upper and lower end walls, and the gap will not change with the translation of the blade, thereby avoiding the problem of large leakage loss in the end area of ​​the rotary variable geometry turbine guide vane and low turbine efficiency. Preferably, the turbine guide vane and throat area adjustment method proposed in the present invention can use a conventional flat flow channel in the adjustable guide vane section, without the need to perform complex design of the flow channel profile to reduce the leakage loss in the end area. Preferably, the turbine guide vane throat area adjustment method proposed in the present invention can use a linkage limit device to control and adjust the adjustable guide vanes that account for half of the number in the guide vane, and the control method is simple and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the structure of a turbine guide vane according to an embodiment of the present invention.

[0019] Figure 2 It is a schematic diagram of the partial structure of a turbine guide vane according to an embodiment of the present invention.

[0020] Figure 3 is a schematic diagram of an adjustable guide vane according to an embodiment of the present invention.

[0021] Figure 4 FIG. 1 is an axial cross-sectional view of a turbine guide vane according to an embodiment of the present invention.

[0022] Figure 5 FIG. 4 is a schematic diagram of a conventional turbine guide vane cascade throat width according to an embodiment.

[0023] Figure 6 Schematic diagram of the throat width of a turbine guide vane cascade according to an embodiment of the present invention.

[0024] Figure 7 It is a trend diagram of the change of the throat area of ​​the three-dimensional turbine guide vane with the blade adjustment distance according to an embodiment of the present invention.

[0025] Figure 8 It is a cloud diagram of the Mach number in the front and rear plane cascade passages according to an embodiment of the present invention.

[0026] Fig. 9 It is a comparison diagram of the total pressure loss coefficient curves at the outlet of the plane blade cascade before and after adjustment according to an embodiment of the present invention.

[0027] Reference numerals: 1-fixed guide vane, 2-adjustable guide vane, 3-inner casing, 4-outer casing, 5-inner casing slide, 6-outer casing slide, 7-leading edge, 8-trailing edge, 9-pressure surface, 10-suction surface, 11-guide vane inner slider, 12-guide vane outer slider, 13-guide vane inner end surface, 14-guide vane outer end surface, 15-inner casing outer end surface, 16-outer casing inner end surface DETAILED DESCRIPTION

[0028] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] The present invention proposes a novel turbine guide vane and a throat area adjustment method thereof, wherein the guide vane blades are divided into two groups of fixed guide vanes and adjustable guide vanes according to the interval method, the fixed guide vanes are fixedly connected to the inner and outer casings, and the adjustable guide vanes can be driven by the inner and outer sliders at both ends of the blades to move along the slide grooves on the inner and outer casings, changing the axial and / or circumferential positions of the blades, thereby achieving the adjustment of the throat area of ​​the turbine guide vane. Preferably, the present invention can adopt a conventional flat flow channel, without the need for special design of the flow channel profile.

[0030] refer to Figure 1 and Figure 2 , Figure 1 Schematic diagram of the structure of a turbine guide vane according to an embodiment of the present invention. Figure 2 It is a schematic diagram of the partial structure of a turbine guide vane according to an embodiment of the present invention.

[0031] The turbine guide vane is a variable geometry turbine guide vane, which divides the guide vane blades into two groups of fixed guide vanes 1 and adjustable guide vanes 2 according to the interval. The fixed guide vanes 1 and the adjustable guide vanes 2 constitute the blade grid of the turbine guide vane. The two ends of the fixed guide vane 1 are fixedly connected to the inner casing 3 and the outer casing 4. In addition, the inner casing 3 has a slide groove 5, and the outer casing 4 has a corresponding slide groove 6. The adjustable guide vane is located between the inner casing 3 and the outer casing 4 and is installed in the slide groove on the inner casing 3 and the slide groove of the outer casing 4, so that the adjustable guide vane 2 can move in the slide groove on the inner casing and the slide groove of the outer casing.

[0032] The slide groove 5 on the inner casing 3 and the slide groove 6 on the outer casing 4 can be linear, curved or spiral, and can extend along the axial direction of the turbine guide vane, or can be at a certain angle to the axial direction of the turbine guide vane. The slide groove 5 and the slide groove 6 can penetrate the corresponding inner casing 3 and outer casing 4, or can be grooves or openings on the inner casing 3 and outer casing 4, respectively, and the grooves or openings face the adjustable guide vanes. When the adjustable guide vanes 2 move in the slide grooves, the adjustable guide vanes 2 can move in the axial direction and / or circumferential direction of the turbine guide vane.

[0033] The fixed guide vanes 1 and the adjustable guide vanes 2 may be distributed alternately with each other along the circumference of the turbine guide vane. In one embodiment, the fixed guide vanes 1 and the adjustable guide vanes 2 may be distributed one at a time, for example, each fixed guide vane 1 is adjacent to an adjustable guide vane 2 in front and behind, and each adjustable guide vane 2 is adjacent to a fixed guide vane 1 in front and behind. In other embodiments, two or more fixed guide vanes 1 and two or more adjustable guide vanes 2 are distributed alternately, for example, there are two or more fixed guide vanes between two adjacent adjustable guide vanes, or there are two or more adjustable guide vanes between two adjacent fixed guide vanes. In one embodiment, the total number of blades of the turbine guide vane is an even number.

[0034] In one embodiment, the fixed guide vanes 1 are arranged evenly and equidistantly along the circumference of the turbine guide vane, and the slide grooves on the inner casing and the slide grooves of the outer casing can be arranged evenly and equidistantly along the circumference of the turbine guide vane. For example, when the adjustable guide vane is located at a specified position of the slide groove, the fixed guide vane 1 and the adjustable guide vane 2 can all be arranged evenly and equidistantly along the circumference of the turbine guide vane. In other embodiments, the fixed guide vane 1 and the slide groove can each have other specified positions without being arranged evenly.

[0035] Figure 3 Schematic diagram of an adjustable guide vane according to an embodiment of the present invention. Figure 2 and Figure 3 In one embodiment, the two ends of the adjustable guide vane 2 are provided with an inner guide vane slider 11 and an outer guide vane slider 12, respectively. The inner and outer sliders at both ends of the adjustable guide vane can slide in the inner casing slide groove 5 and the outer casing slide groove 6 respectively to adjust the position of the adjustable guide vane. Figure 2 and Figure 3 A rectangular slider is shown, but it should be understood that the specific shape of the slider is not limited, and other suitable shapes and sizes may be adopted, such as square, circular, elliptical, trapezoidal, wedge-shaped, etc. The shapes of the inner casing slide groove 5 and the outer casing slide groove 6 are adapted to the sliders at both ends of the adjustable blade, so that the adjustable blade can be stably installed in the inner casing slide groove 5 and the outer casing slide groove 6.

[0036] Figure 4It is an axial cross-sectional view of a turbine guide according to an embodiment of the present invention. In one embodiment, the adjustable turbine guide provided by the present invention adopts a flat flow channel in the adjustable guide vane section. When the guide vane inner slider 11 and the guide vane outer slider 12 at both ends of the adjustable guide vane slide in the inner casing slide groove 5 and the outer casing slide groove 6 respectively, the arc surface of the guide vane inner end surface 13 and the inner casing outer end surface 15 can maintain a complete fit, and similarly, the arc surface of the guide vane outer end surface 14 and the outer casing inner end surface 16 can also maintain a complete fit. Ideally, there can be no gap between the guide vane inner end surface 13 and the inner casing outer end surface 15 and the guide vane outer end surface 14 and the outer casing inner end surface 16. In actual engineering applications, a certain blade tip clearance can be appropriately left according to engineering needs, and the clearance can be less than a specified threshold. The uniformity of the clearance is not affected when the blade is adjusted, and the clearance level is also much smaller than that of a rotary adjustable turbine guide.

[0037] Figure 5 Schematic diagram of the throat width of a conventional turbine guide vane cascade according to an embodiment, the conventional turbine guide vane may include all fixed blades. The blades are arranged evenly and equidistantly along the circumference, and the blades have the same axial position. The point where the distance from the trailing edge 8 of the turbine blade pressure surface 9 to the adjacent blade suction surface 10 is the shortest is the location of the blade cascade throat, and the throat width is a. Since the blades are evenly distributed along the circumference and have the same axial position, the throat position of each blade cascade channel is the same, and the throat width a is equal.

[0038] Figure 6 Schematic diagram of the throat width of a turbine guide vane cascade according to an embodiment of the present invention. In one embodiment, the fixed guide vane 1 and the adjustable guide vane 2 are arranged adjacently and spaced apart, the geometric center position of the fixed guide vane 1 is o, and the geometric center position of the adjustable guide vane 2 is o'. The adjustable guide vane can slide along the adjustment trajectory, i.e., the direction of the dotted line oo', to adjust the size of the throat area of ​​the cascade channel. On the pressure side of the adjustable guide vane, the throat position of the cascade channel appears at the point where the distance from the near trailing edge 8 of the adjustable guide vane pressure surface 9 to the adjacent fixed guide vane suction surface 10 is the shortest, and the corresponding throat width is a. 1 The throat position of the fixed guide vane suction surface is moved forward compared to the conventional turbine guide vane. On the side of the adjustable guide vane suction surface, the throat position of the cascade channel appears at the point where the distance from the rear half of the adjacent fixed guide vane pressure surface 9 to the front half of the adjustable guide vane suction surface 10 is the shortest, and the corresponding throat width is a 2 , the throat position of the pressure surface of the fixed guide vane will be significantly moved forward compared to the conventional turbine guide vane. When the axial position of the adjustable guide vane is adjusted forward, the throat width a of the adjacent channel 1 and a 2 Compared with before adjustment, there will be an increase, so there is a 1 +a 2 >2a.

[0039] In one embodiment, the angle between the extension direction of the chute and the blade direction of the adjustable guide vane may be less than a set threshold, such as the extension direction of the chute is consistent with the blade direction of the adjustable guide vane. For example, the angle between the adjustable guide vane 2 adjustment trajectory direction (for example, the chute direction) and the blade cascade frontal line direction is θ, and the angle θ can be selected with reference to the blade installation angle ±1°, so that the throat areas of adjacent channels can be uniform and the blades can be guaranteed not to interfere with adjacent blades during translation. During the blade adjustment process, the axial distance that the adjustable guide vane moves forward is S, and the axial chord length of the blade is b. In a preferred embodiment, the throat area adjustment method may require that the maximum axial distance S of the adjustable guide vane adjusted forward is not more than 0.3b, so as to ensure that the flow in the blade cascade channel is in an attached state and avoid flow separation on the suction surface of the fixed guide vane at the rear axial position.

[0040] Figure 7 It is a trend diagram of the change of the throat area of ​​the three-dimensional turbine guide vane with the blade adjustment distance according to an embodiment of the present invention.

[0041] By using the adjustable turbine guide vane throat area adjustment method provided by the present invention, a three-dimensional turbine guide vane throat area variation trend diagram with the blade axial adjustment distance can be calculated. The turbine guide vane throat area has a parabolic growth relationship with the relative axial distance S / b of the adjustable guide vane forward movement. When the maximum relative axial distance S / b allowed to be adjusted by the adjustable guide vane is limited to no more than 0.3, the blade throat area adjustment capacity can be guaranteed to be above 20%.

[0042] See also Figure 8 and Fig. 9 , Figure 8 is a cloud diagram of the Mach number in the front and rear plane cascade passages according to an embodiment of the present invention, Fig. 9 It is a comparison diagram of the total pressure loss coefficient curves at the outlet of the plane blade cascade before and after adjustment according to an embodiment of the present invention.

[0043] Computational fluid dynamics (CFD) was used to analyze the flow field characteristics and flow losses of the variable geometry turbine plane blade grid provided by the present invention before and after axial position adjustment under the same pressure ratio. The flow condition of the plane blade grid is directly related to the relative axial position of the adjustable blades. Taking the two cases of S / b=0 and S / b=0.2 as examples, the changes in the flow field characteristics in the blade grid channel before and after blade adjustment are explained. When the adjustable blade moves forward to S / b=0.2, the flow in the plane blade grid channel increases by 20% compared to before adjustment, that is, when S / b=0. Due to the increase in flow, the Mach number level in each channel of the blade grid increases significantly, see Figure 8 , the flow still shows good periodicity when the blades are in groups of two. As the Mach number level in the channel increases after the blades are adjusted, the total pressure loss coefficient at the outlet of the plane cascade also increases accordingly compared with that before adjustment, see Fig. 9It can be seen that the plane cascade flow field still presents good flow characteristics after the blades are adjusted.

[0044] The total pressure loss coefficient at the cascade outlet is defined as: Where P r0 is the total pressure at the cascade inlet, P t1 is the total pressure at the cascade outlet, P s1 is the static pressure at the cascade outlet.

[0045] As described above, the present invention divides the guide vanes into two groups, namely fixed guide vanes and adjustable guide vanes, according to the interval method. The fixed guide vanes are fixedly connected to the inner and outer casings, while the adjustable guide vanes can be driven by the inner and outer sliders at both ends of the blades to move forward and backward along the slide grooves on the inner and outer casings to change their axial positions, thereby realizing the adjustment of the throat area of ​​the turbine guide vane. This method can achieve a guide vane throat area adjustment capacity of more than 20%.

[0046] In a preferred embodiment, when adjusting the throat area of ​​the turbine guide vane, the method for adjusting the throat area of ​​the turbine guide vane proposed in the present invention does not require a large gap to be left between the two ends of the adjustable guide vane and the upper and lower end walls, and the gap will not change with the translational movement of the blade, thereby avoiding the problems of large leakage loss in the end area of ​​the rotary variable geometry turbine guide vane and low turbine efficiency.

[0047] In a preferred embodiment, the method for adjusting the throat area of ​​a translatory turbine guide vane proposed by the present invention can use a conventional straight flow channel in the adjustable guide vane section, without the need for complex design of the flow channel profile to reduce end zone leakage losses.

[0048] In a preferred embodiment, the method for adjusting the throat area of ​​a turbine guide vane proposed in the present invention can use a linkage limit device to control and adjust half of the adjustable guide vanes in the guide vane, and the control method is simple and easy to implement.

[0049] The numerical values ​​given in each embodiment are only examples and are not intended to limit the scope of the present invention. In addition, as an overall technical solution, there are other components or steps that are not listed in the claims or description of the present invention. Moreover, a single name of a component does not exclude other names of the component.

[0050] The directions or positional relationships indicated by the directional words used in the description of the present application, such as “front, back, up, down, left, right”, “lateral, vertical, perpendicular, horizontal”, “top, bottom”, “inside, outside”, etc., are usually based on the directions or positional relationships shown in the drawings and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application.

[0051] For ease of description, spatially relative terms such as "on...", "above...", "on the upper surface of...", "upper", etc. may be used herein to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figures. It should be understood that the spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures.

[0052] In addition, it should be noted that the use of serial words such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0053] The disclosed methods, devices, and systems should not be limited in any way. On the contrary, the present disclosure covers all novel and non-obvious features and aspects of the various disclosed embodiments (alone and in various combinations and sub-combinations with each other). The disclosed methods, devices, and systems are not limited to any specific aspects or features or combinations thereof, nor do any disclosed embodiments require the existence of any one or more specific advantages or the resolution of specific or all technical problems.

[0054] The present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can make many forms without departing from the scope of protection of the present invention and the claims, all of which belong to the protection scope of the present invention.

Claims

1. A turbine guide vane, It is characterized in that include: An inner casing and an outer casing, wherein the inner casing and the outer casing are provided with corresponding slide grooves; a set of fixed guide vanes fixed between the inner casing and the outer casing; a set of adjustable guide vanes located between the inner casing and the outer casing and mounted in a slide groove on the inner casing and a slide groove on the outer casing, The adjustable guide vanes and the fixed guide vanes are distributed alternately with each other along the circumference of the turbine guide vane, and the adjustable guide vanes are configured to be movable in a slide groove on the inner casing and a slide groove on the outer casing.

2. The turbine guide vane according to claim 1, Features: The slide groove on the inner casing and the slide groove on the outer casing are linear, curved or spiral. When the adjustable guide vane moves in the slide groove on the inner casing and the slide groove on the outer casing, the adjustable guide vane moves in the axial direction and / or circumferential direction of the turbine guide vane.

3. The turbine guide vane according to claim 1, Features: The inner and outer ends of the adjustable guide vane are respectively provided with sliding blocks for being installed in the sliding grooves on the inner casing and the outer casing.

4. The turbine guide vane according to claim 1, Features: An angle between an extension direction of the slide groove on the inner casing and the slide groove on the outer casing and a blade direction of the adjustable guide vane is less than a threshold value.

5. The turbine guide vane according to claim 1, Features: The gaps between the inner and outer ends of the adjustable guide vane and the walls of the inner casing and the outer casing are smaller than a threshold value.

6. The turbine guide vane according to claim 1, Features: One or more fixed guide vanes are arranged between two adjacent adjustable guide vanes among the adjustable guide vanes, or one or more adjustable guide vanes are arranged between two adjacent fixed guide vanes among the fixed guide vanes.

7. The turbine guide vane according to claim 1, Features: The fixed guide vanes are evenly and equidistantly arranged along the circumference of the turbine guide vane, and The slide grooves on the inner casing and the slide grooves on the outer casing are evenly and equidistantly arranged along the circumference of the turbine guide vane.

8. The turbine guide vane according to claim 1, Features: The adjustable axial distance S of the adjustable guide vane is less than or equal to 0.3b, where b is the axial chord length of the adjustable blade.

9. An engine, It is characterized in that The engine comprises a turbine guide vane according to any one of claims 1-8.

10. A method for adjusting the throat area of ​​a turbine guide vane, the turbine guide vane comprising the turbine guide vane as claimed in any one of claims 1 to 8, the method for adjusting the throat area of ​​the turbine guide vane include: The adjustable guide vane is moved in the slide groove on the inner casing and the slide groove on the outer casing to change the throat area of ​​the turbine guide vane.

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