A turbine guide vane and turbine engine

Abstract

The application discloses a turbine guide vane and a turbine engine, wherein guide vanes are unevenly distributed along the circumference of a turbine casing, a throat interval is arranged between two adjacent guide vanes, and the two adjacent throat intervals are different; by changing the distribution characteristics of the guide vanes on the turbine guide vane, the guide vanes are unevenly distributed, thereby avoiding the periodic airflow excitation caused by the wake of the turbine guide vane when the guide vanes are evenly distributed, i.e. the excitation frequency caused by the wake of the turbine guide vane and the excitation intensity under the frequency are changed, so that the unsteady airflow excitation force acting on the surface of the turbine rotor blade is reduced, thereby avoiding the high-cycle fatigue fracture failure of the turbine rotor blade and improving the safety of flight.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engine, in particular to a turbine guide vane and a turbine engine. BACKGROUND

[0002] In an aero-engine, turbine blades are one of the key parts. The turbine blades will be subjected to the combined action of external factors such as centrifugal load, high temperature, corrosive medium and airflow excitation load in operation, and the design, material, structure and processing technology of the blades will all lead to blade failure. If the natural frequency of the blade in operation is close to or equal to the frequency of the airflow excitation force, the blade will produce a great dynamic stress due to resonance, and when the dynamic stress exceeds the fatigue limit of the material, the blade will be damaged due to fatigue in a long-term high stress state. The safe operation of turbine components is closely related to blade vibration, and if there is excessive vibration of parts, it will have serious consequences. Most of the serious failures of rotating parts of aero-engines are caused by vibration, and the proportion of failures caused by blade vibration is large, and blade high-cycle fatigue fracture accidents account for a large proportion of blade fracture accidents.

[0003] The internal flow of the turbine presents three-dimensional, viscous and unsteady characteristics, and is accompanied by complex flow phenomena such as flow separation, shock wave and boundary layer interference, upstream blade wake, dynamic and static interference. Due to the strong instability and unsteadiness of the internal flow of the turbine, there are often eddies with large scale differences in the flow field, and the pulsation of the pressure, velocity and other aerodynamic parameters of the flow field is strong, so there is a strong exchange of aerodynamic force and momentum on the surface of the blade solid domain in the internal flow field of the turbine. The periodic unsteady pressure pulsation caused by the guide vane wake will act on the turbine rotor blades, inducing unsteady aerodynamic excitation force that causes blade vibration fatigue, and in severe cases, even leading to high-cycle fatigue fracture failure of the turbine rotor blades, affecting the safe operation of the turbine components and the engine. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is to overcome the defect that the turbine rotor blades have high-cycle fatigue fracture failure in the prior art, so as to provide a turbine guide vane and a turbine engine which can improve the safety of turbine components.

[0005] To solve the above technical problems, the technical scheme of the present application is as follows:

[0006] A turbine guide vane, comprising: a turbine casing and guide vanes; the guide vanes are unevenly distributed along the circumference of the turbine casing, and a throat spacing is provided between adjacent two guide vanes, and the adjacent two throat spacings are not equal.

[0007] According to some embodiments of the present application, the distribution of the guide vanes comprises at least a linear distribution with three different changing trends, and the minimum distance between two adjacent guide vanes before the start of each segment is an initial throat distance.

[0008] According to some embodiments of the present application, in the first segment, the throat distance gradually increases;

[0009] In the second segment, the throat distance gradually decreases;

[0010] In the third segment, the throat distance gradually increases.

[0011] According to some embodiments of the present application, when the number of the turbine guide vanes is x, the first segment is in the range of The second segment is in the range of The third segment is in the range of

[0012] According to some embodiments of the present application, in the first segment, the relative change rate of any throat distance and the first initial throat distance is calculated by the formula:

[0013] y1=-a1x 3 +b1x 2 +c1x-d1

[0014] wherein a1, b1, c1 and d1 are constants greater than zero, x is the number of the guide vanes, and y1 is the relative change rate of the throat distance corresponding to the guide vane with the number x in the first segment and the first initial throat distance;

[0015] In the second segment, the change rate of any throat distance and the second initial throat distance is calculated by the formula:

[0016] y2=a2x 3 -b2x 2 +c2x-d2

[0017] wherein a2, b2, c2 and d2 are constants greater than zero, x is the number of the guide vanes, and y2 is the relative change rate of the throat distance corresponding to the guide vane with the number x in the second segment and the second initial throat distance;

[0018] In the third segment, the change rate of any throat distance and the third initial throat distance is calculated by the formula:

[0019] y3=a3x 3 +b3x 2-c3x+d3

[0020] In the formula, a3, b3, c3 and d3 are all constants greater than zero, x is the number of the guide vane, and y3 is the relative change rate of the throat distance corresponding to the guide vane at the number x in the third section to the third initial throat distance.

[0021] According to some embodiments of the present application, in the first section, the change trend of the throat distance increases from 0 to 16% to 20%; in the second section, the change trend of the throat distance decreases from 12% to 15% to 0; and in the third section, the change trend of the throat distance increases from -15% to -11% to 1% to 3%.

[0022] The present application also provides a turbine engine comprising the turbine guide described above.

[0023] The technical scheme of the present application has the following advantages:

[0024] The turbine guide provided by the present application changes the distribution characteristics of the guide vanes on the turbine guide, so that the guide vanes are distributed non-uniformly, thereby avoiding the periodic airflow excitation caused by the wake of the turbine guide when the guide vanes are uniformly distributed, i.e. changing the excitation frequency caused by the wake of the turbine guide and the excitation strength at the frequency, thereby reducing the unsteady airflow excitation force acting on the surface of the turbine rotor blade, and further avoiding high-cycle fatigue fracture failure of the turbine rotor blade, and improving the safety of flight. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the specific embodiments of the present application or the technical scheme in the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0026] Figure 1 The relative change rate of the number of guide vanes and the throat distance of the turbine guide provided in some embodiments of the present application is shown in the broken line graph;

[0027] Figure 2 The size of the throat distance of the turbine guide provided in some embodiments of the present application is shown in the broken line graph along the circumferential direction of the turbine casing;

[0028] Figure 3 The pressure pulsation graph when the guide vanes are uniformly arranged along the turbine casing in the comparative example one is shown;

[0029] Figure 4Pressure fluctuation diagram when the guide vanes in the embodiment of the present application are evenly arranged along the turbine casing;

[0030] Figure 5 Comparison diagram of unsteady airflow excitation intensity of the turbine guide vane in the comparative example 1 and the embodiment 1 of the present application. DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0032] In the description of the present application, it should be noted that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0033] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0034] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as there is no conflict between them.

[0035] Reference Figure 1 and Figure 2 As shown in the drawings, the present application proposes a turbine guide vane, the guide vanes are unevenly distributed along the circumference of the turbine casing, a throat spacing is arranged between two adjacent guide vanes, and the adjacent two throat spacings are not equal.

[0036] Specifically, by changing the distribution characteristics of the guide vanes on the turbine guide vane, the guide vanes are unevenly distributed, thereby avoiding the periodic airflow excitation caused by the turbine guide vane wake when the guide vanes are evenly distributed, that is, changing the excitation frequency caused by the turbine guide vane wake and the excitation strength at the frequency, thereby reducing the unsteady airflow excitation force acting on the surface of the turbine rotor blade, and further avoiding high-cycle fatigue fracture failure of the turbine rotor blade, and improving the safety of flight.

[0037] In the comparative example one, the guide vanes are evenly distributed along the circumference of the turbine casing, the throat spacing between the adjacent two guide vanes is equal, and is a, as shown in Figure 3 , the surface pressure of the turbine rotor blade is a periodic sinusoidal wave fluctuation, and the difference between the maximum pressure value and the minimum pressure value is 95000Pa, that is, the turbine rotor bears the periodic unsteady airflow excitation force caused by the turbine guide vane. As shown in Figure 5 , when the time domain signal of the surface pressure of the turbine rotor blade is converted into a frequency domain signal, the abscissa is the excitation frequency, and the ordinate is the excitation force strength. The frequency corresponding to the peak in the figure is the excitation frequency caused by the turbine guide vane. In the comparative example one, a relatively strong airflow excitation force is generated at a frequency of 25000Hz, and then obvious airflow excitations are generated at double frequency, triple frequency and other multiple frequencies, but the strength gradually decreases.

[0038] In the embodiment one of the present application, the guide vanes are unevenly distributed along the circumference of the turbine casing, and the throat spacing is provided between the adjacent two guide vanes, and the adjacent two throat spacings are not equal, and the throat spacing is represented by b x , and x is the number of the guide vanes, that is, the number of the throat spacing.

[0039] In some embodiments of the present application, the guide vane distribution at least includes linear distribution with three different change trends, and the minimum spacing between the adjacent two guide vanes before the start of each section is the initial throat spacing.

[0040] Specifically, in order to facilitate comparison, the initial throat spacing in the embodiment of the present application and the throat spacing in the comparative example are set to the same value.

[0041] In some embodiments of the present application, in the first section, the change rule of the throat spacing is gradually increasing trend;

[0042] In the second section, the change rule of the throat spacing is gradually decreasing trend;

[0043] In the third section, the change rule of the throat spacing is gradually increasing trend.

[0044] In some embodiments of the present application, when the number of turbine guide vanes is x, the first segment takes a value range of The value range of the second segment is The value range of the third segment is

[0045] In some embodiments of the present application, in the first segment range, the relative change rate formula of any throat gap to the first initial throat gap is:

[0046] y1=-a1x 3 +b1x 2 +c1x-d1

[0047] In the formula, a1, b1, c1 and d1 are all constants greater than zero, x is the number of guide vanes, and y1 is the relative change rate of the throat gap corresponding to the guide vane at the number x to the first initial throat gap in the first segment range;

[0048] In the second segment range, the change rate formula of any throat gap to the second initial throat gap is:

[0049] y2=a2x 3 -b2x 2 +C2x-d2

[0050] In the formula, a2, b2, c2 and d2 are all constants greater than zero, x is the number of guide vanes, and y2 is the relative change rate of the throat gap corresponding to the guide vane at the number x to the second initial throat gap in the second segment range;

[0051] In the third segment range, the change rate formula of any throat gap to the third initial throat gap is:

[0052] y3=a3x 3 +b3x 2 -c3x+d3

[0053] In the formula, a3, b3, c3 and d3 are all constants greater than zero, x is the number of guide vanes, and y3 is the relative change rate of the throat gap corresponding to the guide vane at the number x to the third initial throat gap in the third segment range.

[0054] Specifically, in Embodiment One, when the number of guide vanes is x, in the range of , the relative change rate formula of any throat gap to the first initial throat gap is: y1=-0.0004x 3 +0.0067x 2+0.0016x-0.0086, i.e. the value of a1 is 0.0004, the value of b1 is 0.0067, the value of c1 is 0.0016, and the value of d1 is 0.0086;

[0055] In the range of 0.0001 , the change rate solving formula of the arbitrary throat gap and the third initial throat gap is y3=0.000003 3 -0.0062 2 +0.1336x-1.1004, i.e. the value of a2 is 0.0001, the value of b2 is 0.0062, the value of c2 is 0.1336, and the value of d2 is 1.1004;

[0056] In the range of 0.0001 , the change rate solving formula of the arbitrary throat gap and the third initial throat gap is y3=0.000003 3 +0.0003 2 -0.0307+0.3834, i.e. the value of a3 is 0.000003, the value of b3 is 0.0003, the value of c3 is 0.0307, and the value of d3 is 0.3834. It can be understood that the values of a1, b1, c1, d1, a2, b2, c2, d2, a3, b3, c3 and d3 are not limited by the present application.

[0057] Based on the data of the above-mentioned embodiments, the following can be calculated:

[0058] Table 1 is the throat gap distribution diagram of the turbine guide vane of the comparative example one and the turbine guide vane of the first embodiment of the present application:

[0059]

[0060]

[0061] It can be understood that when the guide vanes are unevenly distributed, the pressure pulsation on the surface of the turbine rotor blade is irregular. As shown in FIG. 6, the difference between the maximum pressure and the minimum pressure on the surface of the turbine rotor blade is 82000Pa-85000Pa, i.e. the strength of the pressure pulsation on the turbine rotor equipped with the turbine guide vane of the present application is lower than that of the existing design in the comparative example. As shown in FIG. 7, the pressure pulsation on the surface of the turbine rotor equipped with the turbine guide vane of the present application is lower than that of the existing design in the comparative example. Figure 4 Figure 5 ​As shown, when the time domain signal of the turbine rotor blade surface pressure is converted into a frequency domain signal, the horizontal coordinate is the excitation frequency, and the vertical coordinate is the excitation force intensity, the peak in the figure corresponds to the excitation frequency caused by the turbine guide vane, and at 25000Hz, the excitation intensity of the turbine guide vane in the embodiment one is reduced by 50% compared with the turbine guide vane in the comparative example one, and as the frequency increases, the excitation force intensity of the turbine guide vane in the application is smaller than that of the turbine guide vane in the comparative example one at the same excitation frequency, and the degree of decrease is obvious, that is, the unsteady airflow excitation force caused by the turbine guide vane in the application is greatly reduced, thereby enhancing the safety of the turbine rotor.

[0062] According to Table 1, in some embodiments of the application, in the first range, the throat spacing changes from 0 to 16%-20%; in the second range, the throat spacing changes from 12%-15% to 0; and in the third range, the throat spacing changes from -15% to -11% to 1%-3%.

[0063] The application also provides a turbine engine comprising a turbine and a turbine guide vane on the turbine.

[0064] Table 2 is a comparison of the turbine aerodynamic performance results in the comparative example one and the turbine starting performance structure in the embodiment one of the application (the structure of the comparative example one is taken as the dimensionless reference value)

[0065] Uniform (conventional design) Non-uniform (present invention) Relative change Inlet flow (kg / s) 1 1.0008 0.08％ Turbine power (KW) 1 1.0001 0.01％ Expansion ratio 1 0.9990 -0.10％ Efficiency 1 0.9997 -0.03％ Outlet flow angle 1 0.9995 -0.05％

[0066] According to Table 2, the main aerodynamic indicators of the turbine equipped with the turbine guide vane in the embodiment of the application change within 0.1%, the turbine inlet flow, turbine power, and outlet airflow angle are equivalent to the parameters in the comparative example, and the turbine efficiency is only reduced by 0.03%, which indicates that the turbine guide vane in the application has no effect on the turbine aerodynamic performance and can achieve the performance level of the comparative example one. Therefore, the turbine guide vane in the application not only meets the requirements of turbine aerodynamic performance, but also greatly reduces the unsteady airflow excitation force of the turbine rotor blade, thereby reducing the risk of high-cycle fatigue fracture of the turbine rotor blade.

[0067] Obviously, the above embodiments are only examples for clarity and do not limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all embodiments need not and cannot be exhausted. The obvious changes or variations derived therefrom are still within the protection scope of the application.

Claims

1. A turbine guide characterized by, The turbine casing comprises: guide vanes, the guide vanes are unevenly distributed along the circumference of the turbine casing, and a throat interval is arranged between two adjacent guide vanes, and the two adjacent throat intervals are different; the guide vane distribution at least comprises a linear distribution with three different changing trends, and the minimum interval between two adjacent guide vanes before the start of each section is an initial throat interval; in the first section, the throat interval gradually increases; in the second section, the throat interval gradually decreases; in the third section, the throat interval gradually increases; in the first section, the relative change rate of any throat interval to the first initial throat interval is solved by the formula: When the number of the turbine guide vanes is one, the first section has a value range of , the second section has a value range of , and the third section has a value range of ; in the second section, the change rate of any throat interval to the second initial throat interval is solved by the formula: wherein , , and are constants greater than zero, is a number of the guide vanes, is a relative change rate of the throat distance corresponding to the guide vane at the number in the first section range with respect to the first initial throat distance; in the third section, the change rate of any throat interval to the third initial throat interval is solved by the formula: wherein , , and are constants greater than zero, is a number of the guide vane, is a relative change rate of the throat distance corresponding to the guide vane at the number in the second section range to the second initial throat distance; The turbine comprises a turbine, and the turbine is provided with the turbine guide of claim 1 or 2. wherein , , and are constants greater than zero, is the number of the guide vane, is the relative change rate of the throat distance corresponding to the guide vane at the number in the third section to the third initial throat distance.

2. The turbine guide according to claim 1, wherein, In a first section, the throat gap varies from 0 to ; in a second section, the throat gap varies from to 0; in a third section, the throat gap varies from to .

3. A turbine engine characterized by, ​

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