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 existing technologies, the throat area of ​​turbine blades is a key geometric parameter of turbine components, determining the turbine's flow capacity and the pressure and temperature parameters between blade rows. The turbine's flow capacity significantly influences the overall working order of the components, which in turn affects the performance of each component within the overall environment. The pressure and temperature between turbine blade rows affect blade cooling, the rim seal between the rotor and stator blades, and the axial force of the rotor. With the overall performance parameters determined, turbine designers need to rationally design the throat area of ​​each blade to achieve a given flow capacity and optimal distribution of pressure and temperature between blade rows.

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

[0004] For turbine components, deviations from the design of the throat area of ​​each row of blades 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 air flow 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] Currently, in engineering, the blade throat area is generally measured in the complete ring state, and only the guide blade throat area is measured. In order to obtain higher aerodynamic, thermal and structural strength performance, the turbine guide blade has 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, making it difficult to obtain the true throat area. The cross-sectional shape of the working blade throat is relatively regular, but due to the certain gap between the blade tenon and the impeller tenon in the complete ring assembly state, the blade spatial position is actually in a non-fixed state, which is not conducive to the accurate measurement of the throat area.

[0006] Therefore, the inventors of this 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 the 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 the blade profile. The method is characterized in that the method comprises the following steps:

[0010] S1. For each blade, select the measurement section;

[0011] S2. measuring the characteristic thickness of the blade profile for each measurement section;

[0012] S3. Measure the characteristic height of the turbine blade throat and calculate the theoretical value of the turbine blade throat height;

[0013] S4. Calculate the turbine blade throat area.

[0014] According to one embodiment of the present invention, step S1 includes: 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 an embodiment of the present invention, step S1 further includes: selecting 3 or 5 measurement sections, which are respectively arranged in the areas of 10%, 50%, 90% relative leaf height and middle leaf height.

[0016] According to one embodiment of the present invention, step S2 includes:

[0017] S 21 , establish the common tangent line l1 between the blade basin side profile and the trailing edge arc;

[0018] 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;

[0019] 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;

[0020] S 24 The translation distance between the arc tangent line l2 and the tangent line l3 of the trailing edge of the blade is one time the radius of the small circle of the trailing edge, rounded up to retain one decimal place;

[0021] S 25 2. Establish the tangent line l4 of the leaf back profile, and mark the tangent point as point G;

[0022] S 26, adjusting the position of the leaf back profile tangent line l4 and the leaf back profile tangent point G to ensure that the line connecting points E and G of two adjacent leaves is perpendicular to the leaf back profile tangent line l4;

[0023] S 27 The projection length of points E and G of the blade itself in the direction perpendicular to the tangent line l4 of the blade back profile is the characteristic thickness b value of the blade.

[0024] According to one embodiment of the present invention, 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 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; and obtain the common tangent line l1 based on the two tangent points.

[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 angle between the line connecting the middle point E and the point G and the tangent line l4 of the back profile of the leaf is less than or equal to 90±0.1 degrees.

[0027] According to one embodiment of the present invention, step S3 includes: projecting the midpoint of a line connecting points E and G on two adjacent blades onto the downflow at the measurement section closest to the blade root, with the projection direction being the z-axis direction, and the projection point H1 being the characteristic height point of the throat of the downflow surface; wherein the distance from H1 to the x-axis of the Cartesian coordinate system is denoted as R1;

[0028] At the measurement section closest to the blade tip, the midpoint of the line connecting points E and G on two adjacent blades is projected onto the upper flow channel in the z-axis direction. The projection point H2 is the characteristic height point of the throat of the upper flow channel 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, step S4 includes: 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 b is the angle between the tangent line l4 and the axial direction at the back of the leaf; i b is the measured b value of the test section; i,nom is the theoretical b value of the detection 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 progress effect of the present invention is:

[0036] The turbine blade throat area measurement method of the present invention, based on the characteristic dimensions of the blade profile, 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 the assembly state.

[0037] The turbine blade throat area measurement method performs throat area detection on blade single-piece castings and parts, which is beneficial to controlling blade throat area deviation and reducing the unevenness of the blade throat area throughout the entire ring. 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 like reference numerals represent like features throughout, wherein:

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

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

[0043] Figure 5 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, 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 illustrated 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 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 herein.

[0047] Furthermore, it is required that the present invention be understood not only by the actual terms used but also by the meanings lying behind 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 includes the following steps:

[0049] Step S1: For each blade, select a measurement section.

[0050] Preferably, the step S1 includes: 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 S1 further includes: selecting 3 or 5 measurement sections, which are arranged in the areas of 10%, 50%, 90% relative leaf height and middle leaf height respectively (such as Figure 2 shown).

[0052] Step S2: measuring the characteristic thickness of the blade profile for each measurement section.

[0053] Preferably, if Figure 3 As shown, the step S2 includes:

[0054] Step S 21 , establish the common tangent line l1 between the blade basin side profile and the trailing edge arc.

[0055] In one embodiment, the step S 21 The process of generating the common tangent line l1 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 (such as Figure 3(as shown in a).

[0056] The common tangent line l1 is obtained from the two tangent points, that is, the geometric theorem that a straight line is determined from two points, and the common tangent line l1 (i.e., straight line l1) is obtained. Here, for a blade profile, the position of l1 is unique.

[0057] Step S 22 , establish the blade trailing edge arc tangent line l2, and the blade trailing edge arc tangent line l2 is perpendicular to the common tangent line l1, and the tangent point with the trailing edge arc is recorded as point K (such as Figure 3 (as shown in b).

[0058] Step S 23 The arc tangent line l2 of the trailing edge of the blade is translated forward along the direction of the common tangent line l1 by a distance δ to obtain the tangent line l3. The intersection of the tangent line l3 and the side profile line of the blade basin is recorded as point E (as shown in FIG. Figure 3 (as shown in c).

[0059] Step S 24 The translation distance between the arc tangent line l2 and the tangent line l3 of the trailing edge of the blade is twice the radius of the small circle of the trailing edge, rounded up to retain one decimal place.

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

[0061] Step S 25 , establish the leaf back side tangent line l4, and mark the tangent point as point G (such as Figure 3 (as shown in e).

[0062] Step S 26 , adjust 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 (such as Figure 3 (as shown in f).

[0063] Preferably, 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 leaf is less than or equal to 90±0.1 degrees.

[0064] Step S 27 The projection length of the blade's own point E and point G in the direction perpendicular to the tangent line l4 of the blade's back profile is the blade's characteristic thickness b value (e.g. Figure 3 (as shown in g in the figure).

[0065] Step S3: Measure the characteristic height of the turbine blade throat and calculate the theoretical value of the turbine blade throat height (e.g. Figure 4 shown).

[0066] Preferably, in one embodiment, step S3 includes: projecting the midpoint of a line connecting points E and G on two adjacent blades onto the downflow at the measurement section closest to the blade root, with the projection direction being the z-axis, and projecting point H1 as the characteristic height point of the throat of the downflow surface. The distance from H1 to the x-axis of the Cartesian coordinate system is denoted as R1.

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

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

[0069] h nom =R2-R1.

[0070] Step S4: Calculate the turbine blade throat area.

[0071] Preferably, in one embodiment, the step S4 includes: 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] p i,nom is the theoretical throat width of the test section;

[0078] r i is 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 The b value is used to detect the angle between the tangent line l4 at the back of the leaf and the axial direction;

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

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

[0083] h nomis 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 the impeller machinery in a gas turbine where the combustion gas expands, performs work, and converts internal energy into kinetic energy. Blades refer to the airfoil in a turbine, including guide vanes (guide vanes) mounted on the stator and working blades (moving blades) fixed to the rotating disc. 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 blade cascade channel with the smallest area. The characteristic thickness b value of the blade profile refers to the projected 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 curve. The airflow pressure is lower along this surface, also known as the back of the blade.

[0087] The pressure side refers to the concave side of the blade's curved surface or profile curve, along which airflow pressure is higher. This surface is also known as the blade basin. The leading edge of the blade is the curve connecting the pressure and suction sides of the blade on the inlet side, typically a segment of a circular or elliptical curve. The trailing edge is the curve connecting the pressure and suction sides of the blade on the exhaust side, typically a segment of a circular curve. Profile accuracy refers to the variation of the measured actual profile relative to the ideal profile.

[0088] The present invention is a turbine blade throat area measurement method based on blade profile characteristic dimensions, which 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 profile characteristic thickness.

[0094] This turbine blade throat area measurement method, based on blade profile characteristic dimensions, detects the throat area of ​​a single turbine blade, rather than measuring the entire blade. This turbine blade throat area measurement method can be applied to guide vanes and rotor blades, as well as turbine blade castings and parts.

[0095] In summary, the turbine blade throat area measurement method based on the blade profile characteristic dimensions 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 the assembly state.

[0096] The turbine blade throat area measurement method performs throat area detection on blade single-piece castings and parts, which is beneficial to controlling blade throat area deviation and reducing the unevenness of the blade throat area throughout the entire ring.

[0097] For those skilled in the art, the above invention disclosure is intended only as an example and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and amendments to this application. Such modifications, improvements, and amendments are suggested in this application and remain within the spirit and scope of the exemplary embodiments of this application.

[0098] At the same time, this application uses specific terms to describe the embodiments of this 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 this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0099] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the 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, and such changes and modifications are intended to fall within the 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.

Images