Test method for obtaining axial deformation of gas turbine casing based on local strain of front support

Abstract

The invention relates to a test method for obtaining axial deformation of a gas turbine casing based on local strain of a front support, and aims to solve the existing problems of high test cost and large calculation error of an axial deformation experiment of the gas turbine casing. According to the scheme, the maximum main strain of the central areas of the air inlet side bottom and the exhaust side top of the front support under different axial displacements of the gas turbine casing is obtained through finite element calculation, a function relation expression of the maximum main strain and the maximum main strain is obtained through fitting, and strain gauges are arranged in the central areas of the air inlet side bottom and the exhaust side top of the front support of the gas turbine respectively. Recording the maximum main strain of the central areas of the bottom of the gas inlet side and the top of the gas exhaust side of the front support of the gas turbine in real time under a slow working condition, a rated working condition or a maximum power working condition by adopting a strain tester, and substituting strain data measured by the strain tester in real time into the function relational expression; and finally, the axial deformation of the casing of the gas turbine under the slow working condition, the rated working condition or the maximum power working condition is obtained in real time, and the axial deformation of the casing is simply, quickly and accurately obtained in real time.

Description

Technical Field

[0001] This invention relates to the field of gas turbine casing axial deformation testing technology, specifically a test method for obtaining gas turbine casing axial deformation based on local strain of the front support. Background Technology

[0002] The common testing method for axial displacement of gas turbine casings is as follows: First, thermocouples are attached to the surfaces of components such as the low-pressure casing, load-bearing casing, and combustion chamber casing, and the temperature data of the surface of each component casing is measured by the thermocouples; then, the axial deformation of each component casing is calculated based on the thermal expansion coefficient of the casing material; finally, the total axial deformation is obtained by superimposing the axial deformations of each component casing.

[0003] The total axial displacement obtained by simply superimposing thermocouple temperature data, thermal expansion data of the casing materials of each component, and axial deformation has a large error. Moreover, due to the non-uniformity of the temperature on the outer surface of the casing, a large number of thermocouples are often required to obtain an accurate temperature gradient on the outer surface of the casing during experimental testing, which further increases the pre-processing time and testing cost of the experimental test.

[0004] In summary, the existing methods for testing the axial deformation of gas turbine casings suffer from high costs and large calculation errors. Summary of the Invention

[0005] The purpose of this invention is to address the existing problems of high testing costs and large calculation errors in the axial deformation test of gas turbine casings. This invention proposes a test method for obtaining the axial deformation of gas turbine casings based on the local strain of the front support.

[0006] The objective of this invention is achieved as follows: a test method for obtaining the axial deformation of a gas turbine casing based on the local strain of the front support, comprising the following steps:

[0007] Step 1: Calculate the maximum principal strain in the central region of the bottom of the inlet side and the top of the exhaust side of the front support under different axial displacements of the gas turbine casing using finite element analysis.

[0008] A three-dimensional solid calculation model of the gas turbine front support is created in the software;

[0009] The three-dimensional solid calculation model 1 is meshed. Through precise control of the mesh, specific nodes are marked in the central areas of the bottom of the front support intake side and the top of the exhaust side.

[0010] Import the mesh file into the finite element analysis software, and define the material data, contact conditions, loads, and boundary conditions of the three-dimensional solid calculation model 1 according to the requirements.

[0011] Submit the finite element analysis calculation file and output the maximum principal strain of specific nodes in the central region of the bottom of the intake side and the top of the exhaust side of the front support.

[0012] Step 2: Plot the curves of axial displacement of the gas turbine casing as a function of the maximum principal strain in the central region of the bottom of the inlet side and the top of the exhaust side of the front support, and fit the functional relationship between the two.

[0013] Step 3: Arrange strain gauges in the central areas of the bottom of the inlet side and the top of the exhaust side of the gas turbine front support, respectively;

[0014] By measuring the distance to specific nodes calibrated in the mesh model, the spatial positions of these specific nodes in the front support are obtained;

[0015] Attach strain gauges at these specific nodes;

[0016] Step 4: Connect the strain gauge to the strain tester 12 and adjust the strain tester 12;

[0017] Step 5: Use a strain gauge 12 to record in real time the maximum principal strain in the central area of ​​the bottom of the inlet side and the top of the exhaust side of the gas turbine front support under slow speed, rated operation, or maximum power conditions.

[0018] During the process of the gas turbine transitioning from idle condition to rated condition and up to maximum power, the strain gauge data changes at the bottom of the inlet side and the top of the exhaust side of the front support are recorded and output in real time.

[0019] Step 6: Substitute the strain data measured in real time by the strain tester 12 into the function relationship fitted in step 2 to finally obtain the axial deformation of the gas turbine casing under idle, rated or maximum power conditions in real time.

[0020] Based on the strain values ​​of the bottom of the intake side and the top of the exhaust side of the front support output in real time by the strain tester 12, the axial deformation of the casing is calculated in real time by substituting them into the function relationship obtained by fitting in step two, thus realizing the real-time output and monitoring of the axial deformation of the gas turbine casing.

[0021] Furthermore, in step one, UG-NX is used to create the three-dimensional solid calculation model 1 of the gas turbine front support in the software.

[0022] Furthermore, the basic principle of mesh generation in step one is:

[0023] Step A: Using the surface segmentation method, perform local calibration on the areas where strain gauges are pasted, including the bottom air intake side strain gauge of the air intake side upright plate 3 (grid node 1), the bottom air intake side strain gauge of the air intake side upright plate 3 (grid node 2), the top exhaust side strain gauge of the exhaust side upright plate 4 (grid node 1), and the top exhaust side strain gauge of the exhaust side upright plate 4 (grid node 2).

[0024] Step B: Refine the mesh in the local calibration area, ensuring that the center point of the refined area is the strain gauge attachment point;

[0025] Step C: Divide the casing connecting plate 2 and the front support base 5 into a grid.

[0026] Furthermore, the basic steps of the finite element analysis calculation in step one are:

[0027] Step D: Define material properties on the mesh model calculated by the finite element analysis:

[0028] Step E: Define the contact and boundary conditions of the front-support finite element mesh calculation model in the finite element analysis software:

[0029] Displacement boundary conditions along the axial direction of the casing are applied to the casing connecting plate 2;

[0030] The contact surfaces of the intake side upright plate 3 and the exhaust side upright plate 4 are all designed to be bonded to the contact surfaces of the casing connecting plate 2 and the front support base 5.

[0031] The front support base 5 is fixedly constrained on the ground.

[0032] Furthermore, defining material properties in step D includes:

[0033] Density, elastic modulus, and Poisson's ratio of casing connecting plate 2;

[0034] Density, elastic modulus, and Poisson's ratio of the intake side panel 3;

[0035] Density, elastic modulus, and Poisson's ratio of the exhaust side plate 4;

[0036] Density, elastic modulus, and Poisson's ratio of the front support base 5.

[0037] Furthermore, the process of obtaining the functional relationship in step two is as follows:

[0038] By applying different axial displacements to the top of the front support, the maximum principal strain values ​​of specific nodes in the central region of the bottom of the intake side and the top of the exhaust side of the front support under different axial displacements were obtained.

[0039] Plot the curves of the maximum principal strain at specific nodes in the central region of the bottom of the intake side and the top of the exhaust side of the front support as a function of different axial displacements, with the maximum principal strain as the independent variable and the axial displacement of the casing as the dependent variable.

[0040] The functional relationship between the axial displacement of the casing and the maximum principal strain was obtained by linear fitting.

[0041] Furthermore, the process of arranging strain gauges in step three is as follows:

[0042] Install the #J1 intake-side strain gauge at one of the mesh nodes on the intake-side strain gauge bonding site;

[0043] Install the #J2 intake-side strain gauge at the second mesh node of the intake-side strain gauge bonding;

[0044] Install the #P1 exhaust-side strain gauge at one of the mesh nodes where the strain gauge is attached;

[0045] Install the #P2 exhaust-side strain gauge at one of the mesh nodes on the exhaust-side strain gauge attachment point.

[0046] Furthermore, in step three, the strain gauges are attached in a vertical direction.

[0047] Furthermore, the connection between the strain gauge and the strain testing instrument in step four is specifically as follows:

[0048] The #J1 inlet side strain gauge, #J2 inlet side strain gauge, #P1 exhaust side strain gauge, and #P2 exhaust side strain gauge are each connected to a strain gauge.

[0049] Furthermore, the debugging of the strain tester in step four specifically involves: before starting the gas turbine, clearing the data displayed on the strain tester.

[0050] Beneficial effects:

[0051] By establishing a functional relationship between the maximum principal strain in the central region of the bottom of the intake side and the top of the exhaust side of the front support and the axial deformation of the casing, the axial deformation of the casing can be accurately obtained, realizing a simple, fast, real-time and accurate acquisition of the axial deformation of the casing.

[0052] This invention avoids the problems of high experimental costs and large calculation errors in existing gas turbine axial deformation testing methods. It obtains the casing axial deformation in real time by converting the maximum principal strain of the gas turbine front support. This method is simple to operate, low in cost, and provides accurate data, breaking through the limitations of existing casing axial deformation testing methods. It establishes a functional relationship between the maximum principal strain in the central region of the bottom of the inlet side and the top of the exhaust side of the gas turbine front support and the casing axial deformation. The casing axial deformation is calculated using strain data measured by a strain gauge, providing data support for gas turbine design and realizing real-time testing and monitoring of gas turbine casing axial deformation, which has broad application prospects. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of a three-dimensional solid model of the gas turbine front support of the present invention;

[0054] Figure 2 This is a schematic diagram of a three-dimensional solid model of the gas turbine front support of the present invention;

[0055] Figure 3 This is a schematic diagram of the grid division on the inlet side of the gas turbine front support;

[0056] Figure 4 This is a schematic diagram of the grid division on the exhaust side of the gas turbine front support;

[0057] Figure 5 It is the curve showing the variation of the maximum principal strain of specific grid nodes on the intake and exhaust sides of the gas turbine front support with random casing axial displacement.

[0058] Figure 6 This is a schematic diagram of the maximum principal strain test on the inlet side of the front support of the gas turbine;

[0059] Figure 7 This is a schematic diagram of the maximum principal strain test on the exhaust side of the front support of the gas turbine. Detailed Implementation

[0060] Specific Implementation Method 1: A test method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support, which includes the following steps:

[0061] Step 1: The maximum principal strain in the central region of the bottom of the inlet side and the top of the exhaust side of the front support under different axial displacements of the gas turbine casing is obtained by finite element calculation.

[0062] A three-dimensional solid calculation model of the gas turbine front support was established in the software (1);

[0063] The three-dimensional solid calculation model 1 is meshed. Through precise control of the mesh, specific nodes are marked in the central areas of the bottom of the front support intake side and the top of the exhaust side.

[0064] Import the mesh file into the finite element analysis software, and define the material data, contact conditions, loads, and boundary conditions of the three-dimensional solid calculation model 1 according to the requirements.

[0065] Submit the finite element analysis calculation file and output the maximum principal strain of specific nodes in the central region of the bottom of the intake side and the top of the exhaust side of the front support.

[0066] Step 2: Plot the curves of axial displacement of the gas turbine casing as a function of the maximum principal strain in the central region of the bottom of the inlet side and the top of the exhaust side of the front support, and fit the functional relationship between the two.

[0067] Step 3: Arrange strain gauges in the central areas of the bottom of the inlet side and the top of the exhaust side of the gas turbine front support, respectively;

[0068] By measuring the distance to specific nodes calibrated in the mesh model, the spatial positions of these specific nodes in the front support are obtained;

[0069] Attach strain gauges at these specific nodes;

[0070] Step 4: Connect the strain gauge to the strain tester 12 and adjust the strain tester 12;

[0071] Step 5: Use a strain gauge 12 to record in real time the maximum principal strain in the central area of ​​the bottom of the inlet side and the top of the exhaust side of the gas turbine front support under slow speed, rated operation, or maximum power conditions.

[0072] During the process of the gas turbine transitioning from idle condition to rated condition and up to maximum power, the strain gauge data changes at the bottom of the inlet side and the top of the exhaust side of the front support are recorded and output in real time.

[0073] Step 6: Substitute the strain data measured in real time by the strain tester 12 into the function relationship fitted in step 2 to finally obtain the axial deformation of the gas turbine casing under idle, rated or maximum power conditions in real time.

[0074] Based on the strain values ​​of the bottom of the intake side and the top of the exhaust side of the front support output in real time by the strain tester 12, the axial deformation of the casing is calculated in real time by substituting them into the function relationship obtained by fitting in step two, thus realizing the real-time output and monitoring of the axial deformation of the gas turbine casing.

[0075] In this embodiment: Since the top of the front support is bolted to the gas turbine casing, the axial deformation of the gas turbine casing is transmitted to the top of the front support through the bolts, meaning the top of the front support and the gas turbine casing have the same axial deformation. Therefore, in the finite element simulation, applying axial displacement to the component connecting the top of the front support to the casing can simulate the axial deformation of the casing.

[0076] Specific implementation method 2: Test method for obtaining axial deformation of gas turbine casing based on local strain of front support. In step one, UG-NX is used to establish the three-dimensional solid calculation model 1 of the front support of gas turbine in the software.

[0077] Other implementation methods are the same as those in Specific Implementation Method 1.

[0078] Specific Implementation Method 3: An experimental method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support. The basic principle of mesh generation in step one is:

[0079] Step A: Using the surface segmentation method, perform local calibration on the areas where strain gauges are pasted, including the bottom air intake side strain gauge of the air intake side upright plate 3 (grid node 1), the bottom air intake side strain gauge of the air intake side upright plate 3 (grid node 2), the top exhaust side strain gauge of the exhaust side upright plate 4 (grid node 1), and the top exhaust side strain gauge of the exhaust side upright plate 4 (grid node 2).

[0080] Step B: Refine the mesh in the local calibration area, ensuring that the center point of the refined area is the strain gauge attachment point;

[0081] Step C: Divide the casing connecting plate 2 and the front support base 5 into a grid.

[0082] Other implementation methods are the same as those in Specific Implementation Method 1.

[0083] Specific Implementation Method Four: An experimental method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support. The basic steps of the finite element analysis calculation in step one are as follows:

[0084] Step D: Define material properties on the mesh model calculated by the finite element analysis:

[0085] Step E: Define the contact and boundary conditions of the front-support finite element mesh calculation model in the finite element analysis software:

[0086] Displacement boundary conditions along the axial direction of the casing are applied to the casing connecting plate 2;

[0087] The contact surfaces of the intake side upright plate 3 and the exhaust side upright plate 4 are all designed to be bonded to the contact surfaces of the casing connecting plate 2 and the front support base 5.

[0088] The front support base 5 is fixedly constrained on the ground.

[0089] Other implementation methods are the same as those in Specific Implementation Method 3.

[0090] Specific Implementation Method 5: A test method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support, wherein the material properties defined in step D include:

[0091] Density, elastic modulus, and Poisson's ratio of casing connecting plate 2;

[0092] Density, elastic modulus, and Poisson's ratio of the intake side panel 3;

[0093] Density, elastic modulus, and Poisson's ratio of the exhaust side plate 4;

[0094] Density, elastic modulus, and Poisson's ratio of the front support base 5.

[0095] Other implementation methods are the same as those in Specific Implementation Method Four.

[0096] Specific Implementation Method Six: An experimental method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support, wherein the process of obtaining the functional relationship in step two is as follows:

[0097] By applying different axial displacements to the top of the front support, the maximum principal strain values ​​of specific nodes in the central region of the bottom of the intake side and the top of the exhaust side of the front support under different axial displacements were obtained.

[0098] Plot the curves of the maximum principal strain at specific nodes in the central region of the bottom of the intake side and the top of the exhaust side of the front support as a function of different axial displacements, with the maximum principal strain as the independent variable and the axial displacement of the casing as the dependent variable.

[0099] The functional relationship between the axial displacement of the casing and the maximum principal strain was obtained by linear fitting.

[0100] Other implementation methods are the same as those in Specific Implementation Method 1.

[0101] Specific Implementation Method Seven: A test method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support, wherein the process of arranging strain gauges in step three is as follows:

[0102] Install #J1 intake side strain gauge 10 at point 6 of the mesh bonding node on the intake side strain gauge;

[0103] Install #J2 intake side strain gauge 11 at grid node 27 on the intake side strain gauge bonding point;

[0104] Install #P1 exhaust-side strain gauge 14 at point 8 of the mesh bonding node on the exhaust side;

[0105] Install #P2 exhaust-side strain gauge 15 at grid node 9 on the exhaust-side strain gauge bonding grid.

[0106] Other implementation methods are the same as those in Specific Implementation Method 1.

[0107] Specific Implementation Method 8: Test method for obtaining axial deformation of gas turbine casing based on local strain of front support, wherein the strain gauges are pasted in the vertical direction during step 3.

[0108] In this embodiment: when pasting the strain gauges in step three, the strain gauges are pasted in a vertical direction, that is, perpendicular to the axial direction of the gas turbine.

[0109] Other implementation methods are the same as those in Specific Implementation Method 1.

[0110] Specific Implementation Method Nine: A test method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support, wherein the connection between the strain gauge and the strain testing instrument 12 in step four is specifically as follows:

[0111] #J1 intake side strain gauge 10, #J2 intake side strain gauge 11, #P1 exhaust side strain gauge 14 and #P2 exhaust side strain gauge 15 are each connected to a strain gauge 12.

[0112] Other implementation methods are the same as those in Specific Implementation Method Seven.

[0113] Specific Implementation Method 10: Test method for obtaining axial deformation of gas turbine casing based on local strain of front support. In step four, adjusting the strain tester 12 specifically involves: before starting the gas turbine, clearing the data displayed on the strain tester 12.

[0114] In this embodiment: before starting the gas turbine, the data displayed on the strain gauge is cleared to ensure that the test data is accurate.

[0115] Other implementation methods are the same as those in Specific Implementation Method 1.

Claims

1. A test method for obtaining the axial deformation of a gas turbine casing based on the local strain of the front support, characterized in that: It includes the following steps: Step 1: Calculate the maximum principal strain in the central region of the bottom of the inlet side and the top of the exhaust side of the front support under different axial displacements of the gas turbine casing using finite element analysis. A three-dimensional solid calculation model of the gas turbine front support was established in the software (1); Mesh the three-dimensional solid calculation model (1). By precisely controlling the mesh, specific nodes are marked in the central areas of the bottom of the front support intake side and the top of the exhaust side. Import the mesh file into the finite element analysis software, and define the material data, contact conditions, loads and boundary conditions of the three-dimensional solid calculation model (1) according to the requirements; Submit the finite element analysis calculation file and output the maximum principal strain of specific nodes in the central region of the bottom of the intake side and the top of the exhaust side of the front support. Step 2: Plot the curves of axial displacement of the gas turbine casing as a function of the maximum principal strain in the central region of the bottom of the inlet side and the top of the exhaust side of the front support, and fit the functional relationship between the two. Step 3: Arrange strain gauges in the central areas of the bottom of the inlet side and the top of the exhaust side of the gas turbine front support, respectively; By measuring the distance to specific nodes calibrated in the mesh model, the spatial positions of these specific nodes in the front support are obtained; Attach strain gauges at these specific nodes; Step 4: Connect the strain gauge to the strain tester (12) and debug the strain tester (12). Step 5: Use a strain gauge (12) to record the maximum principal strain in real time at the bottom of the inlet side and the top center of the exhaust side of the gas turbine front support under slow speed, rated operation or maximum power conditions; During the process of the gas turbine transitioning from idle condition to rated condition and up to maximum power, the strain gauge data changes at the bottom of the inlet side and the top of the exhaust side of the front support are recorded and output in real time. Step 6: Substitute the strain data measured in real time by the strain tester (12) into the function relationship fitted in step 2, and finally obtain the axial deformation of the gas turbine casing under slow, rated or maximum power conditions in real time. Based on the strain values ​​of the bottom of the intake side and the top of the exhaust side of the front support output by the strain tester (12) in real time, the axial deformation of the casing is calculated in real time, realizing the real-time output and monitoring of the axial deformation of the gas turbine casing.

2. The test method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support according to claim 1, characterized in that: In step one, UG-NX is used to create a three-dimensional solid calculation model of the gas turbine front support in the software (1).

3. The test method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support according to claim 1, characterized in that: The basic principle of mesh generation in step one is: Step A: Using the surface segmentation method, perform local calibration on the areas where strain gauges are pasted: bottom air intake side strain gauge pasting grid node 1 (6), bottom air intake side strain gauge pasting grid node 2 (7), top exhaust side strain gauge pasting grid node 1 (8), and top exhaust side strain gauge pasting grid node 2 (9). Step B: Refine the mesh in the local calibration area, ensuring that the center point of the refined area is the strain gauge attachment point; Step C: Divide the casing connecting plate (2) and the front support base (5) into a grid.

4. The test method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support according to claim 3, characterized in that: The basic steps of the finite element analysis calculation in step one are: Step D: Define material properties on the mesh model calculated by the finite element analysis: Step E: Define the contact and boundary conditions of the front-support finite element mesh calculation model in the finite element analysis software: The casing connecting plate (2) applies a displacement boundary condition along the casing axis; The contact surfaces of the intake side plate (3) and the exhaust side plate (4) are all bonded to the contact surfaces of the casing connecting plate (2) and the front support base (5); The front support base (5) is fixedly constrained on the ground.

5. The test method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support according to claim 4, characterized in that: The material properties defined in step D include: Density, elastic modulus and Poisson's ratio of the casing connecting plate (2); Density, elastic modulus and Poisson's ratio of the intake side panel (3); Density, elastic modulus and Poisson's ratio of the exhaust side plate (4); Density, elastic modulus and Poisson's ratio of the front support base (5).

6. The test method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support according to claim 1, characterized in that: The process of obtaining the functional relationship in step two is as follows: By applying different axial displacements to the top of the front support, the maximum principal strain values ​​of specific nodes in the central region of the bottom of the intake side and the top of the exhaust side of the front support under different axial displacements were obtained. Plot the curves of the maximum principal strain at specific nodes in the central region of the bottom of the intake side and the top of the exhaust side of the front support as a function of different axial displacements, with the maximum principal strain as the independent variable and the axial displacement of the casing as the dependent variable. The functional relationship between the axial displacement of the casing and the maximum principal strain was obtained by linear fitting.

7. The test method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support according to claim 1, characterized in that: The process of arranging strain gauges in step three is as follows: Install #J1 intake side strain gauge (10) at the mesh node (6) of the intake side strain gauge; Install #J2 intake side strain gauge (11) at the mesh node 2 (7) of the intake side strain gauge; Install #P1 exhaust side strain gauge (14) at the mesh node 1 (8) of the exhaust side strain gauge; Install #P2 exhaust side strain gauge (15) at the mesh node 1 (9) of the exhaust side strain gauge.

8. The test method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support according to claim 1, characterized in that: In step three, the strain gauges are attached in a vertical direction.

9. The test method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support according to claim 7, characterized in that: The connection between the strain gauge and the strain testing instrument (12) in step four is specifically as follows: The #J1 intake side strain gauge (10), #J2 intake side strain gauge (11), #P1 exhaust side strain gauge (14) and #P2 exhaust side strain gauge (15) are each connected to a strain tester (12).

10. The test method for obtaining the axial deformation of the gas turbine casing based on the local strain of the front support according to claim 1, characterized in that: The specific steps of debugging the strain tester (12) in step four are as follows: before starting the gas turbine, the data displayed by the strain tester (12) is cleared.

Images