Turbine blade throat area measuring method based on blade profile feature size

Abstract

The invention provides a turbine blade throat area measurement method based on blade profile feature dimensions, and the method comprises the following steps: S1, selecting a measurement section for each blade; s2, for each measurement cross section, measuring the blade profile characteristic thickness; s3, measuring the throat feature height of the turbine blade, and calculating the theoretical value of the throat height of the turbine blade; and S4, calculating the throat area of the turbine blade. According to the invention, throat area measurement can be carried out on a single blade of a guide blade and a working blade, and the method is suitable for blade castings and parts and is not influenced by an assembly state. According to the turbine blade throat area measurement method, throat area detection is carried out on single blade castings and parts, the blade throat area deviation can be managed and controlled, and the non-uniformity of the whole ring blade throat area is reduced.

Description

Technical Field

[0001] The invention relates to the field of turbine blade throat area detection, and in particular to a turbine blade throat area measurement method based on blade profile characteristic dimensions. Background Art

[0002] In the prior art, the throat area of ​​the turbine blades is a key geometric parameter of the turbine components, which determines the turbine flow capacity and the pressure and temperature parameters between the blade rows. The flow capacity of the turbine has a great influence on the working rules of the components of the whole machine, which in turn affects the performance of each component in the whole machine environment. The pressure and temperature between the rows of turbine blades will affect the cooling of the blades, the rim seal between the rotor and stator blades, and the axial force of the rotor. Under the premise of determining the overall performance parameters, the turbine designer needs to reasonably design the throat area of ​​each blade to achieve the established flow capacity and the optimal distribution of pressure and temperature between the blade rows.

[0003] Due to processing and assembly deviations, the actual blade throat area often deviates from the design target. For the entire engine, the deviation of the turbine guide throat area from the design will cause the engine components to operate in a non-designed state.

[0004] For turbine components, deviation of the throat area of ​​each row of blades from the design will change the pressure and temperature distribution of each stage of the turbine blades, thereby causing the turbine aerodynamic performance to deviate from the design, and reducing the blade cooling airflow or increasing the risk of gas backflow due to the rotor and stator rim seal, thereby reducing the aerodynamic efficiency and working reliability of the turbine components.

[0005] At present, the throat area of ​​the blade is generally measured in the complete ring state in engineering, and only the throat area of ​​the guide blade is measured. In order to obtain higher aerodynamic thermal and structural strength performance, the turbine guide blade is a complex three-dimensional shape in space. Therefore, the throat area window formed between the blades in the circumferential direction is also a complex three-dimensional spatial surface, and it is difficult to obtain the true throat area. The cross-sectional shape of the throat of the working blade is relatively regular, but due to the certain gap between the blade tenon and the tenon of the wheel in the complete ring assembly state, the spatial position of the blade is actually in a non-fixed state, which is not conducive to the accurate measurement of the throat area.

[0006] Therefore, the inventors of the present application have designed a method for measuring the throat area of ​​a turbine blade based on the characteristic dimensions of the blade profile, which is aimed at measuring the throat area of ​​a single blade and is convenient for measuring the throat area when the blade is in a casting or component state. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the defects of the prior art such as difficulty in obtaining the throat area of ​​turbine blades and low accuracy, and to provide a method for measuring the throat area of ​​turbine blades based on the characteristic dimensions of the blade profile.

[0008] The present invention solves the above technical problems through the following technical solutions:

[0009] The present invention provides a method for measuring the throat area of ​​a turbine blade based on the characteristic size of a blade profile, wherein the method comprises the following steps:

[0010] S 1 , For each blade, select the measurement section;

[0011] S 2 , for each of the measurement sections, measuring the characteristic thickness of the blade profile;

[0012] S 3 , measure the characteristic height of the turbine blade throat and calculate the theoretical value of the turbine blade throat height;

[0013] S 4 , calculate the turbine blade throat area.

[0014] According to one embodiment of the present invention, the step S 1 The measurement section is a plane perpendicular to the z-axis in a Cartesian coordinate system, the Cartesian coordinate system is consistent with the coordinate system used in blade shaping, and the z-axis is the height direction of the blade.

[0015] According to one embodiment of the present invention, the step S 1 The method also includes: selecting 3 or 5 measurement sections and arranging them in the areas of 10%, 50%, 90% relative leaf height and middle leaf height respectively.

[0016] According to one embodiment of the present invention, the step S 2 Included:

[0017] S 21 , establish the common tangent line l between the blade basin side profile and the trailing edge arc 1 ;

[0018] S 22 , establish the arc tangent line l of the blade trailing edge 2 , and the arc tangent line l of the trailing edge of the blade 2 and the common tangent line l 1 Vertical, the point of tangency with the arc of the trailing edge is recorded as point K;

[0019] S 23 , the arc tangent line l of the trailing edge of the blade 2 Along the common tangent line l 1 The tangent line l is obtained by translating forward by a distance δ in the direction of 3 , the tangent line l 3 The intersection point with the blade basin side profile line is marked as point E;

[0020] S24 , the arc tangent line l of the trailing edge of the blade 2 With the tangent line l 3 The translation distance is one time the radius of the small circle at the trailing edge, rounded up to retain one decimal place;

[0021] S 25 , establish the tangent line of the leaf back side profile 4 , the tangent point is recorded as point G;

[0022] S 26 , adjust the tangent line l of the back side of the leaf 4 The position of the tangent point G with the back profile of the leaf ensures that the line connecting the points E and G of the two adjacent leaves is tangent to the back profile of the leaf. 4 vertical;

[0023] S 27 , the blade's own point E and point G are on the tangent line l with the blade's back profile line 4 The projection length in the vertical direction is the characteristic thickness b value of the blade.

[0024] According to one embodiment of the present invention, the step S 21 Common tangent line l 1 The process of generating is as follows: take any straight line tangent to the blade, adjust the position of the tangent point so that the straight line can slide along the blade until the straight line has another tangent point with the blade; obtain the common tangent line l according to the two tangent points 1 .

[0025] According to one embodiment of the present invention, the step S 24 The same translation distance can be used for sections at different heights of the same blade.

[0026] According to one embodiment of the present invention, the step S 26 The line connecting the middle point E and the point G and the tangent line l of the back side of the leaf 4 The angle is less than or equal to 90±0.1 degrees.

[0027] According to one embodiment of the present invention, the step S 3 It includes: in the measurement section closest to the blade root, the midpoint of the line connecting point E and point G on two adjacent blades is projected onto the lower flow channel, the projection direction is the z-axis direction, and the projection point H1 is the characteristic height point of the throat of the lower flow channel surface; wherein, the distance from H1 to the x-axis of the Cartesian coordinate system is recorded as R1;

[0028] At the measuring section closest to the blade tip, the midpoint of the line connecting point E and point G on two adjacent blades is projected toward the upper flow passage, the projection direction is the z-axis direction, and the projection point H2 is the characteristic height point of the throat of the upper flow passage surface; the distance from H2 to the x-axis of the Cartesian coordinate system is recorded as R2.

[0029] According to one embodiment of the present invention, the theoretical value of the throat height of the turbine blade is calculated using the theoretical value calculation formula of the throat height:

[0030] h nom =R2-R1.

[0031] According to one embodiment of the present invention, the step S 4 Included: The blade throat area calculation formula is as follows:

[0032]

[0033]

[0034] Where A is the actual value of the throat area of ​​a channel; M is the number of measurement sections; i represents the detection sections at different heights; o i，nom is the theoretical throat width of the detection section; r i is the distance from the detection section to the x-axis of the Cartesian coordinate system; N is the number of blades in the entire ring; β i The b value is the tangent line l of the back point of the leaf 4 Angle with the axial direction; b i b is the measured b value of the test section; i，nom is the theoretical b value of the detection cross section; h nom is the theoretical value of throat height; Δh root Δh is the contour deviation of the throat detection point of the lower edge plate; tip It is the contour deviation of the upper edge plate throat detection point.

[0035] The positive and progressive effects of the present invention are:

[0036] The method for measuring the throat area of ​​a turbine blade based on the characteristic dimensions of the blade profile can carry out throat area measurement for a single blade of a guide blade and a working blade, is applicable to blade castings and parts, and is not affected by assembly status.

[0037] The turbine blade throat area measurement method carries out throat area detection on blade monolithic castings and parts, which is beneficial to controlling blade throat area deviation and reducing the unevenness of the throat area of ​​the entire ring blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] 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 the same reference numerals always represent the same features, wherein:

[0039] Figure 1 The present invention is a flow chart of a method for measuring throat area of ​​a turbine blade based on characteristic dimensions of blade profile.

[0040] Figure 2It is a schematic diagram of the measurement cross section in the method for measuring the throat area of ​​a turbine blade based on the characteristic dimensions of the blade profile of the present invention.

[0041] Figure 3 It is a schematic diagram of the blade profile characteristic thickness measurement in the turbine blade throat area measurement method based on the blade profile characteristic size of the present invention.

[0042] Figure 4 It is a schematic diagram of measuring throat characteristic height in the method for measuring throat area of ​​turbine blades based on blade profile characteristic dimensions of the present invention.

[0043] Figure 5 It is a schematic diagram of the profile in the turbine blade throat area measurement method based on the blade profile characteristic size of the present invention. DETAILED DESCRIPTION

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0045] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Reference will now be made in detail to preferred embodiments of the present invention, examples of which are shown in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to represent the same or similar parts.

[0046] Furthermore, although the terms used in the present invention are selected from well-known and commonly used terms, some terms mentioned in the present invention specification may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this document.

[0047] Furthermore, it is required that the present invention be understood not only by the actual terms used but also by the meanings connoted by each term.

[0048] like Figure 1 As shown, the present invention provides a method for measuring the throat area of ​​a turbine blade based on the characteristic size of the blade profile, which comprises the following steps:

[0049] Step S 1 , For each blade, select the measurement section.

[0050] Preferably, the step S 1 The measurement section is a plane perpendicular to the z-axis in a Cartesian coordinate system, and the Cartesian coordinate system is consistent with the coordinate system used in blade shaping (such as Figure 2 As shown), the z-axis is the height direction of the blade.

[0051] Furthermore, the step S 1 The method also includes: selecting 3 or 5 measurement sections, which are arranged in the areas of 10%, 50%, 90% relative leaf height and middle leaf height (such as Figure 2 shown).

[0052] Step S 2 , for each of the measurement sections, measuring the characteristic thickness of the blade profile.

[0053] Preferably, if Figure 3 As shown, the step S 2 Included:

[0054] Step S 21 , establish the common tangent line l between the blade basin side profile and the trailing edge arc 1 .

[0055] In one embodiment, the step S 21 Common tangent line l 1 The generation process is as follows: any straight line tangent to the blade profile, adjust the position of the tangent point so that the straight line can slide along the blade profile until the straight line has another tangent point with the blade profile (such as Figure 3 (shown in a).

[0056] According to the two tangent points, the common tangent line l is obtained. 1 , that is, the geometric theorem of determining a straight line based on two points, at this time, the common tangent line l is obtained 1 (i.e. straight line l 1 ). Here for a leaf shape, l 1 The location is unique.

[0057] Step S 22 , establish the arc tangent line l of the blade trailing edge 2 , and the arc tangent line l of the trailing edge of the blade 2 and the common tangent line l 1 The point of tangency with the arc of the trailing edge is marked as point K (e.g. Figure 3 (as shown in b).

[0058] Step S 23 , the arc tangent line l of the trailing edge of the blade 2 Along the common tangent line l 1 The tangent line l is obtained by translating forward by a distance δ in the direction of 3 , the tangent line l 3 The intersection point with the blade basin side profile line is marked as point E (such as Figure 3 (as shown in c).

[0059] Step S 24 , the arc tangent line l of the trailing edge of the blade 2 With the tangent line l 3 The translation distance is one times the radius of the small circle at the trailing edge, rounded up to one decimal place.

[0060] Preferably, the step S 24The same translation distance can be used for sections at different heights of the same blade.

[0061] Step S 25 , establish the tangent line of the leaf back side profile 4 , the tangent point is recorded as point G (such as Figure 3 (as shown in e).

[0062] Step S 26 , adjust the tangent line l of the back side of the leaf 4 The position of the tangent point G with the back profile of the leaf ensures that the line connecting the points E and G of the two adjacent leaves is tangent to the back profile of the leaf. 4 Vertical (such as Figure 3 (shown in f).

[0063] Preferably, the step S 26 The line connecting the middle point E and the point G and the tangent line l of the back side of the leaf 4 The angle is less than or equal to 90±0.1 degrees.

[0064] Step S 27 , the blade's own point E and point G are on the tangent line l with the blade's back profile line 4 The projection length in the vertical direction is the characteristic thickness b value of the blade (e.g. Figure 3 (as shown in g).

[0065] Step S 3 , measure the characteristic height of the turbine blade throat and calculate the theoretical value of the turbine blade throat height (such as Figure 4 shown).

[0066] Preferably, in one embodiment, the step S 3 It includes: the measurement section closest to the blade root, the midpoint of the line connecting point E and point G on two adjacent blades is projected onto the lower flow channel, the projection direction is the z-axis direction, and the projection point H1 is the characteristic height point of the throat of the lower flow channel surface. Among them, the distance from H1 to the x-axis of the Cartesian coordinate system is recorded as R1.

[0067] At the measurement section closest to the blade tip, the midpoint of the line connecting point E and point G on two adjacent blades is projected toward the upper flow passage, the projection direction is the z-axis direction, and the projection point H2 is the characteristic height point of the throat of the upper flow passage surface. The distance from H2 to the x-axis of the Cartesian coordinate system is recorded as R2.

[0068] Then, the theoretical value of the throat height is calculated using the throat height theoretical value calculation formula:

[0069] h nom =R2-R1.

[0070] Step S 4 , calculate the turbine blade throat area.

[0071] Preferably, in one embodiment, the step S 4 Included: The blade throat area calculation formula is as follows:

[0072]

[0073]

[0074] Among them, A nom is the theoretical value of the throat area of ​​a channel; A is the actual value of the throat area of ​​a channel;

[0075] M is the number of measurement sections;

[0076] i represents the detection cross sections at different heights;

[0077] o i，nom The theoretical throat width of the test section;

[0078] r i The distance from the detection section to the x-axis of the Cartesian coordinate system;

[0079] N is the number of blades in the entire ring;

[0080] β i Detect the tangent line l of the back side of the leaf for the b value 4 Angle with the axis;

[0081] b i The b value is measured for the test section;

[0082] b i，nom is the theoretical b value of the detection cross section;

[0083] h nom is the theoretical value of throat height;

[0084] Δh root Δh is the contour deviation of the throat detection point of the lower edge plate; tip is the contour deviation of the upper plate throat detection point (such as Figure 5 shown).

[0085] Based on the above description, the terms appearing in this application are explained as follows:

[0086] A turbine refers to a turbine machine in a gas turbine where the gas expands, does work, and converts internal energy into kinetic energy. A blade refers to an airfoil in a turbine, including guide blades (guide vanes) mounted on a stator and working blades (moving blades) fixed on a rotating disk. The throat area refers to the cross-section with the smallest area of ​​the blade cascade channel. The throat width refers to the cross-sectional width of the smallest area of ​​the blade cascade channel. The characteristic thickness b value of the blade profile refers to the projection distance between the throat point on the pressure side of the blade profile and the throat point on the suction side of the blade profile in the throat width direction. The suction surface refers to the convex side of the blade surface or blade profile curve. The airflow pressure is lower along this surface, also known as the back of the blade.

[0087] The pressure surface refers to the concave side of the blade surface or blade curve. The airflow pressure along this surface is higher, also known as the blade basin. The leading edge of the blade refers to the curve connecting the pressure surface and the suction surface on the inlet side of the blade, which is generally a section of a circular or elliptical curve. The trailing edge of the blade refers to the curve connecting the pressure surface and the suction surface on the exhaust side of the blade, which is generally a section of a circular curve. Contour refers to the change of the actual profile being measured relative to the ideal profile.

[0088] The invention discloses a turbine blade throat area measurement method based on blade profile characteristic dimensions, and calculates the actual blade throat area by detecting the blade profile characteristic dimensions of a single blade. The blade profile characteristic dimensions include blade profile thickness and throat height.

[0089] The turbine blade throat area measurement method based on blade profile characteristic dimensions of the present invention also has the following characteristics:

[0090] 1. The turbine blade throat area measurement method does not measure the spatial distance between two adjacent blades, but measures the characteristic size of a single blade, converts the deviation of the characteristic size into the deviation of the throat width, and then evaluates the throat area.

[0091] 2. The turbine blade throat area measurement method is not only applicable to turbine guide blades, but also to working blades.

[0092] 3. The turbine blade throat area measurement method determines the characteristic thickness of the blade profile by establishing common tangent lines at different positions of the blade profile.

[0093] 4. The turbine blade throat area measurement method proposes a mathematical relationship between the throat width and the blade characteristic thickness.

[0094] The turbine blade throat area measurement method based on blade profile characteristic dimensions performs throat area detection on a single turbine blade, rather than measurement in a complete ring state. The turbine blade throat area measurement method can be applied to guide blades and working blades, and can be applied to turbine blade castings and parts.

[0095] In summary, the method for measuring the throat area of ​​turbine blades based on the characteristic dimensions of the blade profile of the present invention can carry out throat area measurement for single blades of guide blades and working blades, is applicable to blade castings and parts, and is not affected by assembly status.

[0096] The turbine blade throat area measurement method carries out throat area detection on blade monolithic castings and parts, which is beneficial to controlling blade throat area deviation and reducing the unevenness of the throat area of ​​the entire ring blade.

[0097] For those skilled in the art, the above invention disclosure is only used as an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary implementation of the present application.

[0098] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0099] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A method for measuring the throat area of ​​a turbine blade based on blade profile characteristic dimensions, characterized in that: The turbine blade throat area measurement method comprises the following steps: S1. For each blade, select a measurement section; S2. measuring the characteristic thickness of the blade profile for each measurement section; S3, measuring the characteristic height of the turbine blade throat and calculating the theoretical value of the turbine blade throat height; S4. Calculate the turbine blade throat area.

2. The method for measuring the throat area of ​​a turbine blade based on blade profile characteristic dimensions according to claim 1, characterized in that: The step S1 includes: the measuring section is a plane perpendicular to the z-axis in a Cartesian coordinate system, the Cartesian coordinate system is consistent with the coordinate system used in blade shaping, and the z-axis is the height direction of the blade.

3. The method for measuring the throat area of ​​a turbine blade based on blade profile characteristic dimensions according to claim 2, characterized in that: The step S1 further includes: selecting 3 or 5 measurement sections, and arranging them in the areas of 10%, 50%, 90% relative leaf height and middle leaf height respectively.

4. The method for measuring the throat area of ​​a turbine blade based on blade profile characteristic dimensions according to claim 2, characterized in that: The step S2 includes: S 21 , establish the common tangent line l1 between the blade basin side profile line and the trailing edge arc; S 22 , establishing a blade trailing edge arc tangent line l2, wherein the blade trailing edge arc tangent line l2 is perpendicular to the common tangent line l1, and the point of tangency with the trailing edge arc is recorded as point K; S 23 , the arc tangent line l2 of the trailing edge of the blade is translated forward by a distance δ along the direction of the common tangent line l1 to obtain a tangent line l3, and the intersection of the tangent line l3 and the side profile line of the blade basin is recorded as point E; S 24 , the translation distance between the arc tangent line l2 of the trailing edge of the blade profile and the tangent line l3 is one time the radius of the small circle of the trailing edge, rounded up to retain one decimal place; S 25 , establish the tangent line l4 of the leaf back profile, and the tangent point is recorded as point G; S 26 , adjusting the position of the leaf back side profile tangent line l4 and the leaf back side profile tangent point G to ensure that the line connecting the points E and G of two adjacent leaves is perpendicular to the leaf back side profile tangent line l4; S 27 The projection length of the blade's own points E and G in the direction perpendicular to the tangent line l4 on the back side of the blade is the characteristic thickness b value of the blade.

5. The method for measuring the throat area of ​​a turbine blade based on blade profile characteristic dimensions according to claim 4, characterized in that: The step S 21 The process of generating the common tangent line l1 is as follows: for any straight line tangent to the blade profile, adjust the position of the tangency point so that the straight line can slide along the blade profile until the straight line has another tangency point with the blade profile; and obtain the common tangent line l1 based on the two tangency points.

6. The method for measuring the throat area of ​​a turbine blade based on blade profile characteristic dimensions according to claim 4, characterized in that: The step S 24 The same translation distance can be used for sections at different heights of the same blade.

7. The method for measuring the throat area of ​​a turbine blade based on blade profile characteristic dimensions according to claim 4, characterized in that: The step S 26 The angle between the line connecting the middle point E and the point G and the tangent line l4 of the back profile of the blade is less than or equal to 90±0.1 degrees.

8. The method for measuring the throat area of ​​a turbine blade based on blade profile characteristic dimensions according to claim 4, characterized in that: The step S3 includes: at the measurement section closest to the blade root, the midpoint of the line connecting point E and point G on two adjacent blades is projected onto the lower flow passage, the projection direction is the z-axis direction, and the projection point H1 is the characteristic height point of the throat of the lower flow passage surface; wherein the distance from H1 to the x-axis of the Cartesian coordinate system is recorded as R1; At the measuring section closest to the blade tip, the midpoint of the line connecting point E and point G on two adjacent blades is projected toward the upper flow passage, the projection direction is the z-axis direction, and the projection point H2 is the characteristic height point of the throat of the upper flow passage surface; the distance from H2 to the x-axis of the Cartesian coordinate system is recorded as R2.

9. The method for measuring the throat area of ​​a turbine blade based on blade profile characteristic dimensions according to claim 8, characterized in that: The theoretical value of the throat height of the turbine blade is calculated using the theoretical value calculation formula of the throat height: h nom =R2-R1。 10. The method for measuring the throat area of ​​a turbine blade based on blade profile characteristic dimensions according to claim 9, characterized in that: The step S4 includes: the blade throat area calculation formula is as follows: Where A is the actual value of the throat area of ​​a channel; M is the number of measurement sections; i represents the detection sections at different heights; o i,nom is the theoretical throat width of the detection section; r i is the distance from the detection section to the x-axis of the Cartesian coordinate system; N is the number of blades in the entire ring; β i b is the angle between the tangent line l4 at the back of the leaf and the axial direction; i b is the measured b value of the test section; i,nom is the theoretical b value of the detection cross section; h nom is the theoretical value of throat height; Δh root Δh is the contour deviation of the throat detection point of the lower edge plate; tip It is the contour deviation of the upper edge plate throat detection point.

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