A research method for considering the influence of fluid-structure coupling on blade tip timing vibration measurement mechanism

Abstract

The application discloses a research method of blade tip timing vibration measurement mechanism considering fluid-solid coupling influence, a three-dimensional model after grid division is calculated and solved in a CFX flow field simulation module, and flow field pressure load of a blade surface is obtained; the obtained flow field pressure load is respectively input into a transient structure field analysis module and a prestressed modal analysis module, 6-order modal analysis is carried out on the blade under different rotating speed conditions in the prestressed modal analysis module, and the installation position of the timing vibration sensor is guided according to each order natural frequency and vibration mode; a deformation probe is added in the transient structure field analysis module, and the torsional deformation amount of each point of the blade tip under different rotating speed conditions is monitored, so that the influence of a certain point on the blade tip timing monitoring is minimized.

Description

Technical Field

[0001] This invention relates to a research method for timed vibration measurement mechanism of blade tip considering the influence of fluid-structure interaction. Background Technology

[0002] Complex blades are key components of large rotating equipment such as aero-engines. Under natural conditions, blades are subjected to a combination of centrifugal force and aerodynamic loads, resulting in vibration, bending, and torsion. When the external excitation frequency of the blade is close to or equal to its natural frequency, resonance is easily induced. Near the resonance frequency, the vibrational force on the blade accumulates continuously and produces a resonance enhancement effect with its own natural vibration frequency, leading to a sharp increase in the blade's amplitude. This increases the stress and pressure on the blade, causing fatigue failure or fracture. Therefore, studying the vibration characteristics of complex blades is crucial to avoid blade resonance. Furthermore, timed vibration measurement at the blade tip can monitor the trend and abnormal changes in blade vibration in a timely manner, ensuring the safe operation of rotating equipment and reducing maintenance costs.

[0003] In practice, the vibration measurement points on the blade surface may be limited by space and structure, sometimes making it impossible to install vibration sensors in ideal locations. The vibration environment of rotating equipment such as aero engines is complex and harsh, and the sensor position may change during operation, causing corresponding movement of the vibration measurement points on the blade, thus affecting the accuracy and reliability of vibration data. Therefore, it is necessary to consider the torsional deformation of the blade tip in a certain direction.

[0004] Fluid-structure interaction is an important factor to consider in the vibration characteristics of blades. By comprehensively considering the interaction between the fluid and the blade, the design and performance of the blade can be improved. Summary of the Invention

[0005] This invention provides a research method for considering the influence of fluid-structure interaction on the timing vibration measurement mechanism of blade tips in order to solve the problems existing in the prior art.

[0006] The technical solutions adopted in this invention are as follows: A research method for timing vibration measurement mechanism of blade tip considering the influence of fluid-structure interaction is proposed. Based on the blade's external dimensions and rotation area, a corresponding three-dimensional model is created using UG software. In the Workbench software, interfaces were created for the geometry module, CFX flow field simulation module, transient structural field analysis module, and prestressed modal analysis module, respectively. The 3D model was imported into the geometry module. Data transmission was established between the geometry module interface and the corresponding interfaces of the CFX flow field simulation module, transient structural field analysis module, and prestressed modal analysis module, respectively, so that the 3D model could be meshed in the CFX flow field simulation module, transient structural field analysis module, and prestressed modal analysis module, respectively. The flow field pressure load on the blade surface is obtained by calculating and solving the three-dimensional model after meshing in the CFX flow field simulation module. The obtained flow field pressure loads are input into the transient structural field analysis module and the prestressed modal analysis module, respectively. In the prestressed modal analysis module, a 6th-order modal analysis is performed on the blades under different speed conditions. The installation position of the timed vibration sensor is guided by the natural frequencies and vibration modes of each order. Add a deformation probe to the transient structural field analysis module to monitor the torsional deformation of each point at the blade tip under different speed conditions, ensuring that the impact on a certain point is minimized when it is monitored at the blade tip at regular intervals.

[0007] Furthermore, the UG software creates a three-dimensional model of the blade as an integrated model with both a blade model and a flow field model.

[0008] Furthermore, when meshing the integrated model in the CFX flow field simulation module, it is necessary to suppress the blade model; When meshing the integrated model in the transient structural field analysis module and the prestressed modal analysis module, it is necessary to suppress the flow field model.

[0009] Furthermore, when the CFX flow field simulation module meshes the flow field model, it adds a boundary expansion layer based on the structural abrupt changes during blade rotation.

[0010] Furthermore, when using the CFX flow field simulation module to calculate the flow field pressure load on the blade surface, the time step and number of time steps of the flow field simulation are obtained based on the blade rotation speed and convergence conditions, and the flow field pressure load generated on the blade surface is calculated using the corresponding solver.

[0011] Furthermore, when applying flow field pressure loads to the transient structural field analysis module and the prestressed modal analysis module, constraints are added; For the transient structural field analysis module, the added constraints are different rotational speeds, displacements, and fluid-structure interaction interfaces; For the prestressed modal analysis module, the added constraints are different rotational speeds and displacements.

[0012] Furthermore, in the prestressed modal analysis, each mode is solved according to the set maximum modal order, and the natural frequencies and modes of the blade under different speed conditions are compared and analyzed.

[0013] Furthermore, in the transient structural field analysis module, different coordinate systems are created based on the mesh nodes of the blade tip, and corresponding deformation probes are inserted as monitoring points at each point of the blade tip. Simulations are performed on the blade under different speed conditions to monitor the torsional deformation of each point of the blade tip in each cycle.

[0014] Furthermore, based on the deformation data from the blade tip deformation probe, the deformation data for each cycle is processed using Origin data processing software to determine the minimum torsional deformation of the blade tip, thereby determining the optimal installation position for the timing vibration sensor.

[0015] The present invention has the following beneficial effects: 1) This invention is simple to operate, has high calculation accuracy, and can realistically simulate the pressure load generated on the blade surface during the operation of complex rotating blades. This invention can apply the blade surface pressure load calculated from the flow field to static and transient structural field models.

[0016] 2) This invention performs modal analysis on the blade at different speeds based on the maximum modal order, in order to compare the influence of rotational speed on the blade's natural frequencies and vibration modes.

[0017] 3) This invention creates a monitoring point coordinate system based on the grid nodes on the blade tip, inserts deformation probes to monitor the torsional deformation of each point on the blade tip under different speed conditions. This invention uses the point with the smallest torsional deformation on the blade tip as the basis for judging the installation of the blade tip timed vibration sensor, and the criterion is clear. Attached Figure Description

[0018] Figure 1 This is a flowchart of the method of the present invention.

[0019] Figure 2 This is a schematic diagram of a 3D model of a blade created using UG software.

[0020] Figure 3 This is a schematic diagram of a fluid simulation model created using CFX fluid software.

[0021] Figure 4 This is a schematic diagram of a structural field simulation model created using the transient structural field and prestressed modal analysis modules, specifically the static structural field.

[0022] Figure 5 This is a schematic diagram of the first three modes of the blade obtained through the prestressed modal analysis module.

[0023] Figure 6 This is a schematic diagram of the pressure load on the structure generated by the CFX flow field simulation module, showing the pressure load on the blade surface.

[0024] Figure 7 This is a schematic diagram of eight coordinate points set at the blade tip using a transient structure field.

[0025] Figure 8 This is a schematic diagram of the total blade deformation obtained through transient structural field module analysis.

[0026] Figure 9This is a schematic diagram showing the change in deformation at a point on the blade tip over time, obtained through fluid-structure interaction calculations. Implementation

[0027] The invention will now be further described with reference to the accompanying drawings.

[0028] like Figure 1 As shown, the present invention provides a research method for timed vibration measurement mechanism of blade tips considering the influence of fluid-structure interaction, comprising: Based on parameters such as blade disk diameter, blade tip clearance, blade spacing, and blade twist angle, an integrated model with blade and flow field models is established using UG modeling software.

[0029] In the Workbench software, interfaces were created for the geometry module, CFX flow field simulation module, transient structural field analysis module, and prestressed modal analysis module, respectively. The 3D model was imported into the geometry module. Data transmission was established between the geometry module interface and the corresponding interfaces of the CFX flow field simulation module, transient structural field analysis module, and prestressed modal analysis module, respectively, so that the 3D model could be meshed in the CFX flow field simulation module, transient structural field analysis module, and prestressed modal analysis module, respectively. When meshing the integrated model in the CFX flow field simulation module, the blade model needs to be suppressed; when meshing the integrated model in the transient structural field analysis module and the prestressed modal analysis module, the flow field model also needs to be suppressed.

[0030] The flow field pressure load on the blade surface is obtained by calculating and solving the three-dimensional model after meshing in the CFX flow field simulation module. The obtained flow field pressure loads are input into the transient structural field analysis module and the prestressed modal analysis module, respectively. In the prestressed modal analysis module, a 6th-order modal analysis is performed on the blades under different speed conditions. The installation position of the timed vibration sensor is guided by the natural frequencies and vibration modes of each order. Add a deformation probe to the transient structural field analysis module to monitor the torsional deformation of each point at the blade tip under different speed conditions, ensuring that the impact on a certain point is minimized when it is monitored at the blade tip at regular intervals.

[0031] In the CFX flow field simulation module, mesh generation software is used to generate meshes for the blade model. This is done by adding a boundary expansion layer based on the structural abrupt changes during blade rotation, thereby improving mesh accuracy.

[0032] When using the CFX flow field simulation module to calculate the flow field pressure load on the blade surface, the time step and number of time steps of the flow field simulation are obtained based on the blade rotation speed and convergence conditions, and the flow field pressure load generated on the blade surface is calculated using the corresponding solver.

[0033] Add constraints when applying flow field pressure loads to the transient structural field analysis module and the prestressed modal analysis module; For the transient structural field analysis module, the added constraints are different rotational speeds, displacements, and fluid-structure interaction interfaces; For the prestressed modal analysis module, the added constraints are different rotational speeds and displacements.

[0034] In the prestressed modal analysis, each mode is solved according to the set maximum modal order, and the natural frequencies and modes of the blade under different speed conditions are compared and analyzed.

[0035] In the transient structural field analysis module, different coordinate systems are created based on the mesh nodes at the blade tip, and corresponding deformation probes are inserted as monitoring points at each point on the blade tip. Simulations are performed on the blade under different speed conditions to monitor the torsional deformation at each point on the blade tip in each cycle.

[0036] Based on the deformation data from the blade tip deformation probe, the deformation data for each cycle is processed using Origin data processing software to determine the minimum torsional deformation of the blade tip, thereby determining the optimal installation location for the timing vibration sensor.

[0037] The research method of this invention on the timing vibration measurement mechanism of blade tip considering the influence of fluid-structure interaction is to divide the fluid-structure interaction problem of complex blades into flow field and structural field for analysis and solution, so as to analyze and compare the natural frequency, vibration mode and torsional deformation at the blade tip under different speed conditions.

[0038] The CFX flow field simulation module was used to calculate the flow field of the blade, and the prestressed modal analysis module was used to perform modal analysis on the blade, providing a theoretical basis for the blade's vibration characteristics. The transient structural field analysis module was used to calculate the torsional deformation of the blade at the blade tip, providing deformation data of the blade under actual operating conditions.

[0039] This invention uses a complex rotating blade as an example, and performs three-dimensional modeling of the blade using UG software. See [link / reference]. Figure 2 As shown; a flow field simulation analysis model is created using the CFX fluid simulation module, see [link / reference]. Figure 3 As shown; a structural field simulation analysis model is created using the transient structural field analysis module, see [link to documentation]. Figure 4 As shown; By introducing pressure loads on the blade surface and adding constraints such as rotational speed, the first three modal characteristics of the blade are obtained. (See [reference]). Figure 5 As shown.

[0040] The pressure load on the blade surface calculated by CFX flow field is applied to the structural field simulation model. (See...) Figure 6 As shown; In the transient structural field, eight coordinate points are set at the blade tip to monitor the displacement and deformation at these points using a deformation probe. See [link to documentation]. Figure 7 As shown.

[0041] The total deformation of the blade is obtained by calculating and solving the transient structural field. (See [reference]). Figure 8 As shown.

[0042] Simultaneously, the deformation of each point at the blade tip under different operating speeds was calculated as a function of time. (See [link]) Figure 9 As shown.

[0043] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A research method considering the influence of fluid-structure interaction on the timing vibration measurement mechanism of blade tips, characterized in that: Based on the blade's external dimensions and rotation area, a corresponding 3D model was created using UG software. In the Workbench software, interfaces were created for the geometry module, CFX flow field simulation module, transient structural field analysis module, and prestressed modal analysis module, respectively. The 3D model was imported into the geometry module. Data transmission was established between the geometry module interface and the corresponding interfaces of the CFX flow field simulation module, transient structural field analysis module, and prestressed modal analysis module, respectively, so that the 3D model could be meshed in the CFX flow field simulation module, transient structural field analysis module, and prestressed modal analysis module, respectively. The flow field pressure load on the blade surface is obtained by calculating and solving the three-dimensional model after meshing in the CFX flow field simulation module. The obtained flow field pressure loads are input into the transient structural field analysis module and the prestressed modal analysis module, respectively. In the prestressed modal analysis module, a 6th-order modal analysis is performed on the blades under different speed conditions. The installation position of the timed vibration sensor is guided by the natural frequencies and vibration modes of each order. Add a deformation probe to the transient structural field analysis module to monitor the torsional deformation at various points on the blade tip under different speed conditions. In the transient structural field analysis module, different coordinate systems are created based on the mesh nodes at the blade tip, and corresponding deformation probes are inserted as monitoring points at each point on the blade tip. Simulations are performed on the blade under different speed conditions to monitor the torsional deformation at each point on the blade tip in each cycle. Based on the deformation data from the blade tip deformation probe, the deformation data for each cycle is processed using Origin data processing software to determine the minimum torsional deformation of the blade tip, thereby determining the optimal installation location for the timing vibration sensor.

2. The research method for considering the influence of fluid-structure interaction on the timing vibration measurement mechanism of blade tips as described in claim 1, characterized in that: The UG software creates a 3D model of the blade as an integrated model with both blade and flow field models.

3. The research method for considering the influence of fluid-structure interaction on the timing vibration measurement mechanism of blade tips as described in claim 2, characterized in that: When meshing the integrated model in the CFX flow field simulation module, it is necessary to suppress the blade model; When meshing the integrated model in the transient structural field analysis module and the prestressed modal analysis module, it is necessary to suppress the flow field model.

4. The research method for considering the influence of fluid-structure interaction on the timing vibration measurement mechanism of blade tips as described in claim 3, characterized in that: When the CFX flow field simulation module meshes the flow field model, it adds a boundary expansion layer based on the structural abrupt changes during blade rotation.

5. The research method for considering the influence of fluid-structure interaction on the timing vibration measurement mechanism of blade tips as described in claim 3, characterized in that: When using the CFX flow field simulation module to calculate the flow field pressure load on the blade surface, the time step and number of time steps of the flow field simulation are obtained based on the blade rotation speed and convergence conditions, and the flow field pressure load generated on the blade surface is calculated using the corresponding solver.

6. The research method for considering the influence of fluid-structure interaction on the timing vibration measurement mechanism of blade tips as described in claim 1, characterized in that: Add constraints when applying flow field pressure loads to the transient structural field analysis module and the prestressed modal analysis module; For the transient structural field analysis module, the added constraints are different rotational speeds, displacements, and fluid-structure interaction interfaces; For the prestressed modal analysis module, the added constraints are different rotational speeds and displacements.

7. The research method for considering the influence of fluid-structure interaction on the timing vibration measurement mechanism of blade tips as described in claim 1, characterized in that: In the prestressed modal analysis, each mode is solved according to the set maximum modal order, and the natural frequencies and modes of the blade under different speed conditions are compared and analyzed.

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